Part of the process is to lightly blast the surface with a special media, this gives a grip for the coating and also allows it to embed into the babbitt material. Even if the surface of the coating is wiped off the DFL is still in the "pores" doing its job.

No bearing coating is supposed to be hard, like the babbit material on the bearing it's deliberately soft, as this is your last line of defence to avoid damaging the crank. The bearing surface is considered sacrificial and is designed to let fine dirt to embed into it, not the crank.

Lets assume that you assembled everything correctly, the short block turned freely, no bead blasting was performed anywhere. The machine shop removed the galley plugs and cleaned everything. You were meticulous in your cleaning and assembly. I assume the engine mounted oil cooler was cleaned and you said that there wasn't prior bearing failure.

That leaves us with the "trash" somewhere that wasn't cleaned and didn't get filtered via the oil tank filter. The things remaining are the oil tank, the S-hose, and the turbo scavenge pump and lines, which return oil to the tank unfiltered (irrespective of the factory "filter"). Were all of those cleaned or inspected?

But back to the original reason you're performing an autopsy. It had a knocking/tapping noise that you couldn't find. I remember watching your video and it sounded like it was from the #6 cylinder area. The bearing, although scratched from trash, doesn't appear bad enough to make a heavy knocking noise. (I've seen far worse on neglected, but otherwise quiet engines) What is the rod bearing clearance now, post mortem? How about the piston to wall clearance? Was there any scoring on the cylinder wall? On the piston skirt? Which pistons were installed? Anything obvious, like a piston installed upside down? Piston pin and bore spec'd out ok? Was the deck height within spec? Did you find anything wrong with the valve train? Rocker bushings were good on the noisy cylinder?

In addition to making sure there is no more contamination in the coolers or elsewhere. Get a new torque wrench. Every bearing that is not scratched by contamination appears to be torqued, twisted and warn all wrong. I over torqued head studs by not using the torque wrench correctly.....happens to the best of us.

Chris

There are many assumptions that can be made. There are only two facts though.

One is, the engine is damaged and needs to be repaired.

The other is, nothing will humble a man more than an angry wife or an engine.

Some advice to anyone who wishes to listen. Do not use those horrible piston ring compressor "POS" to install the pistons into the cylinders. As rings get thinner those things are difficult to use with any sort of confidence. Buy a proper installation sleeve. I think ARP sell these in many bore sizes. the pistons will slide into the cylinders will little force. You can then be sure you have not damaged or broken a ring. Nikasil coated liners require cast and or "softer" materials to be used for rings. This adds to the problem making a chance to break a ring very easy.

When assembling your engine always cover it when you are not working on it. Use a big trash bag. If most DIY's are building in their garage, what are the chances of some foreign object landing inside, unseen?

It comes down to good engine building habits. And those habits start before you even take the engine out of the car. Maybe I will post something later on how I would rebuild an engine if I was doing this at my house. God forbid that ever happens.

Sorry to see this.

My question... During your disassembly did you find what was causing the knock/tick? Yes, the bearings had some FOD go through them and are gouged. But I do not see anything indicative of an ill fitting part and movement.

Was crank tight in bearings?
Were rod bearings tight to crank?
Was intermediate shaft tight in bearings?
Etc...

Your measurements seem to show that everything was basically in spec. I would look closely to find the source of your noise. The cleaning process is pretty much self-evident.

My $0.02.

Neil,

Thanks again for all the advice. Trust me when I tell you I'm listening loud and clear to you, with just moving forward.

The exercise of trying to figure out what was wrong has been really helpful though. Just for example, the comment on the torque wrench was a good one I hadn't thought of.

Just want you to know I hear you loud and clear on just moving forward, and this engine has me MUCH MUCH less upset than if I had an angry wife on my hands.

Also I bagged my engine up every night during the rebuild (even have the dirty one bagged up in my garage right now).

This came up today on my amazon photos as today in 2016:

http://forums.pelicanparts.com/uploa...1561602702.jpg

1st - Yes engine mounted oil cooler was cleaned by pacific oil cooler.

2nd - No I didn't clean them, but I did plug all hoses and kept the oil filter on the tank during the time the engine was out. But it's certainly within reason to believe one of my plugs could have come off and I didn't notice for a couple days. So crap could have been in there or gotten in. I don't remember this happening, but I don't remember why I enter rooms sometimes so...

