Timing chain slap/rattle BAMBOOZLED

[jakeb]

I am guessing the passage to the tensioner or maybe one of the check valves.. I really have no idea. The marvel broke it down and it is all good now.

Been tuning more and upping the boost. It's a built lower compression m42 in a 2002. CP pistons, MS3 pro, GT28RS turbo, etc etc

[roguetoaster]

glad you got it fixed! the timing chain system can be bumfuzzling

Seems like a great word to describe automotive conundrums.

I too would like to know which passage blocked the entire oil system.

[bmwman91]

Which oil passage did the stuff get stuck in? I'd think that the filter would have got it, unless it was jammed up somewhere in the sump/pump.

[squidmaster]

glad you got it fixed! the timing chain system can be bumfuzzling

[jakeb]

Well the issue was a chunk of RTV..well "the right stuff" stuck in an oil passage. After we pulled it all apart we ran it and there was no noise... drained pan again and there was some broke down (from the marvel mystery oil) bits of sealant. Put it all back together and it has been quiet sense....

[bmwman91]

Can you get some photos of the timing case assembly with the covers off? I always forgot to take pictures when I did overhauls, and every now and then it would be handy to have photo references of positioning and stuff.

[jakeb]

Yes all guides are new and yes longer bolt there. I remember putting it in and it being too short.

So we pulled it all apart, ran it with the covers off (what a mess) and no noise.... Dropped the oil pan again and there was some more bits of sealant in the pan. But much more dissolved from the marvel mystery oil. Getting more oil this morning and will start again with the cases off. Then put together and start here and there as things go on. BUT if there is no sound this morning I am guessing there was some debris in an oil passage and causing the issue..... At least that's my hope before I push it into the river.

[bmwman91]

Thanks, it would be good to know what the cause is.

Did you install all new guides and stuff? The long driver's side one was updated from the metal+rubber design to the plastic+rubber design, and in doing so the very top screw needed to be changed from a M6x40 to M6x45. Many people reuse the original shorter one which strips out of the head and leaves the top of that guide loose.

Other than that, I cannot think of what else would be the reason.

[jakeb]

Well I think the issue is something with the chain guides themselves. I have another m42 swapped 02 here. I put a tensioner in that and it makes zero noise right from start up. I cannot see oil pressure getting to the top of the head that quickly. Has to take a second or two....

So...the spring in the tensioner should be enough to hold the chain tight. My theory now is that maybe a rail...deflector rail (later m42 case) came loose and the chain is a little looser than it should be. So then when the engine starts I get the noise then oil pressure comes up and pushes the tensioner open more. So today the front of the engine gets to come apart. Yippee!!

Will post what we find as I hate when the issue is solved and no one posts what it was.

[bmwman91]

Aah yeah, you are right, the tensioner is in the head not the case. I was thinking of the oil sprayer that shoots oil onto the chain as it slides up the tensioner rail.

So as far as I know, if the relief plunger is stuck in the UP position, oil pressure will be a little too high since it can't recirculate. The plunger is basically the oil pressure regulator. The real danger is when it gets stuck down (open), at least as far as I remember.

[jakeb]

Bore of the tensioner itself or where it goes into the head? The tensioner doesn't move in the bore of the head at all. Well it shouldn't at least.

Could the chain somehow be too tight and pushing the oil out of the tensioner?

I dropped the lower pan..and well upper too. There was some debris in the oil...some was assembly lube but others looked like gasket material or little bits of rtv. Cleaned it all out...checked pressure valve (moved fine and is the new style). Cleaned entire pan, reinstalled, put a quart of marvel mystery oil in it and the rest oil. Started and made the clattering sound. Took maybe 10 minutes then went away....

Let it idle 10 minutes. Sat for a couple hours and started again...noise came back. Let it idle for a good 20-30 minutes to circulate the MMO and that is where we are now....

Letting it cool down and will start again.

Not sure what the next step is other than pulling the front of the engine off to see what the chain is doing. Maybe start it with no front covers....

[TobyB]

M44 tensioner?

All I got is that I would think the spring in the tensioner would keep things tight and
quiet, in conjunction with residual oil in the bore, until pressure came up.
So, binding tensioner, badly scored bore?

t

[uturn]

Maybe pull the cams and chain, crank it to see if this passage is not clogged. Careful oil might spurt out of all the other passages. I'd like to see the mess it makes!

[uturn]

Took a picture of the oil passage to the tensioner. Under the exhaust camshaft tray.

[jakeb]

Are you sure about oil to the tensioner??? The tensioner is connection is part of the head and not the block that would have the front cover...