push rods

dustym

Newbie needs help. I am putting back together a 304 for our Jeep. The engine that came out had the rockers that were tied together, the engine that I just had rebuilt had rockers simular to gm. I had installed new push rods from summit, and torqued them down to 25 ft lbs. When I tried turning the engine around, it stopped and with a little more persusion it rotated and I heard a bad sound. One pushrod was broken in 2 places, and checking the rest 2 more were bent. Took the head back off of the side that the push rod was broken, and everything looks fine. No bent valve or messed up piston. Well I pulled a pushrod out of the old engine and compared to the new ones and they were about 1/8 to 3/16 or so difference. The engine I rebuilt is of unkown year but the machine shop did put hardend seats to use with unleaded fuel, so maybe before 73. The engine that is in the jeep is an 80. Was there a difference in pushrod lengths, and which would be ok to use. Should I just snug the rockers down untill the rod doesnt spin and go 1/4 more turn? Thanks for any help. Tim

jeepsr4ever

7.800" is the length of the stock pushrods. I can see them bending especially if they were the cheap Summit pieces and not hardened. However sinceit did bend them I suspect the timing chain is on wrong and I would b hesitant just to throw a ne wset in and run it.

fifesjeep

I've heard of valves sticking causing the cheap pushrods to bend... I've seen pushrods not seated properly in the lifter seat and or the rocker seat and get bent... but it seems most often or not the timing gears are the issue... The timing Marks should be as follows.... Cam = 6 O'clock, Crank = 12 O'clock... To varify that you have it correct rotate the motor in a Clockwise manner by hand until the Cam gear timing mark is at 3 O'clock... The crank gear timing mark should point about 6 O'clock... Now count the chain links, You should have 10 links or 20 pins (Either or).
For pushrods I normally use CompCams one piece chromemoly pushrods... .080" thick. but then again I'm not running a stock set-up with lift and spring pressures...
If your valves ar sticking... use a deadblow or rubber mallet and give a good tap the top of the valve stem...