A70camaro

OK would like to know the highest lift/duration
that can be run with out having to notch
the stock pistons .From past experiences .

In a few days I will be able to find out myself
but wouldlike a hint now ;-)

One factor being I will not mill the heads
if its gonna cause problems ,if its not gonna
be a problem then they are getting cut down.

AlonzoVersion 1.0

[quote]Originally posted by A70camaro:
<strong>OK would like to know the highest lift/duration
that can be run with out having to notch
the stock pistons .From past experiences .

In a few days I will be able to find out myself
but wouldlike a hint now ;-)

One factor being I will not mill the heads
if its gonna cause problems ,if its not gonna
be a problem then they are getting cut down.</strong><hr></blockquote>229 is the biggest I would go bro even with milled heads.

Colonel

There is no one answer to this. It also has to do with the LSA, centerline, and degreeing of the cam.

I'm no cam expert. Maybe Chris B or someone could elaborate. I know just enough about cams to get myself in trouble. <img src="gr_grin.gif" border="0">

ChrisB

I really depends on the entire setup - like colonel pointed out. More agressive lobes, as well as greater duration generally have a larger effect on P/V clearance than max lift does. You could have 2" of lift as long as it was all at BDC <img src="gr_stretch.gif" border="0"> .

If you are using a cam that no one has used before or is on the edge then you really need to clay it before actually running it. What cam/cam specs are you thinking of going with?

Chris

VINCE

iTrader: (1)

I was thinking of asking this same question.. I have been considering upgrading for a cam with a higher lift, but I am afraid of the piston to valve clearance issue as well. If my heads get milled .030 and I use 7.350 pushrods.. How big a lift could I get away with? Of course you want to get a lift near peak flow #'s.. My peak is at .650, but something between .585 to .595 would be optimal..

One Monkey

Vmoore what duration and intake center and lobe separation are you planning on running?

VINCE

iTrader: (1)

Actually I have not decided exactly what I want to run.. Somewhere between 222 and 228 Intake and Exhaust will be the same.. LSA most likely will be 113 or 114..

VINCE

iTrader: (1)

Oh yeah.. I have the 5.3L heads.. Cam change will be to offset the future increase in compression.. <img src="gr_stretch.gif" border="0">

One Monkey

well if you go with the 222--- or the 228 would make a big diffrence in p/v clearance. so it's no point checking till you figuer what you are running. how ever. I belive they where some 228 cams out there but I would check p/v very carfully at that point.
you want too have .100 clerance. at 10degree before for the EX and 10 degree after for the IN.

[ February 27, 2002: Message edited by: One Monkey ]</p>

ChrisB

FWIW our Pig cam - 226/226 .591/.591 112 clayed at 0.102 on the intake and 0.094 on the exhaust with GTP stage II 5.3 heads (2.02/1.57) - that was on a 110 IC. I would keep a minimum of 80 thou clearance.

But honestly, there is *no* way to know except by claying it yourself. If you go with something on the edge I would *Definitely* do this. Duration can many times make a larger difference than max lift also.

A70camaro

I'm gonna clay it no matter what , I already
have the cam and its is 229 , .580 something
I will make sure I have extra clearance and clay it without head gaskets.

I am also milling the heads , So most likely
I am going to have to touch up the pistons

Hopefully I will only have to change pushrod length if everything else clears .I am running
1.430 double springs and hopefully they will
clear the rocker arms ,otherwise I will be
buying Jesel's :-/ ,if I have to buy those
I wish I had gotten a solid roller.

I see other people are getting away with it
hopefully I can .

And if I have to do that it will be another month before the engine will be running.

VINCE

iTrader: (1)

Once I get my setup situated and give the specs to my cam adviser.. Jason99TA <img src="gr_stretch.gif" border="0"> I will let you guys know. I am still waiting for these XE-R supercams to produce on the street rather than on paper...

VINCE

iTrader: (1)

From experience.. 1.46 double springs do not clear the rocker arms..