@Jonny, @Ed:

On my mag case, I can't see this at all. I did a quick measurement sample and got the same 11mm inner hole diameter on both sides of the case. Also, it doesn't really make sense to me- either way, isn't it the thick washer coming into contact with the case? Meaning, aren't the washers spacing the bolt-heads on one side and the nuts on the other side out from the case the same distance?

So, there may still be a good reason to orient the bolts as the factory did (and that's what I'll do...), but @Jonny, at least from my sample set of 1, I can't see any reason why flipping them would cause a problem! Hopefully the experts will weigh in.

@Mark: I think the pic is misleading. There's absolutely no sealant on that bearing... I think the grey assembly grease is creating a contrast that makes the inner track look white like the the sealant, but it's really just the bare silver surface of the bearing. Here's another pic of the bearing itself, just after removal:

http://forums.pelicanparts.com/uploa...1565205221.jpg


Hoping to get everything back together today...

-Jake

Ok, got everything back together today. I was feeling pretty good about it; went much lighter on the sealants, had minimal squeeze out. Here are some quick pics:

http://forums.pelicanparts.com/uploa...1565236326.jpg

http://forums.pelicanparts.com/uploa...1565236326.jpg


Looked pretty much like that all the way around the seam. All of the pics are oriented with the (EDIT: Left!) half of the case up; that's the half to which I applied the sealant, so when some of the squeeze out looks like it's above the seam, that's actually just the excess from when I fingered-applied it on the surface prior to putting the case halves together (and thus not indicative of the sealant actually getting squeezed out...). Anyway, the actual squeeze out is minimal, almost to the point of making me wonder if I had put too little on.

I didn't notice any issues while putting the case together or torquing down all of the through bolts and perimeter nuts.

Then....


Defeated!


F* me, the crank is frozen.


Not sure what happened. Looks like I get to tear it apart again.


I threw a couple of flywheel bolts in to try to turn the crank with a cheater bar, just to see how frozen everything was. I could rotate the crank, but it took a LOT of force- not good. I turned it only a few degrees, hoping to minimize whatever damage I might be doing.

http://forums.pelicanparts.com/uploa...1565237080.jpg


I went back and reviewed all of the pics I took today during the assembly, hoping to find something obvious like forgetting assembly lube, or an errant glob of sealant on a bearing or something like that... no luck. I'm afraid either a bearing slipped out of place and got wedged somehow, or maybe my excess sealant the first time around (things spun fine then) somehow masked a bearing tolerance issue... I dunno- reaching here.

I'm fairly sure it's not the oil pump or IMS bearings. If the IMS was frozen, I'd still get a little "click" of movement out of the crank.

So, I'll tear it apart again, and see if I can find the offending part and whatever new grooves or scratches I've created. Until then, any thoughts out there?

Good times. Keeping it positive, I'm glad it's my own motor, on my time. Whatever mistake(s) I made would be hard to live down if this were a customer car!

- Jake

Aw crap!!! Well I guess there's a bright side........ you get to reverse engineer your sealing methods again!! (HANG IN THERE!!)

I had to talk myself of a ledge yesterday with this LOL. I think the holes are the same diameter, but on my SC there are (or WERE) chamfers on one side of the through bolt holes only.

I was either stupid enough or arrogant enough to think that I was going to outsmart the factory and add chamfers to the case where they were "missing". I did this for two reasons - first, I did a test of the o-rings and the one on the non-chamfered end was pretty much destroyed. Second, adding the chamfer was recommended by a few different knowledgeable and experienced forum members.

I based my faulty o-ring squish test on putting the bolt through the WRONG WAY!!!! as shown in "The Book". Which I am now referring to as "That Damn Book". I suspect the test would have had different results had I double checked the orientation of the bolts.

Thankfully, the suggestion to add the chamfers, although it may be based on the same incorrect bolt orientation, comes from people who have built a few motors - and were it resulting in chronic leaks from the o-rings they wouldn't have done it more than once, and probably wouldn't be suggesting others do the same.

