Hey, guys --

I just finished swapping a 351M into my '79 F150 that had a 460. I know it's a backwards swap, but sometimes you've gotta use what you've got...

It starts up great, when when I shift it into drive it stalls almost immediately. The only time I was able to keep it running was when I kept the revs pretty high (too high for street driving).

I'm fairly certain that I'm a little low on tranny fluid. Could that be causing the problem? I'm really hoping for a simple fix!

Thanks!
Andy>>


Oh, second question. One of my headlights is very dim. I replaced the headlight, but that didn't work. The plug going to the lamp has three wires. I resume one is a ground, what should the voltage be on the other two? 12v?

 

[updated:LAST EDITED ON 30-Oct-02 AT 12:45 PM (EST)]Hi,

I have lots of questions for you:

1. Is the choke hooked up? Is it cold where you live?
2. Is the timing set correctly? Vaccum advance?
3. Can you look at the manifold vacuum to see what it is doing?
4. Where is the idle set to when in neutral (too low maybe?)

If you could awnser some of these questions I can probably help more, there are just too many unknowns right now.

Post back and I can help more,
-Brents

PS the tranny fluid shouldn't have anything to do with the problem. As for the headlight, the one pin should connect to ground, and the other pin should be around 13.5 volts with the truck running.

 

Hey, I appreciate the help! My answers below:


>1. Is the choke hooked up? Is it cold where you live?
- No, it's not. I couldn't locate the wire from the harness to plug it in (electric choke, obviously). Yes, it's quite cold here. I did let the truck warm up a bit before trying to shift.


>2. Is the timing set correctly? Vaccum advance?
- I think so, but I can't guarantee it. It ran fine before the swap and the distributor wasn't removed or adjusted.

>3. Can you look at the manifold vacuum to see what it is
>doing?
- I don't have a cav gauge, nor do I know how to use one properly (that's my next mission)

>4. Where is the idle set to when in neutral (too low
>maybe?)
- It's too low. It won't hold an idle without my help.

 

Hi Andy,

No choke could be a problem. How long did you wait before tyring to shift? After 30 mins the motor should be warm and not require the choke.

The wire from the harness should go to the stator (stat) terminal on your alternator. It should be around 8 volts I think (not 12!) 12 volts will make the choke element heat up and come off too fast!

I would recommend getting a vaccum gauge and hooking it to a manifold vacuum port to see what it is doing. I can help you locate this port if you dont know where to look. I suspect a vacuum leak is your culprit.

If the idle is too low when not in drive, then either the idle set screw needs to be wound in, or there is a vaccum leak somewhere.

Post back and I can try to help more.

-Brents

 

You know, now that I think about it, we might have left one nozzle on the vac port open. I'll plug that first.

The truck probably only ran for 3-5 minutes before I tried. I'm not running any exhaust yet, so I'm trying to keep it running for short periods of time only.

It's getting towed to the exhaust shop today. When I get it back tomorrow, I'm going to plug the vac leak, then adjust the idle. I'll go from there.

Can anyone recommend a good site for using a vac gauge on these trucks? I'll start with Bubba's site, which has been a great reference on the 351M/400 engine.

Andy>>

 

Hi Andy,

You can try this site also.

http://www.centuryperformance.com/vacuum.htm

Good Luck,
-Brents

 

While I'm thinking about it...

I seem to have misplaced the AIR pump (and all other emissions stuff except for the EGR). Can the port on the intake be left open, or does that need to be plugged?

 

Hi,

No, it needs to be plugged.

-Brents

 

I had the same problem with stalling when the EGR valve would stick open.
The dim headlight is probably a bad ground at that socket, check for a broken wire.

 

UPDATE:

I had the truck towed to the exhaust shop last night, and went to go pick it up tonight with some shiny new pipes -- hoping to get it to limp home.

Oh, I should mention that before I had it towed I pluged the one known vacuum leak (left a port open on the vacuum port) and I plugged the AIR port. I also cranked up the idle so it runs on it's own now. The electronic helper on the choke is not hooked up -- I don't know about the stove tubes.

It started fine (and sounded pretty cool, I must say) and I let it warm up a bit. Knowing that we lost some tranny fluid during the swap, I added a quart.

I tried to shift it into reverse, and it died instantly. This time to stall was accompanied by an audible mechanical clunking noise. It stalled instantly. I started it up again and let it warm up some more. I tried to shift it into drive, and it tried to die. I gunned it a bit and it barely kept running, but I could still hear the metal-on-metal noise so I shut it off and quit for the night.

The noise sounds almost like something's in the way of the flywheel or something. It's not super-loud, but it's definitely noticeable.

It might still be low on tranny fluid. I wasn't really able to get an accurate reading after I added the first quart because of the fluid reside on the inside of the dipstick tube. We didn't loose -that- much during the swap, though.

So, the truck is still sitting there. I'm annoyed becuase I thought I was getting close to having a driveable truck. Now I'm worried that there is some serious mechanical problem and I'm going to have to pull the tranny or engine again.

Can anyone help?

Andy>>

 

You know, the more I think about this, the more I think that maybe the timing might be off or there's still a vacuum leak. Maybe by putting it in gear with the breaks on there's just enough load that it kills it, you know?

Before I start taking things apart, I'm going to give it a tune up, check the vacuum and the timing.

Any other thoughts?

 

Hey Andy,
Which carb are you using? The one off the original 460 or the one on the 351? Have you had it off? Does it have the aluminum carb spacer/EGR adapter? I've seen those rot out between the exhaust passage and the intake port. Makes for a big hidden vacuum leak. Also, if the carb was on during the swap some crud might have come loose and is blocking a/(the) main jet/(s). Did the torque converter stay on the tranny and did it line up good with the flexplate when it went back together?
Call me if you want to pick my brain, if you still have my #.

Greg

'77 F-250 Camper Special 400ci
'76 F-250 Supercab 360ci
'71 Mach I 429CJ
'79 F150 for parts (you remember this one)

huct on foniks wurkt fer me.

 

Hey, Greg!

I'm using the carb from the 351M. It's the standard 2bbl from the factory. I'm very leary of taking the carb off or rebuilding it... last time I tried that was last May, and my truck hasn't been running since then!!!

The Tq converter is the one from the transmission that was connected to the 460. All of the bolts lined up with no problems.

I talked to my brother (he helped me with the swap) and he said that when he started the truck with the 351 before the swap it did the same thing. I guess it worked fine after it warmed up for a while. So maybe it's possible I didn't mess the whole thing up!!

Were you able to salvage any useable parts from that rig?

Thanks for everyone's help so far. This board is the best!