conv90

I want the LT4 hot cam kit (cam, LT4 springs, retainers... and GM self adj. 1.6 roller rockers).
I know it is not the best cam to use with a Long Tube Runners, but i will update the total intake system soon.
My question is:
Is it safe to use LT4 springs with 1.6 RR and stock valves?
These springs (for sure) are able to manage the increased lift of the cam (.They are in the same kit...) but i think they are built for LT4 valve. (I think LT4 valves are bigger and lighter than stock valves in a stock 113 head).

Thanks for your help
-Beppe-

mos90

the lt4 spring are 1.32 diameter. im not sure if they will work with your heads.
the the lt4 springs that come in the hotcam kit are not the best choice because you push the springs to close to coil bind.
i have an older vette also with a zz425 crate engine in it and ive had problems with the spring until i changed them.
the best bet for springs are tpis 700-132, they are stock diameter and use your stock retainers and are good for .550 unlike the lt4 spring which is good for only .525.

conv90

So GM sells a complete kit with a camshaft with lift .525 with a spring kit able to .525" only??
In this case I have to buy the Lt4 cam, the 1.6 roller rockers and the 700-132 kit using my stock retainers, shims, keepers...?
-Beppe-

mos90

yea gm screwed up on those springs somehow. but yea you need to buy 1.6 rr,s. you can go with self -aligning if you choose, so you dont have to replace your pushrods and guide plates. i would buy new shims and keepers and use your old retainers. unless you want to buy titanium retainers from tpis, but they are expensive.

the gm hotcam is not the best cam by any means. you will 20 more hp if you go with the tpis zz409 cam with 1.5 rockers. and better torque curve.
i just want you to know that max lift with stock 113 heads it about .540 because of the valve guides. if you want to go with more lift you have to machine the guides down. so if you went woth zz409 cam with 1.6 rockers you will have about .556 lift. i have zz409 cam i my car with miniram tpis headers and 200cc dart pro 1 heads and im making 460 fwhp and 420 lbs torque.


[Modified by mos90, 6:49 PM 6/25/2004]

1MoorTym

The LT4 springs are what comes with the ZZ4 crate engine which uses the 113 casting heads.

rocco16

The LT cams are roller cams. Isn't the L98 a flat-tappet engine? You'll need a set of the pricey roller lifters if it is....

Larry
code5coupe

vader86

Everything 87+ is a roller cam.

If I remember correctly, the cam sprocket pin must be driven in further, but otherwise its just like a replacement. I would not run the LT4 valves, I would go with something stiffer. (LT4 stock valves are lighter)

shotchkiss

LT4 springs fit fine on my '89, it should have the same D-port 113 heads as you.