Camshaft is walking forward.

[Turbo1dr]

I've been a busy little bee this year with some custom parts for my Malibu. I cut a front wheel drive lower timing cover in half and welded it to the upper part of a rear wheel drive cover. I done this to get rid of all the wear and stress a HV oil pump puts on the timing components, cam sensor gear and the thrust surface of the block. This also gets rid of some friction. However, by doing this I've also created another problem...maybe. I was cranking the engine on the engine stand with just the starter and noticed the camshaft was walking forward! This was with the heads installed and the valves adjusted. I loosened all the rockers while looking at the cam and the cam thrust button pushed it back into place. The cam is a ATR Roller 214-210 cam and has about 25,000 miles on it. Obviously, it's lasted this long so I'm thinking I should just put an adjustable cam thrust button on it and let it ride. I can't see how the timing cover modification caused this? What are your opinions on this?

One other thing about it walking...the thought of the lifter bores not being perfectly in aligned could also cause this. It's a good thing I was able to catch this before I put it in the car....whew!

Timing cover installed Picture.

 

[TURBOELKY]

Cam Walking?

If My Cam Was Walking, I Would Put A Leash On It :d ............just Kidding Man, Cant Help Here, All I Know Is That People Have Alot Of Cam Problems In These Engines, My Isky Set Up Is A Charm. A Good Old Hydrollic Cam, None Of The Fancy Smanchy Roller This, 800 Dollar That, Adjustable This, Adjustable That. Never Wore A Lobe, Only Broke A Plunger In A Lifter With The Old Cam. Good Luck Dude.

 

[SPEEDSTAR]

Most cams will walk in or out, its caused by the cam bearing bores, cam bearings or lifter alignment, and machining tolerances, some blocks are so bad that some type of cam retaining other than a nose bearing is needed,ie:Weber rear needle bearing ret. or like I am using, gear-drive, which holds it both ways,in and out,. I also use the cam nose bearing. I have heard of race shops measuring how many lbs. of pressure during cam walk on test stands, to be sure its in an acceptible range. On a bad block it can be hundreds of lbs. If you have already ran your without any problems then its probably ok......Jeff

 

[REDS HOT AIR]

any roller should have a roller button with solid shims to set the end play

no spring buttons with a roller

 

[Turbo1dr]

any roller should have a roller button with solid shims to set the end play

no spring buttons with a roller

Been running with a spring button all this time. Guess I've been lucky? :frown:


Those LS1's are starting to look good for a transplant.....

 

[Blown&Injected]

end play must be set tight for a roller. flat tappet cams find theri own way based on the taper of the lobes but a roller does not work this way - maybe the new cover is letting the cam walk more than the original cover

 

[turbo2nr]

Comp Cams sent me a shim kit and needle bearing roller to hold cam in place, no spring. Don't have the tolerances in front of me, but it was a small amount of lateral play to set it at.

 

[REDS HOT AIR]

Those LS1's are starting to look good for a transplant.....

my old school sb will do for me in my el