Cam Eating Block

[m233roller]

Has anyone had a cam ( this is a 210-215 roller cam) eat into the front of your block? If so what was your fix and why are they doing it in the first place?? Thanks Mike

 

[jpwalt1987]

The fix is to get an odd fire style cam with the Torrington bearing. I believe that a billet cam is required for that. I had to do this on the block I am running. Dan at DLS has the stuff you need.
As to why it happens..... My guess is a combination of high oil pressures on the oil pump drive gears forcing the cam into the block and basic design flaws.

 

[Nick Micale]

I know it was only a guess, but a design flaw would be in aftermarket cam or the timing set? Many thousand of these turbo production engines with many different cams have NOT had this issue. I am also puzzled how high oil pressure forces the cam into the block?

There is a force, caused by something out of the ordinary, parts or machining, pushing the cam into the block.

One thing to check is the alignment of the chain sprockets, and how much fore and aft play in the cam.

My first question would be is this a stock timing cover or aftermarket? The off-shore aftermarket covers are well known for their piss-poor tolerances and mis-aligment of the cam sensor/pump drive gear. That could put pressure from the cam sensor to force the cam into the block.

We have seen timing gear sprockets that must be machined or shimmed for proper alignment.

If the crank is a forged replacement one, we have seen the crank gear at different depths than the stock cranks, which will cause the chain to be mis-aligned.

We all have to be continually aware when using ANY aftermarket part, it may not fit like a stock part. Then you add many a/m parts, all of which have been made by different companies and countries, can all have different tolerances and fitment from stock parts.

This is why it is important and imperative to check and re-check when assembling a complex unit like a performance engine.

Mike, I know you have a good engine machinist, and some of these issues are almost impossible to detect on the engine stand, but look at these areas I have mentioned, good luck.

 

[EVIL]

We all have to be continually aware when using ANY aftermarket part, it may not fit like a stock part. Then you add many a/m parts, all of which have been made by different companies and countries, can all have different tolerances and fitment from stock parts.
This is why it is important and imperative to check and re-check when assembling a complex unit like a performance engine.

Very true statement. Especially with these cars!

D

 

[jpwalt1987]

Nick, the only reason I say what I did is from my observation of a 100% bone stock from GM 109 engine that was in my dads car. It had about 100,000 miles on it and the surface of the block was chewed up some. Not bad but I wouldn't have put a factory style cam on it. Only a Torrington bearing setup was feasible. Now I know that is only one but I can see it happening more often.

 

[m233roller]

I thank all you guys for your valuable imput. This engine had all the machine work done by my machinist up here Kevin (and Nick knows) I'll put him up against any in the country. First off this is a full forged engine with a BA crank, K-1 H-beam rods, RJC girdle, J&E pistons, comp 210-215 cam, rollmaster chain and a stock GM front cover with all the oiling mods done by myself. I also put the whole thing together and end play on cam was 0.006 and chain and timing gear alignment was spot on. Thrust on crank was 0.005. Nothing showed up until it had about 4,000 miles on it and then a BIG wad of cast iron sludge on the magnetic drain plug. I had the oil analyzed and the iron was at 115. This is in parts per million by weight. On testing oils twice on my old engine it was only 14 on one test and 16 on another, so something is really going south. I haven't pulled this thing apart yet but I'm next to positive that's whats going on. I have ran Valvoline VR-1 racing oil for YEARS and I also put in a half bottle of ZDDP. I haven't changed or put in any other additives, so that package is and has been the same forever. One thing I don't remember checking when I assembled this engine was the oil hole on the cam !! Here are a couple of pics. of the last oil change with only 500 miles on it and what the hell is that sliver of metal that was stuck to the magnetic plug?? Keep in mind this engine runs perfect, NO noise,NO smoke, does NOT use any oil and has great oil pressure. Oil pressure my be to high at idle only. When engine is up to good operating temp it idles in gear around 40psi. In this 95 degree heat we are having here and once I get on it afew times it will go down to 30-32 at idle. I have the yellow 60 lb.spring in it. Any and ALL imput is greatly appreciated. Thanks Guys, Mike

 

[Mike Licht]

thrust bearing? I have seen MANY billet cams dril into blocks but I cannot remember any stock type cams doing that. If it does it is an oil problem. You can put a piece of silicone bronze in the bad place and drill an oil hole to feed it. If you need some help give me a call.
Mike

 

[BobbyBuick]

Wouldnt a high volume pump cause the cam sensor to push the cam rearward with more force due to the bigger gears and stronger spring .I drill a 1/16 " hole on the oil galley of the block so it oils the surface behind the cam

 

[m233roller]

Iv'e heard yes and no on that Bobby but I'm not running one. I kind of can see how it might though.