Thinking back to a bunch of the threads I read while researching the whole through-bolt thing, people were having trouble with o-ring "squish-out". I am willing to bet this was a result of (incorrectly) putting the bolt head at the non-chamfered side of the case.

So - fingers crossed.

http://forums.pelicanparts.com/uploa...1565270229.jpg

Jake, I must say your doing a fantastic job on this and keeping a positive attitude working through some of the problems that have come up. You will be able to rebuild these engines blindfolded now.
Keep us posted on what caused the bearing/gears to bind up.

Jake,

Before you disassemble the case again, check (if you haven't already) that the rods at the Oil pump end of the crank are not wedged up against the oil pump. Unless you keep them somewhat in their operating stroke, they can tip over and wedge against the pump body.

Good luck.

Neil

@Jonny Looks like you've got it worked out! And, if we weren't all a little stupid and arrogant, we'd probably never attempt any of this stuff in the first place ;)

@Mark Thank you for your nice feedback. I really hope you're still following this thread by the time I get to the MFI tuning!

@Neil Thanks- yeah, I checked that, as well as confirming that neither of the chains were somehow binding. I'm tearing it down now- will post some pics soon.

-Jake

Jake,

Don't worry, we have all been there!!!

Just some of us are too proud to admit it.

Back in the ""olden days"" when I worked at Andial in the race engine dept., my primary role was performing all of the dyno testing with Herr Springer. I know, someone had too!!! But occasionally, I would build an engine or two. Once, the old trick of placing an important O ring or nut was placed on my bench next to my newly completed engine. It doesn't matter how many times that trick is played, it still gets your heart rate up!!

Well, I'm a bit flummoxed.

Got the case apart again this morning, and was expecting to see some horrific gouges or scratches or something indicating that I'd made a terrible mistake. But, everything kinda looked ok- leaving me to wonder what the heck was binding the crank.

First test I did was after loosening the perimeter nuts and through-bolts, but before splitting the case. In that state, the crank turned by hand just fine (as it did in the same state before I torqued the bolts last night). To me this indicates that there's not some mechanical obstruction of some sort, but that the full torque is causing something (probably a bearing, cuz what else is there?) to deform and bind.

http://forums.pelicanparts.com/uploa...1565296288.jpg


Let's take a closer look:

http://forums.pelicanparts.com/uploa...1565296288.jpg

http://forums.pelicanparts.com/uploa...1565296288.jpg

http://forums.pelicanparts.com/uploa...1565296288.jpg

http://forums.pelicanparts.com/uploa...1565296288.jpg

First off, the sealant looks much better! No globs, minimal squeeze-out but full coverage. Looks like I could still go lighter on the 1211 around the #8 bearing; or, at least pull it even further away from the inside of the case.

http://forums.pelicanparts.com/uploa...1565296288.jpg


Here's a good pair of pics, where you can see areas of bare metal on one side, but the mirror image on the other; I think this shows that there was full coverage, as opposed to some kind of dramatic variation in the surface itself.

http://forums.pelicanparts.com/uploa...1565296288.jpg

http://forums.pelicanparts.com/uploa...1565296288.jpg


Here are a few pics of the bearings, crank, etc. I really can't see anything wrong; there's no obvious area on any of the bearing surfaces which would indicate excessive wear or binding.

http://forums.pelicanparts.com/uploa...1565296288.jpg

http://forums.pelicanparts.com/uploa...1565296288.jpg


At this point, my only working theory is that either my bearing journals, or bearings themselves, are slightly out of spec, and once the case is fully torqued down, the offending bearing(s) deform just enough to bind the crank. However, I can't yet find any visual evidence to support this- I just can't think of any other possible reasons.

All suggestions appreciated!

