I have a list I'm adding to as I go along for the important stuff I don't want to forget that's sitting in the car so I'll see it before it starts up. Naturally, I've been alot more careful where I leave stuff from now on. Can't get too fixated on paper towels, since there's a million other things strewn around that could be as bad or worse if left where it doesn't belong.

Im thinking he doesnt. But my only advice is to seriously walk away from it for like a day to give your brain a breather. When refreshed come back to then go over all your work. run through the whole process in your head before finishing. About now your getting very excited because your nearing completion. This is when you start to F up because you start to rush to get the car started. Please slow down and be careful. I would really hate to see you blow up that very pretty engine.

Success and failure...
 

Well, I took breaks to eat...does that count? It's better than I usually do! But anyway, it was a marathon of sorting out all the little ends and pieces this weekend.

I finally got it all together Mon night and fired it up. I ran the battery down spinning it to get oil pressure and found out what really happens when you get the oil pressure sensor wires mixed up. I was cranking and cranking (no plugs), still nothing. Backed the oil filter off enough to see if oil made it that far yet. It did, so I went ahead and tried to start. Well, the extra compression was a little too much for the battery at that point, so I had to charge up a bit. Finally got enough juice and it fired right up. Oil pressure guage instantly pegs, but only as instantly as it typically takes for the oil pressure to come up on a normal car on startup. I let it run and everything seems fine. I shut it off and turn the key right back on and the guage still pegs with the motor off. Eventually it doesn't, but pegs again as soon as the motor fires up. Switched the wires and it worked fine. The idiot light part of the sender will peg the guage once it gets oil pressure.

Anyway, it ran really smoothly right off the bat. I took it out on a test drive and it was quite impressive. New clutch feels awesome! It had warmed up in the driveway, so once I got down the road, I gave it some gas to help the rings start breaking in. Oil pressure is good, OPRV is working fine. I'm hard on and off the gas to load the rings and it's doing fine. I get to a light a couple miles down the road and go to turn right to make a run down the parkway back home, and it starts stumbling and has no power, sort of like running out of gas. I had found fuel leaking from the fuel rail at the pressure line 'cause it wasn't tight enough before I fired it up and I also had to replace the hose between the filter and the hard line, so I thought maybe it was leaking, but I put 4 gallons in it beforehand (guage was reading nothing, but the sender's always been wonky...no fuel light, though). Oil pressure is good, no knocking or other weird noises. I pull over and look everything over. No leaking, no oil anywhere, everything looks normal. After puzzling over it for 10 min, I decide to try to limp home. Well, it seemed to run fine at first, but got progressively bad again. Got home and looked everything over, checked electrical connections, etc. Nothing...no leaking, oil is a little low, but not much. Get my tool kit together and decide to try again.

Granted, it's had 15 min. to cool, which seems to be a factor, but I went out again and it seemed fine. Drove around the block, then headed for the parkway where I've got a little more speed limit to work with. Get on it hard and it just pulls like a draft horse on crack! It's definitely got some power back. Oil pressure is good. Get on it hard and then shut the throttle and let it coast to pull oil up through the rings to lubricate them as prescribed by several sources for ring break in. It's doing great, I turn off the parkway and stop at a light to turn back home and once I start off from the light, it starts doing it again! Oil pressure is a bit lower, but that was a steady development and I'm attributing it to running straight 30 weight for break in, which gets alot thinner when run hard than what I usually use. It was holding a good 4 bar for normal driving, but would dip down to 3 when I got hard on the gas, and would come back up when I let off. Sign of loose rod bearings, right? They plastigaged nicely, no noises, oil is thin, OPRV is working (more later). What I ended up finding out also proves that the WOT maps really are 1D, which is also a big clue to what's going on. It runs perfectly fine at WOT, but without the WOT switch activated, it barely runs at all. I get home and notice oil dripping off the back of the oil pan. Nothing looks like it's leaking up top, and it wetted the back of the flywheel, so it's looking alot like the RMS is leaking like a seive! :mad::mad::mad:

So the summary and resulting questions:
It's got to be something electrical or vacuum related and heat sensitive...and it's not the crank sensors, fuel injection, ignition, or anything godaweful going wrong with the engine mechanicals, since it runs just fine, strong, and smooth at WOT. I'll check the intake for oil just in case it's got some kind of major blowby issue, but it felt it had good compression that did not leak down noticably when cranking by hand. The wiring harness may have gotten broken in the AFM line while re-routing it, the AFM itself is screwed up somehow, or maybe the DME temp sensor isn't working, since I just left the one that came with the block in and it isn't technically proven to be flawless, but seems like it would affect WOT, too.

