Cam bearing
#1
Retired Senior Admin
Expert Gearhead
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Join Date: May 2006
Location: Sheboygan Wisconsin
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Cam bearing
Well, looks like I might be loosing a cam bearing. I finally got the tune right and give it a little WOT. Shortly after that the engine started to make a odd sound out of the exhaust. but only under heavy load. It drove fine and sounded fine. But I noticed my oil pressure was half way between 40 psi and the red. I was scanning at the time and saw nothing odd, other then some KR at WOT. I got back to the shop and shut it down right away. Looked over the engine and saw nothing wrong. So I started it and it sounded fine, but again, oil pressure was about 20 psi. So I again shut it down and drained the oil. It was very thin and looked like there was some metal in the oil. I filled it with 10w30 and started it up again, all sounded fine. Pressure was still about 20psi. When I reved it up to 2000 the oil pressure was about 40psi. Let off the gas and it would slowly drop back down. So the Bonny is grounded. I'll be ordering some new cam bearings and pulling the engine. Not really what I was planning to do.
#2
Senior Member
True Car Nut
If the cam bearing is done, the bore is messed up and needs machining. That and it sent metal particles to all the important parts of your engine.
Low mile shortblock time?
Low mile shortblock time?
#3
DINOSAURUS BOOSTUS
Expert Gearhead
There is a specialized tool for installing them. IIRC it'* about $150 and no one that I could find had one to rent out.
To do the job, the crank has to come out. To me this is the killer, the main bearing caps require a special tool (cost unknown). You would need main bearing cap bolts, piston rod cap bolts, lower conversion gasket set, LIM'* (might be able to reuse, don't tell anyone I suggested that though). Evaluate if the cam is able to be saved. Then evaluate the possibility of another bearing (rod or main) going back from taking it apart. Our engines are very fussy.
When a piston rod bearing went on me, I tossed around the various costs etc and found a 2001 motor (Bonneville, with aluminum pan etc etc) for $600 complete. In your case, it might make sense to consider an L26 engine to go higher compression and run larger pullies keeping the charge cooler and being able to tune a ton of power.
To do the job, the crank has to come out. To me this is the killer, the main bearing caps require a special tool (cost unknown). You would need main bearing cap bolts, piston rod cap bolts, lower conversion gasket set, LIM'* (might be able to reuse, don't tell anyone I suggested that though). Evaluate if the cam is able to be saved. Then evaluate the possibility of another bearing (rod or main) going back from taking it apart. Our engines are very fussy.
When a piston rod bearing went on me, I tossed around the various costs etc and found a 2001 motor (Bonneville, with aluminum pan etc etc) for $600 complete. In your case, it might make sense to consider an L26 engine to go higher compression and run larger pullies keeping the charge cooler and being able to tune a ton of power.
#6
Retired
Bill, I thought I seen in the SM that the piston rod cap bolts were reusable??
Sorry to here about Dan, but welcome to my world.
Sorry to here about Dan, but welcome to my world.
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#8
Retired
Just looked, SM says to inspect rod cap bolts for stretching. To test for stretching, compare to new bolt. If same size, ok to reuse.
No special tool required to remove crank caps. A set of locking pliars is all that is needed. But it does point out that when using the locking pliers, to place them directly on bolt hole. NOT BETWEEN them.
No special tool required to remove crank caps. A set of locking pliars is all that is needed. But it does point out that when using the locking pliers, to place them directly on bolt hole. NOT BETWEEN them.
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#10
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True Car Nut
VERY sorry to hear this Dan. It'* probably less scary to you than it is to me seems how I've yet to get that far into my engine. I've been trying to put back for a new DD incase something like this happens to me though.
Good luck with the diagnosing and repair, looking forward to another great project hopefully.
Good luck with the diagnosing and repair, looking forward to another great project hopefully.