I thought of another question. Once I get the valve cover off, if I find that a rocker shaft has backed out, I suppose its mandatory to disassemble that rocker assembly and check for damage? And is it a major PITA to tap the shaft out with the engine in the car?

You are making a much bigger deal here then necessary. You are allowed...But you have not arrived at the problem so lets find that 1st.
I guessed maybe A rocker shaft...It would make one hell of a racket if one side was loose
that said i have removed all mine in the car one time to install the RSR "O" rings. Was no problem.
the biggest deal if it is the rocker shaft, is the rocker housing broke?

Thanks for suffering through my noob questions. Just hoping to be prepared... ordered Wayne's and Bruce's books along with valve cover gaskets from our host yesterday... expre$$ shipping takes a week to me so you can see why I'm trying to think ahead. Plus you guys stateside are 6-10 timezones away... ;)

I was not flaming you. Just saying find the problem and we all try to be a brain trust to the fix
If it is a rocker shaft, ask john walker what he recommends the torq to be.
After my rebuild I found several loose and decided to go the "O" ring seal route. I torqed to Jn specs expecting something to break...all lived happily ever after.
John owns a very honest shop seattle area. one experienced smart feller. If he says do it just do it.

For reference, this is a good thread for rocker shaft, with some good pictures and the torque setting recommendation by Mr Walker.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/490554-rocker-arm-shaft-installation.html

There it is 20 ft LBS !
It does sound scary. but it works !

I know you weren't flaming me, its all good! :-)

Now I just need to wait for a free weekend to get in there... I'll report back of course!

Awesome, thanks!

I'm a big fan of the turbokraft rocker shaft locks. Especially after putting the orings in.
Lets still hope it's just a really messed up rocker adjustment.

UPDATE: I finally got time to dig into this.

Drained oil and removed upper and lower rocker covers on the passenger side of the engine. Oil has run almost a year/2000 miles, looks clean. Magnetic drain plugs in both tank and sump had no visible debris, wiping them clean made the paper towel grey, but nothing worse then that. Nothing chunky in the oil. Considered removing the sump plate but forgot to order a gasket so that has to wait.

All 6 rocker shafts on this side are in place as they should be, and do not leak oil. No broken studs or anything that seems out of place.

I checked the valve adjustment on both intake and exhaust for cylinders 4 and 5 with those each set at TDC and they seem ok (.004" feeler just fits.) This was about 5 hours after running the engine warm before draining the oil, so I will check again tomorrow when everything is good and cold.

The only thing that I could find that concerned me was the side to side play in the rockers themselves. When the rockers are at the camshaft backside and therefore not in contact with the cam (so free to move) there is a fair amount of play, probably 1mm side to side, maybe more. They clack quite a bit when pushed back and forth. Not sure if this tells you guys anything, since side to side isn't the normal movement of a rocker.

All advice appreciated before I get back to this tomorrow! :confused:

They are allowed a bit of sideways movement. Not an issue. Check the rocker shafts are all symmetrically located - ie none are moving out of their housings - while you are in there. (You will see they have a slightly asymmetric location in the housings - near flush on one end and some room (5mm?)to spare on the other). It is just something to check - esp on a fresh engine - sometimes they do move and you want to catch them early, if possible.
Broken valve springs are hard to spot - but since you have it open now. Usually the inner spring breaks (if any break). With a good light, peek into the coils and see if anything looks odd - you will often be looking for a slightly odd line on one of the coils. But the sure way to test is get them to the unloaded position and lever down on the top of the valve. I can't quite remember how I did this last time - you may need to bolt something down on a cover plate stud or something and lever with a screwdriver. Whatever works, but don't lever against any machined surfaces. If a spring is broken you will definitely feel the difference. You are just levering til it moves - just til the valve begins to open. No need to go any further. If nothing obvious arrives, another thing to try is to look for slight exhaust/head leak. Best way is get under car while idling and move your hand around looking for some hot gas. A small leak at the head or your exhaust gas reticulation plugs can make a serious sounding noise. If at the head you may find a bit of weepage at the cylinder interface. (You can have a look now while you have the car jacked up for oil drain- you are looking for any signs of gas burn/weepage at the exhaust gasket/headers, EGR plugs and cylinder interface)
Check the clearance on #6 valves while you are at it.
Alan

OK, back to it today, fully cold engine. Rechecked valve clearances on 4-5-6 for both the intake and exhaust and could just barely fit the .004" feeler. So I left the adjustments alone for now. As mentioned in my post above the rocker shafts are all perfectly in place and do not leak oil. Everything looks pristine under there though this side is where I hear the clack.

