Just installed a set of TEA 1.5's with Comp 987's and took it to the dyno for tuning. See my sig for current setup info, and keep in mind this is through a fresh, forged shortblock ( < 3,000 miles), HD chromemoly driveshaft, Strange 12-bolt, and 4:10's, so be kind; I know it's not 450rwhp The heads and Jantzer TB picked up 40rwhp from my last cam only pull, so I'm pretty happy

Got it pretty well tuned (ie, 28.5* timing, 13.25:1 a/f (little on the lean side, but the dyno I use seems to consistently log an a/f about a half point higher than others I've tried); however, when I looked at my graph, it's seems to drop off around 6500rpm instead of pulling out to 6800rpm like I'd expected.

Does this look like valve float?? The 987's are brand new, but I've also read quite a bit about 987's and valve float, so I'm kinda wondering if that's what I'm experiencing??

 

I had the same thing happening to my car when I was running the little TR220.. it ended up being because I had installed TR6 plugs and had opened the gap up on them too wide, to .055 and it would missfire above 6,000rpm. I installed a new set and didn't mess with the gap and it cleared it right up.

Is that comp cam on X-ER lobes?

 

That looks like valvefloat a bit...but knows....here is my valve float graph. I didn't get valve float until after I installed the Yella Terra Rockers. Mine TR 230 cam was fine with 987's until then.

https://ls1tech.com/forums/attachmen...achmentid=2292

 

VERBS,

How can you tell from the graph that you are experiencing valve float? 'cause the power falls off at the end so rapidly?

 

gomer,

The cam's not an XE-R; it's pretty similar to the TR230 (ie, slightly less aggressive ramps than the XE-R). I just replaced my plugs with a fresh set of TR55's (gapped at .050), and I'm not hearing or logging any misfires at higher rpms??

verbs,

How high did your cam pull before the YT's? Did it pull up to 6800rpm, or did it seem to tail off around 6500rpm like mine?

BTW, thanks for the responses, guys!!

 

that doesnt really look like a sharp enough drop off for it to be valve float, does it???

 

How about knock retard?

 

Mine pulled all the way to 6800......like this:

 

Thanks, verbs! That's kinda what I expected it to look like; the graph out on Thunder's site looks similar.

Instead of looking at valve float, maybe I should ask a different question...

Does my graph seem to trend similarly to those of you running 230/224's?

 

graph looks good to me.

 

The graph looks fine to me.We had a car with the same Cam have the same looking graph.Figured it might be valve float and changed the springs to crane duals.Ended up being exactly the same.

 

Cool, thanks for the info Slowhawk!!

That makes me feel a li'l better!! I was really going to kick myself if I ended up having to swap out the springs now that I've got the heads installed

 

The 987's should be good to abotu .580-.590 lift depending on install heigth. The YT's seem to add some weight back onto the lifter so you'd actually require some Comp R's to fix the valve float in that case. MHO

Oh and for what it's worth I do have the 987's running on a .588 lift cam. No YT's yet but it pulls all the way through 7000 on mine.

 

My graph looks similiar. And you can't diagnose valve float for sure. I pulled the heads and saw that the intake valves smacked all the cylinders mainly on the drivers side. This was the TEA 987 S2 heads with TR 224/224 112, and Yella Terras. Definitely valve float here.