- Jake

Here are a few more bearing pics:

http://forums.pelicanparts.com/uploa...1565297054.jpg

http://forums.pelicanparts.com/uploa...1565297054.jpg

http://forums.pelicanparts.com/uploa...1565297054.jpg


In this pic you can see some dark cloudy areas under the assembly lube. I wonder if those are a sign of anything.

http://forums.pelicanparts.com/uploa...1565297054.jpg


The only real trend I can see is that there seems to be less assembly lube at the bottoms of a few bearing-halves. Maybe that indicates uneven squeeze on the bearings? I'm reaching here... I guess maybe I'd expect to see that on right side bearings, as that's where the crank was sitting before torquing down the other case half.

Gotta think on it. For now, my only rough plan is to go back and carefully measure the bearings and bearing journals to see if something's outta whack.

-Jake

If you haven't already done so, it would be a good idea to clean the assembly lube off carefully, the surface of the bearings should tell the story. The babbit (the soft surface of the bearing that is easily marked) will have polished up in the places the crank was binding.

The backside of the bearing shells and the case bores themselves should be spotlessly clean and dry when you put the shells in the case halves, I wonder if that detail was missed on your second go-around?

@Neil: Sounds like good times!

@Jonny: Thanks- yeah, I was pretty good about cleaning everything, even the second time around... maybe even better, as I knew I had introduced a bunch of new detritus while I scraped off all of the old sealant. Never knew the bearing coating was called "babbit"- cool.


Ok, I've cleaned up the bearings. Only a few spots stand out.

Left side, #1-7:

http://forums.pelicanparts.com/uploa...1565309778.jpg

#7-1

http://forums.pelicanparts.com/uploa...1565309778.jpg

In the first pic, #5 shows a little horizontal line towards the top. You can also see some of the darker cloudy areas, but I can't tell what that is; might just be some kind of surface imperfection. There's no linear (radial?) component to it, which I'd expect from when I forced the crank to turn a few degrees.

Right side, #1-7:

http://forums.pelicanparts.com/uploa...1565309778.jpg

#7-1:

http://forums.pelicanparts.com/uploa...1565309778.jpg

#3 shows a some wear marks at the top. #1 has a few shiny areas, including a horizontal mark similar to #3.

Bearing journals look clean; can't tell any difference from what they looked like prior to install.

http://forums.pelicanparts.com/uploa...1565309778.jpg

http://forums.pelicanparts.com/uploa...1565309778.jpg


The #1 bearing also has some noticeable wear on the flange. The direction of the grooves suggests to me that this happened while I lowered the crankshaft down into place, as I had to jiggle it around to get the #8 bearing pin to align before the whole crank dropped into place.

http://forums.pelicanparts.com/uploa...1565309778.jpg


The thin lines in the babbit that run along the center of each surface were there from the factory. You can see a little more of the cloudy patches:

http://forums.pelicanparts.com/uploa...1565309778.jpg


So, knowing nuthin' from nuthin', I suppose I'd start by investigating the journals at #1, #3 and #5. Perhaps there's an alignment issue with my case. My machinist said that my case didn't need align boring, but maybe something changed.

Let me know what you think!


Jake

Jake,

First thing to do is to understand you are now building the engine for the very first time. Forget about the other 2 times. So start all over again.

Remeasure measure the main housing bore. Is it to spec and are the bearing housings aligned?

Now fit the main bearings after checking they are the correct ones, ( not an oversize on the inside) and measure the bearing ID's. Why re do this, cause you may have made a mistake before and this could be the problem. As I said, forget about the other assemblies. think this is the first build.

Now measure the crank shaft journals. Do the math and see that you have clearance. Now before you install the crankshaft, check the end play of the crank in the 4/6 side of the case. Then take out the # 1 Tbearing and swap it for the one in the 1/2 side. Recheck the end play. You should see at least 0.002" and probably as much as 0.004" - 0.006". Now you can at least know that each T bearing shell is ok for end play.

I know it time consuming, but did you have the crank checked for straightness. These cranks are always bent as most used cranks are. An easy way to check, although not to accurate, but it will show up a bent crank is to place a dial indictor on the nose of the crank and rotate it. You can do this in the case half. The front of any crank is the part that does the most moving, in any engine. This is why dampers are fitted to the nose.

