hyperzone

Assume you have a completely bone stock LT1 engine. What is the maximum valve lift you can goto without hitting the pistons? I'm sure there's more involved than just the lift so, at least, where is the safe zone and where does the danger zone start?

the_merv

iTrader: (88)

Someone else has a thread very similar to this one..

hyperzone

Well, I started wondering when I read the "another cam thread" thread about this and I didn't want to hijack his. I dont know if my computer is screwed up or something but, the search hasn't worked the last like 3-4 times I went to use it so, sorry about asking this if there's already another thread.

the_merv

iTrader: (88)

I was just throwin it out there cause someone might post your answer there.
That and so no one jumped in your *** about the search..

streetwarrior96

Well with the LT4 Hot cam you already need to upgrade. I have a friend running stock with the Comp Cam 503

seawolf06

iTrader: (8)

He means until you hit the piston, not until you need new valve springs.
I would assume you can go higher than any shelf cam has in it. The gaskets are about .050 thick and the pistons are about .025 in the hole. The LT1 chamber is much smaller than other sbc, but I think you'll be ok with about .650 or so. What were you planning on running and why were you going to do it on a stock LT1 shortblock? Most LT1 cams that people run on stock blocks are around .550-.590 valve lift.

speed_demon24

iTrader: (6)

Lift has nothing to do with valve-piston clearance.

Sweetred95ta

iTrader: (2)

Exactly, it's the duration.

Armyman2445

iTrader: (17)

I had a cc305 on stock springs before never had a problem but i know that a hotcam requires new springs. Ive always been told that .510 is the max lift for the springs before they would break.

seawolf06

iTrader: (8)

Wouldn't it be a combination of the two? This is interesting.

Sweetred95ta

iTrader: (2)

Kind of. Basically, it doesn't matter how much lift the cam has (realistically speaking), if the duration is causing the valve to be open too far as the piston is at TDC, you will have contact. You can run a high lift cam with a smaller duration and get away with it. Run a lower lift cam (Hotcam, CC305, ect.) with a **** ton of duration, and you'll have problems. Am I making sense? This is a little harder to type and explain than I thought.

SStrokerAce

iTrader: (2)

It has to do with the piston being up around TDC and the valves are both open.... IF you open the intake valve sooner and close the exhaust valve later then P to V will tighten up. So to put that in laymens terms.... lower LSA or higher duration or both will tighten your P to V.

As for the lift last time I checked you could do over 1" of lift without problems there.

Bret

seawolf06

iTrader: (8)

speed_demon24

iTrader: (6)

LT1nitrouZ

Well hate to hijack a thread... but how do you calculate max lift on a set of springs? Most of them dont have that listed and I am tired of calling folks

trax

iTrader: (2)

http://www.compcams.com/technical/va...art/216-06.pdf

SStrokerAce

iTrader: (2)

Generally the rule is you look thru that chart and find the coil bind height add .080" to that number. Subtract your installed height from the number you just got and that's the max lift.

Depends on the valvetrain but you can push that coil bind number tighter if things are correct.

Bret