jpurban

Hi,

If you want to upgrade an LT4 engine from the factory cam to the "LT4 Hot Cam" from GM, are there any other parts required other than the cam?

I'm asking because I think the LT1's need new valve springs when upgrading to the LT4 Hot Cam. Does the LT4 engine also need new springs? If so, what springs do you recommend?

Thanks,
John

BADDUCK

Definatly put in new springs. Why take a chance for $40.

James93LT1

It all depends on how much mileage you currently have.

If you have a lot of miles, spring, lifters, timing chain.

dizwiz24

if considering a cam upgrade be aware that there are now better cam options than the hot cam.

The hotcam will provide a performance benefit.

However, it doesnt spend a lot of time at its peak .525/,525 (lift).

The good news is that its easy on the valve springs (gradual ramp rate). The valve springs in the hotcam kit are the weakpoint of the kit.

Theres other cams out there that ramp up more sudden to high lift rate. With good flowing heads, you will make more power.

However, the hotcam kit (i have one) still provides a great power increase in a time-proven package.

I made 353 / 355 rwhp/rwtq with the hot cam kit and longtube headers.

hgh pwr

the springs are the lt4 springs for the hot cam,as others have said great on parts and has a mild lope which sounds good.

if your milage is high replace timing chain at the very least,I also have the kit in my car and have been very happy with it and get a lot of compliments on the sound and performance.

GREGGPENN

For mild modders, I happen to like the HC option for it's "mild" wear characteristics. Not everyone wants to redo springs (or the rest of their mods within a couple of years). And, the extra power from a steeper-ramped cam may not produce as much extra power as you hope/think.

I like this response, though, as it's very informative. And, it suggests that readers need to consider more than one/two aspects of a modification. Tuning will also be required.

Don't "throw" in a cam if you aren't willing to look at other aspects of the motor, age, use, and ramifications...

tombrammer

I put the hot cam in my 93 this spring, hot cam, new LT4 springs, 1.6rr's and LT headers, it is a very nice increase in power. However I have since had to rebuild my motor. When i pulled the hot cam back out you can see where I was getting into serious valve/lifter float. I would NOT use the hot cam springs but upgrade to something better unless you plan to keep your rpm's below 5600 rpm. Good luck.

C4orce2

I had a LS3 "Hot Cam" GMPP crate engine installed last year in my '92. I also have a 700r4, long tube headers and a 3" exhaust all the way. I love the power the hot cam provides over the stock LS3. It has been dynoed on a loaded dyno and put out 429/442 rwhp/rwtq. However, be careful if you have tough emissions regs in your area. With the cam there is no way the engine will ever pass the Arizona standards. I was able to avoid the problem by getting the car qualified for the Arizona "Collectible Car Waiver". But for that waiver I would have been in real trouble. Make sure you will not have the same problem in your jurisdiction.

GREGGPENN

Of course, LS3 "hot" cams aren't the same specs or config as the LT4 units.

C4orce2

I'm sure you are correct. Forget I said anything.

larryfs

You may spin a bearing within 3 months of installing the hot cam.

BADDUCK

You may spin a bearing within 3 months of NOT installing a Hotcam.

larryfs

not likely

BADDUCK

Not likely

larryfs

If you did some simple basic research, most LT1's & LT4's spin a bearing after a cam swap. It's common knowledge.

etteroc27

Can you follow up on this info and show your stats? You say most LT1 and 4's spin bearings after a cam change. What percentage? What connection?

cv67

Probably driving an aging motor harder it happens.

Strick

I've asked about and studied this problem with just adding a cam to a LTX motor. What really seems to happen is the cam allows for higher rpms and guys drive them harder with the new found power increase. So it is easy to exceed the factory redline (5500 or so). The bottom end just isn't designed for rpms above the OEM redline and the results usually is a spun bearing. If you can, respect the oem redline and you'll be just fine. If you plan on exploring the 6500rpm or higher range, please upgrade the bottom end. Oil starvation also seems to be a problem in the higher rpm ranges. Speed costs a lot of $$$, but there is always a need for speed.

STL94LT1

Maybe I'm just lucky but my stock short block LT1 has seen two camshaft changes and 6500 rpms on a regular basis.

In full disclosure: My first camshaft change was at 15k miles, and the car now only has ~30k miles.

SouthernSon

I hope this is due to other reasons besides cam change or RPM. I installed the HOT cam in my LT4 at 66k miles several years ago. It now has 133K miles on the engine with regular ventures into the raised rpm of 6500. I installed the cam myself and was very careful about the whole procedure. I always let the engine come up to temperature before romping on it. Am I to believe mine is the exception?