stub pipe and header flange, can a leak make my car run like crap? Options

[machina]

i think one of my stub pipes is leaking where the flange meets with the header. Can a leak there make the car run really bad? Right now it idles OK since i cleaned the carbs but part throttle and mid speed is awful, bucks and kicks...

[r_towle]

it should not make that much of a difference, certainly not enough to make it buck. loud yes, buck ,,,I doubt it unless you have a really high strung motor that runs at 6-9k and has a tuned exhaust...

did you sync your carbs?
If you are unsure of if the carbs are synced, try this
Un hook the throttle linkage and snyc the carbs by the book, adjusting each port to match...by this I mean that the two ports on any given carb must flow the same...not carb to carb, but on the same carb.

the two carbs can be different from each other,,while that is not optimal, it can be tuned out with the linkage.

In an ideal world, with a perfect motor, no leaks in the cylinders/valves, you want all four cylinders to pump the same amount of air.
This can be done by adjusting each individual port using the air adjustment screw on each port.

If you can make all of them flow the same at idle, you are almost there.

Then, put the linkage back on and adjust it so both carbs flow the same, all ports, both carbs, so now you know the linkage is correct.

Now, bring it up to 2k, 3k, 4k, 5k and check all four ports at each step.

This is where the carb tuning gets wierd.
Your motor is not perfect, and there are leaks, get over it.

Try to tune the carb so you are flowing the same when you drive it...so between 2-4k...WOT takes care of itself.
Idle may suffer a bit, but you drive the car between 2-4k and you should tune your carbs there as well.

Also, before you go hog wild, tighten all the intake bolts, manifold to head, manifold to carb...check all of them..you might have a leak that is causing the bucking..

Rich

[machina]

it should not make that much of a difference, certainly not enough to make it buck. loud yes, buck ,,,I doubt it unless you have a really high strung motor that runs at 6-9k and has a tuned exhaust...

did you sync your carbs?
If you are unsure of if the carbs are synced, try this
Un hook the throttle linkage and snyc the carbs by the book, adjusting each port to match...by this I mean that the two ports on any given carb must flow the same...not carb to carb, but on the same carb.

the two carbs can be different from each other,,while that is not optimal, it can be tuned out with the linkage.

In an ideal world, with a perfect motor, no leaks in the cylinders/valves, you want all four cylinders to pump the same amount of air.
This can be done by adjusting each individual port using the air adjustment screw on each port.

If you can make all of them flow the same at idle, you are almost there.

Then, put the linkage back on and adjust it so both carbs flow the same, all ports, both carbs, so now you know the linkage is correct.

Now, bring it up to 2k, 3k, 4k, 5k and check all four ports at each step.

This is where the carb tuning gets wierd.
Your motor is not perfect, and there are leaks, get over it.

Try to tune the carb so you are flowing the same when you drive it...so between 2-4k...WOT takes care of itself.
Idle may suffer a bit, but you drive the car between 2-4k and you should tune your carbs there as well.

Also, before you go hog wild, tighten all the intake bolts, manifold to head, manifold to carb...check all of them..you might have a leak that is causing the bucking..

Rich

thanks rich, don't know if my motor is really high strung compared to full on race motors, it is a rat 2270, runs race gas, spins to 7500 but i shift much earlier most of the time. I guess i was wondering if an exhuast stub pipe leak is as bad as an intake leak. i have synched the carbs with the linkage disconnected but she still runs bad. Was thinking of checking the ouput of each accel jet (do you know how to do that?)

anyway its really hard to test the motor on the street the way it gets driven on the track. i can really only get a couple seconds blast at WOT before things get going real fast. I R&R the carbs yesterday and will re-synch and check it out.

[rhodyguy]

any snapping back thru the carbs when you give it throttle or back fires out the exhuast on decel? just eliminating some indications.

k