Stalls when put in gear

[buening 63]

Pak what total timing does your motor run at? While a set number won't work on all cars, for mildly modded or stock SBF motors anywhere in the 32-34° of TOTAL timing is a good number to start with. This is based on numerous SBF motors I've worked on. Different distributors have different weights and springs in them, so some with lighter weights may want a higher initial timing so that they get around the total 32-34° timing. Those with heavier weights need less initial to get to the 32°. Going by ear works for some people, but others you could end up with 45° of total timing and be slightly pinging but unnoticed due to loud exhaust or an untrained ear.

 

I myself have a Duraspark distributor that I put 12L weights and lighter springs. Initial timing is set at 10° BTDC, so with 24° of mechanical advance I end up with a total timing of 34°. My point is, use a timing light and not only pay attention to your initial timing but the total timing that typically gets all in around 3000rpms depending on your springs.

 

A good link about distributors: http://www.carbdford.com/viewtopic.php?t=5543

[panteramatt 1]

Ok, did a couple quick tests as thats all I had time for. The coil is getting the full 12 volts at idle so thats not the problem. Hooked up a vac gauge and Im getting 16" of vacuum at around 800 rpm. Is this good. I did notice once I removed the cap that the engine didnt noticably run worse. Any thoughts. Tomorrow Im gonna time it and clean the carb. After that, I dont know what it could be.

[bigperm2 10]

I don't know exactly what the reading should be, but 16 seems high for ported vacuum, and about right for manifold vacuum. Assuming you are checking ported vacuum... If you plug the line into your vacuum advance, does the idle speed go up? If it does, I think your throttle blades are too far open. See if you can set your idle speed lower with the throttle, and set it back to 800 or so by fattening it up with the mixture screws. Recheck the ported vacuum and see if it is coming down. This could possibly explain why one mixture screw will not make any difference on the idle. If the throttle is too far open at idle, your idle is controled my the intermediate and main circuit (jets) and not by the mixture screws. The ported vacuum source inside the carb is from a hole by the throttle blades. This hole should be above the throttle blades at idle, and at part thottle is is below the blades to get the same vacuum as manifold vacuum.

[buening 63]

Was the vacuum gauge needle steady or did it bounce around?

[panteramatt 1]

Vacuum gauge was steady as a rock and was taken from the rear manifold T where on part is capped and the other goes to the tranny.

[panteramatt 1]

Bigperm, what you said makes sense but can you tell me how to check ported vacuum? Sorry to be a little ignorant on this stuff but afteer owning 10 other mustangs in my life, this is my first carbed one and is actually easier to work on so far just a little learning curve.

[foothilltom 33]

Hi Matt, I think it would be very unusual to remove the vacuum gauge and not hear the engine run much worse, but 16" of vacuum isn't bad at all. I'd definitely get on the timing first and see where it gets you. Avoid shot-gunning solutions.

 

Best of luck!

Tom

[bigperm2 10]

Looks like it is the small port on the front drivers side of the carb. http://static.summitracing.com/global/images/instructions/edelbrock%20carb_owners_manual.pdf I do agree with tom, get your timing set, your car should be in great running condition while the vacuum advance is disconected and plugged. Vacuum advance is an economy thing, not a performance thing. However, the ported vacuum should be next to zero at idle.

[Fordrevhead 29]

I've never heard that Pertronix requires more timing. Timing is timing regardless of the ignition used. I typically recommend 32-34° total timing all in by 3000rpms. It may come in sooner or later depending on the springs you have, and mechanical timing is dependent on the weights in the distributor. quote]

 

It depends on the engine, distributor, how the points were set up before... some fall right in and work great others are very retarded based on the location of the hall effect sensor. Point is, always recheck timing when changing ignitions, thats all.

[panteramatt 1]

Found the problem. After all the tuning and checking, it was a DIRTY CARB!!! Go figure. Thats why that mixture screw didnt do anything. Took it out, blew into the carb, and voila, she runs great. So I got the vacuum to 19" and theres no leaks anywhere. Cleaned the carb out, and got the timing to 10. Now I noticed it runs hot so I belive it to be a thermostat, it never ends. Anyway, thanx to yall for your help and wisdom, I learned a LOT!!!

[foothilltom 33]

Congrats. Way to stay with it.

 

Before you go too nuts chasing around your thermostat, you may want to not trust your temp gauge too literally. They don't tend to work great if they are original.

 

Start a new thread if you want, but it's helpful to know if you're getting boiling coolant out your overflow, is it feeling really hot, etc. Thermostats don't tend to go bad in the "closed" position so I wouldn't suspect that first.

 

Do you have a shroud around your fan, fer instance?

 

Keep us posted.

[panteramatt 1]

No shroud around my fan and I have an aftermarket mechanical water temp gauge and it got up to almost 220! Felt really hot underhood also and the upper radiator hose felt like it was empty. Didnt boil into the overflow though.

[Fordrevhead 29]

I had a particularly tight fresh 302 that I absolutely couldnt get to run cool. The shop didnt want to build it to my specs (tight side of cylinder bore) because they said I wouldnt break it in right and it would seize up. I tried lower temp thermostats, a new and bigger radiator, different fans, eventually it was the fan and shroud combo that did the most... then once it was broke in and ran cooler of course. Anyway the shop was almost right but that was 10 years ago and it is still running strong today.

 

good luck, but for the money and safety I would try a shroud.

[panteramatt 1]

Well eventually I want to put a 3 row radiator and electric fan in it.

[foothilltom 33]

You can spend your dough any way you want, but an electric fan can leave you stranded should it decide stop running for whatever reason. I don't recall that you've modified your 302, so a stock radiator and shroud (with a clean cooling system properly filled) should keep that baby running cool. You could get away a lot cheaper by investing the $30 in a shroud and see where it leads you. Even if you upgrade your radiator, you'll want a shroud.

[Fordrevhead 29]

you can spend a hefty amount on a radiator and electric fan setup but in the meantime spend $40 and save your engine... or else you may not need the electric fan and radiator by the time you save up the cash.

 

http://cgi.ebay.com/ebaymotors/67-68-69-MUSTANG-20-FAN-SHROUD-NEW-REPRODUCTION-/130386227266?cmd=ViewItem&pt=Motors_Car_Truck_Parts_Accessories&hash=item1e5b9ff042

[buening 63]

Found the problem. After all the tuning and checking, it was a DIRTY CARB!!! Go figure. Thats why that mixture screw didnt do anything. Took it out, blew into the carb, and voila, she runs great. So I got the vacuum to 19" and theres no leaks anywhere. Cleaned the carb out, and got the timing to 10. Now I noticed it runs hot so I belive it to be a thermostat, it never ends. Anyway, thanx to yall for your help and wisdom, I learned a LOT!!!

 

Now you can get the Tshirt too :tongue: Glad you got it figured out