The other thing is oil pressure and oil. Is it a good idea to run hard on 30 weight for break-in? It had good oil pressure under normal driving, but when I ran hard for a couple minutes on and off, it seemd to thin out to the point I was a little worried. I don't want to damage the new bottom end, and I can't think of why the oil pressure would do the classic rod knock pressure dip on a brand new bottom end. I had run 10W-30 Brad Penn in my old motor last winter and it didn't do the same thing no matter how hard I drove it, but when I did the oil cooler seals before that, I didn't get the housing lined up exactly right, which causes the OPRV to get cocked slightly, which doesn't allow the piston to open fully (seemed to limit about 1 mm or so), which made the oil pressure tend to run high, but not enough to warrant going through hell all over again to set it right, so I left it. It would run a healthy 4-4.5 bar normally, but would ramp up to the peg as the rpms maxxed out, and it would never Idle less than 3 unless it was really hot. This one behaves more conventionally, sits at 4 throughout the rpm range), but when it got good and hot, it would idle at 1, bounce around a little when the engine was stumbling and barely running due to the unknown issue, and would drop to 3 under power and pop up to 4.5-5 when let off. Please advise! I'm thinking of changing to some Castrol 10W-40 for fear of something bad happenning. Why are all the official break-in oils 30 weight if this could be a problem?

And the apparent RMS leak. Don't know why it would, unless either there's pressure in the crankcase blowing oil out, it wasn't installed perfectly straight, or it burned up because I didn't lube it enough. The crank had a slight groove on it, but not any worse than my old one, which didn't leak a drop. i did oil it, but I didn't drown it in oil. I should have smeared assembly lube on it like I did to all the other ones, but for some reason that didn't happen. It was oily, but not liberally so. I used Curil-T on the outside and drove it in to the stop in the bore with a pipe. It did get "a little" crooked in the process, but once straightened out and driven in, I hammered around it a bunch of times to make sure it was even. I'll be pissed if I have to replace it again, esp not knowing why it leaked in the first place. Any chance they just need to run in and may leak initially? It was bad enough to drip a few times on the driveway once I stopped, and there was oil sprayed across the underside of the car from the air turbulence while driving.


Some pictures from the weekend. Broke my new camera again!!! Had it in my pocket and must have leaned on something and cracked the screen! Oh well...it was "only" $100! :mad:

No more auto tensioner anymore! It was kind of a PITA anyway. I finally got the special thin wrench and it made tensioning a piece of cake!

http://forums.pelicanparts.com/uploa...1257299636.jpg


Well, surprise, surprise! Turns out the front and rear belt covers are not interchangable between manual tensioner and newer auto tensioner covers. It was weird, because parts of it fit fine, and other parts not so much... Had to get a bit creative and makeshift. I didn't get the parts from the new motor thinking the stuff I had would fit. I'll be hunting the correct part soon enough.
http://forums.pelicanparts.com/uploa...1257299853.jpg

Port matched throttle body lines up perfectly.
http://forums.pelicanparts.com/uploa...1257299887.jpg

Wow! I've finally made it!
http://forums.pelicanparts.com/uploa...1257299974.jpg

Oil pressure should increase linearly with RPM. With a hot motor, at idle oil pressure should be around 2-2.5 bar. As RPM/load increases oil pressure should instantly rise, and at higher RPM (4500+) and load should always be above 4 bar.

For no reason whatsoever should oil pressure drop with increase in load and RPM. It should always go up.

This sounds like its an OPRV problem. It's, for some reason, once the car gets to operating temp, it's popping off too early under load. There also is a pressure relief valve in the head- did you mess with it?

I'm going to have to think on this one a bit.

On the RMS.

If the seal was seated to the bottom shelf of the block and that the seal was evenly pressed in, there may not have been enough oil on the crank or the inner seal. I do not think the groove in the crank could cause the seal to leak as soon as it did--eventually yes.

If the seal does not "set" and stop the leak, you will need to replace the RMS. I wince at the added work you will have to do.

If the crankshaft has the seal groove you mentioned, you might consider the Pelican RMS. It is a little shorter, and should seat deeper in the block. In the picture, old seal on top and Pelican Kaco seal on bottom.

http://forums.pelicanparts.com/uploa...1257338824.jpg

The seal is also easier to install because it does not have the "ribs" from top to bottom of the outter seal area. It "starts" easier. Make sure that any damage caused by the removal of the old seal around the "seal removal indent" is cleaned, filed and polished.

Remarkable work you have done.

GL
John_AZ

I did get my seal from Pelican and it does look like the lower one in the picture, but that may have been the same type that the motor originally had. I can't remember, since I pulled another motor apart before that and it's all kind of blurred together. I agree on the theory that if it was the groove, it wouldn't have leaked so soon. I had balance shaft seals last a couple months on bad flanges before leaking. The grove literally is not that significant, no worse than my old crank. I wouldn't have expected it to be a problem. I did second guess the amount of lubrication I gave the seal, soon after I got the motor in, so it may have really just been too dry. I'm kind of pissed about it, but sadly, pulling the transaxle and clutch back off sounds like nothing compared to this entire ordeal...and I notched the bellhousing. ;) What seal is best? Is that 2 colored Elring seal on Paragon worth the extra 8 bucks?

