mcm95403

Hi Guys,
I've found all the specs for the stock LT-1 springs, but I want to double check that they are single with a damper and 1.25" from the factory.

I have a stock LT-1 cam for my 84 and I'd like to swap the cam in sometime in the next month or two. I'll use retrofit rollers and buy a set of pushrods. I need to replace the valve seals anyways, so while I have it apart that far.............well, y'all know how that goes

JAKE

Are you sure you have a cam designed for your block? The 84 block doesn't have provisions to control fore and aft movement of the cam.

How had you planned on dealing with that?

Jake

JAKE

1996 LT1 Valve Springs; info taken from 96 FSM:

INSTALLED HEIGHT 1.78" BOTH INTAKE AND EXHAUST

SEAT PRESSURE 81-89 LB FT @ 1.78"

OPEN PRESSURE 245 - 265 @ 1.33"

SPRING FREE LENGTH 2.02"

No mention is made in the FSM if the springs have a damper or not, however my 96 LT1 springs did not have dampers.

Jake

Churchkey

If the LT cam will bolt to the gen 1 timing gear the gear will control aft movement.

An aftermarket cam button will control forward movement.

http://www.summitracing.com/parts/CCA-200/

mcm95403

With a modified lock plate and a cam button. I'll either use a cast timing cover or get the Edelbrock water pump with the adjustable stop provision for the cam button.

JAKE

I've had a timing chain gear eat away the front of the block without having a brass washer or Torrington bearing to deal with the rearward cam movement on back walkers.

Back in the day I had to have the front of the block machined to account for the thickness of the washer/bearing. Nowadays Cloyes sells a timing chain set with the cam gear already machined and it comes with the 3-piece Torrington bearing set.

Be sure to check out what's called for to work with your setup.

BTW, no mention of the diameter of the stock LT1 springs in the FSM. Someone outta know and chime in, though.

Jake

Strike3

Reguardless of the fit problems, have you considered the fact that the 84 block does not have provisions for the factory roller lifters used on the 86 and later blocks? Flat lifters will not work with the LT1 cam. The LT1 cam is not particularly great cam in the first place and after market cams made specifically for your car would be a much better way and probably cheeper way to go in the long run.

BADDUCK

LT1 cam is a poor choice for your car. TPiS, Comp Cams, and others will have the proper cam choices for your car.

mcm95403

As I said in the original post, I'll use retrofit rollers so that takes care of the non-roller block issue.

Why do you think the LT-1 cam is a poor choice? It has the moderate lift and duration I want, good idle quality and broad power band.

JAKE

I see those kinds of posts all the time; members posting there are "better" cams available. You'd have to define "better" when comparing the cam you have Vs the others.

Remember, if you opt for a different cam the cost of the different, "better" cam has to be factored into your decision making. Somewhere in the area of $300

I'm trying to figure out which cam you have. There are THREE possibilities - the LT-1 cam, which would be a flat tappet cam; then there's the stock LT1 cam which would be a hydraulic roller; and finally the LT1 HotCam, a higher performance cam - higher than the stock cam..

Since you mentioned retro-fit lifters, the cam you have can't be the LT-1 cam. That little dash (-) makes a big difference.

Also, although you didn't state it specifically, but from your posts you have a ". . . stock LT-1 cam . . ." NOT a LT1 HOTCAM, right?

Another thought is the weight of the lifters. The retro-fit lifters are heavier than the stock, GM HR lifters so you'd need more spring for valve as the RPMs climb.

It would be best to check the pressures (seat and open) of the springs you have to see if they're capable of handling your valve train setup. If they're not your engine will have valve float at a lower RPM. If you don't have the equipment to do that a local machine shop can do it for you.

I doubt the springs you have will fit the bill though. I'd hate to see you install the springs you're asking about only to have to change them once the engine is running with them.

Just some things to consider.

Jake

mcm95403

Hey Jake,

You're right, I have a stock 95 LT-1 hydraulic roller cam. The lifters from Howards and Lunati are a little lighter than the stockers, but regardless, I'm not going to rev the snot out of my 125K mile L-83 with its cast rods and crank and 2 bolt mains. I doubt I'll ever (intentionally) rev it past 5500.

I'm wanting to make the change for the torque improvement of the hydraulic rollers and the improved throttle response as well. I think this cam is mild enough to keep the drivability as nice as it already is but still give a nice performance upgrade. Before I make the change I'm going to dyno the car, then dyno it again afterwards so that we can all see how it works - for better or worse.

I don't have springs yet, which is why I'm asking about them. I'd like to go with something as close to stock as possible - I may even just buy a set of stockers and run those. Summit also has a spring kit that looks like it would fit the bill for about $70 and it includes the keepers, retainers and new seals as well.

Pete K

You do not need alot of spring pressure for that combo. I would pick an inexpensive set that fits your seats and retainers that will give approx 100 pounds on the seat, and 300 or so open. A little higher (20#'s or so) will not hurt, and will help above 4500 rpm.

mcm95403

Thanks for the input Pete. That pretty much covers the $70 set from Summit.