neals98

iTrader: (9)

Ok i have a 98 trans am with a carb set up with the 6ls box i am having toublel with the car popping at around 6800 to 7000 rpms it runs clean all the way up to the high rpm....I thought it was just on nitrous but it is also on motor to has anyone else had a problem like this or know what it might be......Any help please..... or call 601 416 4117

Shawn MacAnanny

iTrader: (12)

Do you have the edelbrock box or the msd box?
What timing pill are you running?
Do you have the timing retard hooked up for the nitrous?
Are you sure it's not valve float or spark blow out?
What cam are you running?
How many degrees timing?
Are you running a MAP?
What octane are you running?
What's compression are you running?
What spark plugs are you running and at what gap?
Are you sure you are getting enough fuel?
What's you're carb setup (jets, PV) and fuel pump?

I think it could just be valve float at those rpms if you are running the stock rockers.

Cam72aro

iTrader: (28)

It kinda sounds like it is on the rev limiter.

neals98

iTrader: (9)

it has no pill in it has a timming cure of 36 to 34 in the upper rpms.
launati custom soild roller cam with harland sharp rockers...
No using the map
It has a 750 holley with 80 in the front and back.
BG 400 fuel pump..
It does it in every gear in the upper rpms I did not know if it was the box or what i am going to send the carb back and get it checked out
I have heard of a lot of people having trouble with the 6LS BOX just trying to see if that is what is wrong with it......thanks...
the rev limiter is set at 8500 I even went up higher with it and it still done it....

Cam72aro

iTrader: (28)

It kinda sounds like you might have to much timing in the upper rpms. I know on the injected ls1's they only like about 28 degrees of timing max. YOu might be too high, I dont know much about the carbed motors, but I would try kicking the timing down some and see if that helps.

SMAX

iTrader: (11)

Yeah, it sounds like too much timing. Have you checked your plugs and plug wires? Also check your fuel filter(s). Check the cheap easy stuff first and then if nothing check the big stuff like the carb or the box.

I bet you have plug or plug wire problems or maybe valve springs.

neals98

iTrader: (9)

I just put a new set of plugs and msd wires on it. It pops out both sides of the exhaust...I also pulled the fuel lines down and cleaned them i am sending carb back to have it checked...

SMAX

iTrader: (11)

pull the valve covers and make sure there aren't any broken valve springs.

neals98

iTrader: (9)

I pulled one side and none were broken i am going to pull both sides and check for seat pressure on them if i can find someone with the tool....

SMAX

iTrader: (11)

Are you running a power valve? If so have you had recent backfires through the carb?

neals98

iTrader: (9)

no power values

Shawn MacAnanny

iTrader: (12)

Back the timing down to 26 degrees then see if it still pops. Maybe your carb floats have come unadjusted? do you have a fuel pressure regulator? Or atleast pressure gauge?

Cam72aro

iTrader: (28)

I would put money on it thats its the timing. Put it down to 26 or 28 and try it, easy enough.

Pop N Wood

iTrader: (1)

80 jets are a good bit larger than most guys run. Have you checked the mixture at high RPM? if you are running rich that will contribute to explosions in the exhaust.

neals98

iTrader: (9)

Ok i think i might have found what is wrong with the car..I just bought it so i dont know much about the motor.........OK this motor has a soild roller cam in it which needs about 230 closed spring pressure and 650 open spring pressure....I pull a sping off and had it checked a little while ago and the closed pressure is only...110 pounds..witch is only good a hyd roller cam..I talked to the guy i got it from and he said that somewhere between him and the machine shop is where they got confussed.... I am getting a set of springs and will let everyone know what happens.......Mybe i will go a little faster...

Shawn MacAnanny

iTrader: (12)

Yup valve float. Why did they install a solid roller cam just out of curiosity? be sure to periodically check your rocker adjustment then too.

Cam72aro

iTrader: (28)

More agressive lobe profile, higher rpm potential, not relying on hydralic lifters to open valve.

neals98

iTrader: (9)

Thats right cam72aro. Even though it had the wrong springs at first it ran good I guess over time the got weaker and now a really big problem but this motor picked up 4 tenths from the swap of the cams. and that was with less nitrous.....I should have some springs as soon as I find the right one's ...........................................and we will see what it will do.....this time..

neals98

iTrader: (9)

Well just for a small update i could not find the spings that would fit in the spring pocket with the right pressure so last night i pulled the heads so i could take them to the machine shop and have the pockets cut bigger and the springs put on.......When i pulled the heads off and looked at the pistons you could see where the piston was hitting the valves....This car has been running for a while like this...I hope when i put the right springs on it will pick up on the track times....It has already ran some good numbers but a little faster wont hurt....As soon as i get everything i will let everyone know how it does.....