SB push rod legnth checker, how to

[Dakota_Don]

hello, 72 360,.. decked with unmiled 70-72 cc heads.. .039 head gasket.. not sure of the deck height.. any way i want to use stock style hyd rockers with shafts.. since my deck is decked id like to check the PR legnth.
i set number 1 cly TDC, rotor pointing to no 1 cly...anyway i adj the rod checker till all lash is gone right? then do i tighten another ??? or what? I am affriad to throw stock ones on.. what do u think?

camshat is a hyd comp cam, xe274h

Thanks

 

[Dakota_Don]

thanks

 

[67Dart273]

No, do not check lash at TDC. Either use the Mopar chart or the "EOIC" method

Either method insures that the lifter is on the backside (heel) of the cam, which does not happen at TDC

When the EXHAUST valve starts to OPEN set the intake on that cylinder

When the INTAKE has opened and is nearly CLOSED set the exhaust on that cylinder

The chart, which requires you to mark the balancer every 90*

 

[72bluNblu]

What you need to do is make sure lifter is on the base circle of the cam lobe for the pushrod you're checking- ie, the valve is completely closed. The methods 67Dart mentioned work great, I just look and make sure the thing is on the base circle, but that's because I measure for the push rods before I install the intake.

Once you've figured out that the lifter for the valve your checking is riding on the base, adjust the checker until you feel solid contact. You don't want to worry about the lash, just figure out what the length is for zero lash. The lifter won't be pumped up, so you'll feel it start to compress if you go too far. I usually try to figure it out down to the 1/8 of a turn, that's about as close as you can eyeball the checker.

Once you've checked all the lengths, you can just add preload to the length. You probably want between .020" to .060", depending on your school of thought and type of lifter.

With any luck all of your pushrods check out in that range (or closer) and you can just buy one length. If you're really lucky, it will be close enough to a "standard" length to just catalog order something. Otherwise you're buying custom pushrods. Smith Bros. makes awesome pushrods, I've used them a couple times now (since I wasn't luck enough to be close to a standard length). Not cheap, but man are they nice...