Is my piston to valve clearance measurement correct
01-24-2004, 03:56 PM
#1
TECH Enthusiast
Thread Starter
iTrader: (7)
Join Date: May 2002
Location: East Tennessee
Posts: 747
Likes: 0
Received 0 Likes
on
0 Posts
Is my piston to valve clearance measurement correct I will eventually clay the new setup. But for now I just want to take a measurement and see what I found. Let me know if I am on track.
1. I put the piston at TDC but getting the dot to dot close on the cam and crank sprocket and watching that the valves closed and before any opening of the valves. I know this is not perfect TDC as I need to remove the heads to do that which I will eventually do.
2. I took off the spring to the intake. Pushed the valve down to the piston.
3. Set the dial indicator on top of the valve and zeroed it.
4. Pulled the valve up.
I know this is not exactly the same as other ways described but the measure taken should be the same. If I am wrong please set me straight.
The measurement was 0.147. So, if I want to put in a G5X2 cam I would have to fly cut. Right? That would be .147 - .120 = PVC of .027 which is not enough for that cam - just using that cam as an example.
Did I get this right?
How could I find out if this is enough intake pvc for a TR 236/230 or a TR 230/224 or a MTI X1 or the TSP 231/237?
1. I put the piston at TDC but getting the dot to dot close on the cam and crank sprocket and watching that the valves closed and before any opening of the valves. I know this is not perfect TDC as I need to remove the heads to do that which I will eventually do.
2. I took off the spring to the intake. Pushed the valve down to the piston.
3. Set the dial indicator on top of the valve and zeroed it.
4. Pulled the valve up.
I know this is not exactly the same as other ways described but the measure taken should be the same. If I am wrong please set me straight.
The measurement was 0.147. So, if I want to put in a G5X2 cam I would have to fly cut. Right? That would be .147 - .120 = PVC of .027 which is not enough for that cam - just using that cam as an example.
Did I get this right?
How could I find out if this is enough intake pvc for a TR 236/230 or a TR 230/224 or a MTI X1 or the TSP 231/237?
01-24-2004, 06:50 PM
#2
Launching!
Join Date: Jun 2003
Location: St. Louis, MO
Posts: 233
Likes: 0
Received 0 Likes
on
0 Posts
If you have an old head gasket installed and a few bolts tightened and these are the measurements you have, then YES, your measurements are correct and you will have to flycut a notch about .065" deep. With stock heads the valve drop is about .205" with the piston at TDC so you need to be around .210"-.215" to be safe. Also, the lift of the G5X2 is .128" @ tdc not .120"!
Do not look at the sprockets to find TDC. If you have the heads off, use the indicator on top of the piston and rotate the crank until the piston reaches its highest point, this is TDC.
Do not look at the sprockets to find TDC. If you have the heads off, use the indicator on top of the piston and rotate the crank until the piston reaches its highest point, this is TDC.
01-24-2004, 06:52 PM
#3
You can measure that way, but it isn't "perfect. It does give you the idea of whether or not you need to cut or not though. I would push the valve down till it hits the piston, and while keeping pressure on the valve, knudge the motor clockwise or counter till the valve is at it's utmost highest point. This is a pretty good way to know that your piston is all the way up. Then take the same measurments again. I was told by LG that the X3 112 lsa would need .220" valve drop. I'm sure the X-2 will need a bit less than that. Not sure of your equation, but if you have .147 valve drop, you would need to fly cut .073" to get the manufacturers reccomended valve drop for a X-3, 112. Best thing to do is call the cam manufacturers, and ask for the reccomended valve drop for the cam to clear safley.
01-25-2004, 01:54 PM
#4
Originally Posted by BB
I will eventually clay the new setup. But for now I just want to take a measurement and see what I found. Let me know if I am on track.
1. I put the piston at TDC but getting the dot to dot close on the cam and crank sprocket and watching that the valves closed and before any opening of the valves. I know this is not perfect TDC as I need to remove the heads to do that which I will eventually do.
2. I took off the spring to the intake. Pushed the valve down to the piston.
3. Set the dial indicator on top of the valve and zeroed it.
4. Pulled the valve up.
I know this is not exactly the same as other ways described but the measure taken should be the same. If I am wrong please set me straight.
The measurement was 0.147. So, if I want to put in a G5X2 cam I would have to fly cut. Right? That would be .147 - .120 = PVC of .027 which is not enough for that cam - just using that cam as an example.
Did I get this right?
How could I find out if this is enough intake pvc for a TR 236/230 or a TR 230/224 or a MTI X1 or the TSP 231/237?
1. I put the piston at TDC but getting the dot to dot close on the cam and crank sprocket and watching that the valves closed and before any opening of the valves. I know this is not perfect TDC as I need to remove the heads to do that which I will eventually do.
2. I took off the spring to the intake. Pushed the valve down to the piston.
3. Set the dial indicator on top of the valve and zeroed it.
4. Pulled the valve up.
I know this is not exactly the same as other ways described but the measure taken should be the same. If I am wrong please set me straight.
The measurement was 0.147. So, if I want to put in a G5X2 cam I would have to fly cut. Right? That would be .147 - .120 = PVC of .027 which is not enough for that cam - just using that cam as an example.
Did I get this right?
How could I find out if this is enough intake pvc for a TR 236/230 or a TR 230/224 or a MTI X1 or the TSP 231/237?
