thebulgd

iTrader: (6)

What is the proper way to measure out of hole? Pistons flat at TDC, measure at top of block or Piston at TDC and "rocked" ?

Engine has
Eagle 6.125 Rods
Mahle -4 pistons
out of hole is .018 flat
out of hole rocked is .033

measured with a feeler gauge, will be getting dial indicator today and will measure with that.

405HP_Z06

iTrader: (11)

The proper tool to check piston deck height is a deck bridge:



Generally you use the hole in the center to check piston deck height.

KCS

iTrader: (20)

You rock them at TDC using the deck bridge shown above^^^^

Zero out on the deck, then put the indicator tip at the edge of the piston (thrust side). Rock the piston, measuring up and down positions. The average is your in/out measurment. Repeat on the opposite side of the piston.

thebulgd

iTrader: (6)

WTH? Been reading 15+ pages and never saw that that thing, LOL. I dont think I'll be buying on of those for my garage build, but if I were to use one of those wouls the piston be flat or rocked?

KCS

iTrader: (20)

Rocked. Now push the piston down and see what it says then. If it's .033" out and then it says .00" when you push it in, the piston is about .016" out of the hole.

thebulgd

iTrader: (6)

ok, so now which measurement do I use to get my quench height? Can I use GM MLS gaskets?

KCS

iTrader: (20)

Use the largest measurement out of the hole. If the thrust side measures .016" out and the opposite measures .018" out, go by the .018" since it's closest to the cylinder head. Subtract your "out of the hole" measurement from the head gasket thickness, and thats your quench distance.

GM gaskets are usually .051" thick, so .018" would leave you with .033". That is pretty damn close and really doesn't leave much of a margin of safety. Personally, I wouldn't run that unless I had good reason to know it would clear.

Michael02hawk

iTrader: (26)

Isn't there a little more to PTV clearance than what has been talked about in this thread so far? How about the head, and if/how much its milled? That would play an equal factor into clearances, along with how much the piston is coming out of the hole.

405HP_Z06

iTrader: (11)

The OP was asking about piston to deck clearance, not piston to valve clearance.

Michael02hawk

iTrader: (26)

Got ya, Thanks!

ZMONSTER!

iTrader: (9)

OP has no reason to worry about PTV clearance, bastard.
Hope you can figure this stuff out OP, but ive heard your not too bright.

Gary Z

Measuring deck clearance with flat-top pistons is easy. Locate TDC using a dial indicator near piston center. Then place a straight edge across the center of the piston parallel to the wrist pin and measure deck clearance with a feeler gauge. The tricky methods are only needed with domed pistons.

thebulgd

iTrader: (6)

I'll tell you the main dam problem, too many people who have no experience regurgitating mis-information. That leads to confusion for the inexperienced (like me) and makes me have to read through pages and pages of search results to find the few postings by people who have actually built an engine and know what the are talking about. Thats not just in this section but through out this dam site. People who have never used/tried something run around talking as if the know something about something when all they know is nothing (confused yet?)

anyways, problem solved build going forward.

and wheres my dam hood hinges? Ima be needin em soon