Check the Oil pump for something that doesn't belong in there too.

Go slow and be deliberate.

I wonder if it might be worthwhile removing the rods and trying out the crank in the case, with nothing else. See my post:

http://forums.pelicanparts.com/porsche-911-technical-forum/979976-project-heavy-metal-all-steel-classic-remastered-33.html#post10529154

Thanks for pointing me to this thread. I’m doing a redo of my case closure. It made me aware of Ed Mayo’s comment on the acorn nuts going on the side without chamfer in the bolt holes.

I noted my o-rings (some) were a bit smashed from my bolt per the orientation in Wayne’s book. I’ll be switching my through bolts so acorns are on the side with no chamfer.

Thanks for sharing this was helpful.
Only the acorn nuts on the oil cooler side are the ones in the cooler cavity. I got it

You got it! Enjoy.... at least everything gets easier the more times you do it!

My 73 E did not have the screen I see next to your oil pump. There were also tabs on the oil pump screws to keep them from backing out. Guess possible difference in models / years?

Chris

73 E

splash screen
 

my 72 had the splash screen and 2 cases I bought also had them...

My 73 2.4 E had the 7 R case. Maybe thats the difference.

Chris

Hi Chris, yeah- pretty sure the screen is normal/stock for my motor. I did have the little tabs for the oil pump screws, but I removed them in favor of Loctite (and as suggested by Neil Harvey).

Jake

Quick status update: I've been carefully measuring the heck out of everything, to see if I can understand what the issue is. I'll post pics soon, but the short version is that I don't yet trust my measurements!

My bore gauge can only reach bearing journals 1-4 (with the #8 bearing in place for alignment), and my measurements are showing that the journals are...undersized? I'm regularly seeing bore diameters of 2.43xx, when stock should be 2.44094 - 2.44169. Not sure how that would happen, but my bore gauge technique is certainly suspect. If my measurements are correct, that would certainly explain the crank binding.

Anyway, I'm going to re-measure everything, and look into getting/borrowing a longer bore gauge so that I can get at the 3-7 bearing journals. Or, I'll attempt one of the "manual" case-alignment techniques, so that I can use my current bore gauge from the #8 side.

I'm also going to see if Ted (machinist) can give me a hand. That's probably my best option!

Jake

You're readings are to be expected with a mag case. The main bearing saddles become out of round, actually closing up horizontally. The original bearings slowly wore that way, now with new bearings they pinch the crank.

@Ed: thanks- I guess that makes sense. I just can't quite visualize how the heat cycles over time would cause the mag to expand that way, but I'm willing to accept that that's what happens! I always thought that when metal heats, it expands, and then when it cools, it contracts- but, if anything, it would contract more than it had expanded... at least, that's what happens in welding steel (granted, we're not welding steel here...).


Anyway, here are some pics of the measurements.

Starting with the bearings themselves, I used an old ball-end dial gauge on a nifty stand. I liked this setup, because it let me apply just enough hand-pressure to the gauge to get repeatable measurements without marring the "babbit" surface of the bearing too badly. I took measurements at 3 positions along the center line of each bearing half.

http://forums.pelicanparts.com/uploa...1566011870.jpg

http://forums.pelicanparts.com/uploa...1566011870.jpg

http://forums.pelicanparts.com/uploa...1566011870.jpg

http://forums.pelicanparts.com/uploa...1566011870.jpg


Here's a table of my measurements.

http://forums.pelicanparts.com/uploa...1566011870.jpg


I couldn't find a direct spec for the bearing thickness, but if I'm reading the shop manual correctly and doing the proper math, then the spec should be 2.48 - 2.49mm. My measurements are all right in there, excluding a couple of on bearing #1 just over at 2.5mm.

In other words, I think my bearings look fine. Time to check the case bores.

Jake

Before getting to the case bores, I wanted to check the crank itself. I put another dial gauge on a flexible stand to confirm the "roundness" of the crank bearing journals, and to attempt to check for any wobble in the crank. Unfortunately, the only dial gauge that would fit my flexible stand reads in inches, so I'll have to keep converting back and forth to mm just to keep things interesting.

