BOSS 357

iTrader: (1)

I've been researching a couple of measurements I'll need to make during this head swap. FYI, I run a hydraulic cam/lifter setup. Please calrify a couple things:

-if I use the "clay on the piston" method to measure the PTV clearance, how do I measure the clay? Is that with a dial indicator?

-the lifters I have will not be replaced during this swap and the engine will be cold. Is there any priming or whatever that I need to do to the lifters to measure pushrod length?

-should i use the solid lifter (the one I will use to measure PTV clear) to measure the pushrod length or should I use the hydraulic one already in the engine?

-I've seen the EOIC method of valve preload, one cylinder at a time. My Chilton manual uses a method that by setting #1 to TDC, I can do like 4 intake valves and 4 exhaust valves. Then rotate to #6 TDC and do the rest. Does the Chilton method apply to my hydraulic setup? Is one method more accurate than the other?

Thanks again..
Eric

Sonix

iTrader: (1)

ok, seriously give us some information hey? You have what, 4 cars? Which one are you talking about here?!?
Hydraulic WHAT? Hydraulic ROLLER, or flat tappet??!? I'm assuming roller here, but c'mon cough up the information already!

1) Clay - you cut it in half, and pull it off the piston and measure it with your calipers. You'll basically have a cross section. Measure the thinnest part. Probably the valve relief area.

2) no

3) won't matter. the spring inside the lifter holds it in place anyway. If you want you can buy a single solid roller lifter to play with.

4) Use EOIC. The chilton method is good enough for LAME factory grinds with no overlap, not any kind of aggressive aftermarket grind.

Good luck!

BOSS 357

iTrader: (1)

Sorry Sonix. I only have 1 car, the other 3 have taken their leave of me.

My car is a 355 TPI, hydraulic roller tappet & lifters.

Guest

Dont cut the clay. Use the depth gauge end of a micrometer (thats the small pointy thing off the back side) and push it into the clay until it contacts the piston where you think its the least clearance. Then slide the mic down until it contacts the face of the clay where its not deformed from the end of the mic, and use that number.

The Chilton's method is fine. Most people forget that even a cam with 360 degrees duration has 180 degrees on the cam thats on the base circle. Thats why there is nothing wrong with doing it that way unless your cam timing is way out of whack. Even with a Nascar cam.

Apeiron

I think you mean a caliper.
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The Chilton's method has you set the lash in only 2 cam positions. You can easily have a cam that's on the ramps on some valves in those two positions.

Guest

I know what the Chiltons method is... who stole it from GM anyway. Draw it up, mark out valve timing events and locations, and see for yourself. When you have the engine in one position, at least half the valves are completely shut, even with 360 degrees advertised duration. I dont think anyone here is running much past 310 if that, giving you a rather large margin of error. Then 180 out, you get the other half. As I said, Chiltons method is fine.

You're right, dial caliper is what I use.