Timing a Ford 370

[Duromax04]

Does anybody have experience setting the base timing on a Ford 370 or 429?
This truck is an 85 F-800. It has the dura spark ignition on it.
My question is: Is there a jumper plug that I have to pull or something I have to unplug before I set the timing?
The reason I ask, I checked it with an adjustable timing light on it this weekend, and with the vacuum advance unplugged it was showing almost 18 degrees of timing. I can't really believe it could have that much base timing and not ping like crazy or start hard.
I have not driven this truck with a load on it yet, but did drive it a little bit when I brought it home, and I didn't notice any pinging.

Any Ideas?

Thanks,

 

[funwithfuel]

If you're looking for the little spud like the GMs have, I don't think you'll find one. I've always set them with the vacuum line disconnected and verified that your on a metered port. Not straight manifold vacuum. Gotta remember 70s going into the 80s were not a good time for gassers. Low compression is common. I reckon you'd be lucky to have 8:1 in that old girl. Especially if she's a 370 Lima.

 

[Old Doug]

I have 2 manuals on them at another place i will look and see what it says. If its running ok i would leave it alone its very common for the balancer to slip on the rubber so the marks will be off.

 

[Duromax04]

Forgot about the Harmonic balancers slipping, that could be what has happened.
I am on ported vacuum, so that is not an issue. I figured I need about 10degrees advanced base timing.
I really need to know if the dura spark ignition is changing the timing at idle and if there is something I need to unplug, like a jumper plug or anything.

It seems to run fine, but again, I have not driven it much or with a load at all. I guess I will leave it for now, and see how it hauls a load.

Old Doug, thank you for looking that up for me. Much appreciated. If that dura spark is somehow advancing the timing, then that is probably why it is reading so high.

Thanks,

 

[Old Doug]

I looked at several manuals i have and they all say 6 degrees but i have yet to find out what if any thing has to be unhooked other than the vac advance. I will do some more reading and see if i can find anything.

 

[Duromax04]

Thank You,
Much appreciated. There has to be something out of wack either the harmonic balancer has moved or the dura spark is affecting it. It is showing 18 degrees at idle. I would think under load it would ping badly if it indeed has that much base timing. Do you know if there is anything else that could cause that kind of issue. I don't think this dist has advance weights in it that could stick.

 

[Old Doug]

I went and looked at a truck like yours and it had a sticker on the engine that said unhook the vac advance line and plug it then check timing. One book showed a high altitude model it had 3 plug on the module it could change the timing on its own to adjust to the altitude.

 

[Duromax04]

Thanks Old Doug,
I think this truck has been around this area all its life, so I don't think it has a high altitude setting, but I am going to check and verify. You said it has a 3 plug on the module. Is the module the dura spark box? When you say 3 plug is it 3 separate plugs, or one plug with 3 spades in it. Thanks again for the help.

 

[Old Doug]

If it was the special one it would have 3 separate plug ends the normal one has 2 plug ins on the box. Back in the 80s a guy came buy the shop with a tester to test the ford module. The problem with normal testing was they could fail after they were heated up so this new tester heated the module up. We had saved a bad one that when the truck got warmed up it would die and not restart until it cooled off. We tryed it on his tester and it tested good.

 

[Duromax04]

Update on this, I did verify that it has only 2 plugs on the Dura Spark Module. I did notice that half way in between module and the dist on the wiring loom, there is a plug that has nothing plugged into it, and it is a female plug that looks like you could put a large fuse in it or a jumper in it. I was wondering if there was a jumper that went in there for setting base timing. Has anyone had any experience with that?

Thanks,

 

[OFF]

Those engines were very low compression compared to car engines. It probably can survive just fine with 18 degrees of timing. What does it do when you rev it up? 30 something total is about right. If it runs good, starts good, and doesn't ping under load, go with it. That's where it will make the best power.