As for the oil pressure, it did work as expected when at normal temp, holding 4 bar throughout the rev range and idling at 2. It is the older three piece valve, but was not worn or scoured looking, and slid smoothly into the bore. I used the alignment tool on the cooler housing and got the alignment spot on. I think I'll try my 10W-40 and see how it goes. Damn...they mic'd the rods and the crank at the machine shop AND the plastigage showed oil clearance right in the middle of the range! I'll be pissed if the bearings are screwed...already! WTH could have happened? Think of it...2 months of pins and needles worrying about it and REALLY taking the time and being careful to get it all put together right and stuff like this happens. Hoping it's just 30 weight oil turning to water. The pressure dipped with no initial change in rpm, only load, so the OPRV shouldn't have had a chance to factor in that much, unless it was sticking open and not compensating for the increased oil clearance on the non-loaded side of the bearings passing more pressure. I did not mess with the valve in the head.
Schumi, when you say hot motor, do you mean auto-X hot or just normal running temp down the highway hot? High rpms and load for very long would thin out even the 20W-50 oil I ran in my old motor, but not as much as this seemed to.

I've found getting enough sleep has been difficult with school, work, and this mess all at once. Snoozing during stress and strain topics in mechanics of materials class sucks, since I was literally having nightmares of broken bolts, stripped threads, and cracked engine parts.

u should take my burnt crankshaft and submit it to the class as a lab project. hehe

Hot as in highway hot.

When starting up cold, thick oil will peg the gauge to 5. The viscosity causes the oil pressure to be high and thus needing the OPVR to bleed off excess pressure. A stuck-closed OPVR would cause leakage out the crank seals due to too high of pressure.

Once the engine is warm, at idle the pressure should read around 2 bar and increase linearly to 5 bar with increase in RPMs.

At no stage in the process, ever, with the car running, should the oil pressure drop when you step on the gas pedal. The oil pump is driven off the crank directly; if the crank revs faster, the oil pressure increases.

There are only 2 things I can currently think of that would cause a drop in oil pressure when the car is revved. A) the OPRV is blowing off early- leaving out the internal spring that presses on the small piston would do this. B) the oil pump is cavitating. And B is nearly impossible.


There is one more possibility and that is the possibility that your oil pressure is fine and the signal to the gauge has gone wrong. You mention a massive loss in power.... if there was some massive short circuit or you lost ground to the engine, it would cause the motor to nearly die, and also cause a high current draw on all the electrics. Do the dash lights dim when the power starts to die? A short or grounding problem in the electrical system would cause the oil pressure gauge to loose some power and since it is really just a volt meter, the needle would go down.



Make sense?

I have not used the Elring seal. I am sure it is of superior quality.

In April I used the Pelican Kaco seal on the '87. So far no leaks. There has been old discussion (Rennlist) on the Kaco or Victor Reinz "black" seals are prone to leaks. They recommend the red seal in the above picture.

GL
John_AZ

Did you replace or mod the throttle switch? Seems you've got the right signal out of it at WOT and idle, but not at part throttle. Disconnect it and see if that makes a difference.

As for the RMS, the short seal has two inside lips, right? If the outer lip runs in the crank groove, no matter how small the groove is, that would contribute to a leak there. I'll bet the old seal was the deeper one and if you replace the short one with a deep seal the leak will stop.

I replaced the rod bearings in my 944 after seeing my oil gauge behave the same way yours does. The bearings I took out were okay but since I was there I replaced them. Guess what? The oil gauge does exactly what it did before. Your rod bearings are fine. Maybe switch to a 1-piece OPRV. The tolerances on the 3-piece will have increased simply due to age. My oil pressure pegs on startup, idles at about 2 to 2.5 bar, sits at 4 to 4.5 on the highway and dips a little under hard acceleration. At some point I'll get a 1-piece OPRV but I've been driving the car for a long time the way it is. Oil starvation is the big killer...

BTW, fantastic thread and a great topic for those who come after you!

Get the Elring rear main, there are a number of threads about this on RL, specifically the 951 forum. The Elring has no complaints while the others are all questionable, mainly seating depth..etc. I used the Elring on my clutch job fearing the instant oil leaks some report using the other seals. I put hylomar on the outter ring and straight motor oil on the inner. No leaks, dry as a bone. My oil pan never looked so clean!

I had some concerns when I got the RMS in and saw it was the black one, since I saw some of those threads over time. Kind of the same as why the vitton valve stem seals are superior to the standard issue black ones. I'll have to dig out my collection of old RMS. I have the red vitton one from my original motor, and there's two others hanging around from this one and the first replacement that didn't turn out so well. They may both be the black ones, which would make it easier. I'll run it a little more and see what happens, but I don't want to contaminate the brand new clutch disk, and I HATE oil leaks, especially the ones that drip all the time, make a mess under the car, and leave me adding a qt of oil every time I turn around. I'm going to look under there and see if there's a remote possibility of avoiding taking the exhaust off. It would speed the process up quite a bit, since I can reach the bolts to the U-clamps on the driveshaft with the exhaust in place.

