pushrod length
#3
Re: pushrod length
OP
did you try using your stock PR and see where the witness mark lands vs with the PR checker set at 7.050"?
if the witness mark is more towards exhaust side than yes you would need a shorter PR
I answered your ? on the other site but curious where the witness mark winds up testing with stock 7.200 and your test spring
maybe your particular cam is just he way it is getting you the measurement you get and all is fine. with that said most doing a cam swap and keeping stock heads/block & head gasket wind up fine with stock length PR....maybe your cam is more "small" base circle cam than stock..
did you try using your stock PR and see where the witness mark lands vs with the PR checker set at 7.050"?
if the witness mark is more towards exhaust side than yes you would need a shorter PR
I answered your ? on the other site but curious where the witness mark winds up testing with stock 7.200 and your test spring
maybe your particular cam is just he way it is getting you the measurement you get and all is fine. with that said most doing a cam swap and keeping stock heads/block & head gasket wind up fine with stock length PR....maybe your cam is more "small" base circle cam than stock..
#4
Re: pushrod length
Sounds a little on the short side.
For comparison AI did my heads as well, the heads were marked .017 when i got them back so I would assume that's what they took off.
My block was also decked down to about 9.015
With that being said I am running 7.100"
Without touching the block I would expect closer to 7.150
For comparison AI did my heads as well, the heads were marked .017 when i got them back so I would assume that's what they took off.
My block was also decked down to about 9.015
With that being said I am running 7.100"
Without touching the block I would expect closer to 7.150
#5
Re: pushrod length
Disregard my post I didn't notice that your heads are stock. I have aftermarket valves installed by AI which would affect PR length. Like previously stated I would expect your length closer to the stock 7.2" length.
#8
Re: pushrod length
if not centered and closer to the exhaust manifold side then yes you need a shorter PR
Weird though that using same heads, head gasket and no block & head machining you come up with a PR that short
what brand, model # of cam you put in??
#9
Re: pushrod length
Advanced induction 226/234 cam ls7 lifters cc 1.6 roller rockers I used comp cams checking spring also when checked pr length I just installed the stock pushrod just to see started to tighten up the poly lock nut and noticed the rocker tip sitting more toward exhaust side
#10
Re: pushrod length
well it sounds like you checked properly. maybe the base circle of the AI cam stock is just larger than OEM
go with what your measurements show for 7.050" PR
go with what your measurements show for 7.050" PR
Last edited by Chimera96; 02-14-2015 at 11:36 AM.
#12
Re: pushrod length
I measured it today again with the stock push rod it marked the valve toward exhaust side but somthing seemed wrong didnt notice other time I measured. when I put it to zero lash I should just feel the rod drag a little right well I did that but when I spun the motor by hand I noticed the roller rocker come loose wen it was at #6 TDC kept spinning the motor like 3 or 4 turns by hand when I would stop back at #1 TDC the rocker pushrod is tight again removed and mark was toward exhaust then did it with length checker did the same becomes loose like I mentioned with other pr then at #1tdc is normal but mark on valve stem is in the middle any ideas did it with solid and regular lifters thanks in advance
#13
Re: pushrod length
I am not sure what you are trying to say..
but for finding "zero" lash you stop when there is no more UP/DOWN movement. If you are spinning between fingers until you feel drag, you are past zero lash.
for checking PR length you want to do it zero lash, no pre-load
but for finding "zero" lash you stop when there is no more UP/DOWN movement. If you are spinning between fingers until you feel drag, you are past zero lash.
for checking PR length you want to do it zero lash, no pre-load
#15
Re: pushrod length
small base circle refers to the size of the cam lobe base. Maybe AI cuts smaller base circles or larger seeing as your PR check comes in at 7.050. No big deal. This is why when changing cams or doing "heads" or getting block decked or changing head gasket thickness you always need to confirm PR length. If witness mark is off center that side loads the valve and you will kill valve guides that way