Clackety clackety clackety clack

[Alan L]

No , I doubt the exhaust leak will sound like that through the screwdriver either. But they can sound like metallic clunk standing near the car. I know the springs are a bit tricky, but it can be done (I've done it). It is just useful to eliminate as much as we can, before having to dive into the motor. Nothing worse than tearing a motor down and finding nothing - ask me how I know -x2.
We have eliminated valve clearance and rocker shafts (both likely candidates). If we can eliminate valve springs that would be good too - not much left in the top end then. I noticed re reading your list , they don't seem to have done any head work. I was pondering a loose valve guide - I think someone may have already suggested that. This is unchartered water for me - I've never had that issue on a 911 (but have on a m/cycle and it sounded like your noise).
I'm not sure if you would see a sign or not - but while you have the covers off and are pressing on valve springs, try and have a look to see if the guides are all consistently situated. You may be able to see the top of the guide oil seal, near the base of the springs (I have a set of 930 heads on my work bench at the moment and can see the seals through the springs). Even better, while you are using 3 arms and 12 fingers to depress the springs, try and see if the seal moves at all.
You may not have quite enough leverage depressing the valves, if you are finding it hard to open them. They will crack open relatively easily if you have enough leverage. But just crack them open- no more - or you may run into a piston.
Failing all this, How far away is the shop that did the work/PPI? The noise is quite obvious in your postings - maybe it is easier to hear now than previous. Maybe they can go straight to the source?
Alan

[Alan L]

Screwdriver-ear test on the chain covers revealed no clack, just chain noise.

I'm just going on what he is posting, and at the end of the day, he will have to make the call. But based on what is posted above, you would have to suspect the issue is not in the chain covers, and there are other possibilities.
The parts list seems to suggest rod bearings were replaced - but I'm guessing the big ends were done, and not the wrist pin bushings. That may be a possibility on one cylinder (which you would pick up with the screwdriver on each cylinder). Or maybe a valve guide has come loose, that would be picked up, hopefully with the screwdriver on each head.
Hard to say. Or he could just pull the chain cover, like you say, and maybe find something.
Alan

[47silver]

Easy to pull chain covers. Get new bolts, nuts for the muffler connection. Get new gaskets and nuts, washers for the chain covers. Hardest part was removing the muffler bolts. I had to Drexel them off.

[evan9eleven]

Thanks everyone.

It doesn't look like they did wrist pin bushings, unless those were part of another kit of parts. But yeah, I only see the big end bearings on there.

I couldn't get much movement on the springs on this side, and I can't see in there very well either. No debris. I don't know what head work was done but I suspect it was minimal or not at all. So the valve guides remain a mystery, and though a spring could be broken, I really can't tell.

I have a fresh gasket and nut set for the chain covers. Looks like a major PITA to get to them but thats likely my next move since there is no oil in the car anyway. However, as Alan pointed out, I didn't hear the clack noise through the chain covers, so I don't know if I expect to find anything there. Wouldn't there be lots of plastic debris if the ramps were failing? And perhaps a problematic tensioner could cause this type of clack as you pointed out...

[afterburn 549]

Wrist pin or pins could emit a noise a double rap at top of stroke
Chaun related stuff is going to be very noisy.
Like said its pretty EZ to do a inspection.
That would be next on my list. If it is wrist pins you have wasted no time..if it is chain related then you found it.
Make sure when you inspect that the whole chain is running on the sprocket not just 1/2

[svenski]

I accedently stumbled on this thread in search for clutches,and noticed your video.

This sound Clack-Clack from your 1st video is the same as i have in mine 82 sc, altough i don't have the rattle when i shut the motor off as in you're 2nd video.

I had a thought that it was piston slap on my sc.
But i still haven't got the time to confirm it on my car(I dropped engine and tranny having clutch problems).

And i have been searching on 911sc piston slap videos on this forum but couldn't find a video.


I've seen the list of parts off the rebuild of your car.
There are a lot of new internal parts.
But they used a used set of cylinders and pistons.(makes me think)

But i'm just guesing at the moment and i'm no expert,maybe you can do a search on pistonslap.

I'll be folowing this thread closely,as it is in my interest also.

I hope for you it will be solved easely and soon.

[afterburn 549]

True , "some " clutches are noisy !
One way to tel,l is there a difference in noise by pushing clutch pedal up and dwn ?
I had a aluminum PP that had a rattle at low idle.

[toddu]

+1, my aluminum PP and lightweight flywheel make noise in neutral ONLY with clutch out. Don't think it's the TO bearing as it's brand new.

Todd

[afterburn 549]

Originally Posted by toddu

+1, my aluminum PP and lightweight flywheel make noise in neutral ONLY with clutch out. Don't think it's the TO bearing as it's brand new.

Todd

Agreed.

[Heinz911]

An easy way to check if it is either piston lash or a rod bearing without tearing down the engine is to take the spark plugs out one at a time. If the noise disappears when there is no plug, and therefore no compression, you no this is the failing cylinder.
You can do this with a running engine but it is easier to hear the difference if you crank it with the starter without ignition and fuel.

[svenski]

That's interesting mine was a aluminium pressure plate also.

But if i was evan9eleven, first i would try Heinz911 approach to pull a plug from a cylinder while idleing.

Easier then pulling an engine

[47silver]

you will be pushing raw fuel into your engine bay and with a spark plug firing loose nearbys i would not recommend it.
sounds like pre-ignition could it be fuel related as in too low of octane?