3rd - Onto the tapping noise.

1. I installed New JE Pistons in New Nickie Cylinders
2. I'll have to get some plastigauge and check the rod clearances now. Most of the bearings are not nearly as scratched as the #6
3. Cylinder walls look fantastic.
4. Piston Skirts also look good, but I'll take a closer look tomorrow as well.
5. I'll also check piston to wall clearance
6. The piston Pins were all new as well. I don't think the machine shop checked those though. Coming out of the engine they didn't look bad or have abnormal wear. I'll try and get a photo tomorrow.
7. Deck height was checked and I found it to be all good.
8. I've taken the 456 valve train out. I was surpised by some of the wear on the rocker shafts. The 5mm hex bolts were also very tight. I'll try and grab a decent photo of those tomorrow as well.

Thanks Jamie.

Crank wasn't tight in the bearings. Felt just right to be totally honest with you.

The rods all seemed good on the crank, but as dannobee mentioned maybe I should check the clearance now post mortem to see how they are.

Intermediate shaft also felt fine in its bearings, but it did have a noticable wear spot, and the thrust portion of the bearing on the outside of the case sure seems to have excessive wear. Almost like when combined with the wear on the thrust bearing for the crank it seems as though the crank and intermediate shaft were shifting back and forth too much or was too tight.

http://forums.pelicanparts.com/uploa...1561604640.JPG
http://forums.pelicanparts.com/uploa...1561604640.JPG

I have seen some intermediate shafts try to bind on the splines and not spin free. Neil mentioned this about oil pump alignment. Another way is to change how the shaft is clocked to the splines. I would also check the shaft on a V-block and make sure it is straight and not bent. Maybe the tick was the shaft rocking back and forth on the shaft and putting lateral pressure on the thrust bearing. You might see this in abnormal wear at some point on the aluminum layshaft gear.

possible tight links in a chain? Were they new chains? New or old sprockets? Chain lines good? Rubbing the case?

Loose wrist pins? pistons rocking/slapping?

Jamie brings up another question, how did the small end of the rod look? Was the bushing within spec?

The reason that I ask about upside down piston(s) is that the pin is offset to quiet down piston slap noise. It doesn't hurt anything if it's in upside down (it's an old stock eliminator drag racer trick, it'll actually make more power), but it'll have a noticeable rattle.

"DO you do the same to the IMS shaft bearing?"

Yes. With the pump and drive tube removed and the IMS sitting in each case half. Then assemble the case and check IMS end float.

930
 

Verdon Tools work has always been meticulous.They remove the plugs in the case and make their own threaded plug as a replacement.Your issue came from the oil tank.You have to be careful when changing the oil filter as there can be some dirt around it.Always spray some brakecleen around the base to remove any loose grit.Does not take much to spoil a fresh motor.The 993 filter housing is a nice way to ferry out any initial gremlins then install the factory cooler after initial runs.Fred

OK, just to simplify things... there seem to be lots of small issues with the motor. But most don't seem fatal...

1) Unusual wear on the IMS bearing. Seems to me that if it were tight, after about 10 rotations of the IMS shaft the bearings "makes" its own clearance by rubbing material down. Not optimal, but is what it is.

2) Main bearings have debris in them. Again, not optimal, but that debris likely landed there in the first 5 minutes of running. After that, it is what it is. Those bearings could have gone 50,000 miles like that, no?

The only really odd thing, is the weird wear on the thrust bearing, like the case was aligned way off. Or somehow the coating on the bearings was 5x thicker than normal...

The inner ims bearing looks like it was "pinched" when tightening the case. Same as dozens of pics on this site when people used glyco bearings in their rod ends and found out they were uneven thickness, etc...


Take your current worn thrust bearings, put them on the crank and IMS shaft, reassemble, retorque, and measure the endplay clearance...just to see what it is now.

Like I said before, my removed IMS bearing had lots of wear on the thrust surface...

The "new" IMS bearing fit, but had almost zero play...


Before you start putting in new parts, use the old ones and measure everything again. Until you find what was wrong it will continue to worry you...

If you used glyco bearings, my limited experience showed that they had waaay more clearance than the Porsche bearings. Measure the glyco bearing against the Porsche bearing, its about .0005 thinner, adding an extra .001 clearance when both are installed...

If your rod clearance was too great, that could be your clicking sound you heard...