Nothing visibly wrong with the valve springs either and they are nearly impossible to compress.

I also pulled the sump plate and screen and it was clean. Found a 1mm X 4mm piece of something that looks like a piece of gasket material, and a tiny 1mm piece of something amber colored and brittle. Hard to call these major debris, I was almost hoping to find half a chain ramp in there so I wouldn't still have a mystery on my hands.

Fudge. Only I didn't say fudge. :confused:

I think your have to pull the timing chain covers as i am sure it is chain ramp material.

Can you post a pic of the 1x4mm bit - may be able to tell if chain ramp or gasket material.
Alan

I can take a pic tomorrow. Its fibrous like paper, thus my reference to gasket material. The other piece could be ramp plastic I suppose. It stinks if these can go to pieces so quickly after a rebuild with new chains and ramps. Tensioner maybe?

It bears mentioning that the noise is distinctly metallic in nature, like tapping a socket extension against the case, but not so sharp a sound. I was really betting on the valve train being the culprit. Of course, I haven't opened side 1-3 but the noise doesn't seem to be coming from there. Was strongest from the rocker cover stud at #4 using the screwdriver-ear test and there was nothing to see under there. Screwdriver-ear test on the chain covers revealed no clack, just chain noise.

If I have to pull the chain covers can it be done without a partial drop, or is that the best way? I have a lift.

You can remove the chain covers without dropping the engine - but you have to remove exhaust, rear bumper etc and lower the rear of the engine a bit (on the engine mount bolts).
A pic might help but I suspect you have gasket material.
I wonder if a chain tensioner has failed (as distinct from the ramp). These are spring loaded (and serviceable). I am assuming yours have not been upgraded to the hydraulic ones. If they were you would have small steel lines exiting from your chain covers to the top edge of your engine case. If the tensioner fails you will get excessive chain slap, but no broken parts (at least initially).
Alan

Having just read your post again, it seems not to be coming from the chain covers, which leaves us with internals again. But before you did anything else I would close up the valve covers and run it again while underneath - looking for an exhaust type leak. They can sound like a clack too. I recall now, to check the valve springs I ended up bending a piece of flat steel to lever against the top of the stems. You may like to try that before closing it up again.
Alan

Right, having listened to the noise - and I can hear it, I had something similar once in my SC after I rebuilt it. I suggest checking for no broken springs then close it up. Run the engine then get underneath while going. Make sure no exhaust leaks anywhere, then with your screwdriver place it on the cylinder and heads of #s 4-6. I am sure you will isolate it to one of those. You may even be able to feel it with your fingers (briefly). This will tell you whether it is in the chain case, or specifically where it is.
Alan

Thanks Alan.

I have the Carrera chain tensioners. I have previosly felt for exhaust leaks also and found none. With the screwdriver test the clack is a distinct mechanical and metallic sound. I can't imagine that an exhaust leak would sound like that through a screwdriver handle?

I tried compressing several springs today and could barely get them to budge with respective cylinders at TDC. But these are really difficult to get to and see. No debris in the rocker covers either.

Just pull the chain covers and take a look.
simple.
I am sure that is where your problem is.

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

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

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.

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...

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

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.

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.

+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.

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.

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

no sure pulling plug is safe
 

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?

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

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..)

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

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

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... :rolleyes:

Photos:

http://forums.pelicanparts.com/uploa...1411235745.jpg
http://forums.pelicanparts.com/uploa...1411235768.jpg
http://forums.pelicanparts.com/uploa...1411235780.jpg
http://forums.pelicanparts.com/uploa...1411235789.jpg

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

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.