Clackety clackety clackety clack

[47silver]

the drivers side tensioner does not look like it is extended much at all.
is the chain tight?
can you leverage the ternsioner upwards to make the chain tighter easily?

[evan9eleven]

Originally Posted by 911pcars

Can you compress the tensioner shaft? They look a little extended, but if they're tight, should be okay. The driver side idler arm is normally close to the top of the chain box anyway. However, i too close, it will hit and make noise. Sure? Crank the engine while observing the chain, sprockets, etc.

I think you've done all you can for accessible diagnosis. Make sure you haven't overlooked the basic looks (e.g. distributor shaft vertical play, ......)

Sherwood

Chains are tight, I'll try cranking it and observe what happens. Checking the basics: so far its spinning the fan/alternator with no belt; removing rocker covers on the right ride and checking everything there; checking for exhaust leaks. I guess I could pull the left side covers, but the noise was very clear on the right and not audible on the left using the screwdriver listening test. How do I check the distributor shaft for play?

Originally Posted by afterburn 549

Is there enough shoe left ? Looks flat to me. The adjusters look like they are at the end of the extension.

Worn chains ? ( Too long)

Chains and ramps were replaced 4k miles ago so they are basically new (see my original post with parts list.) Ramps look spotless, with the raised "tracks" clearly visible. I have no idea how far these should be extended?

Originally Posted by 47silver

the drivers side tensioner does not look like it is extended much at all.
is the chain tight?
can you leverage the ternsioner upwards to make the chain tighter easily?

Chains seem tight to me, I can't get them to move much at all (either just the chain or by leveraging the tensioner.) I was able to compress the tensioner on the left side by less then 1mm, the right side won't compress at all.

[afterburn 549]

I am sorry i can not go back and read 5 pages, just trying to help.
Did this noise come on just recently ? ( I would guess)
Can you take a mirror and look inside and see if ALL the chain is on ALL the sprocket ? (not halve off )

[evan9eleven]

Originally Posted by afterburn 549

I am sorry i can not go back and read 5 pages, just trying to help.
Did this noise come on just recently ? ( I would guess)
Can you take a mirror and look inside and see if ALL the chain is on ALL the sprocket ? (not halve off )

Noise was noted on PPI, that was at 2k miles after rebuild. I've driven it 2k since then and the noise has not changed. Finally decided to investigate. Some new parts in the motor, lots (bottom end) that has seen 160k miles.

Chains are seated properly on the sprockets- you mentioned that the other day so I was sure to check.

Rebuild was done by a pro shop, but the PO ordered the bare minimum overhaul so I'm dealing with that...

[afterburn 549]

If you have gone 2000 miles ( with no change ) it must be not as big emergency as I once thought.
When you roll the engine over, the chain and sprockets must look all ok?
Perhaps recheck the exhaust system,........... i am sure you have.
But it is coming from somewhere that bothers you.

[evan9eleven]

I made a little video showing the tightness of the chains. Squeezing the chains like this I can't get the tensioners to compress more then 1mm in. The left side tensioner is further in then on the right side, but still pretty far out. The left side chain has more slack the the other side as well, the right side is really tight, left doesn't seem bad though I can force it to make a clackety noise as you see in the video..

The only other thing I discovered is that the idlers have a fair bit of space to move side to side on their shafts, I assume this is by design to help the chains and ramps stay aligned with each other.

As previously mentioned everything in these boxes looks pristine. I may just close them back up.

[afterburn 549]

Your starboard tensioner seems to leak oil and collapse out when you put pressure on the chain..
I am not at all sure how long they should hold static hydraulic residual , but it looks suspicious .

[911pcars]

Pressure-fed tensioners are like hydraulic lifters. Engine oil pressure constantly replenishes oil that bleeds out from the tensioner. While the piston rod is slightly extended but still firm, it looks okay.

