Does spring height absolutely need to be measured when installing LT4 valvesprings? I'm going with these since I am just running the stock cam but with my 1.6rr's, and LT4 springs seem the most economical way to go.
Anything else I'll need for this install besides springs, retainers, and locks?

Thanks!

 

ttt

 

as long as it is stock valves, etc. you should be able to "slap em on" with the stock shims in place.

If you do not already have the springs, I would reccommend the C M 612's from Combination Motorsports for $80. they will work great and be able to accept a larger cam in the future where as the Hot Cam springs are pretty much done with the Hot Cam and ANY of the XE cams are out of the question.

Lloyd

NightTrain66

 

Thanks.
I'm just going witht he LT4's until I can scrap together an extra motor to replace the one in the car now. I figured in the meanwhile, I better go back in there and replace those springs since I didn't do it when I added the 1.6rr's. I'm kinda fixing odds and ends this spring.

 

How about the 612's?
Do you need to check spring height with them?

 

I installed my 1.6 rockers and LT4 springs without any measuring and I haven't had any problems.

 

As long as the valves are stock length and set up between 1.78 and 1.80, you can just slap em on.

It is ALWAYS a good idea to check springs on a spring tester and find out what set up ht you will need and then shim the spring accordingly but these LT1's set up pretty short and most of the stuff designed for LT1's work OK.

If it is an XE cam, they NEED 140 lbs on the seat and I would check the CM 612's and make sure that you get that. I was mainly refering to the Jason (original poster) and his stock cam with 1.6's and Hot Cam springs.

The ramp is pretty slow and the spring pressure is OK, it just needs the extra travel of the Hot Cam sping to work. As for anyone using a different cam (like the XE stuff), the Hot Cam springs will NOT work. Seat pressure, open pressure and coil bind are ALL peroblems to consider.

Jason, If you need somr Hot Cam springs and reatiners, I have some used ones for $25 shipped if you need them.

Lloyd

Nighttrain66@msn.com

 

So definitely 140lbs seat pressure with my XE 230/236 .112 lsa on the EX-612 springs?

 

yea, ANYTHING less and there you WILL have problems with valves bouncing off of the seat since the valve shuts pretty quicly with these lobes and springs can not control it 100%. If the valves are not staying closed when they should, you will OBVIOUSLY not be making as much HP as you could.

This will cause "rough" lines on the dyno that look like detonation and it will be IMPOSSIBLE to tune since there will be un burnt A/F escaping the cylinder and effecting the A/F ratio, even if it is lean, it will look OK or rich.

Lloyd

NightTrain66