RedIrocZ-28

My car with the HSR is finally starting to make more power after OMINOUS_87 and I burned a few chips for it. Problem lies in my valve train. I can either free rev the motor or put it under high load (WOT) and at about 5750-5800 rpm the valves start to float audibly. It sounds like the top end is coming apart, and to a certain extent I guess thats true.

Is there anything short of pulling the heads again and having them machined for bigger spring seats that I can do?

Right now I have the Comp Cams 982-KIT springs installed. 1.250" spring seat Single coil Conical.

AFR Hydra Rev kit? Opinions?

Fevre

Curious as to whether or not those are the recomended springs for the cam, shouldn't float at <6000 rpm's if they are. Here is a single spring by Crane that might work but I am not sure what your head specs are:

http://cranecams.com/springs/single.htm

OMINOUS_87

RedIrocZ-28

Dude, post the inner and outer diameters along with the seat and open load specs. This way everyone will know how small they are.

NastyL98_T/A

What are the seat and open pressures of the springs? What kind of heads?

NastyL98_T/A

Just looked at your sig and saw the 10.3 compression. Are the heads milled, different pistons or what? I'd be really careful. If you've got valve float and tighter clearances,your chances for valve to piston impact are greatly increased.

RedIrocZ-28

Ok, Spring seat is 1.250" Installed height is supposed to be 1.750", max lift is .525" They are single spring crap.... Seat pressure is 100# closed and ~281# (@ .500) open... just a little more actually. See my dilemma? The machine shop told me they were gonna be getting me the springs that went with the cam. Well... that obviously didn't happen. You can see that my cam called for a 986-16 kit or somthing.

Heads are milled yes. Pistons are Keith Black's flat tops with the valve releifs cut in them. They haven't hit yet and I don't think that they will. They would have by now anyway.

Thing is the motor has ALWAYS done this. Stock springs didn't like 6000 rpm and neither do these. hell they're only 20# more at closed valve.... Looks like the heads are coming off again. This is an easy 12 second car, Hell I run with low 13 cars up until the valves float in 1st gear and then off they go as I stumble and the nose dives.

hotrod85z

iTrader: (1)

you should try a big spring,i am running .600 lift springs on my zz4.
ask any reputable machine shop, you should allow alittle lift for margin. if your runnin a .500 lift max cam, you'll need .550 lift max springs. always allow .050 lift for safety!

NastyL98_T/A

Ditto. I run the comp 987 springs on my ZZ4. People say it's too much spring, but I don't think there is such a thing.

OMINOUS_87

To big a spring will colapse a hydralic roller lifter. Comp 987 is getting pretty big and right near that threshold. But I agree, every Comp XE Cam 218 and bigger should be running the 987 spring kit.

That is several steps up the food chain from where you are right now RedIrocZ-28.

RedIrocZ-28

Yeah, ya live... ya learn.... ya pull the heads again for the 3rd time in 3 years.

NastyL98_T/A

I agree, but the LS1's use the same lifters and those guys are making me think that the hydraulic lifters are stronger than everyone thinks. Guy's are running .600 lift cams with springs that have close to 380-400 lbs. open pressure with no problems. I'm still sceptical and belive that the 987's are on the edge, but.........