Just installed the Canfeild 23500.

Im concerned about finding specific information about : cam base circle, deck height and my lifter length.

Im using lifters fom a roller cam alum L98. The pushrods I have seem to short.
Does anyone have a good link showing me how and where to find info about buying the right length of push rods?

Thanks,

 

All you need is an adjustable checking pushrod, a lifter, light weight checking springs (or an old inner spring) and some Dykem (machinists blue). Any good machine shop that does alot of racing engines will probably give or loan you a set of checking pushrods, because every set of Jesel rockers comes with a set. They're so common that the shop I use often uses them for welding rod when fabricating jig's, etc.

Bring the engine to TDC #1. Assemble and install a cylinder head on the block, with gasket, torqued into place. Be sure to use lightweight checking springs or some old inner springs to avoid pushrod deflection. The adjustable checking pushrods are usually made of aluminum, and with the threaded tip, they will deflect if high pressure springs are used, skewing your results. Lightly apply some Dykem to the valve stem tips of an intake/exhaust valve pair.

Install the lifter on the #1 intake lobe and install the adjustable pushrod and rocker arm. Rotate the engine over a complete turn and note the pattern that the rocker tip made across the valve stem, indicated by the Dykem. The goal is to keep the rocker arm tip within the center 1/3 of the valve stem tip. Movement of the rocekr tip will be indicated because the Dykem will be worn off in the affected area.If the valve stem tip shows rocker movement on it's inner 1/3 diameter, lengthen the length of the adjustable pushrod. If the valve stem tip shows rocker movement on it's outer 1/3, shorten the adjustable pushrod.

It's a matter of repetition. Once you're able to adjust the pushrod to maintain rocker arm travel over the ceter 1/3 of the valve stem tip, remove the rocker arm without turning disturbing the pushrod. With the rocker arm removed, remove the adjustable checking pushrod, and measure it's length - the result is the length of the pushrod you need to order. Remember that pushrods are offered in incrmental lengths of .050".

Usually the pushrod lengths are identical for both intake and exhaust, but it's always wise to check the exhaust as well, especially if rocker arm ratios are mixed.





[Modified by Monty, 3:04 PM 2/26/2002]

 

Monty,

Thanks a lot for taking the time to type that out, I appreciate it.
I will head to my nearest builder and ask for a set of adjustable push rods and get this done. Im very close to having the vette back out on the track.

Thanks

 

Is this the same for a roller and flat tappet?

 

Yes, roller vs. flat tappet doesn't make any difference. The only real concern is when you use hydraulic lifters, whether roller or tappet. You need to use light springs for the additional reason of not wanting to compress the plunger in the hyraulic lifter. With light springs you won't.

When doing a hydraulic lifter, roller or tappet, it's always advisable to either replace the lifter with a solid lifter of the same design and height to eliminate the chance for error if the plunger collapses. Unfortunately, most of us don't have spare solid lifters of the same hieght sitting around if we're using hydraulic lifters. In this case, you could remove the plunger from the lifter and reinstall it upside down. This will eliminate the movement of the plunger, but will still give you the same pushrod seat height for taking your measurements.

Just use some light checking springs and you won't have to worry about the lifter variance.


[Modified by Monty, 11:17 AM 2/27/2002]