chuyz28

Hey guys got a question did a cam swap a I 226/234 cam did not remove heads installed checking spring and length checker got a 7.050 does this sound about right thanks in advance

maybe2fast

I used the stock length hardened rods...

I did the sparpie on the valve tip and the contact was in the correct spot.

Chimera96

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..

8cylinders>4

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

8cylinders>4

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.

97WS6SCharged

Sounds like your lifter has bled down. You need to use a solid roller lifter to get an accurate measurement from the pushrod length checker.

chuyz28

I did it both ways regular lifter and also solid got same measurement of 7.050 can't upload pics but mark is centered on valve tip

Chimera96

so did you try a 7.200 length to see where the witness mark landed?

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??

chuyz28

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

Chimera96

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

mzgp5x

I run a Cam Motion 231/240 wit 580" lift an, 1.5 comp rockers. I measured it to 7.30" PR's/

chuyz28

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

Chimera96

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

chuyz28

OK I'm going to do it that WAy but the valve stem marks in the middle with the 7.050 push rods and also what do u mean by small base circle

Chimera96

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