Timing.... It either bogs or wont start

[asdfghjkllkjhgfdsa]

1986 ford f150 300-I6. Completely rebuilt engine. No electronics. Motocraft 2150 new carburetor. HEI distributor.

I inherited this project truck from a teenager trying to make a race car.

Anyways I am having a hell of a time getting it to run right. Either I set the timing and it runs great and has good power, but will not start well and needs to crank multiple times to start. (When it does start it runs at a very high idle too)

Or I set the timing for an easy start but then it bogs down when im out driving and sometimes it feels like it will die after a hard acceleration.

This is most definitely a timing issue. I have checked for vacuum leaks. Fuel pressure is good. This happens with another carb I bolt on just to make sure. Good spark on all cylinders. I have the the vacuum advance on the HEI distributor pluged into the port next to the choke ( I think ported vacuum), but I have also attached it to manifold vacuum with the same problem. I timed it orginally to 14degrees, but then started timing it with a vacuum gauge. I can get it up to 20psi vacuum and it sounds great, but thats when it wont crank. If I time it to around 16-17 psi vacuum then it starts easy but bogs down even easier.

Any tips?

[1986F150Six]

On my 1986 with 4.9L engine, I found the "sweet" spot regarding timing to be 18 1/2" vacuum.

[ArdWrknTrk]

Gary's going to say that you need to go to the new members section to read and acknowledge the forum rules, and make an introductory post, like the boiler plate member response said....

I'm going to suggest that you get a 5 pin HEI module from an '80 Tornado and a relay triggered by the (I) terminal of the fender relay to ground.

This should retard the HEI while cranking, and make things a lot easier for you.

[asdfghjkllkjhgfdsa]

Gary's going to say that you need to go to the new members section to read and acknowledge the forum rules, and make an introductory post, like the boiler plate member response said....

I'm going to suggest that you get a 5 pin HEI module from an '80 Tornado and a relay triggered by the (I) terminal of the fender relay to ground.

This should retard the HEI while cranking, and make things a lot easier for you.

Thanks, I went ahead and posted in the new user form. As far as the HEI module and retarding the initial timing for starting the engine, thanks for pointing this out. I wasn't even aware you could do that.

For what parts I already have on hand, could I put a solenoid on the vacuum advance line and have it closed (IE no vacuum reading) during startup to stop those initial 10-12 degrees of advancement that's puts on the distributor, and would this be enough to ease startup? After startup I could turn on the solenoid and open it to full vacuum reading as it normally would be if hooked up without it in line.

Thoughts?

[ArdWrknTrk]

Thanks, I went ahead and posted in the new user form. As far as the HEI module and retarding the initial timing for starting the engine, thanks for pointing this out. I wasn't even aware you could do that.

For what parts I already have on hand, could I put a solenoid on the vacuum advance line and have it closed (IE no vacuum reading) during startup to stop those initial 10-12 degrees of advancement that's puts on the distributor, and would this be enough to ease startup? After startup I could turn on the solenoid and open it to full vacuum reading as it normally would be if hooked up without it in line.

Thoughts?

There's no vacuum if the engine isn't running, and you say you can't get it started.

You could come off the ported vacuum nipple of the carb, and you'd have no vacuum with the throttle closed, high vacuum as you get into the transfer's and it would taper off as the throttle opens.

But you seem to have the initial too far advanced, and vacuum has nothing to do with that.

I'd be checking for about 10° initial and high 30's at 3k or later.

Who knows what the PO did???

I'm not expert on the 300, and I've got no idea what intake or cam you have.

Maybe Dave (FuzzFace) or our admin David could better help you.

[1986F150Six]

There's no vacuum if the engine isn't running, and you say you can't get it started.

You could come off the ported vacuum nipple of the carb, and you'd have no vacuum with the throttle closed, high vacuum as you get into the transfer's and it would taper off as the throttle opens.

But you seem to have the initial too far advanced, and vacuum has nothing to do with that.

I'd be checking for about 10° initial and high 30's at 3k or later.

Who knows what the PO did???

I'm not expert on the 300, and I've got no idea what intake or cam you have.

Maybe Dave (FuzzFace) or our admin David could better help you.

I posted above and will add a link to my work on my 6 cylinder truck and hopefully something can be helpful. Jim, your suggestion regarding using the 5 pin GM module is very good! Thanks for sharing!

https://www.ford-trucks.com/forums/1325963-gas-mileage-recipe-4-9l-300-a.html

[85pig]

Makes me wonder if the kid that worked on the engine may have installed a multi-position timing set, along with a cam that was ground "straight up". Ford retarded the cam timing of the 300 4 degrees, so setting the timing set at the 4 advanced position plus a cam ground straight up might cause some issues, depending on cam timing events. Does it spark knock under load when you have it where it runs good?

[ArdWrknTrk]

Makes me wonder if the kid that worked on the engine may have installed a multi-position timing set, along with a cam that was ground "straight up". Ford retarded the cam timing of the 300 4 degrees, so setting the timing set at the 4 advanced position plus a cam ground straight up might cause some issues, depending on cam timing events. Does it spark knock under load when you have it where it runs good?

I'm 100% behind 'its a mystery what the kid has done'

This is why I'm suggesting go back to basics and find a baseline for whatever has been done to this engine.

If it was some kid wanting a race engine you ought to be reading posts from the Frenchtown Flyer on Ford Six.

ETA: But, as 85pig says, it would be good to see where the cam is centered.

At least with the 300 you have a choice of valve cover or pushrod cover.

[asdfghjkllkjhgfdsa]

Okay I did my timing again and found out that I was getting no mechanical advance. The timing would sit at whatever i set it at which was around 14-16 degrees. When I hooked up the vacuum advance I would get it to advance a bit when I reved the engine.

So I took apart the HEI distributor, and kinda just moved everything around. It felt like the weights might be sticking so I moved them a couple times and put it all back together. After that I was getting mechanical advance and thought I must of done something to unstuck it...

Now that I have done this it still runs... odd.

First thing I noticed is if I disconnect the vacuum advance line and plug it, the engine will die a couple seconds later.

The other thing is Im still getting hesitation at certain times that acts like its about to die and then self corrects. It seems to happen while im cruising down a street without giving it any gas, and then I go to give it just a little and it bucks/hesitates and then corrects and goes.

Any ideas what I should do next?

[asdfghjkllkjhgfdsa]

Makes me wonder if the kid that worked on the engine may have installed a multi-position timing set, along with a cam that was ground "straight up". Ford retarded the cam timing of the 300 4 degrees, so setting the timing set at the 4 advanced position plus a cam ground straight up might cause some issues, depending on cam timing events. Does it spark knock under load when you have it where it runs good?

When I got the truck there was a camshaft in a new box in the back. I cant tell if it was the old original one, or the one he wanted to put in. How can I determine what cam shaft is in the engine now?