I did check the throttle switch before mounting the throttle body and it worked fine. I just found out that I did not tighten the J-boot clamp on the AFM, and it's pretty loose, so with any luck, that's all it is. The symptoms are 99.9% consistent with a vacuum leak there. http://forums.pelicanparts.com/support/smileys/wat5.gif

Slam, did you plastigage the new bearings when you put them in? What oil do you use? I used the same oil pressure sender that came off my old motor so I wouldn't be wondering if there was a difference if something like this happened. The wiring harness is always a question. I guess the 1 piece OPRV is better, but I would have to try to find a good used one that is also the early retrofit. $400 new is pretty steep.

I did not notice any lights dimming. Realize that the oil pressure does not decline while increasing the rpms. When the rpms increase, the pressure does, too. When I open the throttle up, especially at low rpms in higher gears, i.e. the load increases but the rpms don't, the pressure dips a little. At "highway hot" it seemed fine. Revving WOT on and off for a couple miles gets it more like auto-X hot and maybe 30 weight just gets too thin in this motor. I will carry on the investigation today and try some thicker oil.

Yes, I did plastigage number two - partly because it's the usual suspect and partly because it was the only rod bearing that showed any wear. I mic'ed the rod journals and things were fine, so in the bearings went. I'm running Pennzoil 15W40 at the moment. Not the best but it suits my budget/demands.

Try George for a good used 1-piece OPRV.

Good luck with this. And again a big thank-you for the documentation.

Well, the good news. No white smoke on the second startup now that it's had a chance to sit, so the HG checks out. Oil level stayed good after the test drive. Not a whisp of oil smoke even at full tilt and closing the throttle (keep in mind the first test drive was at night). Oil pressure looked good. Ran 5 bar warmed up and only dipped maybe .5 on heavy loading. Once it got good and hot on the way home, it held a good 4 bar, still with maybe a .5 dip on application of heavy load, and idled at 1.5. The factory manual specifies 4 bar at 5000 rpm and I'm still running the 30 weight conventional, so I think it should be good.

the bad news. It still lost power even with the J boot clamp tightened up, and still only once I started running it hard and heating it up. WOT still worked fine, like hitting a switch. I don't know if it would still eventually do it if I drove normally for a longer period of time, or if it's just the extra heat from hard running. This time it did not start doing it after sitting at a light, but suddenly developed while driving down the parkway. I could hear some hissing in the throttle body and intake manifold area when I got home. I'm not ruling out an electrical problem with most likely the AFM, since it seems kind of extreme and sudden for a vacuum leak. I'll have to figure out how to put pressure in the intake system and see if it's leaking anywhere. There was no oil in the intake, so it probably can't be any kind of blow-by problem, crankcase vacuum leak or excess pressure problem.

I also saw the RMS is still leaking. I haven't jacked the car up to crawl under there and have a good look at it so see if it's not the oil pan gasket or something like that, but it's creeped all over the back of the flywheel, so it's probably the RMS. I did find that my other two old seals are a red Kaco and an Elring, but I can't remember which came from the motor I'm running now. Interesting thing about the two is the inner part of the Elring looks like the same stuff as the Kaco is made out of, but the sealing lip on the Elring looks like a double lipped seal. It's got two small lips very close to each other on the main sealing lip, whereas the Kaco has just one contact area. They both have the secondary outer sealing lip. I'll just get the Elring seal and hope it works.

Today was interesting. I started testing all the wiring for the various engine control parts to get a baseline for when it was cold. Everything checked out fine. DME relay checked out fine, AFM voltage checked out. I found a pvc plug to put in the J-boot in place of the AFM to test the intake system for leaks and found nothing significant. So I wire up a voltmeter to the AFM signal coming back to the DME so I can watch what it does while driving, which was pretty interesting, but I was specificly looking if, when it did start screwing up, if the voltage declined from normal ranges. I also rigged up my O2 sensor jumpers so I could read the O2 sensor output with the sensor heater still hooked up, and went out for a drive.

Interesting thing is the 02 sensor was reading lean at part throttle, only 0.02V, but the engine seemed to be running just fine. WOT and idle were around 0.74V. I had done some investigation with the 02 readings with the stock chip but never tested what the MAX chip does, so it may just be the way it is. Russel did say the chip was tuned to not run so rich. AFM seemed to work fine. I warmed it up and then started working it hard again. I could not get it to screw up again this time. I don't know if it was just a wiring problem that went away from messing with the wires testing them, or if it was the 02 sensor turning out bad and throwing the DME into some weird state. It ran fine no matter how hard I drove it. I'm afraid to plug it back in and try again. I'll drive with it unplugged for awhile and see if it screws up again. I don't think it's a vacuum leak, since it would take a pretty big one to screw it up as badly as it was, all the seals and gaskets were replaced, hoses were inspected, and the intake/vacuum system held pressure. I'll probably replace the 02 sensor anyway, since it's not the truly correct universal part and it's seen a few miles.

