NSSINR8 U

iTrader: (1)

LIL HELP! thanks

NSSINR8 U

iTrader: (1)

ttt

felton316

What I did was put a piece of clay on the cylinder then install the head, rocker and pushrod. Next, I turned the engine over by hand until it made a complete revolution. Then I removed the head and took the clay with an impression on it and cut it in half and measured the deepest part of the impression.

pimpmaro

Is there not a way to do it without pulling the head and using a dial gauge? I'm not sure how to do it, just heard it's possible. IF anyone knows about that, I'm interested. I've been wondering about that for awhile.

Slowhawk

iTrader: (12)

Take off the spring,install a tester spring.Use an adjustable pushrod and set it to 0 lifter preload.Install pushrod and lifter.Put dial indicator on valve and while rotating motor push rocker down till valve contacts piston.Do this till you find the tightest spot.That is your clearance.
No need to pull the heads.

BergerMan

The method described above will NOT tell you PTV clearance. It is not the correct way to do it.

First and foremost, find out from your cam mfr. what the valve lift is when the piston is at TDC.
For example: The intake lift on the G5X2 is .120" when the piston is at TDC.


This will take 2 people to do safely!

#1 Fill up the cylinder with compressed air (80-100psi) like you would if you had to change a valve spring.
#2 Remove the valve spring and clean the oil off of the valve stem.
#3 While holding the valve stem up, remove the compressed air from that cylinder. (DO NOT LET GO OF THE VALVE OR IT CAN DROP INTO THE CYLINDER IF THE PISTON IS DOWN)
#4 While still holding on to the valve stem where the keepers go, lower it until your fingers touch the valve seal (DO NOT LET GO!) Have someone rotate the crank slowly until you feel the piston pushing UP on the valve. Continue to rotate the crank until the valve reaches its peak and starts to drop just a little (YOU CAN LET GO NOW!) Now you are very close to TDC. Put an indicator on the tip of the valve stem and turn the crank the other way until you find the highest point. Now you are at TDC. (see now that wasn't so hard, was it!)

#2 Hold the valve up against the seat and using a caliper, measure the height from the top of the valve stem to the spring seat.
#4 Push the valve down until it touches the top of the piston. Measure the distance again. The total valve drop minus what you were told by your cam mfr. will give you the PTV clearance. It must be .080" (intake) & about .100" (exhaust).

EXAMPLE
G5X2 has an intake lift of .120" when the piston is at TDC.
Measured distance from valve tip to spring seat with valve UP = 1.900"
Measured distance from valve tip to spring seat with valve DOWN = 1.680"
Total Valve Drop = .220" (1.900"-1.680")
Minus the .120" lift @ TDC
Equals .100" PTV Clearance

I hope this explains it well enough...

pimpmaro

Just out of curiosity... and NOT that it would be any different if it is possible, but instead of a caliper, can you use a dial indicator in it's place to perform that method?

BergerMan

Yes, you can use a dial indicator and take readings directly from the tip of the valve stem. Just use one with a 1/2" stoke to make setting it up easier.

Slowhawk

iTrader: (12)

My way tells p/v clearance actually better than your way Your going by the manufactur spec.I'm going by actual clearence on rotation and opening closing rates.

BergerMan

Slowhawk, I understand what your procedure is trying to do but using a test spring and adjustable push rod without a solid lifter will not give you accurate results. The hydraulic lifter can bleed down, thus reducing the lift on the valve. Agree?