Reply With QuoteDid you check this with the timing gear installed? Is the gear bottomed out against the block or could the cam plug in the back of the block be holding the cam out?
The cam could be defective.
we are installing a comp cam in a 72 4bolt Chevy 350 stroked
checking for good lifter rotation we fond that the #2 cylinder Exhaust lobe hits the #1 intake lifter just slightly
and the #4 intake lobe hits the #3 Exhaust lifter
now we are replacing the cam with the exact same cam that had a lobe go flat on a different cylinder and the old on clears just fine on the same one that we have problems with now
WTF this blowes
Did you check this with the timing gear installed? Is the gear bottomed out against the block or could the cam plug in the back of the block be holding the cam out?
The cam could be defective.
Did you check this with the timing gear installed? Is the gear bottomed out against the block or could the cam plug in the back of the block be holding the cam out?
The cam could be defective.
cam gear on every thing is good with the block had it checked out by a top notch engine guy and there was no problem with the came he used to test with
I guess you pulled the lifter and could see the cam lobe was hitting it? It could not be possible that the higher lift cam is touching the rod bolts? That can be a common problem if you used a 3.75 stroke crank with stock rods, just an idea.
I guess you pulled the lifter and could see the cam lobe was hitting it? It could not be possible that the higher lift cam is touching the rod bolts? That can be a common problem if you used a 3.75 stroke crank with stock rods, just an idea.
we are working on a rebuild this motor had a cam lobe go flat so
after installing the cam we used a single lifter and rotated the cam and checked each lifter journal for proper rotation
I guess you pulled the lifter and could see the cam lobe was hitting it? It could not be possible that the higher lift cam is touching the rod bolts? That can be a common problem if you used a 3.75 stroke crank with stock rods, just an idea.
rods have clearance
You say you have tried two cams...one that had clearance issues, and now another that dosen't? Did you lay the two cams along side eachother to see what the physical differences might be?
The block needs to be checked with something like a BHJ lifter truing fixture or something similar. I wouldn't trust a cam to check lifter alignment with.
Make sure you have all rods installed, and check each one for clearance. Also, make sure the cams are degreed as you would run them...a few degrees difference can cause issues between different cams. Installing them in the same place on the gear dosen't mean they're in the same place in relation to the crank or int. C/L.
You say you have tried two cams...one that had clearance issues, and now another that dosen't? Did you lay the two cams along side eachother to see what the physical differences might be?
The block needs to be checked with something like a BHJ lifter truing fixture or something similar. I wouldn't trust a cam to check lifter alignment with.
Make sure you have all rods installed, and check each one for clearance. Also, make sure the cams are degreed as you would run them...a few degrees difference can cause issues between different cams. Installing them in the same place on the gear dosen't mean they're in the same place in relation to the crank or int. C/L.
the first cam had no clearance issues but we had a lobe go flat
replacing the cam with the exact same cam but now we have problems
its like the two lobs are to far back and are encroaching on the ajason lifter
the first cam had no clearance issues but we had a lobe go flat
replacing the cam with the exact same cam but now we have problems
its like the two lobs are to far back and are encroaching on the ajason lifterI pretty much got that part...did you lay the old cam and new cam along side eachother to see if there's a visual, obvious difference? If the new core has the lobes out of place, then you should just be able to get e new cam. Do you know why the old cam went flat? LIfter to lobe palcement is somewhat critical on a flat tappet. If the relation isn't right, there may not be adequate rotation of the lifter. The lifter will sit slightly off-center of the lobe for this reason. (to cause rotation) Also, if the lifter isn't perfectly square with the cam, the lobe face and lifter face won't "mate" properly, resulting in premature eja...I mean wear. Lifter bores being all fk'd up is pretty common in big blocks...not sure about small blocks, but sounds to me like the cam.
I pretty much got that part...did you lay the old cam and new cam along side eachother to see if there's a visual, obvious difference? If the new core has the lobes out of place, then you should just be able to get e new cam. Do you know why the old cam went flat? LIfter to lobe palcement is somewhat critical on a flat tappet. If the relation isn't right, there may not be adequate rotation of the lifter. The lifter will sit slightly off-center of the lobe for this reason. (to cause rotation) Also, if the lifter isn't perfectly square with the cam, the lobe face and lifter face won't "mate" properly, resulting in premature eja...I mean wear. Lifter bores being all fk'd up is pretty common in big blocks...not sure about small blocks, but sounds to me like the cam.
it looks like the new cam has a little rougher casting and its protruding out just a little more we will be calling comp cams tomorrow to see about a replacement
Posting Permissions