|
I am not sure how many folks do or don't do this, but if your among those that do not, you should. Not only can your engine benefit, it also add to your knowledge on how to tailor your engine to specific needs.
Step 1. Determine TDC with your pulley. Having your engine our and disassembled to a short block is the best, so I will go with that. Have your engine on a stand, with the #1 P/C installed and held down square on the case. Using a dial indicator, measure .050" BTDC and .050" ATDC. Add those two measurements up, then divide by 2. The difference is TDC on your pulley. This will also show if your pulley is accurate as marked.
Step 2. Total lift. This is easy. Using a dummy lifter and half a pushrod epoxied in the lifer, position the dial indicator to zero and watch the dial indicator rise to the point of stopping. Note the needle on the dial indicator and you have total cam lift. Write this down, its imprtant.
Step 3. Duration @ .050" This is probably the most accurate measurement. To do this, zero the dial indicator on the TDC of the #1 piston. Rotate the crank clockwise till the dial indicator rises to .050". Write that number down. Continue turning the crank in the same direction till it lowers back to .050". Write the measurement down. Okay, now that you have the IO and IC measurements, add 180 degrees. Example, 26 degrees Intake Open + 56 degrees Intake Close + 180 = 262 degrees. That would be an Engle 125.
Step 4. Advancing/Retarding - This will help you if you want more grunt on the low end or more oomph at the top end. Advancing helps with the "out-of-the-hole" low end. Retarding helps with the top end. Generally 2 degrees does not do much either way unless your cam is advance 2-3 degrees from the factory. Then it helps to bring it back to "Straight up" status. Until you do 4 degrees either way, then you start to notice. Most just run straight up.
Hope this all helps...
_________________
Now, it's a 2387...
C'mon, I dare ya...
www.bayareavwclub.com
|
Login
Register
FAQ
Search
