melted camshaft bearings

One possible answer is there are oil passage restrictors installed in the block by a previous owner.

These are allen set screws with small oiling holes drilled in them.

They restrict oil to the lifters and can only be used with a solid lifter camshaft.

Thanks for the the input. When I had it all apart
I looked at all that. there is evedence of drilling and tapping from the main bearing journals but no restrictors are installed.

I think that the camshaft bearings don't melt if they are being oiled properly.
Are the oiling slots in the cam bearings alighned properly?

Since the cam bearings are right off of the main bearing oiling, anything that happens after them is really not relevant.

The likeliness is that there is a restriction in one of the main passages supplying the cam bearing galleries.

A lot of the FE blocks need to have thier cam bearing bores alighn honed.

The C block is not know for lack of machining inaccuracy. Even if it was this is something that you would find in a new block, not in one that has been seasoned and then rebuilt.

Perhaps it needs a stint?

Maybe this is another lack of zinc addative in the oil situation. I've had a few problems with aftermarket camshafts myself.

The blanks they are cut on have very little quality control done on them. CompCams said they are only spot checked. Something like 1 out of 10 blanks is check by a paid human being.

I had one where the distributor teeth broke off the cam when I opened the box, brand new.

I have seen this in even stock engines. Pulled a guys cam out to change it and found that all the cam bearings were flaked away. I have never had this problem myself, even when a cam rotated a little rough. I Suggest oil type and quality or engine temperature. Pehaps it could even be high spring pressure. OR it could be the brand of bearing. Perhaps the machine shop is using cheap bearings. I press my own and use Clevite. I have even once reused stock bearings from another engine and it worked ok.

The bearings are cooled by oil, so obviously we're talking about a lack of oil. I'll suggest 3 causes.

1. The hole in the bearing was not lined up with the oil passage in the block.

2. Oil restrictors are installed and the orifices are plugged with debris.

3. The oil passages are packed solid with varnish and gunk. I have seen this in many motors, Clevelands included.

cowboy from hell

Thanks for all the replies. the block has melted 2 sets of camshaft bearings and this is the second camshaft. Each time the block has been stripped down and the camshaft bearings have been installed with the oil entry slot aligned to show 5 good clean holes to the main bearing galley so I don't think that oil supply is the problem. The latest camshaft is a Comp Cam 270H with matching lifters.
There was one point made as to springs, I'm using a set of springs (duel coil) that I was told by 2 shops were "just fine for the camshaft I was using" I did a little homework and found out the springs from Comp Cam call for a part number #924 which recommends an installed height of 1.950" for my Manley stainless valves, at a closed valve spring pressure of about 114 pounds and an open spring pressure of about 288 pounds. My springs have a supposed closed spring pressure of 155 pounds. I think I'm on to something!! I'm going to have the existing springs checked further and probably go with the #924 springs. What the consensus?

Steve
#5974

Lotsa guys run high spring rates & don't melt cam bearings.

Are you align-honing the bearings after installation?

cowboy from hell

I had the springs checked today, the closed seat pressure was 130 pounds closed at 1.950" installed height and 275 pounds open pressure at .510" lift which closely matches the recommended specs for the Camshaft so I don't think that is the problem. I did not have the camshaft align-honed after the camshaft bearing installation but the shop that installed them said "it feels fine" needless to say when it comes out again I'm definitely going to be dealing with a shop that will do a more meticulous job of checking these things. I also have excessive top end rocker noises using Crane Engergizer roller rockers with a Comp Cam 270H with matching lifters. Having tried Crower and also generic aluminum rockers with the same noises this obviously is not the problem. Would anyone like to take this engine off my hands?

Steve

Steve,
Sorry to see your having this problem.
I noticed that you put a melling standard oil pump in, I was wondering what was your oil psi when it ran, mine is stock and run approx 70 psi, I do believe the cleveland ran with higher pump pressures due to there oiling problems

Mark

My oil pressure is about 35 hot at idle.