JaSSon

iTrader: (11)

Up grading up tp 978s with new heads due to concerns about 987s,YTs and valve float with the X1. Are my stockers up to the task? Im not in a pinch for money but i can use it else where if the stock ones are up to it. Car has 60,000 on it and been using mobil 1 since 16,000 and change it too much. Thanks.

Damian

iTrader: (89)

Yes. A local guy near me is running 978's & stock lifters, no problems. They are close to pushing the limit, but do not produce enough pressure to calapse a stock lifter. The 977's WILL kill a stock lifter however...

Josh

JoSeY

I had Rev Duals (The big ones that required machining) and an X1...spun it to 6500 all the time...stock 110,000 mile lifters....(SHRUG)

JaSSon

iTrader: (11)

My main concern was my use of the YTs and the extra valvetrain weight added with the use of 987s, hence the upgrade to 978s. I guess the addition of Comp Rs will be added insurance. I was just wondering if someone had a set-up like this with stock lifters and how are they holding?

BLUEBYU

iTrader: (1)

Change them out when you get into your heads. When I get my TEA heads "hand finished to competition level" I am going to change to some Comp OEM replacements. I am not going over 580 lift on the cam swap ....... just bigger durations.
Your lifters will let ya know if they are failing and won't harm anything if they do. If they do, what a good reason to upgrade your heads.

Y2K2LS1

Is there anyway to quantify this with numbers? Like a stock lifter can take XXX amount of pressure at XXX rpm, and this spring has xxx pressure and that spring has xxx pressure and so on.. or is it not that simple?

Everyone keeps saying go doubles go doubles for insurance with the bigger cams. Yea but if my lifters are going to collapse from too much pressure then wtf? What is too much pressure or too much cam or a combination of both? This is where I get confused.

Maybe we need some valve spring 101

Brian Tooley Racing

iTrader: (13)

I have run 180 seat and 400 open pressure on stock lifters to 7000 rpm, (what I went 9's with), the new Ferrea spring was supposedly developed on a spintron, but checks almost 500 open on our checker The Comp 987 spring open pressure 360.

JaSSon

iTrader: (11)

So are the 978 too much pressure for the stock lifters with the YTs?

Damian

iTrader: (89)

No. The 978's have 400 lbs open, which isn't to much for stock lifters..

Josh