piston rod clearance ?
Thread Starter
Drifting
Joined: May 1999
Posts: 1,697
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From: Joliet IL
piston rod clearance ?
Just took the oil pan down and noticed that one of the rods has a little bit of movement from side to side. I looked in the book and it should be between .006-.014. Mine seems to be around .018. I've been getting a knocking sound that comes from the bottom end. Could this couse the sound. Also, is there a way to remedy this problem?
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Re: piston rod clearance ? (maduraj)
The only cure is wider rods or a narrower crank journal. This isn't a critical dimension, but it could be symptomatic. Also, it isn't likely the source of the noise. What was the clearance when you put it together? The noise could be a rod knock. Loose rod bearings could have caused the side clearance to open up. I'd be pulling the rod caps for a look-see.
RACE ON!!!
RACE ON!!!
Thread Starter
Drifting
Joined: May 1999
Posts: 1,697
Likes: 1
From: Joliet IL
Re: piston rod clearance ? (CFI-EFI)
thanks for the reply. I just looked at the rod bearings and they look good. I haven't measure the clearance, but there isn't any movement (up-down) that you can feel. No knocking or anything. About 1 1/2 years ago I replaced the main bearings, but I never did anything to the rods and the rod bearings. That's all how it came from the factory. Oh well, I'll just drive it until it falls apart, then maybe I'll get something bigger. The main reason I even looked at this was because the front seals started leaking a lot and I'm taking the vette on vacation on Friday. Gonna have to be working all night to get it ready :cry
[Modified by maduraj, 10:35 PM 5/17/2004]
[Modified by maduraj, 10:35 PM 5/17/2004]
Burning Brakes
Joined: May 2000
Posts: 958
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From: Brisbane, Australia 1985 Coupe
Re: piston rod clearance ? (maduraj)
Is there any of the bearing visible? My No 3 rod bearing let go and the piston was kissing the head. Bearing was mashed but all others were ok!
I'm assuming that your noise wasn't as loud as mine? :nonod:
[Modified by Chris O', 2:43 PM 5/18/2004]
I'm assuming that your noise wasn't as loud as mine? :nonod:
[Modified by Chris O', 2:43 PM 5/18/2004]
Thread Starter
Drifting
Joined: May 1999
Posts: 1,697
Likes: 1
From: Joliet IL
Re: piston rod clearance ? (Chris O')
I haven't taking the caps off so I don't think I can see the bearings. The noise wasn't too loud. If the hood was closed and you were about 5 feet away, you couldn't hear it over the exhaust.
I think I might have found the knock problem. Not sure if that would cause it but I guess I'll see in couple days when I put it all together. Below are couple pics of the shield that sits in the oil pan. For some reason a piece broke off where the oil pump is bolted to the engine. When I moved that piece around, it seemed like it might have made the knocking sound.
I think I might have found the knock problem. Not sure if that would cause it but I guess I'll see in couple days when I put it all together. Below are couple pics of the shield that sits in the oil pan. For some reason a piece broke off where the oil pump is bolted to the engine. When I moved that piece around, it seemed like it might have made the knocking sound.
Burning Brakes
Joined: May 2000
Posts: 958
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From: Brisbane, Australia 1985 Coupe
Re: piston rod clearance ? (maduraj)
It's a pretty violent place to be down there so it is possible. Put it all back together and if it doesn't fix it then all you have lost is a gasket and some skin off your knuckles.
:cheers:
:cheers:
Thread Starter
Drifting
Joined: May 1999
Posts: 1,697
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From: Joliet IL
Re: piston rod clearance ? (Chris O')
some skin? There is only some skin left on my knuckles :)
Actually it wasn't too bad. I had the oil pan and the timing cover off in about 4 hours or so.
Actually it wasn't too bad. I had the oil pan and the timing cover off in about 4 hours or so.
