Checking valvetrain clearances, please help!

I am finishing up my 4.0 rebuild, Bottom end came out beautifully, plastigauged all the bearings and everything was spot on....phwew, thank god! I finished the port/polish job, and valve job on the H.O. head I am putting on (I have a renix machine). You can see some of the head work here ( Head porting )

Now, here is where it gets a little gray.... what is the proper way to check the pushrod clearances/lifter preload this is something I haven't had to deal with yet?? on my small block 383 in my old cj, the rocker arms were adjustable and could be adjusted with the engine running, I haven't dealt with a motor with non adjustable rockers and I am assuming that you need shims/different lenght pushrods to change the valve train geometry. It would be a shame for me to lose the top end cause I did it wrong! :doh:

Also, I was planning on running the stock valve springs, but have been having second thoughts. I am running a new Crane 753905 truck power cam, (it replaces and has the exact same grind as the powermax 753901 cam)
If I do need to upgrade the springs/retainers/locks, where is a good source online for these parts, and is mopar my only choice, or is there other aftermarket support for these?

To sum the build up, its an 80(renix) 4.0, bored .040 over, Crane 753905(753901)cam, H.O.head ported/polished, 99+intake, H.O. throttle body, Melling H.V. oil pump. Any guess as to how much HP & TQ it may put to the wheels are always welcome. :shocked: It will be going to the dyno after I get 500 miles on it, probably next weekend!

Thanks for any help in advance.

Josh

You should either shim the rocker stands or use shortened pushrods, IF you shaved the head and/or block. I don't like shims if you can find pushrods of the right length. Basically, add the amount you shaved the head and block, and either shim by that much or buy pushrods that are that much shorter.

Or ... get adjustable studs. In the "good old days," stock AMC engines had studs with shoulders and the valves weren't adjustable, but the AMC cam kits came with adjustable studs and locking nuts.

Mopar JEEP ENGINES book recomends using shortened push rods with the standard type rocker arm.
If the head was not milled too much stock push rods should work.How much lift is in the cam? Stock springs? Wouldn,t want coil bind or to stack them solid.
Wayne

With turning the motor by hand there seems to be plenty of coils space left, but if I get into the higher revs and the lifters pump up, I don't want to break anything! The cam specs are here 753905 The deck was not machined, nor was the head, so I am pretty confident that the stock pushrods will be ok


Thanks for the help

Josh

My engine is a 2.5 but the principals remain the same. I broke a valvespring from too much preload...the result after the intake valve sucked was massive carnage. What happened was I over revved the engine from sudden wheelspin, floated the valves...(I later found that the Hi limit chip in my MSD had worked loose from vibration) when the lifter "took up the slack" there was coil-bind...an autopsy revealed that there was .165 of preload...after some discussion with my machinist and some input from Bennie at Hesco, we selected some different pushrods to give .047 preload. At that point the engine had some lifter chatter...the problem was from excessive bleed rate in the lifters...changed the lifters to some good TRW HP lifters (never use lifters that come loose in a plastic baggie from a so called "performance parts supplier") and that took care of the problem...