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Push rod length

Yesterday I got the motor running in the Supercab. I was getting a popping sound, didn't sound like it was coming out of the exhaust. Anyhow I just pulled the valve covers, set the motor to TDC and on the intake valve of the #1 cylinder I measured .063 thousands clearance beween the rocker and the valve. The book calls for .098-.0198 with the lifter collapsed. I dont have the tool to collapse the lifter and they don't list a spec other than that. So if they call for .098 with the lifter collapsed and I have .063 uncollapsed I think I need to order some longer push rods. Does this sound right?

I should also add that the heads were shaved .012 thousands.


Edit:

So after looking at comp cams sight it looks as though push rod length is either .060 short or .060 long over stock?


Ford

7837-16 9.500" V8 351M & 400M, 1971-79 5/16" H-H No
7838-16 9.440" V8 351M & 400M .060" Short, 1971-79 5/16" H-H No
7839-16 9.560" V8 351M & 400M .060" Long, 1971-79 5/16" H-H No



So if I go with the .060 longer pushrod it will close up my .063 gap in the uncompressed state. Does this sound about right to you guys?

Cam info: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&vxp=mtr&item=300948677200
 
Well after more diagnosing it looks as though I have no lifter preload. I also measured the push rod travel, valve opened all the way and valve closed all the way and only have a 1/4" of travel in the push rod.

So to me it looks as though I need the longer push rods.
 

DNFXDLI

The Token Canadian
Staff member
I can't recall specifics a the moment...but I'm pretty sure I needed longer pushrods for my build.
 
I can't recall specifics a the moment...but I'm pretty sure I needed longer pushrods for my build.

I ordered .060 longer push rods. After I get those and do some in motor measurement checks if I need to make any adjustments I can get a shim kit for the rockers. I'll get this figured out, thanks Duncan.
 
Well I haven't been able to really let this go and have been reading a lot and getting more info from other guys. Most of them seem to think with the heads shaved .012 thousands and the taller cam I should need short push rods. AND with more work on my part have come to the conclusion they are correct. After more reading I went out and with the motor at TDC and I installed the pushrods back in these holes and torqued the rockers down. Each of these cylinders will be at TDC so I should get a very accurate reading this way. I put a pushrod in, tightened down the nut till I could just barely spin the pushrod and then tightened the nut down fully. Here's my results on these cylinders once again confirming the push rods are to long.

#1 I 1 1/4 turns
#1 E 1 1/4 turns
#3 E 1 turn
#4 I 3/4 turn
#7 E 3/4 turn
#8 I 1/4 turn

I'll finish up the rest of the cylinders once I rotate the crank. I'll know all my numbers and should be able to figure out what shim to put on each rocker.

Stock push rods and a shim kit ordered from Jegs. Looks like I'll have a .060 longer set of push rods for stock.
 

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