Push Rod adjustment
Jimbos76cj
Full Time Jeeper
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- Location
- St.Cloud FL
- Vehicle(s)
- 83 CJ-7.. 4" YJ springs front rear, J-10 44 front/AMC 20 rear,6 cy auto dana 300 35' bfg Done and gone!!
Ask me about my head light upgrade harness!!!
I found a crack in my block last week and luckily had another good AMC 258 i6 / 4.2l block in the shop. I verified all the clearances on the bottom and were good and replaced all the seals and gaskets.
After bolting down the head I went to work on the rocker arms and came up with a problem. My push rods are to long. When the lifters are on the cam lobe base torquing down the rocker arm bridges will cause both valves to open enough that a shop vac placed on one port will pull alot of air through the other.
So heres what Im working with. Im using the head from the motor with the cracked block. Its a good head that was remanned less then 10k miles ago by the PO.
The new block was machined also around 15k miles ago by its PO. The new block has a bigger cam and had a 4.0 head on it that Im not using for now. The the paper work for the motor and info from the guy both show a shorter push rod was used with the 4.0 head along with a "thinner gasket" I think it shows as a .03 thick compared to the .043 standard gasket.
I swapped over the push rods from the 4.0 head and they are to short by a lot.
Unfortunately I dont know how much maching was done to either head or block in the reman process.
Ive done some reading and it seems like I have 3 options
1) Shim the bottom of the pedestal and use the longer rods
2) Have the bottom of the rocker arm surface machined to make them shorter and use the shorter rods.
3) Custom length push rods.
Any one have any input or ideas on how to fix this?
After bolting down the head I went to work on the rocker arms and came up with a problem. My push rods are to long. When the lifters are on the cam lobe base torquing down the rocker arm bridges will cause both valves to open enough that a shop vac placed on one port will pull alot of air through the other.
So heres what Im working with. Im using the head from the motor with the cracked block. Its a good head that was remanned less then 10k miles ago by the PO.
The new block was machined also around 15k miles ago by its PO. The new block has a bigger cam and had a 4.0 head on it that Im not using for now. The the paper work for the motor and info from the guy both show a shorter push rod was used with the 4.0 head along with a "thinner gasket" I think it shows as a .03 thick compared to the .043 standard gasket.
I swapped over the push rods from the 4.0 head and they are to short by a lot.
Unfortunately I dont know how much maching was done to either head or block in the reman process.
Ive done some reading and it seems like I have 3 options
1) Shim the bottom of the pedestal and use the longer rods
2) Have the bottom of the rocker arm surface machined to make them shorter and use the shorter rods.
3) Custom length push rods.
Any one have any input or ideas on how to fix this?
