XLR8NSS

iTrader: (4)

Just figured that G5X2 thing might get people in here. <img border="0" title="" alt="[Razz]" src="gr_images/icons/tongue.gif" />

Is .031-.033 to tight? It seems that some aftermarket LS1 pistons come outta the hole .01". With a Fel-Pro gasket that would get the quench height mentioned above.

I've read a little about it but, don't know much so any general discussion on the subject would be great.

How does pin height and bore diameter play a role in determining a safe quench height?

Thanks

John

<small>[ March 10, 2003, 06:53 PM: Message edited by: XLR8NSS ]</small>

XLR8NSS

iTrader: (4)

<img border="0" alt="[chug]" title="" src="graemlins/gr_chug.gif" /> <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" /> <img border="0" alt="[pimp]" title="" src="graemlins/gr_pimp.gif" /> <img border="0" alt="[barf]" title="" src="graemlins/gr_barf.gif" /> <img border="0" alt="[cry]" title="" src="graemlins/gr_cry.gif" /> <img border="0" alt="[boring]" title="" src="graemlins/gr_zzz.gif" />

<img border="0" title="" alt="[Razz]" src="gr_images/icons/tongue.gif" />

BurnOut

iTrader: (1)

Some interesting reading: http://www.speedomotive.com/Building%20Tips.htm

I don't have the resources (to play with) to verify what's been said there, and I haven't needed to build a motor since I read that.

SStrokerAce

iTrader: (2)

A quench area of .035-.040 is optimum on a sub 7000rpm steel rod motor. A .031-.033 like you said could be a bit to tight and you might run into having the pistons hitting the bottom of the heads, some cams will give you PV problems with that low of a height.

A .050+ Qunech will start getting into detionation issues if you are running a high static compression ratio or a high dynamic one due to a small cam. I generally run tradtional small block chevys with a zero deck block and a .0395-.0410 gasket to get the quench height in the right range. On a LS1 stock gaskets are in the .054-.062 range if I remeber right so you need to run the piston out of the bore. Now the new Fel Pro's allow you to keep more of the piston in the bore.

"How does pin height and bore diameter play a role in determining a safe quench height? "

By pin height do you mean compression height, liek when you move the pin closer to the top of the piston due to longer strokes and longer rods?

Pin height itself give you the axis about which the piston rocks, and the larger the bore the farther up and down the rock can be depending upon the wall clearance you run. A hyperutectic piston like a stock one will rock less due to the taller compression height, small bore and hyper piston. A 4.125" bore, Forged Piston, with a short compression height will rock more. So therefore need a few thou more clearance.

I hope that helps.

Bret

<small>[ March 11, 2003, 02:07 AM: Message edited by: SStrokerAce ]</small>

XLR8NSS

iTrader: (4)

Bret - Thanks, that helps. People using the felpro .041" compressed gaskets should be careful then if using some of the -.01" deck height aftermarket pistons I guess. When I said pin height I did mean compression height. I've heard that measurement referred to both ways. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> I imagine a smaller bore could run less quench height due to the fact that the piston "rock" would be less pronounced on the outside edge of the piston than with a bigger bore.

Burnout - I read that article. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> That's what made me wonder what people have been doing with the LS1 in this area.

John