The acid test is to run the engine w/o the china box covers and observe the chain at various engine speeds (e.g. idle to 2000 rpm). Sure, oil will be thrown and w/o a muffler, a little noisy, but it's only for a little while. Purchase some pastry for the neighbors. Lights, camera, action.

If the above is okay, button it up. Don't remember if this was already suggested, but with the engine at rattling rpm, short out each cylinder in turn (disconnect spark plug wire) and see if noise diminishes.

Sherwood

[evan9eleven]

So, tonight I put everything back together and filled the engine with oil. Went for a nice long drive, topped up oil level hot, and then tried pulling one plug wire at a time to see if the clack changed. Same result all the way around: there was much more clack noise running on 5 cylinders regardless of which plug wire was removed! Clack at idle is much less audible then oil-cap-removed slow idle, then I really hear it. Leaning towards just running this engine as-is another season...

[afterburn 549]

I would too

[Alan L]

try putting a screwdriver on each cylinder (with rear of car raised), then on each head. See if it isolates itself to one piece. I have had this type of noise go away all on its own before.
Alan

[evan9eleven]

Originally Posted by Alan L

try putting a screwdriver on each cylinder (with rear of car raised), then on each head. See if it isolates itself to one piece. I have had this type of noise go away all on its own before.
Alan

Will do, I'll get it on the lift and do some serious listening. Is a stethoscope worth getting too?

Also, is there any harm idling the motor for longer periods (say 15 minutes) with the oil cap off? I still read just over 1 bar oil pressure on the gauge in no-cap-slow-idle mode, but it does make me nervous.

[Alan L]

You don't really need a lift, nice but not really needed. Just jack the rear of the car up, put jack stands under the torsion bar ends, and lay under it. Screw driver is just as good as stethoscope for this. Place the blade end on the cylinders, then on the heads. I am quite sure you will isolate it. It should only take 5 minutes. (Been there, done that).
1 bar pressure is plenty at idle. For long periods you just need to watch the oil temp. But no need really to run it for 15 minutes.
Good luck.
Alan

[911pcars]

Suggest a long screwdriver to provide plenty of space between your ear and the warmish engine, heat exchangers, etc.

If there's a Harbor Freight nearby, buy their cheapish but usable mechanics stethoscope. Simple and handy to help isolate noises.

Sherwood

[evan9eleven]

So, I finally ordered a mechanic's stethoscope, should arrive soon. I'll do a thorough job of listening everywhere you guys suggested.

In other news I sent my oil in for analysis just for grins, since I was changing it anyway. Here is the report if anyone is interested:

[Pellesin]

I've bought a car just recently. The previous owner said something about a noise at the same side of the engine. Did you ever discover what the problem was?

[gjmascoli]

The suspense is killing me. I gotta know what was the cause. I'm hoping it was loose exhaust!

[Reiver]

This is an explanation but might not be the cause.
The Euro SC's 930-10's have forged pistons in nickies due to the higher CR. Forged pistons, in most every 'built' high CR V8 I've owned, have piston slap at idle that is the same kind of knock I hear in that vid. The cast US Alusils don't have this slap.
It goes away at higher rpm (not completely) but def gets quieter.
I have a 930-10 and it has a knock at idle, is freshly rebuilt by a pro...has fantastic leak down and goes like stink for the last 20k miles....also uses about 8-10 oz of oil in 3k miles.
I doubt you have an issue as this 'may' be your circumstance.

[Steve@Rennsport]

Mahle & KB pistons run very quietly, unlike JE and other 2618 pistons which need much more clearance.

Valid comparisons between Mahle & other 2618 forged pistons are impossible to make due to their totally dissimilar alloys and applications.

[Reiver]

Steve,
My experience is pretty shallow but I've listened to 2 other euro 3.0's and they both had a bit of slap/knock in each one. As they warm it goes away but not totally and is only heard at idle.
Another shop owner told me it's pretty normal.
OTOH, what's in the video might be anything as trying to compare recorded sounds always escapes me.