Thread: BBC 402 looking for advice on head work, cam and stall

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Life sort of beat me over the head about mid January so I've been really not paying much attention to this build. I'm gaining interest again now and getting ready to put it all back together again!

Went with COMP XR-270-HR/11-422-8 ( 1600-5400rpm, 110LSA, 270/276adv-dur, 218/224 @.050" ) roller kit with all components from COMP including cam and lifters. Will be installing roller rockers and molly pushrods.

The #063 heads were kept stock except for SS valves and the upgraded dual springs/retainers/keepers/seals, etc. as per the specs on the roller cam.

Hopefully I'll have this thing assembled and running in no time eh!

My current worries are...

o need to figure a way to either make one "set" of my lifters solid or purchase a single pair of solid roller lifters for pushrod length checking. I figure the pushrods I'll need will be an inch minimum shorter than stock so my check procedure needs to be spot on. What do you guys do in this situation to determine proper pushrod length

o without proper pushrods, which you really can't get without torquing down at least one head, how then will I be able to accurately do piston to valve clearance checking prior to getting accurately sized pushrods?

chicken => egg

Anyways,

Thanks,

-unix

Originally Posted by unixoracle

What do you guys do in this situation to determine proper pushrod length

https://www.youtube.com/watch?v=o5is9BsH5OU&t=16s

Originally Posted by unixoracle

Without proper pushrods, which you really can't get without torquing down at least one head, how then will I be able to accurately do piston to valve clearance checking prior to getting accurately sized pushrods?

Pushrod length will not vary valve lift. We try to get the proper pushrod length in order to center the shoe or roller of the rocker arm on the valve stem tip. Drop two oiled solid lifters into the block. Clay the pistons and sit the heads in place without head gaskets, just snugging them down with a few bolts. Install pushrods and rockers. Snug rocker bolts down to zero play. Install the head with a couple of bolts and just snug them down. Roll the crank over two full revolutions and remove the head to cut and measure the thickness of the compressed clay. Add the thickness of the compressed head gasket to your findings. DO NOT USE PLAY DOH, IT WILL NOT RETAIN ITS SHAPE AFTER THE VALVE HAS MADE AN INDENT. Use only oil-based (gray) clay from a craft or hobby shop. Oil the valve faces so that the valve will not stick to the clay.
https://www.youtube.com/watch?v=tjs61-TCZYw
https://www.youtube.com/watch?v=Dz7Fqo_oufU
https://www.youtube.com/watch?v=Y66lvdHbm60&t=285s

WATCH THESE VIDEOS SO YOU CAN ASK QUESTIONS BEFORE YOU DO THE PROCEDURE.

Some pictures...