So the motor has 40 miles on it and no problems yet so it seems. I changed the oil and found the drain plug was loose and leaking, so maybe by some stretch that was where the oil was comming from under there. Still running conventional, but 10W-40 now. I'll leave it in for about 1500 miles before the next change. No bits and pieces came out of the oil pan. I did notice a few metal looking flecks at the bottom of the drain pan, but nothing out of the ordinary. I saw similar pieces in the oil every time I changed it on the old motor and from other cars, so I'm not worried. The filter was full of pearlescent looking oil from break-in. No chunks of anything, just very fine aluminum particles. I got one of those filterMAG filter magnets sold here on Pelican and it was a really good idea. There was definitely some metal sludge on the inside of the filter housing where the magnet was and the drain plug magnet was very clean. I'm sold on it! It's perfect for engine break-in and will probably help the engine last longer when used all the time in the long run, since it catches metal particles too fine to be trapped in the filter. Check out the website. They have some oil analyses to prove it.

So far, all is good! :D

this thread is amazing, thank you.

I'm going to do the same thing to my '88 924S. The block/head are at the machine shop and I'm waiting to hear what work needs to be done. If you don't mind me asking, about how much did you spend on parts for this rebuild? Any advice on how to buy things smartly to save money?

Sweet! I would have been alot happier if I could have had some 88 pistons, but it's got lots of power already. I'm going to have to finally replace the old battery, since it doesn't seem to like the extra compression too well. :D

Altogether I lost track of what it cost. I made a valiant effort to try to get all the parts I thought I needed all in one order...yeah right! I had all kinds of odds and ends I needed to get along the way. Something like $500 for the main Pelican order, $130 for the centerforce clutch disk, $30 for the Sunnen AN-30 paste, $400 delivered for the motor (head looked like a recent rebuild, so I just cleaned it and ported it) + $60 more to deliver the second one, $200 for new main bearings, $560 for the machine work (cleaning, measuring, polishing crank, bottom end balance including the flywheel, pressure plate, and front pulleys, machine flywheel). A couple more hundred for a bunch of tools and supplies. More odds and ends... Wow...it was an expensive project! There really was alot at stake!

It's had some more hard running on the highway today and has about 150 miles on it with no problems whatsoever...yet (besides the RMS).

As far as buying smartly, It's mostly not buying until you know what you're dealing with and what you'll need, but you'll inevitably be making 10 other orders to pick up more odds and ends you forgot or turned out you needed after all. Get the red vitton valve stem seals instead of using the black ones in the gasket kit, and get a couple extras, just in case you bend one up trying to remove it because it went on too far, crooked, etc. The top end gasket kit also comes with the two exhaust Y-pipe gaskets. The Deves rings sold on Pelican are half the price of OEM and seem to work fine. They are high quality and didn't smoke even slightly right off the bat. Shop around and find the Elring RMS. It seems to be the best. The copper exhaust header stud nuts are also really good. Some Curil-T and Locktite 574 is a must, as well as kimwipes (shop towels SUCK for wiping bearings and gasket surfaces!). Acetone is the best for final surface prep before sealing up with specified sealant. Copper gasket spray seemed to work well on the head gasket, and is perfect for the exhaust gaskets. Have a good M6 and M8 tap on hand to chase threads. Dealing with corroded, screwed up theads is alot easier before you have your hands full with clean parts with sealer already on them. I would recommend helicoiling or time-serting the water pump bolt holes while the engine is out. Those threads always feel very weak and are only going to get worse when they corrode. I didn't and I kind of wish I did (I chased them all and one still kind of halfway pulled out!). Take some pictures of wiring routing BEFORE you pull it all out. It gets really confusing to try to figure it out again after 2 months. A box of small and large ziploc bags are also a must for keeping important stuff clean and organized. Treat yourself to some intake system port matching and maybe even some smoothing out of the intake ports with 150 grit sandpaper. It'll never be easier. Make sure you have a good torque wrench. Definitely notch the clutch bellhousing. Can't think of anything else off hand.

I would love to do this for my car but its pretty much been done already. Well im not sure how far the PO went with the rebuild, I know he resealed everything. i dont know. If I did do it I would do it to learn about my car and to truly know whats it's condition is. Everything is a mystery to me with my car. I hate that. You know the complete ins and outs of your car now. I am jealous for that.

LOL. That's one of the reasons I decided it would be worth the expense. I didn't want to have to roll the dice on a totally different car, and have to fix all kinds of other stuff I've already squared away on this one. The list of original parts on my car is shrinking. Neither the transmission or the engine is original now. I did re-use a bunch of parts from the original motor, so it does live on in a sense.

