Need help - Loose Timing Chain

[Redd]

Originally Posted by GORDON.M3

The first thing is to find a proper mechanic to diagnose/re-do the timing. In past experience, many cars that have their timing tampered with have never been re-done properly. A good 80-90% of cars will end up throwing VANOS-related codes down the road again.

That amount of chain slap is unacceptable and something was done wrong when re-doing the vanos covers. Double-check the timing chain guides to see if it hasn't broken or shifted out of place, and I'm not sure but perhaps replace the timing chain tensioner?

Guides and tensioners all brand new. I checked the tensioner myself and it's working. Swapped tensioners left-right, problem does not follow the tensioner.

[spammysammich]

But the vanos units themselves were not replaced?

[Redd]

Originally Posted by spammysammich

But the vanos units themselves were not replaced?

No Vanos units were not replaced.

[spammysammich]

Are codes thrown while it is running? It is possible they are damaged internally from metal debris.

[spammysammich]

Personally I would not reuse an engine that had metal circulating in the oiling system. Too many places for debris to hide.

[Redd]

Originally Posted by spammysammich

Are codes thrown while it is running? It is possible they are damaged internally from metal debris.

But would vanos units cause slackness in the chain? I think not?

[spammysammich]

It might be a moot point; if you've run metal through those vanos units, they're fuct. I don't know any variable valve timing system that plays nice with metal swarf. I don't know any mechanic that recommends reusing a block that has had forbidden glitter come out of it. Does this make sense?

[spammysammich]

If you're looking for a mechanical reason why it won't time up, there are vanes inside the vanos units. If there is enough metal in the vanes/pockets to prevent them from moving to the correct position when you set timing, that could cause slack in the chain and timing errors in ISTA. As for clacking, it could be broken vanes in the vanos unit or a spun rod bearing from having aluminum run through the oil.

[Redd]

Originally Posted by spammysammich

It might be a moot point; if you've run metal through those vanos units, they're fuct. I don't know any variable valve timing system that plays nice with metal swarf. I don't know any mechanic that recommends reusing a block that has had forbidden glitter come out of it. Does this make sense?

Yes it makes sense. Believe me a used engine was top of the option list. However, none are available here. Malaysia has some weird law that requires an import permit to bring in an engine and those permits cost the same as the price of a used engine. So a rebuild was the only viable option without leaving the car stranded for God knows how long waiting for a used block/engine to be available in-country. It is what it is, the owner is trying to make the best out of a messed up situation.

[spammysammich]

I hope I’m wrong about this but if you haven’t completely flushed the block, oil pan, changed the oil cooler and rebuilt/flushed the heads to remove all the chewed up aluminum in that engine, your friend is just pissing in the wind. That engine is a boat anchor.

[charliev68]

Things don’t add up! The whole thing seems unKosher!

[spammysammich]

I think the lead may have been buried a bit. This motor had aluminum vanos caps that became detached, chewed up into little pieces and sent aluminum bits all over the inside of the timing covers and thus through the engine. The owner then attempted to just replace vanos related components EXCEPT for the actual vanos gears and install bolt on caps without throughly cleaning the engine thinking there wouldn’t be aluminum in the oiling system. Am I missing anything?

[e90sanmarino]

To the OP,

Has the mechanic confirmed the timing was done correctly? Are you able to set the tool flush? If not, its most likely due to debris in Vanos gears. I had trouble timing recently also and following deansbimmer recommendation to change out the Vanos gear solved the issue. Problem is, I think the Vanos gear for exhaust side is out of stock everywhere lol

[Redd]

Originally Posted by spammysammich

I think the lead may have been buried a bit. This motor had aluminum vanos caps that became detached, chewed up into little pieces and sent aluminum bits all over the inside of the timing covers and thus through the engine. The owner then attempted to just replace vanos related components EXCEPT for the actual vanos gears and install bolt on caps without throughly cleaning the engine thinking there wouldn’t be aluminum in the oiling system. Am I missing anything?

No no. Engine was completely stripped down to bare block. All bearings and seals were replaced and everything cleaned out. Basically it went thru a complete engine rebuild. However the VANOS gears themselves were not replaced.

[Redd]

Originally Posted by e90sanmarino

To the OP,

Has the mechanic confirmed the timing was done correctly? Are you able to set the tool flush? If not, its most likely due to debris in Vanos gears. I had trouble timing recently also and following deansbimmer recommendation to change out the Vanos gear solved the issue. Problem is, I think the Vanos gear for exhaust side is out of stock everywhere lol

I'll ask him to check the vanos gears again. After the rebuild the engine ran fine without errors for a couple weeks. Owner even brought it for a trackday with no issues. Just that the chain clack sound started getting louder so the owner brought it back to check and they saw the chain slackness. Til now there are still no Vanos/timing errors. Just the sound.

[Redd]

Popped by to the mech today. As of right now, they've reinstalled the chain more than 10 times. Each time following TIS procedures to the letter. Bank 1 chain is always loose. They have swapped tensioners, and even VANOS gears left to right and the chain slack is always on Bank 1. The only thing they didn't swap yet are the cams.

This is what it sounds like now. Zero errors.

[Redd]

Update - Problem solved. That amount of chain slack on Bank 1 is normal. There was nothing wrong with the entire chain assembly.

The noise was caused by a bad valve lifter. The mech replaced it and sound is gone.