Engine 94 GT breaking up

996stang · Sep 21, 2024

Alright guys i bought a 94 gt, supposedly a built 331, carbed, full msd ignition with a 6al. Seems like it has a small cam if its not a factory cam. i tried to tune it today, (timing and carb) as i took it to the track and it was breaking up real bad. it has between 5 an 10 inches of vacuum. timing reads almost 30 degrees advanced and thats where it wants to run. i managed to find an intake leak so im getting on that tomorrow but why would i have 30 degrees at timing on idle and dthat be where it wants to run? it doesnt make sense to me. what am i doing wrong?

General karthief · Sep 22, 2024

Bring the #1 piston up to TDC and check the position of the balancer

996stang · Sep 22, 2024

yea i pulled the intake today and set it to top dead to pull the distributor, naturally i was questioning the balancer being spun but turns out 0 is in fact 0. i have no idea why it wanted to run at 30 degress at idle. i did find that the intake does not line up, it sits a quarter inch forward and down so the ports on the heads and intake do not line up and was causing a massive vacuum leak, my theory is maybe is was such a large air charge it wanted high advance like in high rpm scenario but i honestly still dont have an answer.

Noobz347 · Sep 22, 2024

Pull Codes

996stang · Sep 22, 2024

Noobz347 said:
Pull Codes

Lol, no codes its all carbed.

Noobz347 · Sep 22, 2024

Vacuum advance or electronic?

996stang · Sep 22, 2024

Noobz347 said:
Vacuum advance or electronic?

electronic, msd distributor, ran through a 6al

Noobz347 · Sep 22, 2024

That's where you're going to have to look then. Whatever component is dictating your advance is likely the culprit, all the way back to the pickup.

In a possibly related note, I have seen electronic pickups that 'reported' two pulses for every one.

996stang · Sep 22, 2024

Noobz347 said:
That's where you're going to have to look then. Whatever component is dictating your advance is likely the culprit, all the way back to the pickup.

In a possibly related note, I have seen electronic pickups that 'reported' two pulses for every one.

i think it may have a lot to do with the fact it had such a massive vacuum leak from the intake port on the intake and head not lining up. i think im just going to fix that and put it back together and try again. i did find out is has some kind of hydraulic flat tappet cam in it. still unsure what it is exactly but its not stock so maybie between that and the aluminum unknown heads thats just where it wants to run.

996stang · Sep 22, 2024

General karthief · Sep 23, 2024

I'd peek at the date code on the block, that may be a hint as to why the timing is all advanced.
Can't ID the heads?

AeroCoupe · Sep 23, 2024

Is the MSD distributor locked out? See the bottom of page 4:

https://documents.holley.com/frm29111_8473_8580_8582_85827_85805_85801_081921.pdf

996stang · Sep 23, 2024

AeroCoupe said:
Is the MSD distributor locked out? See the bottom of page 4:

https://documents.holley.com/frm29111_8473_8580_8582_85827_85805_85801_081921.pdf

i dont believe so as it definitely advances, but i will check.

996stang · Sep 23, 2024

General karthief said:
I'd peek at the date code on the block, that may be a hint as to why the timing is all advanced.
Can't ID the heads?

Ill have to check, its pre 94 as it is a hydraulic flat tappet setup with the old firing order

996stang · Sep 23, 2024

i mached the intake back up today using some paint to transfer the gaskets imprint onto the head as i figured maybe there was a misalignment when installed. the ports do not match up and are about 1/8th inch lower then the head port and the top of the head port is basically exposed. my best guess is that someone milled the intake for a decked block and or heads. i have the aluminum heads i had planned to use on my other build i could use for testing purposes however i dont have another carb intake to test so i guess im going to just pull the trigger on a new intake and see what happens.

AeroCoupe · Sep 24, 2024

You should be able to get I. The intake manufacturer website and get stock dimensions. That would let you know how much it is milled.

996stang · Sep 24, 2024

AeroCoupe said:
You should be able to get I. The intake manufacturer website and get stock dimensions. That would let you know how much it is milled.

hmmm, i guess i didnt know that, how would you measure that exactly?

AeroCoupe · Sep 25, 2024

What intake do you currently have on the car? Manufacturer and model number if you have it.

996stang · Sep 25, 2024

AeroCoupe said:
What intake do you currently have on the car? Manufacturer and model number if you have it.

all i can say right now is its a weiand stealth. i do have a couple gt 40 intakes im just not sure if that would help for mach up or not

AeroCoupe · Sep 26, 2024

Go here and the front and rear dimensions are under the "Overview" section.

https://www.holley.com/products/engine/intake_manifolds/carbureted_intake_manifolds/dual_plane/parts/8020WND

I think you can flip the intake upside down and place it on a flat surface (countertop or the like) like this:

Next would be to use a straight edge on the flat part of the intake that seals to the valley of the block and measure from the straight edge down to the flat surface. You would do this at the back and front of the intake and the measurements should be the same as what is listed on the website.

Hopefully one of the guys with machine working experience can jump in here and correct me as I am probably off.

Engine 94 GT breaking up

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wonder how much it would cost to ship you a pair

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Stangnet Facilities Maint Tech... Er... Janitor

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Stangnet Facilities Maint Tech... Er... Janitor

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Stangnet Facilities Maint Tech... Er... Janitor

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wonder how much it would cost to ship you a pair

lube between the nut and the face. I know my lubes

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lube between the nut and the face. I know my lubes

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lube between the nut and the face. I know my lubes

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lube between the nut and the face. I know my lubes

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