You'll figure you car out in time. It takes time. It felt like re-sealing was a full time job when I got the car, so at least that's taken care of. As long as it pulls strong and runs smoothly with good oil pressure, it should be good for awhile. I was surprised at just how good a shape most of the motor was in, besides the seized rod bearings of course, even with 150K miles on it, 60 of which were mine and not exactly easy ones. My plan from the start was to fix it, drive the crap out of it, rebuild when the time came (a little prematurely, but I LOVE the fresh engine with a little performance work!), drive the crap out of it again, rinse, repeat... I love the fun factor of these cars, relatively simple to work on (no OBDII!), well balanced, very reliable once sorted out and maintained, really good cheap used parts market, and it says PORSCHE on it all at the same time. Nothing will stay new and perfect, so enjoy it, fix it, and enjoy it again. I'm just really glad I was able to pull it all off as well as it did. It was a pretty intense project from start to finish, and a relatively difficult motor to go through a first full rebuild on. I wondered a few times "am I building engines or character here?!?". A big lesson in patience and persistence, both of which are not always my strong points. :cool:

Thats exactly what i love about these cars.

Thanks for the tips. Will definitely look for the Elring RMS. Notch the bellhousing? (5 minutes and a google search later) THANK YOU FOR THAT! I was wondering how I was going to index my sensors. Will definitely do my best to restore the threads before assembly. thanks again!

short note - if you have to replace the O2 sensor do it after ring break in so the new O2s does not get all oil fouled from the new rings.

Good idea. I didn't get the new sensor until the motor had about 900 miles on it. Probably not totally broken in, but the motor did not smoke even on the first run, so I think the rings were a pretty good fit right off the bat and seemed to break in very well right away. The motor uses hardly any oil now, only some out the RMS.

Right now she's got about 1500 miles and still going strong!

Just stumbled across this thread -- I've been away too long!

Fantastic writeup. Thanks alot HondaDustr.

How is the oil pressure issue? Still losing power?

Dan C.

Power delivery is top notch. I don't know if the cutting out was some corrosion on the DME connector or the O2 sensor was bad, but it resolved itself when the O2 sensor was unplugged, and also with a new O2 sensor installed.

Oil pressure seems to run a bit lower than the old one. The one thing I did not do was disassemble and inspect/measure the oil pump, so the gears may just be a little loose or something. Once warmed up, it runs a decent 3.75-4 bar below ~3500 rpm and climbs to ~4.5 bar at full rpms. Idle is around 1.5-2 bar...a little lower than the old motor, but still within spec. The guage still dips ~0.25 bar when going from coasting to throttle below about 3500 rpm, but no knocking or any other problems yet, and all the crank and rod bearings are new, crank and rods mic'd good at the shop, oil clearances plastigaged good, and I was absolutely obsessive about clenliness during assembly, so I have no idea.

It's mere miles away from turning 3000 mi on the rebuild. I'll be changing the Castrol conventional oil out and going back to Brad Penn and consider it broken in once it does. Still pulling strong as ever and still no smoking, bad noises, or other stuff indicating serious problems. I also have to say throttle response is so much crisper and quicker than the old motor and the top end is so much more useable.It made it 300 and some miles up to NY and back this past weekend performing beautifully...it pulled hard well on its way to the 7000 rpm rev limit in 3rd on the LR chip, which the old motor would have never done. Maybe the porting work and the gutted cat actually do make some difference there. :cool:

Only thing yet to be squared away is replacing the RMS, which I have a Elring seal on the way for that, and also swapping out a lifter that's been randomly liking to go flat on cyl #3 or 4. If it behaves itself after I switch to Brad Penn, I'll just let it go, but otherwise, the cam housing is coming off sometime soon, too.

There actually is a difference between Porsche and Glyco bearings besides price
 

Interesting info I came across on the 911 rebuilding forums as to the apparent slipping quality control of aftermarket Glyco bearings.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/521208-bearing-still-crap-my-oil.html

I almost wish I spent the extra $200 to upgrade to original Porsche parts in that department. Interesting thing I just figured out, there's a way you can tell the Glyco from the Porsche parts, which are still made by Glyco but are thickness and quality checked. The aftermarket Glyco bearings are smooth and the Porsche certified parts have two little marks on them from the factory thickness checks. Read through the thread above. The old mains out of my motor were original, as you can see the two lines on each edge of the center of the bearing shell perpendicular to the bearing.

http://forums.pelicanparts.com/uploa...1252647033.jpg

You can also see there's no sign of the washboard pattern on my old bearing. The rods had some, but not as bad as the 911 motor in the thread (especially the one on the second page), but that was also a race motor.

The rod bearings must have been replaced once before, since none of them had the same marks, but the picture of the Porsche rod bearings on Lindsey racing have the same two marks on each bearing halve.

