ok valvetrain guys, tough question.. pushrods

[jetuomi]

I am getting many conflicting answers to the "do I need new pushrods" question..

I am maintaining the same stock base-circle cam (custom cam with more lift), pedestal mount 1.6 roller rockers, but with edelbrock heads (and upgraded spring package)..

I can't picture anything on this setup that would require me to check valve-train geometry (but what do I know?)

I've been getting mixed reviews, can anyone say for certain? (also, how much is it to get my valve-train checked, is it like a 5 minute job, if so, I'll just do it and make 100% sure)

THANKS !

 

[Killercanary]

Yeh, just double check it. Put a dial indicator on the tip of the valve when its all assembled and then rotate the engine and take down measurements of what your max lift value is (it will be different than what your cam card says because of the lifter bleeding off since there is no oil pressure). Once you know what this is then start at max lift and rotate the motor until you arrive at exactly 1/2 of what your max lift value is... if your geometry is right then the pushrod, rocker and valve should all be a 90* to one another. This is hard to see with the motor in the car, and I have always done it with the motor out of the car for this reason. You definitely should check it. There are a TON of things that can make the geometry off, anything that changes the distance from the block (more importantly the lifter) to the end of the rocker can change you geomety, some exmples are: the head gasket is a different thickness from stock, the head itself positions the rocker a little higher or lower than before, etc. Hope that helps...

 

[JETHRO]

GIVE ME A CALL KILLER. 935-8709. id pm you but it was full. got a new project.

 

[jetuomi]

Yeh, just double check it. Put a dial indicator on the tip of the valve when its all assembled and then rotate the engine and take down measurements of what your max lift value is (it will be different than what your cam card says because of the lifter bleeding off since there is no oil pressure). Once you know what this is then start at max lift and rotate the motor until you arrive at exactly 1/2 of what your max lift value is... if your geometry is right then the pushrod, rocker and valve should all be a 90* to one another. This is hard to see with the motor in the car, and I have always done it with the motor out of the car for this reason. You definitely should check it. There are a TON of things that can make the geometry off, anything that changes the distance from the block (more importantly the lifter) to the end of the rocker can change you geomety, some exmples are: the head gasket is a different thickness from stock, the head itself positions the rocker a little higher or lower than before, etc. Hope that helps...

OK, thank you !! By the way Killer, how's the stock-bottom end for revving up to 6000 rpm?? no worries? (trying to figure out if I should rebuild or not yet)

 

[Killercanary]

Well its seen 6000+rpms more times than I can count and its still running strong, however I do have tons of blowby and it is in need or a rebuild in the next year or so. I've drag raced this car nearly every week since it had 18K miles on it, it now has 63K. If your compression is good I wouldn't worry about your bottom end. My dad shifts his at 6500+ and it has seen 7000rpms on more than a few occasions. It has a stock block, stock crank, stock rod, SRP standard bore pistons, a main girdle, and it is fully balanced. He's raced it now for two years nearly every week without a sign of any problems except it appears we installed the wrong pistons as the compression seems low. With some added compression, we expect the car to really pick up... it runs 12.01 at 115mph at 3350lbs now NA.

 

[jetuomi]

Well its seen 6000+rpms more times than I can count and its still running strong, however I do have tons of blowby and it is in need or a rebuild in the next year or so. I've drag raced this car nearly every week since it had 18K miles on it, it now has 63K. If your compression is good I wouldn't worry about your bottom end. My dad shifts his at 6500+ and it has seen 7000rpms on more than a few occasions. It has a stock block, stock crank, stock rod, SRP standard bore pistons, a main girdle, and it is fully balanced. He's raced it now for two years nearly every week without a sign of any problems except it appears we installed the wrong pistons as the compression seems low. With some added compression, we expect the car to really pick up... it runs 12.01 at 115mph at 3350lbs now NA.

sweet.. thanks.. and good luck on the re-build, you'll see 11's soon !! (totally sick)...

 

[Killercanary]

I doubt it will happen, but I'd like to take a shot at the 11's NA on the stock shortblock. When I do a rebuild I feel pretty confident I could run those times then, but I'd LOVE to do it with the factory shortblock. We will see come april. I have plans in the works as we speak to take nearly 100lbs off the nose of the car which should help some... will it be enough... doubtful but I know I will be closer than I was before!!! It still feels and sounds weird to even mention running 11's NA, a yer or so ago I think everyone here would have siad it was impossible, myself included. i never thought the car would run 12's!!!