98RedBird

iTrader: (77)

I recently built a H/C car and have noticed that the car pulls pretty well once i get around 4k. Question is somewhere between 5 and 5500 it seems to just flatten out and stop pulling. I thought this thing pulled very hard up top and continued to pull all the way through 6xxxrpm? Is there something I should be looking at to figure out why it falls out a little on the top end? I'll be getting it on a dyno soon so I'm sure I'll be able to see more then but for now I was wondering if anyone else has had this problem? Thanks.

Raise

iTrader: (31)

Im assuming its tuned

sidewayz28

iTrader: (24)

could it be valve float? wait until the dyno to rip it on the top end

98RedBird

iTrader: (77)

Yeah

Yeah, I'm not ripping on it yet. I'm just questioning by a seat of the pants feel, which I know isn't very accurate. I'll see what happens on the dyno. I very much so doubt that it's valve float though

02 BLK WS6

iTrader: (11)

MS4 should pull to 6700+ RPM if everything works together correctly.

sidewayz28

iTrader: (24)

yeah, **** my torquer 2 goes through 6k rpms so quick i barely have time to even think!

5.3LJimmy

iTrader: (10)

It's probably leaning out on the top if it hasn't been dyno tuned yet.

98RedBird

iTrader: (77)

Yeah, it hasn't been dyno tuned yet. The plugs looked good however the outer electrode had a whitish color to it, which I think means it's leaning out a little or too hot, correct?

ws66

Get that thing dyno tuned I had the same prob i was leaning out and I got it tuned and that thing was pulling all the way up to 7k.

geterdone

I would not be ripping it without a dyno tune, that large of a cam is going to run like **** without a tune, I hope you planned on getting it tuned when buying that cam. If not your car is going to be a turd like all of the other locals around here with their cammed LSx's, untuned.

bww3588

iTrader: (49)

im in the same boat as you. seems like you and me have been having some similar problems. i took mine down for a dyno tune, and after 5500, the power falls off. im thinking its valve float because the springs have around 5000 miles on them, but they were roadraced before i got them, so they are hard miles. im in the process of changing springs, while im in there im going to check to make sure the cam and crank are dot to dot. also, i was told to check pushrod length. my engine is quiet as hell, no tick or clatter you would expect from a large cammed engine, so im thinking the pushrods might be too long.

what length pushrods did you go with? i have the same heads milled to 58cc's and using a stock MLS gasket (.051) and went with 7.350. im thinking they need to be shorter.

98RedBird

iTrader: (77)

I went with the 7.350's. You have your heads milled slightly further than I do but I went with a thinner head gasket (Cometic .040). Mine clatters and sounds like a sewing machine. I know mines not valve float though because the heads springs and cam are brand new from TSP, just turned over 400 miles.

I am selling my setup though. I've decided to pull the motor and set it up for about 12lbs of boost. I've always wanted a FI application as opposed to a N02 setup.

7845

iTrader: (1)

you can still have valve float with new springs. if you have incorrect valvetrain geometery you can also encounter valve float. i experienced a similar issue to yours. my heads were milled and had new springs but i floated a valve and wiped out my motor.