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Draker

Rebuilt L20b Timing chain noise (by the oiler)

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I've started to notice a bit of timing chain noise on my rebuilt L20b. It sounds like a diesel. Motor probably has around 800-1000 miles on it. I installed a new OSK timing set on it with new guides, tensioner, chain, upper and lower sprockets, etc... 

 

I've been hearing a noise that I thought was valves/rockers. Breaking out my stethoscope, It's clearly the timing chain. Specifically down by the lower sprocket/oiler. Post rebuild I had great oil pressure. I have not checked it since, but I'll do that tonight for sure. I've popped off the valve cover and looked at the chain, everything is tight. I didn't bump the starter to see if it slacked up. I'll do that tonight as well. My guess is that might not be a good test anyway since the tensioner would not have any oil pressure.

 

Anyone have any thoughts on this? I'm going to put 600+ miles on this engine starting tomorrow.. I'm not too worried because the chain is still tight, and everything is new. If the oil pressure is good, I'm rockin it.

 

Oil changed 100 miles ago.

Oil: Delo 400 15w40.

filter: purolator gold

 

 

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I assume you are familiar with how to set the geometry on the timing chain guides...right? So let's assume it was all set up properly, there is a possibility that one of the guides has broken, or a bolt has come loose/broken and the guide is slapping. I have seen both of those problems before.

 

If the geometry was not set up properly, I have seen guides and tensioners wear out prematurely.

 

Have you checked to make sure the bolt holding the crank pulley is tight? How about the bolt holding the cam sprocket?

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I assume you are familiar with how to set the geometry on the timing chain guides...right? So let's assume it was all set up properly, there is a possibility that one of the guides has broken, or a bolt has come loose/broken and the guide is slapping. I have seen both of those problems before.

 

If the geometry was not set up properly, I have seen guides and tensioners wear out prematurely.

 

Have you checked to make sure the bolt holding the crank pulley is tight? How about the bolt holding the cam sprocket?

 

Yes, set the geometry. The noise is coming from the lower sprocket on the side with the flat guide, not on the tensioner side. I pried on the flat guide to see if it was loose. From what I could see, everything looked great.

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Both Cam and crank bolts are tight.

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Post video with audio, I would fire it up without valve cover on for few seconds (just idling) and take a peek down the front cover with a strong light to see how the chain behaves under normal operation, as long as its idling the oil mess won't be bad.

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How about the oil pump/dist drive shaft? It could be worn and making noise.

 

It's possible, but it looked fine. 

 

Post video with audio, I would fire it up without valve cover on for few seconds (just idling) and take a peek down the front cover with a strong light to see how the chain behaves under normal operation, as long as its idling the oil mess won't be bad.

 

Not a bad idea. I'll try this tonight. I didn't want to spray oil everywhere.

 

 

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You say engine noise is loud enough to sound like a diesel??

  Get out your timing light and run engine while watching light pulses..  If the sound ,, sounds like a lifter rattle but twice as fast it might be a rod bearing..  Have you pulled any plugs and looked at them to see if electrode broke off and is rattling around in there or something weird?? I have seen shit get down into cylinder that sounds like a rattle ,,,

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You say engine noise is loud enough to sound like a diesel??

  Get out your timing light and run engine while watching light pulses..  If the sound ,, sounds like a lifter rattle but twice as fast it might be a rod bearing..  Have you pulled any plugs and looked at them to see if electrode broke off and is rattling around in there or something weird?? I have seen shit get down into cylinder that sounds like a rattle ,,,

 

I've pulled plugs a few times. In the last 1000 miles. Everything is fine.

20150729_185718_zpsxvzql2po.jpg

 

The sound is definitely the chain and the sound goes away off idle. I've pinpointed the sound using a stethoscope on the front cover.

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Stoffregen, you have been inside a lot more L-engines than I have. 

I have an idea on how set timing chain geometry, but I am not sure if I am doing it right.  Can you briefly describe how you set it up?  This would be for my benefit, and a lot of other people who read this thread.

The timing chain on my daily driver 521 Ratsun rattles until the oil pressure light goes off.   After that it is quiet.

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Set using Hainz's video.

