how to solve the problem
help!
any feedback is good

 

 

Time for some machine work or a new block.

Looks like a lack of oil problem. The timing set isn't getting any oil. I use a cam gear that has a torrington bearing behind it so the gear itself doesn't ride on the block. Small holes are drilled in the gallery plugs behind the gear to supply it with oil.

Are you using a cam button? If so, is it too tight? When the engine is running, the cam wants to walk out of the block. That wouldn't explain why the cam gear wore into the block unless it was forced in by a too tight cam button.

 

looks like there should be a camshaft thrust plate bolted to the block like the 87 up 5.7 liters use and a newer style timing chain too....... the thrust plate keeps the camshaft from walking and also keeps the timing gear from chewing up the block like that

 

Looks awfully dry there.

I'd guess the front cam bearing wasn't put in properly and starved that part of the engine for oil.

 

That's a possibility.

Exactly what block is it?
Flat tappet or roller cam?

From the holes on either side of the cam, it looks like it's supposed to have one of these.

http://paceperformance.com/index.asp...D&ProdID=37092

 

I'm not as familiar with roller big blocks, but that looks like a flat tappet cam snout to me.

Even with a cam button, I can't imagine so much force that it wears the block like that.

With a flat tappet cam, two things hold the cam back so the timing gear takes the thrust, the distributor drive gear, and the slight angle on the lobes that spins the lifters. Without oil, the block/timing gear are going to scream against each other.

 

block 454 346236.....454.......75-76...2-bolt
Flat tappet

chain used again and again

I want to do roller cam

fill in the gap ? solution : Camshaft, Wear Plate?
http://www.summitracing.com/search/B.../?autoview=SKU

 

 

solution helps good or bad??

 

thats the ticket. i suggest getting the surface machined flat on the block tho

 

mine did exactly the same thing its a 1988 chevy 7.4 liter truck engine 4 bolt main
why did it do that i lost my mains right after i am going to have it machined flat and use a hardend were washer summit and jegs sell them in thicknesses for what you need