Cam bearing.
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
Cam bearing.
So im doing a cam swap.
When i pulled the original cam I can se some copper spots on the front cam bearing.
Nothing major, and I cleaned up the camshaft and the lobes are perfect as well as the journals.
Just like a mirror. No pits, scratches, nothing.
Also the bearing has no dents in it.
I installed the new cam with oil on it, and it spins smooth by hand installed.
Questions is, is this "normal" wear, or should I replace the cam bearings?
Motor only has 55000 miles on it.
Its a 1991 vette..
When i pulled the original cam I can se some copper spots on the front cam bearing.
Nothing major, and I cleaned up the camshaft and the lobes are perfect as well as the journals.
Just like a mirror. No pits, scratches, nothing.
Also the bearing has no dents in it.
I installed the new cam with oil on it, and it spins smooth by hand installed.
Questions is, is this "normal" wear, or should I replace the cam bearings?
Motor only has 55000 miles on it.
Its a 1991 vette..
Racer
Joined: Dec 2007
Posts: 416
Likes: 3
The cam bearings shouldn't be worn out at 55k miles.
Was the oil pressure good?
You can either put it back together, or take it down to the bare block and change them. It's not something that can easily be done in the car. I dont think anyone successfully changes cam bearings in the vehicle.
Was the oil pressure good?
You can either put it back together, or take it down to the bare block and change them. It's not something that can easily be done in the car. I dont think anyone successfully changes cam bearings in the vehicle.
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
Oilpressure whas good.
When I come to think of it now later, I seen this on all of the engines i changed cam on, its only 4 so far, but anyway.
Both L98 and LT1.
There were some spots on the cam bearings that whas down to the copper.Not much, but some "stains".
I came across some threads on the internet about this.
And some says its "normal wear" ( if its not to much ofcourse, and you got grooves in the bearing ), some says that GM "..line bores the blocks with the cam bearings installed to correct there machining problmes".
And of course you have the "doomsday sayers" that you need a complete teardown
Im somewhere in the middle.. So I need more info before I deside what to do..
Cheers
When I come to think of it now later, I seen this on all of the engines i changed cam on, its only 4 so far, but anyway.
Both L98 and LT1.
There were some spots on the cam bearings that whas down to the copper.Not much, but some "stains".
I came across some threads on the internet about this.
And some says its "normal wear" ( if its not to much ofcourse, and you got grooves in the bearing ), some says that GM "..line bores the blocks with the cam bearings installed to correct there machining problmes".
And of course you have the "doomsday sayers" that you need a complete teardown
Im somewhere in the middle.. So I need more info before I deside what to do..
Cheers
Last edited by devilfish; Mar 25, 2015 at 12:51 PM.
Melting Slicks
Joined: Jan 2009
Posts: 3,482
Likes: 196
From: folsom california
Can you get an inside mic, or even a well calibrated metal (not plastic) dial caliper, or a snap guage and outside micrometer and get a measurement of the inside diameter of the front cam bearing? that might tell you a lot
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
All other cam bearings looks fine, its just the front cam bearing that has this spots.
I guess its from the timingchain that pulls a bit on the cam?
I dunno..
Is it ok to just replace the front bearing?
Cheers
I guess its from the timingchain that pulls a bit on the cam?
I dunno..
Is it ok to just replace the front bearing?
Cheers
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Ive read the worn cam brgs can reduce your oil pressure. How is your oil press? If wear is visible better to replace them now or at least that first one in the front that has visible wear.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
Oil pressure whas ok.
I talked to alot of speedshops about this during the last days.
And the verdict is about the same.
Some say: "I have seen brand new OEM blocks with copper showing on the cam bearings. Remember GM line bores then cam tunnels with the cam bearing installed to make up for there imperfect machine work."
Other says: "I wouldn't touch it, the Babbit flash is only a few millionths of an inch thick, what it shows is there is a slight dimension mismatch in the alignment of that bearing to the others, it could be a thickness difference in the bearing shell or plating, or of the bulkhead that supports that bearing. Messing around may well make things worse, this doesn't appear to cause any issues as it is so I'd recommend just leaving it alone".
As im planing a total rebuild somewhere in the future, I will , based on many phonecalls and forumreading, install the cam and run it like this.
And keep a eye on the oil pressure.
Thanks all
I talked to alot of speedshops about this during the last days.
And the verdict is about the same.
Some say: "I have seen brand new OEM blocks with copper showing on the cam bearings. Remember GM line bores then cam tunnels with the cam bearing installed to make up for there imperfect machine work."
Other says: "I wouldn't touch it, the Babbit flash is only a few millionths of an inch thick, what it shows is there is a slight dimension mismatch in the alignment of that bearing to the others, it could be a thickness difference in the bearing shell or plating, or of the bulkhead that supports that bearing. Messing around may well make things worse, this doesn't appear to cause any issues as it is so I'd recommend just leaving it alone".
As im planing a total rebuild somewhere in the future, I will , based on many phonecalls and forumreading, install the cam and run it like this.
And keep a eye on the oil pressure.
Thanks all