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-   -   Strange sound from rebuilt engine... (https://rennlist.com/forums/993-forum/739444-strange-sound-from-rebuilt-engine.html)

Mike J 02-07-2013 04:39 PM


Originally Posted by Mike J (Post 10202744)

So the real question is to let it run a bit more to see if the lifter pressurize, or start to tear it down looking for visual clues? Tough one to answer, I would do a few things first like pull some easy to get at plugs just as a check to see how they look, I would then pull the DME relay and crank the engine to see if any metallic noises are made (it should be fairly quiet), and if you want to run it, I would spend some time trying to see where the noise is from using a mechanic's stethoscope (or in a pinch a long screwdriver held to the ear...). You can also do a quick compression test and if possible leakdown to see if the timing looks correct, if its way off the valves will not be seated at TDC.

Let us know how it goes, best of luck!

Cheers,

Mike

Ok, did you;
- quick pull of some plugs to check if they looked good?
- use a stethoscope to try to locate the noise?
- compression test (required no compressed air)?

#2 above is a good one because location may help - it also may be hard to determine. I doubt if its tensioners unless it's allowed the cam timing to be out by skipping on the sprocket, but keep confirming the direction is correct.

Lets review the rebuild a bit - did you do the valve clearance test? I seem to remember you had the index pin on the cams so they cannot slip, right? You timed to 1.0mm or ?

The noise is regular and with the engine rotation - I assume if you rev it up the noise frequency also increases?

I also agree to stop running it up to full temp - use short bursts if you think you can chase this down externally, or be prepared to start the teardown process. You might be doing more harm than good by running it.

Oil pressure is a red-herring I think, or might be a side product of the actual cause, but I agree with Alex, check with an external gauge.

The chances of getting a bad set of lifters for all 12 is small, but there have been batches of lifters lately that are failing - I recently had to do over a lifter change because of that. In that case, they started failing in a few miles of installation, not right away....

If you can use the stethoscope idea (or a screwdriver) to at least find out is the noise from under the valve covers, or chain covers, or where, that would help.

Cheers,

Mike

Vorsicht 02-07-2013 04:55 PM


Originally Posted by Steve Weiner-Rennsport Systems (Post 10205153)
Hey Peter,

Did you split the case for this rebuild?

If so, there are some very serious issues about oil pump sealing rings that cause VERY low oil pressure.

Let me know!

No. Top end only. Did not split the case. Perhaps the pump and or seals are going?

Mike J 02-07-2013 04:56 PM


Originally Posted by Steve Weiner-Rennsport Systems (Post 10205153)
Hey Peter,

Did you split the case for this rebuild?

If so, there are some very serious issues about oil pump sealing rings that cause VERY low oil pressure.

Let me know!

Steve, he said earlier it was just a top end, not splitting. I assume he did not re-ring, so its all around the heads, cam carriers, timing, etc.

Cheers,

Mike

Mike J 02-07-2013 04:59 PM

We are chasing some possible red herrings here - heating up too much, or low oil pressure, noisy -> you need to be systematic and eliminate variables.

Get an oil pressure gauge and use it to confirm if your oil sender is hooped.
Again, try to isolate the noise more to figure out if it can be localized. Where is it loudest (can be misleading but might give us a hint).

I doubt if your pump is going, but since you dropped the engine, you do need to re-hook up the car - I would double check the rubber line on the feed side (its between the tank and the solid line that runs to the engine). See if that is collapsing, if so it may be something in the tank - again likely not.

Cheers,

Mike

Quadcammer 02-07-2013 05:02 PM

Are there galley plugs in the cam towers that could have been left out?

Vorsicht 02-07-2013 05:13 PM

My responses in ALL CAPS.


Originally Posted by Mike J (Post 10205171)
Ok, did you;
- quick pull of some plugs to check if they looked good? NOT YET, WILL TODAY.
- use a stethoscope to try to locate the noise? I DON'T HAVE ONE BUT WILL GET ONE. MY BELIEF IS THE NOISE ORIGINATES UNDER VALVE COVERS.
- compression test (required no compressed air)? NOT YET, ON LIST.

#2 above is a good one because location may help - it also may be hard to determine. I doubt if its tensioners unless it's allowed the cam timing to be out by skipping on the sprocket, but keep confirming the direction is correct.

Lets review the rebuild a bit - did you do the valve clearance test? I seem to remember you had the index pin on the cams so they cannot slip, right? You timed to 1.0mm or ? YES.YES.YES.

The noise is regular and with the engine rotation - I assume if you rev it up the noise frequency also increases? YES.

I also agree to stop running it up to full temp - use short bursts if you think you can chase this down externally, or be prepared to start the teardown process. You might be doing more harm than good by running it. AGREED.

Oil pressure is a red-herring I think, or might be a side product of the actual cause, but I agree with Alex, check with an external gauge. DON'T HAVE A GAUGE BUT WILL PICK ONE UP WITH STETHOSCOPE. I HOPE IT IS A RED HERRING. I HAVE NEVER SEEN THE LIGHT COME ON BEFORE THIS.

