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wayner..that idle of the engine was way too low...and the alt belt also too loose

ivan
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Old 02-08-2018, 04:48 PM
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Originally Posted by wayner View Post
Does it sound like this?

Saving a 73 from the crusher...
No. My noise is much more subtle, more like a tapping or light knocking. Not like the clunking noise your motor made.

What was that? Sorry it's been a long time since I was following your old threads.
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Old 02-08-2018, 05:11 PM
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Ivan - that was my first guess, but nope,
flywheel worked its way loose.


Gordon
AS far as yours is concerned, aren't JE piston known to have higher thermal expansion, a little looser and possible piston slap until warm, and the noise goes away as they swell up to spec?
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Last edited by wayner; 02-08-2018 at 06:03 PM..
Old 02-08-2018, 05:56 PM
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Quote:
Originally Posted by wayner View Post
MINE
Ivan - that was my first guess, but nope,
flywheel worked its way loose.


Gordon
AS far as yours is concerned, aren't JE piston known to have higher thermal expansion, a little looser and possible piston slap until warm, and the noise goes away as they swell up to spec?
That was definitely a thought of mine as well. And possibly there may be some of that going on. However, I put my scope on the actual cylinders underneath, and wasn't hearing the knocking or anything like a piston slap.

The JE pistons I have are interesting in their construction. The skirt of the pistons are very close to the cylinder. Mine measured out less that 0.002" clearance. But at the top in the ring area, you could actually rock the piston back an forth. Oh well, the rings seem to be seated.

My noise is most definitely coming from the right hand chain cover mostly right in front of where the cam sprocket is located. FWIW, I clearly recall torquing that cam bolt.
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Last edited by Trackrash; 02-08-2018 at 07:33 PM..
Old 02-08-2018, 07:31 PM
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I have experienced a JE piston skirt contacting the case web. Solution was to mill the skirts down to increase clearance.

Slight contact would go away as engine heats and expands.

Check all your rockers first.

Also, pull plug leads one by one. If noise goes away it could be rod bearing problem. #5 is often the worst offender.
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Old 02-08-2018, 07:36 PM
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Originally Posted by jpnovak View Post
I have experienced a JE piston skirt contacting the case web. Solution was to mill the skirts down to increase clearance.

Slight contact would go away as engine heats and expands.

Check all your rockers first.

Also, pull plug leads one by one. If noise goes away it could be rod bearing problem. #5 is often the worst offender.
OK, now I'm worried. I'll have to get out my scope again tomorrow and listen to the bottom of the case. I should be able to hear a rod knock or pistons hitting on the bottom of the case.

And I never thought to check the piston clearance at the BOTTOM of the stroke. Hmmmmm.
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Old 02-08-2018, 08:04 PM
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Quote:
Originally Posted by Trackrash View Post
And I never thought to check the piston clearance at the BOTTOM of the stroke. Hmmmmm.

Yeah, who would've. They have likely sold thousands of air-cooled 911 piston sets. I guess the CNC operator could've taken lunch break before the program was done or something like that resulting in a set not being like the others. Weirder things have happened i guess.

I can barely hear the noise in your video. In everyday life, I can't hear ****. My better half always complains that I can't hear and she has to yell. But if it involves one of our cars i hear EVERYTHING. We'll be on a trip and I'll hear a tick or a thunk and ask her if she heard it too. Nope. She could drive her car thru a nitroglycerin plant and not hear any noises! However, she could have a conversation in grand central station with someone across the way speaking with a whisper and perfectly hear every word. Funny how that all works.

Have you checked oil for tells?
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Old 02-09-2018, 06:09 AM
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It's still on its break in oil. So when I change it we'll see how it looks. Looks clean on the dip stick still. But your point is a valid one. I'll definitely pull the strainer and take a look at the screen. Probably worth cutting the filter open as well.
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Old 02-09-2018, 08:30 AM
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piston slap.

you say it is bad when it idles very low?
probably nothing to worry about.
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Old 02-09-2018, 08:58 AM
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Originally Posted by T77911S View Post
piston slap.

you say it is bad when it idles very low?
probably nothing to worry about.
Hope you are right. I am just wanting to cover any eventuality, considering it is a newly built motor.
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Old 02-09-2018, 10:28 AM
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The oil point is a good one...before even dropping the oil out, grab a sample and send it out for testing so you will know if there are particles that are not visible, plus you will have a base line to work from.

My wife says my hearing is going out too...and I can hear everything thing in all my cars perfectly, and I can for sure hear that knock too. Even if it harmonizes out under rev that doesn't mean it is gone. Good luck, man.
Old 02-09-2018, 11:55 AM
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Hi Gordon..i did listen non stop 20x with closed eyes...glo glo glo glo ,i hear...verify for me if you put the stato..on intake number 4 you do not hear anything...

Ivan
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Old 02-09-2018, 12:12 PM
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Yeah, I have an '88 Volvo with the B230F engine with about 150,000 miles on it. That particular engine because of it's aluminum pistons and cast iron block has had piston slap for years and years. I hate that sound when it's cold, but everything I've read says not to worry about it. Not saying you have piston slap, but your description of its coming & going depending on engine temperature sure sounds like the Volvo.
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Old 02-09-2018, 01:06 PM
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Quote:
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Hi Gordon..i did listen non stop 20x with closed eyes...glo glo glo glo ,i hear...verify for me if you put the stato..on intake number 4 you do not hear anything...

Ivan
I spent some more quality time with my scope this morning. I listened all around on the under side of the motor. It was not coming from the #4 cylinder or head or anywhere underneath.

I confirmed the only place I hear it with my scope is right behind where the cam sprocket is on the right side when I listen at the chain cover.

So I will definitely be pulling the chain cover on that side and taking a careful look at that sprocket and chain assembly.
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Old 02-10-2018, 03:46 AM
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Hi Gordon ,that would be something ,2nd chain tensioner going bad on same side..But better then taking the top apart;-)

Ivan
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Old 02-10-2018, 04:30 AM
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OK, I have the chain cover off. I'm not seeing any problem. The chain is tight, no sponginess in the tensioner. The sprockets look good, no bad teeth or gullets that I can see. Chains and guides look like new, since they are. Cam nut tight and no end play in the cam.

The only thing I noticed is when I wiggle the idler back and forth it makes a clicking or clacking noise. I wonder if that is it.

Thoughts?

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Old 02-18-2018, 05:14 PM
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Hi Gordon ..hmm.. is your tensioner fully open??? Look at this pic .plus the angle bend seams different???

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Old 02-18-2018, 05:48 PM
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The new chain in my motor doesn't allow the tensioner to extend as far as what is shown in your picture. The tensioner is definitely working, and is applying tension to the chain.
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Old 02-18-2018, 05:54 PM
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so that leaves the idle gear as the noise culprit?

Ivan
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Old 02-19-2018, 12:02 AM
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Can you run it - briefly - with the cover off?
Alan
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Old 02-19-2018, 12:45 AM
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