rickyricardo1969

iTrader: (6)

How much can you safely mill L92 heads for a ly6 for more compression b4 you have problems?
my local speed shop said around 20thou? sound about rite?
my cam is a 226/234/.602 and my pushrod length is 7.425

WKMCD

iTrader: (2)

Mine are .030 - no problems.

briancb1

Mine are .030" as we'll. It took the chambers down to 66cc's

cbr600rx7

iTrader: (12)

^ have to agree with the guys above. I have seen a few guys running .030 with no problems on here.

69LT1Bird

iTrader: (1)

.030 here too, cut away.

rickyricardo1969

iTrader: (6)

sounds good but will i have to change my 7.425 pushrods?

69LT1Bird

iTrader: (1)

Most likely, the best thing to do is check to make sure. Logic says yes. Do it right the first time and save some aggravation later.

NemeSS

iTrader: (127)

I never go more than .030 on any oe head. .030 is a typical cut

Rreemo

I was told to go .030 with mine, but I am running VVT with a MAST stage II cam, and I'm afraid of clearance issues due to the VVT.

rickyricardo1969

iTrader: (6)

Well i sent pat g a email on this subject here is his reply.
"Rick,

I wouldn't mill too much...maybe .010". P to V is tight with no valve
reliefs.

Geoff"

i have decided not to cut in the future i might do a 408 untill then there going to stay stock.

Gregory

iTrader: (4)

I have always wondered this. I once considered a set of L92 heads but the vendors were reluctant to mill to anything less than 62cc saying the flow is disrupted and the chamber would need rebuilding. But, my thought is that a shallow chamber gets the valve into the larger cylinder area earlier where flow is unrestricted. Maybe it is a turbulence thing.

My LS6 style heads have 53cc chambers and I run like 12.2:1 static and 8.5 dynamic. In the past, the ET Heads people offered chambers as small as 35cc I believe.

With this I am not including the issue of deck thickness or warping because it was mentioned, but not considered a factor for a N/A engine without extreme compression. I have had no head gasket/sealing issues. P/V clearance and push rod length should also be ignored for argument. They are adjusted and fine.

I'm just throwing this in the mix for conversation.

Thanks!

RONIN LSX

iTrader: (44)

I am opposite of you all lol. I am saving for the stage 3 l92 west coast cylinder heads and I'm looking to open the chambers up. If I remember right rich said they can open up to a 75cc chamber.

briancb1

Why are you trying to do that?

RONIN LSX

iTrader: (44)

I's guess that you're talking to me lol.

Because of my setup and to get the CR that I want I need a larger chamber. If I go the other route and dish the pistons to get the desired CR, that would make them to thin and top ring land to weak.

towbar

[QUOTE=Gregory;14948669]I have always wondered this. I once considered a set of L92 heads but the vendors were reluctant to mill to anything less than 62cc saying the flow is disrupted and the chamber would need rebuilding. But, my thought is that a shallow chamber gets the valve into the larger cylinder area earlier where flow is unrestricted. Maybe it is a turbulence thing.


I think the 'cylinder area' might be just the problem. On an L92 engine the bore is actually smaller than the chamber in the head. The bore itself shrouds the valve. Cutting the head makes things worse because the valve now goes deeper into the bore.

jimmer1g

So would taking off .030 and keeping the VVT be ok or not with a cam that has around .600 lift

rpturbo

iTrader: (47)

That means BOOST!!!!