Here I go again,
The tow truck is having a problem Why does the distributor need 5 psi of vacume constantly? I can move the distributer advance or retard aslong as the vacume is on constant! HELP !!!!

 

A little more info needed.

I see by your gallery that the truck is a '60 (very cool, by the way, I like it!)- but is the engine original, & do you know anything about the distributor? What is it, or what year did it come from? And, what are you trying to do? Set the timing? Is this at idle?

I'm wondering if you have a LoadOMatic distributor. Alternatively, if it's the '57-up style, is the centrifugal advance working OK?

 

I love that tow truck!!!!

 

It Is The Original 292 With A New Bottom End Ie; Crank Bearings Ect...
Anyway The Dist Is The Old Style With The Weights.
What Happens Is When I Try To Start The Darn Thing It Wont Start Unless I Use A Vacum Pump And Set It At 5 Or More Psi. It Just Started Doing This 2 Days Ago And I Cant Figure What Is Wrong Or Why It Is Doing It.

 

Well, a couple of things come to mind. You are basically adding some advance to the timing, or that's what it sounds like. This makes me think that the initial timing is way off. I'm assuming from what you've said that it has been running fine for a while, until just two days ago.

If you haven't done anything to the dizzy to cause this, & it wasn't loose, and/or it wasn't removed & replaced, then I'd have to wonder if the advance mechs. are broken, or if the timing chain has jumped a tooth (presuming the timing set was installed right, you remember the marks don't line up when installing a timing set on a Y), or the gear pin has partially sheared; something to move the initial timing.

Again, I am assuming that it was fine until just a few days ago. (Therefore the timing set was probably put in properly.) I'm also assuming you've covered all the basics- fuel, air, spark, spark at the right time. Plug wires weren't removed or anything, right?

If you can't get it fixed (& it easily could be something simple that I've overlooked/not mentioned), then I would probably first try rotating the plug wires on the cap one position advanced & see if that makes a difference; then, I would pull the distributor, check it over, including both advance mechanisms, bring the engine to TDC, & reinstall it from scratch.

Hope this helps a little. Not trying to knock your mechanical skills, just going through the basics.

 

That is correct nothing was moved or adjusted when the problem started. Like I said it was running fine until a few days ago.
Right no I have the distributor full foward and 5 psi vacume advance and it starts good and runs well. It maybe a bad distributor.... You think?

 

"It maybe a bad distributor.... You think?"

It's possible, but I think it's less likely. Normally, at idle, you would have the initial advance, plus, possibly a little centrifugal & vacuum advance, depending. From what you are saying, it sounds as if you are having to put in as much initial advance as possible (as far as you can turn the dizzy body), PLUS apply some vacuum advance, just to make it run. This makes me think that the rotor is WAY off (retarded) from where it should be at TDC. Typically, this is caused either by improper installation (aka "a tooth off"), or the timing chain jumping a tooth, which almost always retards the cam & ignition. Since the dizzy wasn't taken out...


That's why I suggested this:

"If you can't get it fixed (& it easily could be something simple that I've overlooked/not mentioned), then I would probably first try rotating the plug wires on the cap one position advanced & see if that makes a difference; then, I would pull the distributor, check it over, including both advance mechanisms, bring the engine to TDC, & reinstall it from scratch."

If you move the wires over one cap post, you might/might not need to back off the dizzy from its full advance position to make it run again.

Again, I could be way off- this is just what I'm seeing from here. At least these two areas are fairly easy, & free, to check.

If the distributor does prove to be bad, & unfixable, Advance Auto, NAPA, AutoZone, etc. all can get the current Cardone-rebuilt dizzy within a few days. OTOH, if moving the wires or the dizzy seems to help, & nothing is wrong with the dizzy or its centrifugal advance, I would seriously suspect the timing chain (or broken gear pin/gear)- & if it's jumped once it'll do it again sometime.....


P.S.- also assuming point gap & dwell are reasonably close to where they should be...

 

It's fixed !!!!
Well this is what I did, I put on a new distributor with petronix ignition and now what a difference.
Thanks for all your help!!!!!

 

Toole,

That is a nice-looking wrecker you got there. However, it appears to be larger than an F-350, perhaps an F-500? I ask this because of the five-lug wheels, since my '56 F-350 has the six-lug wheels...

Johnny

 

No it is just a 1 ton. someone just changed up some stuff.