Otherwise, the motor is still running great with a bit over 4K miles so far. It's running fine on Brad Penn and it's coming up on 1000 miles after the oil change and I still haven't seen the oil level light yet, despite the RMS leak. I'm waiting for better weather to deal with that job. I still need to pull the cam tower and swap a lifter or 2. I pinpointed the lifter to be most likely on cyl 3, maybe #4 exhaust. I'll probably eventually try to find a complete assembly with less miles and hasn't had the lifters swapped/mixed up so many times. There's no telling how much wear is on the camshaft, since there's pretty much literally no way to tell, plus it's had a hard life. http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/526255-help-dilemma-anybody-know-camshaft-lobe-wear-specs.html

I really need to take a compression test but I just haven't gotten around to it yet.

I am in the process of rebuilding my engine and found HondaDustR's info invaluable. I wanted to contribute my experiences to this thread to help anyone who may attempt this in the future.

I decided to have my pistons ceramic coated and bore my cylinders out to accept the enlarged pistons. Information on the ceramic coating and related cylinder size issues is contined in this thread http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/541623-piston-cylinder-clearance-piston-coating.html so I won't repeat it here.

I do want to go into some detail on the process I used to enlarge and finish the cylinders. First off, for the enlarging I used a cheap 3 arm hone from Harbor Freight. For honing oil I used WD-40 which worked ok but I would not recommend it to others. I found that the actual cutting rate of the hone was dramatically influenced by the amount of WD sprayed. Lots of WD meant very little cutting, and very little WD meant very fast cutting. In general, I recorded cutting rates of 0.0003 to 0.0006 inches (increase in cylinder diameter) per 60 seconds of honing depending on the amount of WD sprayed. Obviously, purpose formulated "honing oil" would probably be the best thing to use. If you failed to plan in advance and are impatient (like me) I'd suggest trying mineral oil, vegetable oil, or automatic transmission fluid instead. I think any of those would result in more consistent cutting rates than the WD.

After honing the cylinder walls had a fairly deep cross-hatch pattern and a rough textured finish.

Immediately following the honing I tried finishing with AN-30 as described above but found that the deep cross-hatch pattern from the honing was barely reduced. I then tried red scotch brite* wrapped around the hone as described by HondaDustR above and that did a great job of knocking down the depth of the cross-hatch and resulted in a noticeably less rough finish.

*I recommend using standard green scotch brite as it is a little more agressive than the red stuff. I had already used up my green scotch brite with my original finishing proceedure (before I realized I'd have to enlarge my cylinders) and only had a sheet of red SB handy.

After the SB treatment, I returned to the AN-30 which was now able to do a great job finsihing the cylinders resulting in a dull grey finish with a very light cross-hatch pattern that was smooth to the touch but not "polished smooth".

Between my original cylinder reconditioning and post-honing reconditioning I used up an entire can of AN-30. I also experimented along the way and learned some things. I have to admit that when I first read HondaDustR's experience, I thought that he was making too big an issue about thinning the AN-30 and didn't understand why it wouldn't produce good results straight out of the can. After all my experience I now understand exactly what he was talking about and wished I had listened to his advice from the start.

When I first opened the can of AN-30, the paste on top was nice and thin. The original refinishing of the frist cylinder went very well. After that, the paste got thicker and thicker. You should definitely stir the can of AN-30 well before starting to use it. To thin out the remaining thick paste I added automatic transmission fluid. This mixed well with the paste and did thin it out but I only had a little ATF left at the bottom of my bottle and it wasn't enough to get the consistency I wanted. I then tried spraying WD-40 into the paste. This also did a good job of mixing with the paste and thinning it out. From my experience I'd say that both performed well as thinning agents. HondaDustR used mineral oil and it seemed to work well for him. FWIW, I added the cutting agent right into the can of AN-30 and stirred with a paint stick.

The problem with using thick AN-30 is that it cakes to the walls of the cylinders and the felt covered hone rides on top of that caked layer of AN-30 without really rubbing the AN-30 along the cylinder wall. Once thinned you could actually see the AN-30 being pushed along the cylinder wall by the hone. Without this pushing / rubbing action you don't get much "lapping" done.

I bought my felt from JoAnn Fabrics. They had about 20 different colors of felt available. I chose dark gray and ended up wishing I'd picked a lighter color so I could see if I was getting any staining and/or material deposits on it. I did use thread to sew it around the stones on the hone.

On my original attempt, I covered the stones with duct tape then sewed a double layer of felt on. In retrospect, I think that created too much "padding" on the hone and probably contribued to the hone riding over the caked layer of AN-30. After I honed out the cylinders I sewed a single layer of felt directly over the stones. I think the single layer provided a firmer surface and better lapping. The felt held up just fine after two 90 second runs in every cylinder. The first run I did clockwise and the second run I did counterclockwise. not sure if this is necessary but it seemed like a good idea to me. I had some issues with hone coming apart (it uses a threaded connection for the flex drive) when I initially tried to go counterclockwise, but I tightened it up with a couple pairs of pliers and it worked fine after that.

