Just wondering if the LT4 springs that come with the LT4 hotcam kit are capable of handling a gm847....i am sure that it's not...but i just want to be sure before i do any purchases....:P

Thanks!

 

I highly doubt it. The 847 is a considerably bigger cam than the LT4 hot cam and I doubt the LT4 valve springs have the seat pressure.

Additionally, valve springs are something you don't want to cheap out on. That is unless you like valve float and lots of misses.

 

You'll need to do the math. Cam lobe lift x the rocker arm ratio = valve lift. From memory, I believe the LT4 springs can "only" handle about .550 lift, but check to be sure.

WD

http://www.cardomain.com/ride/2189634

 

Negative. LT4 springs are rated to safely handle .525 lift, and honestly barely good enough to handle the hotcam, the 847 is way too much cam for those.

 

Maybe just get a set of the 918 beehives. There a pretty nice spring that seems to work with many different cams. I looked at Engineers web page and he's using them and so is Colin91Z. I am also using them, and there is a good chance that Kain is too, seeing that he also has a set of LE heads.

 

i think i will use the 918's actually....

i was just looking for a cheaper alternative....i guess there is such a thing as too cheap...lmao....

anyone know of someone that might have a complete cam swap package for less than $750..including 1.6rr, gm847, 918's, locks, retainers, etc?

also...how do you keep the valves up as you change out the springs? i wanna do it myself but i don't wanna jack anything up....lmao.

oh yeah...and i'll be using an AFR Hydra-Rev kit...

 

Yes I'm using the beehives, and my cam is more aggressive than the 847
Other options on springs would be the Crane 10803 (i think thats the right part #) kit, but if you go that route it would be best to spring the extra money for the titianium retainers because that cam is gonna want to turn 67-6800 rpm. The steel retainers that come with the cranes are quite heavy for that kind of rpm. I've also heard of people using K-motion springs, the K800s I believe, although I honestly don't know much about those...

 

http://shbox.com/ci/valve_spring_swap.html

That tells you exactly how to change your springs without dropping a valve into the engine. Check the rest of his site for cam removal/install and RR adjustment. I would never have been able to do my cam swap without that site. Just make sure you read through EVERYTHING before you begin. I ended up making countless trips to the hardware store and parts store for things I could have gotten right away.

The K-800's have A LOT of seat pressure. You won't need them for the GM847, but if you want to get them, you'll have to get some heavy duty lifters like the morels.

918's are a great spring.

 

Yes, I'm using the Comp beehives (918s) w/ the largest XFI H-roller cam and everything is working great together! In addition to handling the lift, the valve spring seat pressure must be correct for the cam. The new Comp XFI cams are really high-tech and maybe you should consider one of them.

Don't forget to change the valve stem seals while you're changing the springs if you have any miles on the engine.

WD

 

thanks for all the replies guys....i had completely forgotten about shbox....

its looking like i'm gonna be using the 918's..i can't really afford titanium retainers at this point...but i think the steel ones should be sufficient...at least until i get a new engine...and since i am using a hydra-rev kit...i don't see too many difficulties from the valvetrain once everything is installed.

 

I've got steel retainers on my 918's; thats what the guys at CompCams recommended since my motor won't see over 7000 rpm. On the other hand having less weight in the valve train is always a good thing.

 

I believe many are using the K-Motion K-800 springs with the 847, also.

Frank
CPT

 

no way the LT4s will handle an 847

 

You should really learn the differences and how to calculate spring rates, spring pressures/install height and coil bind. VERY usefull info to know!

 

If you use those, make sure you get Morel lifters since they'll trash the stock ones.