How do the valve guides look? Any loose valves? What about the rockers and their shafts?

FWIW, IMO that ticking sound did not sound like it was coming from deep in the motor.

And the turbo itself and the turbocharger sump.

Danno - VWs, with their flat piston crowns and no valve reliefs, had offset wrist pins, with an arrow on the crown which you pointed at the flywheel. Since the crowns were flat, following the arrows produced anti-slap. Hot rodders (Formula Vee) immediately reversed the orientation, and gained a tiny bit of HP. At one point Chevrolet did this on V8s, but their piston crowns weren't the same rightside up as opposed to upside down, so to speak. So they produced right and left side pistons. Eventually they tired of the inventory issue this created, and went back to centering the wrist pin.

Porsche has never had right vs left side pistons. At least not in the air cooled cars we have. But, to my amazement, I found that some models did have wrist pin offset. So one side has anti-slap, and the other makes a bit more power.

Chris Seven once offered his considerable automotive engineering expertise in explaining why this isn't a crazy thing to do. So it must not be, but I still don't understand it - you'd think the loss of noise (from being centered to being offset) on one side would be cancelled out by the noise gain from the other.

You could have aftermarket pistons made about however you want - the offsets aren't all that large. I pondered this when having some pistons made, but decided not to - it's a good idea to have seven made, so you have a spare. But if he ordered them, or had the documentation, it should be easy to verify - or if he hasthe pistons loose and handy.

Agreed. They're JE's, so who knows where they're putting the pin. If it's straight up, then no harm, no foul. If it's offset, one way is quiet, one way is noisy.

The offset pin changes the dwell time of the piston, parking the piston near TDC a tad bit longer, allowing cylinder pressure to increase (installed in the "power" direction). It's more beneficial on 2 valve heads and lousy combustion chamber design. On a 4 valve head with a pent roof chamber, it makes less difference because the flame front is so short and far less ignition timing is needed. On the intake side, the dwell time gives the benefit of better timing the intake stroke with the breathing of a 2 valve head. On a 2 valve head, it takes a bit of time for the air to start flowing. Low lift numbers are nowhere near as good as 4 valve heads, where decent airflow starts much sooner. You could also change the rod ratio to better match the head. And obviously, the cam also plays a big part in this. With the 2 valve head, as the cylinder goes through overlap, the exhaust backpressure could pollute the intake charge because of the poor low lift flow. If you just added more overlap to the cam, the BSFC goes to crap because of reversion and the engine becomes more "peaky." These effects are obviously for all out race engines. On street engines the noise is one of the main issues. FWIW. YMMV

A common number for the amount of offset is 0.050".

The way you get the noise is the piston rocking because of the cylinder pressure. If the piston hasn't rocked yet, the combustion event exaggerates the rock and the associated noise. If the pin is offset and the rock has already occurred, that noise is minimized.

I see a valve relief in the piston picture. That suggests each piston will only work in one orientation. Anti slap might make sense in a Turbo, but the better breathing of the opposite offset on a forced induction engine doesn't make sense to me.

My VW 1600 and 1775 race motors were so loud you couldn't hear piston slap if you tried.

I think the source of the noise has yet to be identified.

Exactly on pinpointing his noise. Although none of us like the look of the bearings or their thrust surfaces, it's not the source of his noise.

Hey guys. My apologies on not getting back in groove with responding to these questions. Just had a busy day today.

Yes I did use JE pistons in LN cylinders, and I did have valve reliefs cut in the pistons, and I did double check my photos from the build and they were all orientated with the large valve relief at the top.

Interesting discussion on the offset pin though.

I do have some markings on the case where the chain goes through the case on the way to the chain housing. There were some on it when I took it apart time #1, and I found an OK photo from the first time that I'm going to compare with the current setup. I did use new chain gears on the intermediate shaft and the main cam gear. I did not alter the idler arm gears.

I'll get back to the rest of the questions asap.

Thanks again for all the help!

