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]

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]

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]

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]

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]

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?

[mat in tn]

mystery camshafts can be a real pain to discern. measuring the cam in the box might help at least answer some questions. like what is supposed to be in the box.

[ArdWrknTrk]

If it was the one that came in the truck it would be burnished on the entirety of the lobes, and look used....

[mat in tn]

absolutely. but measure it to know

[asdfghjkllkjhgfdsa]

Okay Im starting to piece together what the previous owner did/wanted.

He locked out the distributor because he put a large cam in and was looking to make a track vehicle. Thats why when I set timing to something the engine is happy with it idles at 1000+ rpm, and has nearly 36 degrees of advance. Plus i need the idle set screws almost 5-6 turns out to idle without stalling.

My question is, I need a work truck, something reliable at low speeds with good torque and reliable start. If he put a large cam in it, can I ever get back that good low end power and reliable start? I dont have a way to remove the engine and replace the cam, so it would all have to be done in my front driveway, whatever that is. Some people have mentioned an MSD system to retard the timing during start. Can a MSD system like this be hooked up to a DUI HEI distributor? The other option was modding some type of pin control in the distributor. And then am I only ever going to have power at 3000rpm and up?

I really love the truck, and love the idea of a no computer, simple reliable, 300 I6, but if I need a shop to make it so then I probably just need to sell it and get something else.  

[mat in tn]

it's also very possible that the previous owner did not get the results expected and gave up on it. what carburetor is on it? I'm wondering if you might not just need another carb or a rebuild.
you say that you have a cam in a box, is it possible that the info is still in or on the box saying what the cam is? that may help .

[ArdWrknTrk]

In the 3rd post I suggested that you get a 5 pin GM module and wire H through a relay to ground and have it triggered by the (I) post on the starter relay so it retards 10° while cranking

If you have a cam with a load of overlap it's never going to pull from idle.
You're going to have to wind it up to where there's enough dynamic compression to make power.

[ArdWrknTrk]

Matt, He stated 2150 in the first paragraph of the thread.
I asked which manifold, but still don't know.

[mat in tn]

I find it rather odd that anyone dug deep enough to do a radical cam and still put a 2150 on top. I'm hoping to get cam specs if possible. my bigger concern is how it was rebuilt more than what with.

[asdfghjkllkjhgfdsa]

The manifold is an Offenhauser dual port 240/300 cfm. I have a phenolic spacer/2-4 port adapter that is open, so the dual port thing shouldn't much matter.

The box that has the cam in it says comp cam part# 66-248-4, grind# f66 268h-10, gross valve lift .456 duration at .006 tappet lift 268 valve timing open @.006 int 28, btdc 60 exh 68. (The cam looks new too me, so it might have never been installed, but it could be the old one too)

The original carburetor was a Holley 4160. I replaced it with a Motocraft 2150. I have the same stumble off idle issue with both carburetors, which is what led me to thinking this is a timing issue.

Ever since I cracked open the distributor and unstuck the centrifugal weights, I have not been able to get the timing back down under 32 degrees without killing the engine. It seems happy around 36-40 degrees and will idle @800rpm (dropping to 600 when in gear) and an idle vacuum of 20.

Tried turning over the engine before kicking the start and that seems to help with the hard starting. Thanks for that tip!

Anyways I took it out for another drive after setting it to sound decent and somewhat steady (still fluctuates a bit). Good acceleration, good feel for about 2 minutes (like always) and then it starts to stumble when coming off an idle. This stumble gets worse when you push the accelerator, and to keep from killing it you have to completely take your foot off. It also progressively gets worse doing this off idle stumble more and more over the course of minutes. Finally the stumble will get to the point it kills the engine entirely. You then have to wait a couple minutes to restart the engine.

I also noticed that a small oil leak at what I think is the rear seal, seems to get worse after driving it like this. Maybe the engine oil pressure is going up above a threshold when its running poorly, because the leak doesn't seem to happen all the time.

[asdfghjkllkjhgfdsa]

This is the DUI HEI Distributor opened up. Looks fine to me, but I'm open to any input