VAC Rod bearing condition after 13k miles

[deansbimmer]

You wouldn't be able to see anything ring related from below. Even at TDC.

I would still suspect timing system.

[Doc Oc]

Originally Posted by bluemonster

Which rod bolts did you use with your VAC bearings?

I used the arp bolts from vac.

[Doc Oc]

Originally Posted by deansbimmer

You wouldn't be able to see anything ring related from below. Even at TDC.

I would still suspect timing system.

Found that out Buttoned it back up tonight. What do you mean by timing related? Also noticed that when I turn the crank about every 1/2 turn there is a small clank. Not sure if this is the failure or just cam/crank noise?

[pbonsalb]

I have not taken apart an S65 or studied its known mechanical problems other than rod bearings, but would guess it is vanos timing related like a timing chain that has lost its tension for some reason such as a bad tensioner or guide.

[deansbimmer]

A very slight clack as you rotate is ok. The rotating can lobes will make a slight clatter against the lifters when there is no oil pressure. If the noise is more pronounced then it's likely one of the vanos is damaged. Remove a valve cover and see if any of the cans can be rotated independently. They shouldn't move. If they do then that vanos is defective. You can also check for broken valve springs.

[Doc Oc]

Thanks guys. Turns out the clank I heard was just the intake valves opening/closing. Still clueless. Valve covers coming off next.

Edit: got covers off, everything appears fine! Cams don't budge and from what I can see of the valve springs they appear fine. Boy I hate to sell this engine without knowing what's wrong.

[Doc Oc]

Sorry to be a post whore but I've been sitting here staring at the picture of those main bearings and thinking that the problem has to be in cylinder four or eight given how the back main bearing was by far the worst and then they got progressively better the farther away from the back cylinders you go. Does that tell anyone anything?

[deansbimmer]

Is your car a 6MT? Just thinking out of the box... It's possible the clutch has been damaged or the flywheel has been out of balance for a long time, causing the abnormal wear. The clutches are known to lose spring straps but that would be hard to mistake as a thrown rod unless the flywheel ate sh!t completely. I will say...You don't get wear like that from a sudden mishap to a ring land. It would have had to be a problem for many miles.

[deansbimmer]

You can button up the bottom end and use a remote starter to crank the engine for a couple seconds. It will help to localize the noise. Be sure there is plenty of assembly lube on the wear surfaces. If you feel adventurous you could pull the trans to inspect the clutch. Crank the engine with the trans out.

[Doc Oc]

It's a dct. Tranny is still in the car mated to the new engine though and running fine. The engine in question is the old one which is disassembled in the garage.

[admranger]

I got nothing.

[pbonsalb]

I like the broken valve spring or vanos/timing chain theories. A few of these motors have suffered broken valve springs. I dont recall the symptoms but you may be able to search for the posts.

[deansbimmer]

I didn't realize the engine was out. It should be easy to pinpoint the issue. Use a remote starter switch to rotate the engine, it will really help. Jump the starter solenoid...its wire is the 14gauge black wire in the white engine harness connector.

[Doc Oc]

Thanks guys, I'll put the starter back in and see what happens.

[///Mobbin]

Interested to hear the diagnosis. Also, curious what bearings you choose for the new engine?

[anerbe]

Any metal shavings in the oil? Based on your breakdown so far, I don't expect any.

[Doc Oc]

Originally Posted by ///Mobbin

Interested to hear the diagnosis. Also, curious what bearings you choose for the new engine?

Got a warranty for awhile so it's not something I'm going to worry about right now. Come time I might throw the VAC's in if they're reusable (got to have them checked out first), if not I'll probably go BE.

[Sneaky Pete]

Originally Posted by Doc Oc

Come time I might throw the VAC's in if they're reusable (got to have them checked out first), if not I'll probably go BE.

Surely you should stick to the VAC bearings having had a good experience with them...why risk the BEs with more clearance and an unknown outcome?

[Doc Oc]

I figured someone would ask as it does seem counter-intuitive. Probably going to sell the car before my warranty runs out anyway but my reasoning is this: I like the way the car runs on recommended weight oil in the super hot climate I live in. I ran 0/5w40 for the last year and the engine made a lot of noise and just didn't seem as happy. And possibly, whatever failed could be related to running a thinner oil than spec'd. Dunno yet, obviously, and may never know. But I've always been told you can run tight bearings and thin oil or loose bearings and thick oil, but not the other way around...so if I were to change bearings I think I'd prefer to run an industry standard clearance and factory recommended oil weights as opposed to the tighter VAC's and m1. If I didn't live where it was 95+ from late May through mid- Sept things might be different because I know there are benefits to running tighter clearances, but in the heat of summer, I'm not comfortable with w40 anymore.

[Doc Oc]

Originally Posted by deansbimmer

I didn't realize the engine was out. It should be easy to pinpoint the issue. Use a remote starter switch to rotate the engine, it will really help. Jump the starter solenoid...its wire is the 14gauge black wire in the white engine harness connector.

Just realized that the starter jump won't work...no flywheel However I cranked it with a monkey wrench as fast as I could and I'm hearing a pretty loud clack everytime the intake valves open on the 1st and 3rd cylinders. Not sure if it's the intake valves opening or the exhaust valves closing, but it's definitely only happening on those two cylinders. The timing chain seems to jump slightly when it happens. Anyone have a guess? I checked the springs for the third cylinder but it's impossible to see them on the first. I pushed down on all the lifters and nothing seemed out of the ordinary.

[Doc Oc]

Little update. Got the heads off today. Not sure what to make of it. Combustion chambers are very carbed up was the first thing I noticed. Also, notice the one clean exhaust valve? Not sure what that indicates. All pistons were tight with no vert or horizontal play and all bores were clean.

[deansbimmer]

I think your vanos is kaput.