what causes cam to wear on the block?

[oneslobuick]

background: I had my engine rebuild by a respectable and thought to be knowlegeable person. here is what he did dimond racing pistons, stock rods, 2 billet main caps, 206/206 comp cam, high vol oil pump/ housing, balanced thats all I can think of. anyway, i was breaking it in gently and changed the oil at 2500 mi and found metal in the oil. He pretty much said it was my problem. Well i tore the motor down to find the main bearing wiped out. So then I took it to another shop and they saidthe cam was rubbing the front ot the block and that they could mill it and build it up with brass. Has any one ever done this and what causes it to rub in the firstplace???

 

[Red Regal T]

When you say the main bearings were wiped out, describe the damage. Did you see damage on the cam or block? Did you have any kind of remote oil filter system?

 

[oneslobuick]

reply

no remote oil system, the bearings were showing copper with grooves in the crank and the bearings the rods looked good. I did not remove the cam before i took it to the shop. The guys at the shop said that the cam had ate into the block, they recomended machining it and building it up with brass.

 

[REDS HOT AIR]

what was the oil pressure on the motor

Im betting it carried alot of oil pressure

 

[87buick3825]

Did they line bore the block ????? You did say ya did main caps but didnt mention a line bore . I have had a few motors where the cam wore a groove in the front of the block . I machined a spacer for it . no big deal ..

RD

 

[Mike Licht]

If this was a billet roller it is fairly common. We used to machine th nose back and install a torrington to pervent that. The cam is harder than the block and the wear surface is small
Mike

 

[oneslobuick]

broke

The engine had about 25 psi oil pressure warm at idle 40psi at cruise.

87buick3825 Did they line bore the block ????? You did say ya did main caps but didnt mention a line bore . I have had a few motors where the cam wore a groove in the front of the block . I machined a spacer for it . no big deal ..

yes it was line bored. What did you use for a spacer?


Not a billet roller just a mild hyd comp

 

[Ormand]

Did the builder put the roller cam button in front of the cam? Sometimes it needs a little plate attached to the inside of the front cover to get the clearance right, but if the button was left off, the cam would certainly rub the block.

 

[87buick3825]

I machined a spacer to fit the groove

 

[oneslobuick]

thanks

yes the roller button was installed


Thanks guys

 

[FJM568]

Oneslo,
Same thing happened to my block...My build was almost identical to yours w/ the exception of I used TRW forged pistons...The front of my block was worn too...This is just my personal opinion, but on a fresh, tight tolerance motor, I WOULD NOT use a HV oil pump...IMO, it puts too much pressure on the front of the cam and forces it back into the block...HV pumps may be fine on a high mileage motor where the clearances are greater, so there is more oil pressure bleed-off...The reason I'm saying this is that the Big Block Buick's have virtually the same problem with using HV oil pumps, except they destroy the front cam bearing from the pressure on the front of the cam...

On a tight tolerance fresh motor, I would just use the std oil pump...You should have no problem seeing 20# at idle...

 

[REDS HOT AIR]

Originally posted by FJM568
Oneslo,
Same thing happened to my block...My build was almost identical to yours w/ the exception of I used TRW forged pistons...The front of my block was worn too...This is just my personal opinion, but on a fresh, tight tolerance motor, I WOULD NOT use a HV oil pump...IMO, it puts too much pressure on the front of the cam and forces it back into the block...HV pumps may be fine on a high mileage motor where the clearances are greater, so there is more oil pressure bleed-off...The reason I'm saying this is that the Big Block Buick's have virtually the same problem with using HV oil pumps, except they destroy the front cam bearing from the pressure on the front of the cam...

On a tight tolerance fresh motor, I would just use the std oil pump...You should have no problem seeing 20# at idle...

Thats what I was getting at by my post above ..you beat me to a responce ...cool now I dont have to type it