I put my crank on my wooden stand, set the gauge, and turn the crank. While measuring the bearing journals supported by my stand, I found no deviation in readings (the dial never moved off of zero), which indicate that the journals are nice and round (as expected). This doesn't tell me anything about the straightness of the crank, though.

http://forums.pelicanparts.com/uploa...1566014768.jpg

http://forums.pelicanparts.com/uploa...1566014768.jpg


With my stand supporting journals 1 and 6, I tried to measure any deflection in the shaft at the #8 position. The shop manual calls this "runout", and says to put journals 1 and 7 on v-blocks and to measure #4 and #8 with a max runout of 0.04mm. So, my test isn't perfect. Also, my setup isn't perfect; and I quickly found that I could influence the measurement by leaning on the crank, or when I'd apply the initial torque to turn over the crank. It was a fiddly setup, to say the least... anyway, I measured 0.0254mm runout on #8, in what was certainly an exercise in false precision.

http://forums.pelicanparts.com/uploa...1566014768.jpg

http://forums.pelicanparts.com/uploa...1566014768.jpg


Ok, on to the journals.


Jake

I cleaned off all of the remaining sealant residue and bolted my case halves back together, without the bearings, crank, etc. I kept the #8 bearing in place to keep the case aligned. Here's a pic using the bore gauge:

http://forums.pelicanparts.com/uploa...1566073151.jpg


I was able to reach into the case far enough to measure the bores for bearings 1-4. For the uninitiated, to use a bore gauge, you set the zero to a known dimension (I used a micrometer), then add or subtract the bore gauge reading from that. I measured each bore at three positions, roughly corresponding with the locations I had previously measured on the bearings themselves.

Here's a table of my measurements. You can see my gauge readings, then the subtraction from the "zero" dimension to calculate the actual diameter.

http://forums.pelicanparts.com/uploa...1566073151.jpg


A couple of things immediately stand out. First, my bores are not perfectly round. I couldn't find the spec for "roundness" per se, but the data sheet shows that the bores should be 62 - 62.019mm. I interpreted this to mean that different bores (e.g., #1 vs. # 4) should be within that spec, but maybe it also means that a singular bore could diverge from round by up to .019mm (?). In any case, I'm seeing variance of 0.1mm within a single bore.

Also, and most obvious, is that the diameters are too small. The min spec is 62mm, and I'm showing a max of 61.93. This would certainly explain why my crank was getting pinched.

As I previously posted, I'm still not confident in my measurements- but signs are increasingly pointing towards needing an align bore job. I had been working under the assumption that my case had a clean bill of health, but, you know what they say about assumptions... Hopefully I'll get a chance to visit with Ted next week to check it out.

Good times!

Jake

I really wasn't happy with my bore measurements, so I went back and did it again. This time I was extra careful about setting the zero of the bore gauge, and I think that made a difference. I was also more careful to get the bore gauge as close to the center line of the bore, consistently across the 4 bearing bores I could reach.

http://forums.pelicanparts.com/uploa...1566077710.jpg


Here's my new table of measurements. They're much closer to spec than the previous set, but, still, only 2 of 15 values are actually within spec.

http://forums.pelicanparts.com/uploa...1566077710.jpg


If the trend continues, all I have to do is keep measuring, and eventually everything will be in spec! Ha.


Jake

Has your case been line bored ? If not , more confirmation that a high milage mag case needs line boring . Otherwise , I'll be curious to know the problem .

I had the same issue on a stock build on a 73 2.4. The first time I put the case to gather, with through bolts all to torque, the crank spun fine. During final torquing of the perimeter nuts, one of the flywheel end studs pulled.

So I pulled it apart. Repaired the one perimeter stud and reassembled using same bearings, etc. this time the crank was stiff.

After much measuring I had the case line honed, not bored, to spec. Engine has been running well since.

To this day I do not understand why the crank spun fine on the first closure, and not the second.

