I have the comp springs 987-16 it's a dual coil spring rated at 344 lbs, it says the installed height should be at 1.800 inches and at open it is at 1.200 with coild bind at 1.150 so this spring should be good for for a cam with .6 on lift with no problem, am I correct?

The two cams I'm looking at are both comp pieces, the one I was running was a
TS224XL 224/236 on a 114 @050 it was 536/555lift w/1.6 rockers and I've thought about just throwing it back in, springs handeled it fine, but I can't help but want to go a bit bigger

in comes the TS233XR it sits at 233/242 on a 114 @050 with 569/576 with 1.6 rockers form what I understand the 987-16 springs should hold this cam just fine as well as it is still well below .600

The car has gasket matched heads with a little work done in the ports to open them up a bit. longtubes 1.6 RR, it was tuned for the 224 236 and it's an M6 car

so lets hear it, will the car support it and will those springs support it? those are my two main questions, feel free to add any opinions

 

Its good to go.

 

I would go with a stiffer spring with the larger cam. And you will need HD pushrods to go along with it.

Rich Krause

 

Are those ratings on the cam for 1.6 rockers? Better make sure, if the lift is .540 for example it will be more like .560 with 1.6's.. Why not get the CC 306? 114 LSA ??? Why not 112? 114 is going to take some of that great sound away...

 

yes those are lift numbers with 1.6s

Want to keep the LSA there for FI
A cam with that much lift is going to sound healthy regardless

got the pushrods, the rest of the vlave train was upgraded when I put in the other cam


Rich any reason you would go with stiffer springs? Because of the ramp? How much stiffer would you like to see?

 

I think the 987 would only be barely adequate and would limit the rpm by couple of hundred, thus giving up some "free" hp. The 978 spring, or equivalent, is a better bet. The 987 has a rate of 344lb/in while the 978 is 403lb/in. Seat pressures at 1.800" for the 978 is 147lbs vs. 121 for the 987. Worth switching if you already have the springs? Hard to say. You could sell what you have though, I'm sure, if they are new.

Rich Krause

 

Going to start out by saying I'm not second guessing here, I want to learn and it's why I ask.


Why do you feel the 987 would be inadequate? Is it simply the difference in spring rate? It' sthe only thing I can think of considering those springs look identicle.
Why do you think I would loose a few hundred rpm? Lack of ability of the spring to keep everything in contact?
Is there a way to judge what spring pressure to use with what kind of lobe?


installing a dual design is a pain LOL!

I already have the 987s installed, they've been ran for around 4 thousand miles with the 224/236 cam I had, if it would be wiser to not run the larger cam with those springs I'll just replace it and stay with the setup I had as it was quite fun.

 

The weaker spring will probably allow valve float at a lower rpm than the cam peaks. Based on experience with similar, though not identical combos. Won't hurt to try it though.

Rich Krause

 

RS... You have a PM

 

well I can't afford for ANYTHING to go wrong when I toss this motor in LOL! I'll go ahead and stick with the smaller one as I know it'll be fine from expierence.
thanks for the advice though, I appreciate it





and yes I know with that statemnet I set myself up for failure LOL

 

nov empty your PM box

 

whoops, got it cleared lol