The chances of getting a bad set of lifters for all 12 is small, but there have been batches of lifters lately that are failing - I recently had to do over a lifter change because of that. In that case, they started failing in a few miles of installation, not right away....

If you can use the stethoscope idea (or a screwdriver) to at least find out is the noise from under the valve covers, or chain covers, or where, that would help.

Cheers,

Mike


Mike J 02-07-2013 05:31 PM

It does sound like pressure loss somewhere that is not providing the oil to the lifters - there are also bridges from the block to carrier that need to be in place - but there would be oil everywhere if not there. The cam carrier does have an internal spray bar for the cam and passages to feed the lifters, etc.

Where there any modifications or removal of plugs in the cam carrier?

Cheers

Mike

Vorsicht 02-07-2013 05:35 PM


Originally Posted by Mike J (Post 10205317)
It does sound like pressure loss somewhere that is not providing the oil to the lifters - there are also bridges from the block to carrier that need to be in place - but there would be oil everywhere if not there. The cam carrier does have an internal spray bar for the cam and passages to feed the lifters, etc.

Where there any modifications or removal of plugs in the cam carrier?

Cheers

Mike

Did not remove or modify plugs. Oil bridges in place not leaking.

Mike J 02-07-2013 05:50 PM

Hmm- if we think around the idea of oil loss, where else can we lose oil that is internal on the top side of the engine?

The rocker shafts are keyed so I seem to remember they are almost impossible to get wrong - but they can be flipped, but they will not look right when installed. Did you take a picture like this one to confirm the shaft is oriented correctly? (if not, the oil feed hole will be blocked and the lifters will not pressurize).

http://www.pcarworkshop.com/images/t...33_-_small.jpg

Did you change out the lifters? I cannot remember if you did or not. If might be worth taking a valve cover off the engine to check things - should be easy given all the bolts are newly put in.

The overall carrier is pretty simple, not many places to go wrong....

http://www.pcarworkshop.com/images/t...37_-_small.jpg

Cheers,

Mike

Vorsicht 02-07-2013 06:06 PM

4 Attachment(s)
Pulled two plugs. The one on the left is Cyl. 2 lower. The one on right is cyl. 6 lower. Plugs are brand new.

No. 2 is much blacker and the central core is black. No. 6 central core is much lighter in color. What does black indicate?

Attachment 701415

Attachment 701416

Attachment 701417

Mike J 02-07-2013 06:11 PM

Are those brand new with just the startup time on them? They should not be black - that is incomplete combustion. Do a compression test to see how well the valves are seating, it also checks your timing (i.e. low compression may mean your timing is off and valves are left open, although that would usually result in contact happening).

I am thinking lifters OR maybe a mistake on timing? -> Have you timed these engines before (i.e. is it your first time?).

Vorsicht 02-07-2013 06:13 PM


Originally Posted by Mike J (Post 10205378)
Hmm- if we think around the idea of oil loss, where else can we lose oil that is internal on the top side of the engine?

The rocker shafts are keyed so I seem to remember they are almost impossible to get wrong - but they can be flipped, but they will not look right when installed. Did you take a picture like this one to confirm the shaft is oriented correctly? (if not, the oil feed hole will be blocked and the lifters will not pressurize).

http://www.pcarworkshop.com/images/t...33_-_small.jpg

Did you change out the lifters? I cannot remember if you did or not. If might be worth taking a valve cover off the engine to check things - should be easy given all the bolts are newly put in.

The overall carrier is pretty simple, not many places to go wrong....

http://www.pcarworkshop.com/images/t...37_-_small.jpg

Cheers,

Mike

Yes, of course. Actually, that was my next thought as this is at least something I can do without dropping the engine. Yes, I changed out all the lifters. They are new.

Vorsicht 02-07-2013 06:19 PM


Originally Posted by Mike J (Post 10205438)
Are those brand new with just the startup time on them? They should not be black - that is incomplete combustion. Do a compression test to see how well the valves are seating, it also checks your timing (i.e. low compression may mean your timing is off and valves are left open, although that would usually result in contact happening).

I am thinking lifters OR maybe a mistake on timing? -> Have you timed these engines before (i.e. is it your first time?).

Yes, the spark plugs are brand new. Yes, this is my first time doing the timing. I pretty much followed Wayne's book with the exception that I did each side independently; left, then right. And I did backdate to the pin method.

Steve Weiner-Rennsport Systems 02-07-2013 07:32 PM


Originally Posted by Vorsicht (Post 10205216)
No. Top end only. Did not split the case. Perhaps the pump and or seals are going?

Excellent,..thank you. Do not worry about your seals or pump.

MarkD 02-07-2013 09:21 PM

Sounding like an oil flow issue.

I see Bobt suggested this previously...
Chain tensioners installed properly?

Maybe I missed it but I didn't see that you checked it off the list yet.

EDIT: Scratch that, found it, you checked it off
Hmm...

You didn't remove one of the pressure relief valves, right?


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