Floating valve Maybe

Coreymm

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This Is a fairly new build and I'm having trouble in the higher Rpm range on the dyno. The engine is a built 03 cobra motor with stock heads and cams. posi ported trilogy 4lb lower 3.0 upper I'm having trouble where the car makes good power and then flat lines at 5500 rpm, Fuel is good twin gt pumps 40 amp kb boost a pump, modded fpdm 60lb injector and so are the spark plugs tr6 gaped at .27 and new weapon x coils with a sct 2600 maf. So I have come to the conclusion that I might have a floating valve. and there also a slight head tick on the driver side that I have been noticing. any inputs to what is going on with this car. at first I though there was belt slip but that's not the case

 

Jon01

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It could be valve float, does it sound like it's breaking up out the exhaust on the top end?
Could also be spark problems.
Also it looks like it's richening up on top, that might be ok though, I just cant see the scale of it well enough on the chart above...if it's loading it up with too much fuel that could be part of your problem - do you have the numerical print out of hp/afr/rpm?
 

Coreymm

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This is the only chart I have. It feel like its hitting the rev limiter at 5500, from what this tuner said and another tuner fuel is fine. the last tuner did 13 pulls trying to figure out the problem
 

Zack

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Put stock COP's back in and set the gap to .025 or lower.

Valve float just doesnt happen on mod motors unless you make over 1k Horsepower, or the shop screwed up
 

wolfe

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yeah, I don't see valve float happening on an overhead cam motor. How do you know it's not belt slip?

Edit: Just reread, you have your plug gap set at .27? I sure hope that's a typo, if not I'm surprised your shit even runs. Close that gap, you're blowing out your spark.
 

Coreymm

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the stock cops took a crap on me 3 at a time. I think the shop screwed up on the heads since day one I have had this problem. Ill change the gap and see what happens. but I still think theirs a issue because of the head tick I hear
 

Zack

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the stock cops took a crap on me 3 at a time. I think the shop screwed up on the heads since day one I have had this problem. Ill change the gap and see what happens. but I still thing theirs a issue because of the head tick I hear
Ive owned 6 Marauders and never had a bad COP.
 

Coreymm

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It gave me 3 codes so I just changed them out recently. I still had this problem before I changed out the stock coils. I'm going to change the gaps on the plugs and see if that does the trick
 

Jon01

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If it did it before and after the COP swap I'd be inclined to look real hard at the valve springs.
Haev you had the cam covers off since it's been together to check things out?

OEM COP >any aftermarket garbage.
 

Coreymm

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Just changed the gaps and its doing the same thing. it feel likes it bouncing of the rev limiter at 5500. I think im going to go ahead and take the heads off
 

musclemerc

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If it did it before and after the COP swap I'd be inclined to look real hard at the valve springs.
Haev you had the cam covers off since it's been together to check things out?

OEM COP >any aftermarket garbage.
I agree.
What cams are you running?
 

Coreymm

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stock cobra cams. I think the guy who built the motor fuck up on the heads. any good valve train kits out there. Im looking to just rebuild them both new valves springs valves and all
 

wolfe

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It gave me 3 codes so I just changed them out recently. I still had this problem before I changed out the stock coils. I'm going to change the gaps on the plugs and see if that does the trick
What codes was it giving?

Where is the rev limiter set at?

How bad is the ticking sound? The mod motors are pretty noisy and a lot of them have a slight tick and it's nothing to worry about.
 

musclemerc

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stock cobra cams. I think the guy who built the motor fuck up on the heads. any good valve train kits out there. Im looking to just rebuild them both new valves springs valves and all
Unless your adding high lift cams stick with OEM springs.

+2 on what codes were you throwing?
 

Coreymm

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I just got a code on cylinder 7 8 and 4 coil. once I cleared the codes and replace the coils I haven't had a code and Ive been beating on it pretty hard trying to solve this problem
 

Coreymm

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change the spark plug gap to 020 and did some data logging today and this is what I got. tell me what you guys think, this is 2nd gear only. idk how to lock the car in 3rd gear

 

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