[afterburn 549]

Originally Posted by Heinz911

An easy way to check if it is either piston lash or a rod bearing without tearing down the engine is to take the spark plugs out one at a time. If the noise disappears when there is no plug, and therefore no compression, you no this is the failing cylinder.
You can do this with a running engine but it is easier to hear the difference if you crank it with the starter without ignition and fuel.

Same effect if you shut the spark dwn to that cylinder. ( that you want to listen to)

[RedCoupe]

I don't believe it's wrist pin bushings. I think that the OP told us that the noise isn't sensitive to throttle loading and unloading list a loose wrist pin bushing is. Like was suggested earlier, I would inuspect the entire timing chain. Something wrong with a master link? (If it has T-chains with master links..)

[afterburn 549]

My bet has been on the chains from day one ( after rocker arm shafts ).........and clackety clack?
I would think "HOPE" it is chain related .
Otherwise .......split the case

[911pcars]

Pull the chain box covers will you? It seems you're spending more time speculating than diagnosing. Yes, there are many parts that can go south and cause worry. Those who volunteer their personal engine history is anecdotal and may or may not have anything to do with your engine.

If inspecting the valve train and timing chain areas looks good, then that's about all you can do before going further into the engine (dis-assembly), especially since you've isolated the noise is from inside the crankcase as opposed to the clutch area or elsewhere.

The next major engine components to remove are the cam housings, then the heads. After inspecting those items, you'll be down to the short block. At that point, it's an easy reach to the con rods (even without splitting the crankcase).

Back to diagnosing, in order of easiest to perform:

For grins, remove the fan belt and run the engine, just to eliminate the alternator/fan as the noise source.

Yes, don't remove the spark plug and run the engine. There's raw fuel in the cylinder and perhaps an ungrounded spark plug wire. Air, fuel and spark = combustion, actually just fire.

To isolate con rod bearing failure noise, merely run the engine at the speed where noise appears, then remove each spark plug lead (at plug or distributor) one at a time. The offending cylinder will be the one where the noise decreases with no spark. The trailing engine rattle when the engine shuts down indicates something is loose.

Is the engine noise loudest at idle and decreases when engine speed increases? If so, that's a classic symptom of excessive slack in the timing chain (chain tensioner failure).

Once again, pull the chain box covers off and take a look. Hope for a malfunction here as it will be more expensive when you to begin to remove major engine pieces.

Sherwood

[evan9eleven]

Originally Posted by 911pcars

Pull the chain box covers will you? It seems you're spending more time speculating than diagnosing. Yes, there are many parts that can go south and cause worry. Those who volunteer their personal engine history is anecdotal and may or may not have anything to do with your engine.

If inspecting the valve train and timing chain areas looks good, then that's about all you can do before going further into the engine (dis-assembly), especially since you've isolated the noise is from inside the crankcase as opposed to the clutch area or elsewhere.

The next major engine components to remove are the cam housings, then the heads. After inspecting those items, you'll be down to the short block. At that point, it's an easy reach to the con rods (even without splitting the crankcase).

Back to diagnosing, in order of easiest to perform:

For grins, remove the fan belt and run the engine, just to eliminate the alternator/fan as the noise source.

Yes, don't remove the spark plug and run the engine. There's raw fuel in the cylinder and perhaps an ungrounded spark plug wire. Air, fuel and spark = combustion, actually just fire.

To isolate con rod bearing failure noise, merely run the engine at the speed where noise appears, then remove each spark plug lead (at plug or distributor) one at a time. The offending cylinder will be the one where the noise decreases with no spark. The trailing engine rattle when the engine shuts down indicates something is loose.

Is the engine noise loudest at idle and decreases when engine speed increases? If so, that's a classic symptom of excessive slack in the timing chain (chain tensioner failure).

Once again, pull the chain box covers off and take a look. Hope for a malfunction here as it will be more expensive when you to begin to remove major engine pieces.

Sherwood

Thanks Sherwood for your detailed and complete response, and everyone for the input. Much appreciated.

FWIW I work 12 hour days. So yes, I spend a lot of time speculating as I'm new to this and read and ask a lot of dumb questions so I can make good decisions when I have the time to finally do the work. I apologize if this tests the patience of some members.

There is no oil in the motor right now so I can't run it without the fan belt. I would have tried this earlier but just got a long handle ratchet that will just fit in between the pully and the bodywork. I removed the belt tonight to see what spinning the fan/alternator alone sounds like. Quiet. Tugging outward on a fan blade makes a clack, but my screwdriver-ear test didn't turn up any clack noises from the fan housing previously (at idle.)

The noise is loudest at idle and quieter with some revs. This is less so when listening through a screwdriver, but yes, idle is worst. Even more so if I pull the oil filler cap to get a really slow idle as in my original video.

I agree, lets hope its under a chain cover or else it will be an expensive winter project tearing down the engine.

evan

[evan9eleven]

UPDATE: Removed the chain box covers today to find nothing suspicious. Absolutely clean-- no fragments of anything, chains are tight, ramps look new (well they are only 4K miles old!) No signs that the chains have ever hit the case or anything else. Nothing seems loose. The tensioners are extended, but I have no idea how to test these for signs of failure. Advice?

So here we are...

Photos:

[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

[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)
Roll your engine in direction of rotation and watch things.