Huston we have a problem!

[87CAM_406CI_SS]

My engine is sounding bad, above 2500rpm it sounds like a badass spray paint can. I have checked everything. At first i was sure it was the timing, but ive since then set it purfectly@ 7 degrees advance, oil pressure is purfect, temp is purfect, fuel is perfect. gas is new. spark plugs are good color. Idle is smooth( well as smooth as it can get with a huge cam) and is responsive, but as soon as it gets to 1800, i can hear a faint rattleing sound, and when it gets up to 2500 it sounds real bad, and it misfires.
I dont think it is anything mechanical, i belive the culprit to be eather the hei destributor ( used last season no problems(mabie was damiged in off season)) or my brand new msd digital 6al box( I am 100% sure it is set up corectly).
the only thing that baffles me is that my full advance kiks in real soon(under 2200 rpm) and i thnk that the sound might be detonation, but ive never heard detonation at so low an rpm. even with the vacume advancer disconected the problem still exists.

today im going to dissasemble my distributor, to see if there are any obvious problems, then im goin to take it to a shop, to get tested, toremove the vacume anvace and stick with mechanical weights only.

I want to drive my car SOOOOOOOOOO BADLY!
please help me, has anyone had this problem before? :-\

[GregZ28]

Ok, I'm no expert by any means, but I would strongly suggest that's an electrical problem...Check your box, your distributor, make sure your leads/caps/etc is all good, make sure the leads are on the right plugs, etc etc...I'd also check the gaps of all your plugs, because an incorrect gap will affect timing...Good luck, hopefully someone who knows more than I (lots of people ;D) can come on and give you some advice...

[87CAM_406CI_SS]

I took apart ther distributor and replaced the cap, rotor and button. didnt fix it. I had some1 come over last night to hear the problem. it sounds like i have a bad case of backfire i think it may bee a valve sticking open at high rpm
any thoughts?

[formula mark]

Is it like a poping sound? Could be a rocker arms that was over-tightend?
Or, like in my case, i flooded it so bad 3 or 4 times when i had no choke that i faked the spark plugs and they were all black. With my messed up spark plugs I had a severe power loss and backfire/poppin @ anything over 2000RPM.

[fast83z28]

i had that at like 2500 and up and it was from detonation >:(..... by the time i figured out wut it was i broke 2 ring grooves in my pistons...luckily the cyl walls werent scored

[87CAM_406CI_SS]

i had that at like 2500 and up and it was from detonation ..... by the time i figured out wut it was i broke 2 ring grooves in my pistons...luckily the cyl walls werent scored
Dude did you ever find out why it was detonating so bad.?

And, i checked all the valve lash, all were still fine.
my next step will be to do a compression test, i have already taken 3 of the 8 plugs out and they were rusty looking which is good.
I hope that my cam timing is good, i am sure i set it up properly, although i did not dial in the cam to double check the cam specs.

[87CAM_406CI_SS]

haha

had to make space sorry

[66chevc10]

do you have high tempature headers?

[87CAM_406CI_SS]

do you have high tempature headers?
uhhhhhhhhhhhhhhhh..............?
you speak greek to me.
I duno?
i have headers from flow tech

[fast83z28]

somebody put 87 octane in my car which was a no no ::)

[66chevc10]

did you check your leads?

[87CAM_406CI_SS]

NOPE gas is new 94 from chevron
all the wires are, and always have been, in correct order 18436572 and on corect cylinder, plus seperated to prevent crossfire. my distrributor has new cap + rotor, my wires are MSD 8mm and my plugs are the proper sise and heat range for my alluminum heads, and i checked before assembly how far the plugs enter the chamber. :-[

[87CAM_406CI_SS]

oh and the plugs are gapped 0.055, wich is the recomended gap for my digital 6 plus box

[66chevc10]

What temp are your leads rated to? leads can tocuh, thats not too big of a deal, heat from your headers can cause them not to deliver the full power to your plugs.

[87CAM_406CI_SS]

I dont think thats the problem. i used the same wires last lear with no problems. the backfire/popping sound after i start it up is still just as bad when its warmed up.

[77 zapper]

i had the same problem before turns out it was the coil, just because it runs doesnt mean the coil is fine. it had a dead spot in it. it worked fine at low rpm because the load on it minimal. try changing the coil, seems like you tried everthing but that.

[87CAM_406CI_SS]

i had the same problem before turns out it was the coil, just because it runs doesnt mean the coil is fine. it had a dead spot in it. it worked fine at low rpm because the load on it minimal. try changing the coil, seems like you tried everthing but that.

Thanks man :), I will check the coil first thing in the morning.
I hope thats it. The coil im using now is a is the same one i used last year, a 60,000volt MSD hei coil. good thimg i have the old one.

[Mike K]

Is it carbed? If so maybe its flooding at that rpm?

[IROC-Z]

check your MSD box... I've heard of faulty ones right from the factory, and not just one of em.

[87CAM_406CI_SS]

Is it carbed? If so maybe its flooding at that rpm?

Could be, I have a bg220 ltr/hr pump with propour regulator and return line, Ive set it at 6psi. I dont know if it overpowering the needle seats. the holly carb asks for between 5-8psi. also my fuel psi guage stays at 6psi all the time and never goes up or down.
check your MSD box... I've heard of faulty ones right from the factory, and not just one of em.
Thats a possabiliy, MSD is known for its quality, but you never know about them pesky yanks. lol! ;D

[79 Z28]

i had the same problem before turns out it was the coil, just because it runs doesnt mean the coil is fine. it had a dead spot in it. it worked fine at low rpm because the load on it minimal. try changing the coil, seems like you tried everthing but that.

Thanks man :), I will check the coil first thing in the morning.
I hope thats it. The coil im using now is a is the same one i used last year, a 60,000volt MSD hei coil. good thimg i have the old one.
60,000 volts? what model is that, i want one. only pro stock use that much, most hi perf ones are 40,000 :)

[66chevc10]

so you figure it out yet or what?

[Mr. TroPiCal]

Huston, can you read me, i dont know how to spell, come in Huston

[87CAM_406CI_SS]

No. the coil didnt fix the problem
I am going to take the car to cc racing this week.
They are a good place to go.

[87CAM_406CI_SS]

60,000 volts? what model is that, i want one. only pro stock use that much, most hi perf ones are 40,000
my bad, mine is 50,000volts

[Blue89rs]

What is full advance timing at? I would disconnect all the aftermarket electronics first when solving a problem like this. If it was knocking, then the timing would be kicked back when it happens. What does your timing do as you ramp it up. Does it do this at load or just at idle?

[89vert]

sounds like you have no spark advace
try setting your base timing to 30 degrees or so and see if that works

do you have vacuum advace with weights or electronic


EDIT nevermind I guess I should read your whole post before I reply

[84Z28]

does it work yet?