Big problem! Clutch or driveline, i dont even know

latamud · Jul 21, 2005

At first I was thinking you had the fuel filter on backwards but you said it still happens with the filter out of the line.

Try swapping out the carb, and if it continues try swapping the coil, or vise versa. I think it is a fuel issue from the sounds of it. But, I have had coils that played tricks before. A lot of people tell me that a coil is either alive or dead, no in between. Like I said, I've had tricky coils. Once swapped out car ran fine.
Another idea, if there is a crack in the fuel line before the pump it could be sucking in air, that would also explain the lack of fuel in the filter while running inline. Cracks typically show up in rubber fuel line on bends and hose clamps but can be anywhere. Try looking near the tank, from the sender to the hard line is a small length of rubber that is sometimes missed.

scottthomp · Jul 21, 2005

all the rubber lines on it are new. i put new caps on the vacuum ports today and checked the pcv valve. everything looks good. i was under the car the other day and check all the tranny bolts, bellhousing bolts and motor mounts, everything was good. i have tried the thinking outside the box, i am a mechanical engineer almost to finish school and i really can't even think of anything to be causing this but fuel or spark anymore. i really think a piece of that teflon tape is in the main jet of the carb, but i have yet to find somebody who could tell me that it would run good under no load, ie neutral in that situation. i guess it is time for a mechanic although i hate the thought of somebody else driving and working on my very expensive showcar that i have spent so long on. nobody else would have the care that i have with it. i hate this feeling so many hours and so long to get it looking good but now it doesnt run. i might just drive it until something brakes or fixes itself, i can hope i guess. it will still run but not good, anyway i have exhausted my knowledge and need someone elses.

the only carb i can swap it with is a quadrajet from a 350 truck. i dont know if that would even run correctly, but i know it will bolt up to my edelbrock intake. let me know if it will work i can swap it and see how it runs to rule out the carb.

latamud · Jul 21, 2005

mfp4073 said:
I dont know if this will help, but think outside the box for a little bit. There may be other things that you are not thinking off. I had a strange, jumpy power issue once. Car would buck and surge power/no power/power when taking off. Turned out to be a broken motor mount and it was lifting and dropping one side of the motor. Also had another problem one time where it would vibrate really bad, grab odd at the clutch, sometimes better, sometimes worse.....that time the transmission had loosen up from the bellhousing and was thus mating the clutch and flywheel inaccurately.

Good luck and keep searchin!

I agree with the broken motor mount too. If it is bad, you should be able to rev the car from idle from under the hood and see the engine torque over. Just give the throttle a few quick romps. A torque strap could fix it.

In the same sense if the U-bolts holding your rear end in are loose it might cause a similar effect. I'm still pushing for the fuel issue though.

latamud · Jul 21, 2005

Try the quadrajet carb. It might run rich if tuned for a 350 but should be consistent. If it does anything similar to what it is now then you can rule out the carb.

krash kendall · Jul 21, 2005

A motor mount could cause the throttle surging too if you have the mechanical bell-crank style throttle linkage.

scottthomp · Jul 24, 2005

Its fixed!!! One of the jets was completely blocked with teflon tape. Although when i blew on it it came right out so there must not be that much pressure on the jets. Thank you for all of your help.

Turns out the shaking/clutch problem is related, its not doing it anymore, i guess it just didnt have enough gas to get moving.

New problem is the fuel inlet elbow on the carb is leaking so now what, i dont think i want to use teflon tape again. what should i use

D.Hearne · Jul 25, 2005

scottthomp said:
Its fixed!!! One of the jets was completely blocked with teflon tape. Although when i blew on it it came right out so there must not be that much pressure on the jets.

There isn't ANY pressure on the jets ( unless you want to count the miniscule "head" pressure from the weight of the fuel in the bowl ) This is a carb, not EFI. The vacuum created from the airflow moving thru the venturis is what "draws" the fuel thru the jets. If you're inlet fitting's are leaking, you may need to change them. What carb do you have, a single feed or dual feed? Single feed uses a gasket to seal it, Dual feeds have fitting somewhat like AN- style to seal them. No teflon tape required.

mfp4073 · Jul 25, 2005

D.Hearne said:
There isn't ANY pressure on the jets ( unless you want to count the miniscule "head" pressure from the weight of the fuel in the bowl ) This is a carb, not EFI. The vacuum created from the airflow moving thru the venturis is what "draws" the fuel thru the jets. If you're inlet fitting's are leaking, you may need to change them. What carb do you have, a single feed or dual feed? Single feed uses a gasket to seal it, Dual feeds have fitting somewhat like AN- style to seal them. No teflon tape required.

Remember, carbs are a metered drip injection system!

1320stang · Jul 25, 2005

Sometimes, the best solution is the easiest problem.

scottthomp · Jul 25, 2005

Being an engineer i associate the word jet to mean something that creates a higher pressure and increases the rate of flow. Guess these things are just advanced holes.

Umm im not sure on the dual or single feed, its a 4160, it has one inlet so im guessing single. The problem is when the elbow is fully tightened in the carb that it is in the way of some screw with a spring on it that moves down when i rev the engine so i cant tighten it the whole way. it is tight right before the screw is in the way but not tight enought to seal. So can i use a washer or something to move it out a little?

D.Hearne · Jul 25, 2005

Most of the single feed Holley's use an adjustable "banjo" style fitting, it's sealed with a couple of rubber coated washers. I'm not getting a picture of what your's might have. The screw in the spring thing is the accellerator pump arm, that's what actuates the accellerator pump diaphram, which squirts the fuel out of the squirter in between the primary throttle bores. You'r right on about the "jets", they ARE just holes that meter the fuel flow when the carb is operating on the main circuit.

scottthomp · Jul 25, 2005

OK i have a bigger 90 degree, piece that goes into the carb and has about 3/4" thread diameter. then going into that is another smaller 90 degree piece that has treads about 3/8" and on the end of that is where my fuel line goes in. so when i twist the bigger one it sends the smaller 90 coming out of it into the accelerator pump.

right now there is just a small rubber gasket on the bigger one that goes in the carb and that is where its leaking. there is nothing on the smaller one and it doesnt leak. so i need to be able to tighten the bigger one without it causing the smaller one to hit that.

D.Hearne · Jul 26, 2005

You'd do well to get a Banjo fitting off another Holley then. I've got a few spares, and I'll bet Larry's ( 1320Stang )got a few also.

1320stang · Jul 26, 2005

Is this sort of what your carb looks like? The fitting on the far right is called a banjo fitting and I think I may have a spare. If you have this type of bowl on it it's called a side hung bowl (as evidenced if you remove it and look inside it) and it has an aluminum tube that connects it to the other bowl. Center hung bowls tyipically look like your double pumper carbs in that the fuel line comes in from the side up at an angle.

If you can take a pic or find one on the 'net to let us know what you need/are talking about, it would help.

scottthomp · Jul 26, 2005

that looks like the same carb but not the same fitting that i have. Although that fitting would fix all my problems. I will take a pic this week

1320stang · Jul 26, 2005

Ah, sounds like you have an AN fitting like this:

scottthomp · Jul 26, 2005

nope not that one either.

Big problem! Clutch or driveline, i dont even know

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