Oh yeah, I almost forgot, I used the highest pressure setting on the hone for all work performed. I actually tried the low pressure setting on the very first cylinder and felt that it was not enough. With the cheap 3 arm hone the pressure is easy to adjust just by screwing down the big threaded knob above the spring as far as you can wihtout preventing the arms from moving through their full range of travel.

I'm tired, so I hope I did a decent job of explaining this. Feel free to ask any questions If anything is unclear.

Damn, great post.

Nice explanation on the finer points of the AN-30 consistency. I kind of just boiled it down to what did work and not so much exactly what didn't work and why. Valuable info and 100% consistent with my experience as well. ATF is probably a pretty good choice, but if it were me, I would use a thin weight non detergent oil...don't know exactly why, other than honing oil is mineral based and not highly detergentized like ATF. ATF is a good weight, though...very similar to the vintage 20 weight oil I lucked out on finding. API SA,SB is the spec for non detergent straight mineral oil.

I cringed a little at the part about the honing with stones, as I saw many many posts saying don't do it, but maybe the scotchbrite and AN-30 smoothed out whatever surface it may have produced. Honing is almost a molecular science, as matching the abrasive material, pressure, speed, lubrication, etc. to the metal and type of honing done has everything to do with obtaining the correct amount and type of roughness (Ra), especially with a soft finicky metal like aluminum that tears easily. With the scotchbrite and AN-30, it's probably pretty good in the end. It's all about producing a surface that's rough enough to wear the rings in and retain an oil film but smooth and consistent, not having been torn or "shredded" by incorrect abrasive stones.

Good luck with the build and keep us posted on how it turns out. Mine's getting very close to the epic 10,000 mile mark and it hauls @ss and doesn't smoke or burn any appreciable amount of oil. Just 700 miles to go and I'll do the first official compression test to celebrate the milestone.

cjpacitto

Yes, very nice followup to the detailed information HondaDustR described.

The last post in the link gave me the information as to what size ring set is needed.

John

I would be so nervous to do this myself. I wouldnt mind saving he money and doing it myself but,.... it just seems risky to me. This is perfectly safe for these alusil blocks? I thought a special honing machine was needed?

Just read this thread and I spotted a major potential problem.....are you using this OPRV? Because it is not supposed to have that groove machined into it...that is a sign that the housing was not aligned and it became stuck and started spinning, which is what caused the groovehttp://forums.pelicanparts.com/uploa...1277365880.jpg

I guess we'll see, right? The factory service manual discusses the proceedure for boring out the cylinders. Remember, oversized pistons are available, so boring and refinishing would have to be performed to fit those.

The Porsche manual says:
1. Rough Turning to 0.1 mm before finished size
2. Dressing to 0.02 mm before finished size
3. Polishing to finished size
4. Lapping with Sunnen silicum mixture

Sunnen also has this technical artile on honing Alusil bores Honing Options for Hypereutectic Aluminum Cylinder Bores - Sunnen which says:
1. Boring
2. Honing
3. Finish Honing
4. Exposure

Here is some more info from the Sunnen article:
Kind of weird they are using an elastometric stone instead of AN-30.

I used the honing stone to take off 0.001 to 0.002 inches of material.
I'm sure the scotchbrite took off at least 0.0001" as it reduced the depth of the honing marks considerably. (and 0.0001" is freaking tiny). I guess we'll know for sure when I get it all back together, but I'm pretty comfortable with it.

FYI, the manual does say you MUST bolt the crank girdle to the block and torque the nuts before doing any honing/finishing work.

[QUOTE=944CS;5420902]Just read this thread and I spotted a major potential problem.....are you using this OPRV? Because it is not supposed to have that groove machined into it...that is a sign that the housing was not aligned and it became stuck and started spinning, which is what caused the grooveQUOTE]

No, I'm running a 1 piece valve now. That's weird... It did seem to function correctly when I did use it.


It's also interesting that Sunnen says you can cut the Aluminum silicon cylinders with regular abrasives. I think the scare was caused by people on the 911 forum suggesting a deglazing hone alone on Alusil to prep for new rings. It's ok on Nikasil, but not on Alusil! Following up with scotchbrite and the AN-30 should be just fine to produce the proper finish.

I would love to do this myself to save the money but I'm afraid things will go terribly wrong.

The rest of the confusion comes from 911 guys who have nikasil cylinders. Nikasil is just a coating on the cylinder wall where as alusil is what the entire block is made of. If you hone nikasil you'll go right through the coating and need to get them recoated. You don't have that issue with alusil.

These two posts contradict each other----I think.

John

Argh im 50/ 50 on whether I should do this,... not sure. Things have changed her a bit and I really need to kind of watch my budget now. Cant do EVERYTHING i wanted. I have to try and do as much as possible without seriously going over the top.

I may mess around and try to drop the short block before any money gets thrown around,

Still got the old one? I would love to get a look at that spring.