I do hope you get to nail the cause before the rebuild. I take on board what Neil says (as do you) with gold plating. But I could not sleep if rebuilding again and not knowing where it went wrong. The worry is inadvertently making the same mistake twice. With these complex engines, could be the simplest of things to overlook. Good luck and commiserations. I think we all feel the pain, knowing the hrs and $s to get that far. Can't add anything really - agree the source of the muck is an issue but unlikely to be the cause of the noise. The torn bit on the thrust bearing would worry me.
I did a crankshaft up rebuild on my SC about 10 yrs ago. Ended up with a noise and could feel a knock in one cylinder. Worried me enough to tear down the top half again :-(. Found nothing. Put back together and still running great 30k later, no noise, no oil burn, no leaks. Explain that. Don't bother - you have enough to contemplate.
Best of luck
Alan

I've taken apart several 70-80s Ferrari motors that were 'running fine', just worn. No clicking sounds, still on factory builds and internals, and found rod and main clearances far and away out of factory clearances with upwards of .005. One Boxer engine had .008 on one of the main journals. Saw a Countach engine with the same main bearing issue. They ran fine before. Bizarre that some of these issues do not audibly articulate themselves yet some other seemingly mundane issue does.

What type of oil filter was being used when the engine was first run? I say this because some filters have a constantly open internal bypass, or can have a very weak internal bypass, meaning unfiltered oil is allowed to just re-enter the engine if a certain pressure is realized. All that fresh engine shrapnel heading straight back into the engine can cause the damages in question sans the oil ring.

Without going thru the pages again, I think your original engine before rebuild, did not have that kind of trash wear/damage? If that is correct, the damage has to be from the rebuild, not trash missed in the clean up. Seems like your engine was cleaned out pretty good. Maybe some small bits (hoses etc) missed, but the trash has to have come since reassembly. If that is correct, the source should be obvious. Has to come from somewhere. Can you post clsoe up pics of the top and bottom halves of the bearing that seems to have damage. May be poking at shadows, but this has to be solveable .
Regards
Alan

"I've taken apart several 70-80s Ferrari motors that were 'running fine', just worn. No clicking sounds, still on factory builds and internals, and found rod and main clearances far and away out of factory clearances with upwards of .005. One Boxer engine had .008 on one of the main journals."

If the oil pump has enough capacity (volume) to maintain oil pressure at the large clearances and a high viscosity oil is used that is entirely possible. Might be a little noisy on start-up though.

I'll check the endplay of the crank with the bearings in the case, ASAP. Might be a couple days. I haven't pulled any bearings out or off of the crank.

I did use Porsche bearings when I rebuilt the engine. My understanding is that they are 996 GT3 bearings.

Here are the small ends of the #6 Rod There is a little spot that looks rubbed a little bit in the first photo. But nothing that says to me this was worn very badly and knocking.

http://forums.pelicanparts.com/uploa...1562005978.JPG
http://forums.pelicanparts.com/uploa...1562005978.JPG

Hey Jamie,

I'll look again at the layshaft gear. It looked Ok when I first inspected it, (no pitting or cracked teeth).

I did use new chains, and new sprockets.

The chain (particularly 1-2-3 Side) could have been rubbing. The case definetly has some wear on the pathway between the IMS and the Cam sprocket. Only problem is I'm just not sure if this wear was there before or not. None of my old photos of the case have this area photographed too well. I do remember there was some wear on this area, but I genuinely can't remember if it was this bad or not. I totally remember the green arrows, I just can't recall if the orange was there before or not.

http://forums.pelicanparts.com/uploa...1562008956.jpg

I haven't taken the heads off the cam towers yet. When I do I'll take a better look at those. I don't think a valve is loose but will check.

I only used Mahle filters on the car.

I did have one idea of shrapnel. I did use my original 3ldz on the car first after the rebuild, and had to have my drip tank modified to have a longer neck to allow for the bigger borg warner turbo. I tried to clean this out pretty well before I put it back in the car, but maybe there was leftover material from when someone welded on a longer neck. Possible that is where it came from.

As an armchair quarterback here...

Looks like something was VERY misaligned in your case...

You wore out your thrust bearings... You wore out the thrust surface of the IMS... and your chain ate into the case...

Could you have put the cam gear sprocket on wrong?

If your chain alignment were WAAAYYYY off, that might explain the IMW wear, chain wear, and possibly the main thrust bearing wear. Then, the aluminum shrapnel where the chain ate the case, destroyed the bearings...

Might also explain the knocking, as the chain was hitting the case...

You sure its the right chain you bought? Cam gear on right (one is supposed to be inverted on install)?

I prefer a clean space. This was for cams. Keep it clean guys.

http://forums.pelicanparts.com/uploa...1562013382.jpg
http://forums.pelicanparts.com/uploa...1562013403.jpg

Hey guys,

I know this is not really relevant to my build as I used JE pistons and not stock pistons.