 

IMAG0515_zpspkmnw8u7.jpg

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It's possible, but it looked fine. 

 

 

 

 

Not a bad idea. I'll try this tonight. I didn't want to spray oil everywhere.

 

 

It won't be bad, I did it to confirm all lubrication points were squirting oil, while you have the cover off run some Lucas down the chain and see if it affects the noise level.

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Fuck to me that looks good

 

only other thing is a long bolt from the stat housing hitting the tight side guide pushing it in.

 

with no oil pressure thaT SUCKER(YENSIONER) IS TIGHT, BUTTED RIGHT UP TO THE HOUSING

 

 

CK THE DISTRIBUTOR.or under neath it

But Im only guessing now

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The oiler did have some wear, but not horrible. Also confirmed the oiler is not plugged.

 

I'll check the housing bolt too.

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The mystery noises dime!

 

Dude, tell me about it!

 

Sans that Cam sprocket bolt on the first startup, I take the time to make sure I tighten every bolt. I torque everything,  if I can find a spec. Yet everything is making noises... lol

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did you loose a bolt in there?

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did you loose a bolt in there?

Naw, sounds goes away off idle.

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That tensioner has a super stiff spring on it. I worked out the oil pressure on the area of the piston behind the shoe and it really wasn't much even at 50 PSI

 

If it's one cm across then that's 0.78 sq cm area. There are 5 sq. cm in a sq. in so 7.8 PSI @ 50 PSI It really isn't much..

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That tensioner has a super stiff spring on it. I worked out the oil pressure on the area of the piston behind the shoe and it really wasn't much even at 50 PSI

 

If it's one cm across then that's 0.78 sq cm area. There are 5 sq. cm in a sq. in so 7.8 PSI @ 50 PSI It really isn't much..

 

That's good to know actually. Thanks Mike!

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I think the oil behind it is to act as a shock absorber and any leakage just lubes the chain.

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The pic shows a nicely set up geometry. Two things to look out for: 1 - there can be so much pressure that it squshes the chain into the tensioner. 2 - when the head is torqued down the tensioner pushes out a bit.

 

Daniel - If it looks like that, everything is hunky-dory, but if it doesn't, sometimes you need to slot the holes in the guides, especially the curved guide, to get it to line up right.

 

Draker - How much oil pressure do you have at idle? Do you have an external cam oiler/spray bar?

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Fuck to me that looks good

 

only other thing is a long bolt from the stat housing hitting the tight side guide pushing it in.

 

 

 

 

I seen this happen with one of those upper bolts before ,, can't remember what kinda sound it made,, or when it made it,,  but it did.. Although it seems like it did it right from the get-go not a few hundred miles down the road.

 

 

While this thing is stressing you out only days before it's big trip,,,,,,,,,you have to just remind yourself how nice that Shasta camping trip is going to be.. 

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The pic shows a nicely set up geometry. Two things to look out for: 1 - there can be so much pressure that it squshes the chain into the tensioner. 2 - when the head is torqued down the tensioner pushes out a bit.

 

Daniel - If it looks like that, everything is hunky-dory, but if it doesn't, sometimes you need to slot the holes in the guides, especially the curved guide, to get it to line up right.

 

Draker - How much oil pressure do you have at idle? Do you have an external cam oiler/spray bar?

 

If I remember right, it was around 30lbs. But I don't remember if that was at temp. Diego might remember, he was there. The pressure was really good. No external oiler on the cam.

 

 

I seen this happen with one of those upper bolts before ,, can't remember what kinda sound it made,, or when it made it,,  but it did.. Although it seems like it did it right from the get-go not a few hundred miles down the road.

 

 

While this thing is stressing you out only days before it's big trip,,,,,,,,,you have to just remind yourself how nice that Shasta camping trip is going to be.. 

 

I'm not overly concerned, when the RPMs climb the sound goes away. I'll bring spare parts and tools and we are traveling as a pack. I'll see if I can get a good video of the sound posted. It's tough because all you really hear is wind noise down in the engine bay.

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Ya oil pressure was right there at the 30psi mark estimated water temp around 180℉, idle was between 800 and 900 range if I recall correctly...

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