I relate to your frustration. Rob

Thanks guys.

@Richey: No, the case hasn’t been align bored. Early on in this adventure I was advised that I should do that, purely based on it being a high mileage mag case- I should have listened! My machinist gave my case the green light, so I thought I was in the clear. Maybe he missed something, or maybe I wasn’t asking the right questions at the time. Even with that, I should have measured everything to my own satisfaction much earlier in the process. Many lessons learned!

@Rob: Glad yours worked out.

It’s a setback, but for the best... I’ll get it worked out.

Jake


Sent from my iPhone using Tapatalk

Jake,

Here's your way forward.

Establish that the housings are under size but straight. They may have pinched in across the parting line. If the alignment is OK, then hone the bores to the correct size. This brings the sizes back to where you need them to be.

BUT!! Be careful here as the hone will follow the front and rear housing bores. The hone will not make the bores straight. The honing Mandell will follow the bores. If its off in any bore, the hone will remove stock only where it touches, which can make the bores even more out of round.

If the bores are out of alignment, your only course of action is to bore oversize or deck and bore back to std. You are looking at $$ for repair labor. Hopefully you can get by with a quick hone to bring the bores back to size.

Just at a glance, I'd say .05mm is WAY out of round. I think in inches (old habits and all my measuring tools are in inches), so I converted and find that .05mm is .0019". That's 2 thousands. In oil clearance terms that a mile.....

I'd say your best plan of action is to find a machine shop that specializes in 911's (Ollies comes to mind but I'm sure there are others, maybe within driving distance to you). And get them to fix up whatever needs fixing. Bore it and straighten it and get it 100%.

That'll give you a good foundation to work from and you can rest easy.

@Jonny: Thanks, well received.

@Neil: Makes sense. Quick question:

Do you have any suggestions on how to establish the alignment/straightness of the bores? I have access to standard measurement tools, but not a lot of specialty stuff... Seems like it'd be a bit tricky to establish a true center line from which to measure the bores against, unless you mount the case into a mill or lathe or something...

Thanks as always!

Jake

Yes, easier said than done for the DIY.

We attach a 1/10th indicator to our boring bar and as the boring bar travels through the case it will show any misalignment.
If they are way out, a simple straight edge will show up any misalignment. But if they are close, this will be too inaccurate.

Do yo have access to a std knee type milling machine with a digital readout in the "Y" direction?

Set a case half up on the table and indicate in the rear #1 & #8 bores and the case level with the table. Lock the "Z" so you measure the same height in the housing bores. Zero Out either end and then traverse along the "X" axis and measure each of the other housing bores. You can swing the indicator 180° to measure the other side of the housing bore.

Good luck.

found this overview.
 

Quick update: My case is now back with Ted @ German Precision. Turns out he's moved his operation out to Yuba City, and says he's as busy as ever.

I'll continue to poke around at a few things while I await the return of the case.


-Jake

Ok, back in action. Here's a few pics of my freshly align-bored case; thanks, Ted!


http://forums.pelicanparts.com/uploa...1568409452.jpg

http://forums.pelicanparts.com/uploa...1568409452.jpg


Just gotta clean 'em up, and then put it all back together (hopefully without repeating the mistakes of the past!).



Jake

Was it align bored or honed?

Bored, to .25mm over. Gotta get some new bearings now...


Sent from my iPhone using Tapatalk

oversized bearings are crazy expensive if still available.

Chris
73E

I've been enjoying this thread and am looking forward to the next update. Hoping it turns out well.
I've read a few thread regarding the oil screens. According to the PET it ended with the -71 engine, but seems in real life they continued till the 2.4 7R case.
901 101 035 01 left: oil strainer -71
901 101 035 01 right
A few threads
https://www.early911sregistry.org/forums/showthread.php?116882-Do-you-need-the-oil-strainers-inside-the-crankcase&highlight=901+101+035+oil+strainer

http://forums.pelicanparts.com/911-engine-rebuilding-forum/933023-windage-screens.html