But earlier in the thread we did have a conversation about the offset in piston pin. I am working on building an excel worksheet for all the measurements I have to take, and came across this bit of information from the workshop manuals.

Appears as though the factory did offset the pistons in 930's at least. I took a photo of the page in my workshop manuals:
http://forums.pelicanparts.com/uploa...1562089698.jpg

Bingo - flat topped pistons, no valve reliefs, physically you can install them with the arrow pointing either way, but with a pin offset one way is anti-slap, and the other not.

Were all the arrows (or whatever the installation mark is) pointing at the flywheel?

But do I remember this engine ran fine for a fair while, then developed the sound, which (perhaps serendipitously) led you to disassemble it and find the bearing issues?

Those marks on the chain housing don't look good. Shouldn't be any at all, ever. However, if the chain wheel on that side was installed out when it should have been in, again I'd have thought you'd hear it right off the bat. Was the tensioner nice and stiff on that side? You have to squeeze it in a vice to reinstall the pin so you can reinstall it?

I don't suppose you saved a sample of your oil? Which could be analyzed for metal content?

Interesting. I just pulled an old Mahle 930 "97+" piston out of the shed. It is indeed offset 1mm. This particular piston had valve reliefs in it too. After measuring, the valve reliefs are the same diameter (arc) of the intake valve, so it could presumably go either way, with a mark similar to that in the pic.

Measure the offset on one of your JE's. It could have been that you installed one upside down and didn't realize it.

Hey Walt,

My ticking noise started right away after the rebuild. I voiced some concerns but most thought it was just valve related and would go away once they were adjusted.

I did not have stock pistons so that is one mistake I couldn’t have made. My pistons had larger reliefs for the intake valve so that made it easy to install them right side up. I also checked my assembly and disassembly photos and they showed that I had the pistons orientated correctly.

I do have some oil saved and some pockets in the engine that Are still there.

After looking at the case for a while today pondering things I genuinely believe that wear on the case was from a time in the past, and not this rebuild. Simply because there is still sealant on the edges where the chain housing meets the case that would have been worn off had the chain been rubbing. In addition to that my chains show no indication of being temporary grinders. I’m sure the steel is harder than the aluminum case but I’d imagine they’d show something from that.

Any reason why it would only make the noise when it was warm? My ticking only happened as the engine heated up.

I think as Neil mentioned this build is going to have to be carefully measured and everything checked and rechecked.

My tensioners were good when I put them in.

I’m almost 100% positive the cam gears were orientated correctly. I did use the stromski straight edge tool to measure them when I assembled it. I’m also pretty darn sure the gears on the intermediate shaft were put on correctly, but those I can check.

Thanks.

OK, lets assume that everything was installed correctly. I thought the noise was from #6 cylinder area, do you concur?

If so, that narrows the microscope down to a single cylinder, and you have 5 "good" ones with which to compare. Check piston to wall clearance, small end rod bushing, big end bearing clearance, piston skirt, etc. Compare those to the other cylinders. It's gotta be something. If these engines weren't so darned labor intensive, I'd just say swap parts with one of the quiet cylinders. But at least you have those for comparison. And measure the pin offset on the JE's, just for comparison.

Just a thought on the ticking, could the non-broken #6 oil ring have been clacking back and forth in the groove as the piston reversed direction? It would be somewhat non supported for the portion that was missing the other side.

I've had ticking from improperly reground cams.

Ok crazy idea, don’t even know if it’s possible...

Could your chain have been riding on only one sprocket of the intermediate shaft?

It’s supposed to ride on both, as it’s a double chain...

I was throwing on my cam thrust plate today, in my eternal rebuild.

Somehow the chain popped of the ims sprocket. It was a bear to get it on. At one point, it was riding on only 1 sprocket not two. Had to take all the chain ramps off to put on properly...

This is only a theory, and I have no way of knowing if it’s even possible...

If you assembled the motor with the chain on one sprocket, could the motor spin over, grind the case and sprockets enough to throw debris all over, then pop onto both sprockets???

Sure would explain your case being ground down, the shrapnel, and everything else...

In this scenario the cam sprockets measure out correctly. The chain is on the cam sprocket correctly...but it’s shifted on the ims double sprocket...