F-Body Lover

finally I swapped the 383 in my 92 Z28 and we cranked it after few tries it back fires through the carb it only back fires if I open the secondarys before starting it up and it fires up and everything was good I faced a problem with fuel it wasnt enough or let me say the mechanical fuel pump couldnt suck enough fuel from the tank because the in-tank fuel pump wont let the fuel pass easily so we dropped the tank today and toke off the fuel pump and replaced it with 3/8 hose and hopefully tomorrow everything will work great,I asked the mechanic about the back firing he told me the engine dont get enough fuel so thats why it back fires I really didnt buy that excuse this is my set up let me know why my engine back fires

383ci 5.7 rods 11.3CR
Edelbrock E-tec 200
Edelbrock air gab RPM
750 DP holley
236/242 520"/540" 110lsa on 1.5 stock rockers
1" carb spacer
MSD wires
Jegs cab,rotor and coil
Platinum spark plugs
Hedman Headers LT

I was thinking about the timing well I dont know im really confused right now

MrOverkill

iTrader: (1)

Timing

F-Body Lover

tomorrow I will open the timing cover and check the notch if its inline or not this picture will show you the position of the distributor



its in retard position so I guess the notch on the timing chain is off the line

MrOverkill

iTrader: (1)

Try to advance the dist by turning it counterclockwise, move it a 1/4"-1/2" or so at a time and see what you get.

Is that a factory HEI from an early car or one from an 80's Camaro with a cumputer controlled Quadrajunk?

F-Body Lover

which way to turn the distributor to advance? Im confused about this and its a factory HEI from early car

MrOverkill

iTrader: (1)

If your looking down from above turn it counter clockwise to advance it, you'll be moving the contact point in the cap closer to the rotor hence advancing the spark. If you go the other way you move away from the contact point creating retard.

ZONES89RS

iTrader: (25)

Sounds like timing, but damn, why the heck did you leave the stock pump in there in the first place? You did right by installing a 3/8 line, it is what i do, will work fine for you.

92builtbird

Timing or a whiped cam. Assuiming the motor is new, its probably timing.

F-Body Lover

I told the stupid mechanic to remove it while he was installing the ring and pinion he told me it wont effect anything,do you suggest that I open the timing cover and check the notch? or should I play with the distributor?

92builtbird the cam is new I dont think there is anything wrong with the cam or the engine at first I was thinking the problem was from the carburetor but its brand new and then I noticed the position of the distributor so it was the timing from the first place

MrOverkill

iTrader: (1)

If you changed the cam you had to pull the dist out and re-drop it, crank the dist like I said and if you still have issues let us know. Crank it ccw until its hard to crank then turn it back the other way a little at a time to get it to run, then you can use a timing light to get it 100% correct.

You could also have the valves adjusted incorrectly but I think its a timing issue, unless you didnt break the cam in properly???

ZONES89RS

iTrader: (25)

Keep slowly advancing the timing till it fires right up with hardly and hesitation what so ever.

F-Body Lover

MrOverkill its a hydraulic cam I dont think it need a breaking in and when the cam was installed there was no intake and dist

ZONES I will advance the cam as soon as I find a good tank

F-Body Lover

btw will a 4th gen tank will fit 3rd gens? I think the 4th gen tank is made of plastic or something like that right?

MrOverkill

iTrader: (1)

Unless its a roller cam you MUST do a break in at 2500+rpm for at LEAST 10 mins. If you didnt do this and you let it ilde you have flattened your new cam I'm sorry to say. You have to heat cycle any new flat tappet cam hyd or solid it doesnt matter, it should have come with instructions on how to do this.

How long have you run it and did you let it idle at all???

Maybe do a little reading because advancing/retarding the cam is not going to cure your problems unless you installed it a tooth off. This is going to be a learning experience for you I think.....

F-Body Lover

oops sorry I didnt mention it was a hydraulic roller not flat even so its a roller cam I didnt let it idle always 2000+rpm but I faced that problem with the fuel delivery,anyways Im facing this problem with the fuel tank I hope I can find a better one do you know if a 4th gen Camaro tank will fit or not?

ZONES89RS

iTrader: (25)

Advance the timing not the cam.

MrOverkill

iTrader: (1)

Run a hose from the pump to a fuel jug or gas can until you sort out the tank issue. You need to get the timing right with a light and as far as the cam a roller needs no break in just start it up....

MrOverkill

iTrader: (1)

Any luck or change yet???

F-Body Lover

Im back again I toke my car to a friend of mine he changed the jets to smaller ones adjusted the carb played with the distributor and still it back fires he told me there is an intake valve is not set properly but I dont know why I got this feeling that there is something wrong with the distributor today I will take my Camaro home,before a week I realised that the mechanic was using the retainer hose instead of the suction I switched them and now the car rev's very smooth and beautiful but when its cold it backfires too is there is something wrong with the carb? It's a brand new Holley double pump 750 I was thinking of switching to Demon vacuum 750 but I dont want to waste more money on something that will not solve my problem

F-Body Lover

I toke my Camaro home and it only backfires when cold since the carb has manual choke its fully opened and when I floor it quickly it back fires any advice please?