First carb rebuild....success

[CamaroAdam73]

Alright, tunings turning out to be a little tougher than i thought but i'll get there.

I got a backfire through the carb...kind've. I thought i had it tuned in so for the first time since the buildup i decided to punch the throttle and see what she'd do. It didn't pop/ hesitate/ stumble or make any noise other than 8 pistons playing my favorite song. But a blue/red flame shot out of the secondaries.

 

[Bonnewagon]

Congrats! I'm glad you hung in there. I think you have a timing or spark problem that is causing the popping. Only a super lean carb would cause that. You never posted the carb #, do so and I can get you the stock rod and jet #s.

 

[pontiacgp]

you might have the secondaries air valve opening too soon...the bottom read arrow shows the angle screw that needs to be loosened before you can adjust the screw...just turn the screw an 1/8 clockwise to put more tension on the air valve. If you feel a bog when the secondaries open there is to much tension on the air valves. If the car sputters the air valves are opening too soon

 

[CamaroAdam73]

First on my list is to bring this engine to TDC and recheck the entire timing process. Like i said, it did shoot a nice blue flame out of the carb but didn't pop/sputter like a typical backfire.

Next i guess would be the wires, like i said before only one or two of them have small dryrott cracks, and the ones that do have them only right before the plug boots.


On the bright side, even after sitting for hours, starts right up without even having to pump the gas once or twice.

 

[CamaroAdam73]

Alright i replaced the plug wires, and that helped allot. no more backfiring. But when i elevate the RPM and hold them at anything over 2000 you can hear a popping in the exhaust.

ALSO, while i was rechecking the timing today, with the vac adv disconnected obviously, i noticed something. My timing light wouldn't have a constant flash, every few seconds it would blink out then come back as if cylinder 1 wasn't firing? I think i might have a problem with my dizzy here, any thoughts?


To sum it up, my timing light skips a beat and i can't tell if it's evenly spaced apart when it does it, i THINK it's missing slightly, and at an elevated throttle it pops in the exhaust.

SEPARATE ISSUE, i still haven't adjusted the air flaps because i don't have that size alen, but they aren't opening when they're supposed too. In fact sometimes they don't open at all. This is because of two reasons, A . to much tension, B. for some reason the secondary throttle plates stick sometimes, i'm going to sand the edges with some 1000 grit till they don't stick anymore.

 

[Bonnewagon]

Good going. I would go through the entire spark system, cap, rotor, wires, just to eliminate the possibility of spark occurring at the wrong time. Separate issue-you will never see the secondary flaps open. They only open when the primary side is maxed out and the motor is wailing. Just be sure you can push the air flap open and it snaps back easily.

 

[CamaroAdam73]

Alright so the engine is definitely missing, me and a friend determined that today and its ignition related which isn't a big surprise lol.

We also determined something else that i suspected anyways, by watching the vacc gauge readout while throttling it up, this engine has an aftermarket cam. And it sounds a good bit bigger than factory spec.

 

[CamaroAdam73]

Did some ignition experimenting today, i have a chevy only mallory laying around that i borrowed the rotor/dist cap and coil from and swapped it out with whats on the 403 now, fired it up and it misses worse lol. I don't even get a signal off of plug wire 1.

I've got a new dizzy coming in the mail, soon as it gets here i'm going to do a full run down on timing and see whats up. Also checking into the potability that the outer ring of the balancer might have spun alittle.

 

[kornball426]

Shouldn't a Chevy and Olds HEI distributor cap be the same? Isn't the only difference that the distributor goes backwards, and the firing order is reversed? As long as its hooked up the right wires to the right plugs I don't see what the difference would be.

At least I think that's how it is... I only ever had one Olds, I know I took the cap and wires off once and left them off for over a week and it gave me fits trying to get it to run. Until my friend came along and after giving him fits to, he remembered the rotor spins the opposite direction on an Olds. :lol:

 

[CamaroAdam73]

Yep rotor spinns counter clockwise, and yeah the rotor/dist cap are the same. however i think the coils might have some differences. With the old AC delco coil it runs but misses, with the mallory coil it runs totally whacky, and i don't get any signal with my light from cylinder 1.

For right now progress is on hold, working on your own cars doesn't make money 😛 I've got tierods and belts/ brakes to do on two nissans today, then brakes again on this ****ing dodge inCREPID. When i get paid friday i'm picking up a new dizzy to slap in, and thats when i'll redo the timing.

Btw does anybody have any idea what size socket i need to get around the harmonic balancer bolt on this 403? i know its bigger than 7/8"