 

[jpwalt1987]

Wouldnt a high volume pump cause the cam sensor to push the cam rearward with more force due to the bigger gears and stronger spring .

That's what I was getting at. Has anyone seen a billet roller that's been cut for the Torrington bearing eat into the front of the block?

 

[BILL HAINES]

Nick, the only reason I say what I did is from my observation of a 100% bone stock from GM 109 engine that was in my dads car. It had about 100,000 miles on it and the surface of the block was chewed up some. Not bad but I wouldn't have put a factory style cam on it. Only a Torrington bearing setup was feasible. Now I know that is only one but I can see it happening more often.

MY FRIEND JAY ALWAYS USED A TORRINGTON - CAM BUTTON

 

[m233roller]

I ran a 206-206 billet roller (odd fire) from Weber for 7 years and it looked new when I took it out. Torrington bearing seems the way to go. Iv'e also ran the torrington cam buttons for years in my engines and in many other engines Iv'e built for guys here.

 

[bison]

Has anyone had a cam ( this is a 210-215 roller cam) eat into the front of your block? If so what was your fix and why are they doing it in the first place?? Thanks Mike

Seems like about 1 in 10 aftermarket cams will wear the thrust in the block. Too tight or imperfect thrust surface on cam can do it. I always deburr the thrust surface on the cam as well as sand the thrust surface smooth. I also check the cam for straightness and straighten as needed. How deep is the wear? Most billet cams use a torrington thrust bearing and an adjustable thrust bumper so wear of this type does not happen. Ive machined a few billet cams to accept these thrust setups when they cam with bronze washers originally.

 

[m233roller]

Bison,
As I stated I haven't tore it down yet but I'm next to positive that's whats going on. Is 0.006 end play to tight? I didn't think so ? I did not deburr the thrust surface as it looked and felt very smooth. Cam was not checked for straightness. Yea I ran a Weber billet cam with the torrington set up and ran it for 7 years, NO problem, all looked new when I took it out. Thanks Mike

 

[BEATAV8]

If the cam moves in far enough it could feasibly lead to lobe contact with the adjacent lifter.

Some COMP cams have exhibited a defective (too thick) thrust face which sets the cam too far forward in the block. Could this be one? Could that contribute to a thrust wear issue? The resulting gear misalignment and chain misalignment might generate additional thrust load during operation.

 

[bison]

Bison,
As I stated I haven't tore it down yet but I'm next to positive that's whats going on. Is 0.006 end play to tight? I didn't think so ? I did not deburr the thrust surface as it looked and felt very smooth. Cam was not checked for straightness. Yea I ran a Weber billet cam with the torrington set up and ran it for 7 years, NO problem, all looked new when I took it out. Thanks Mike

.006 should be ok but I usually run about .010. I want to be sure the cam isn't anywhere near binding. Deburring the thrust surface has proven to help a lot. Id take a .002 cut on that cam to clean the thrust surface and then sand the outer edge smooth and chamfer the hole on the thrust surface so it's not scraping the oil off the block as it spins.

 

[m233roller]

Thanks Brian and that's exactly what I was thinking about doing when I get this thing apart. I know that's whats going on and if the front of the block is to ground up I'm taking it to my machinists (Kevin) and have him machine a pocket in it for a torrington bearing. What do you think of that? Thanks
PS. I'm also going to get alittle more end play in the new set up, like .008 to .010

 

[bison]

Thanks Brian and that's exactly what I was thinking about doing when I get this thing apart. I know that's whats going on and if the front of the block is to ground up I'm taking it to my machinists (Kevin) and have him machine a pocket in it for a torrington bearing. What do you think of that? Thanks
PS. I'm also going to get alittle more end play in the new set up, like .008 to .010

You can do as you described but you can't easily cut a pocket in the block. The block is too tall to fit in most machines and there isn't a lot of material that is removable on the block. You will have to take a lot more off the cam. Use the cam to locate the bearing I.d. With a Torrington bearing you can run the thrust down to nearly nothing. You have to watch the cutting depths or the cam gear wont line up with the crank gear. It's harder to adjust it with a stock cam. The billet ones are easily adjusted by using different size shims. With the various cranks and balancers out there ive found that a washer from a transgo shift kit that goes in the 1-2 servo fits perfectly over the crank and just needs a small slot ground in it to work as a shim for outward balancer spacing. These things are a pain in the ass. Once you start machining surfaces and changing cams, cranks and balancers there are almost always alignment issues.

 

[m233roller]

Thanks for the washer info. and I'm not worried about getting the block cut as my machinist (Kevin) did one for me 9-10 years ago.It was a guy's here that wanted me to build him a nice roller engine and when I tore it down I found the front of the block ate up from the cam. Took it Kevin and he cut a pocket in it for a torrington bearing and it's still running around just fine.