The specs; 85 F150, 300 i6, T-18, 4x4.

What's new; HEI distributor, fresh plugs and Taylor wires, fuel lines, filter, rebuilt junkyard non-feedback carb from an 83 F150.

The issue; This thing wants an insane amount of initial timing. I get maximum idle speed and vacuum (19-20 inHg) with 30+ degrees at idle. If l set it conventionally at 12-14 degrees BTDC l lose vacuum (down to barely 15 inHg) and it idles rough, although it does idle at around 690-700 rpm. I'll be taking it out on the road for a test drive soon, but today was no bueno. Starts and idles on it's own, if a bit rough. Electric choke is operational and set up correctly.

So far; checked voltage at distributor (12-13 volts at idle). Checked for a dead cylinder by pulling plug wires one at a time and using a stethoscope to hear for sticky/stuck valves, loose rockers, bent pushrods, etc. Also moved my timing light across all 6 cylinders and found nothing amiss (yep... puns)

The question; WTH is the problem here? Timing doesn't jump around, it's pretty dang steady according to my timing light. Vacuum jumps around a bit until the rpms come up, then steady. Mechanical timing advance is in by 1800 rpm and takes me to +/- 32°. Vacuum advance is all in by 2500 rpm and brings total advance to about 50°.

Apologies for the long-winded (and probably repetitive) question. I do see similar questions asked here on FTE but it usually comes down to a worn out distributor drive gear, bad fuel, or a jacked-up carburetor. l had the distributor in and out several times yesterday just to make dang sure l had it installed correctly... it is.

Now I'm outta ideas... whaddaya got?

 

When setting base timing vacuum to dist is disconnected and plugged right?
Is the vacuum ported or manifold?
What is the idle speed when setting base?
If you have vacuum on ported vacuum and the idle speed below 900 RPM then I would say you got something wrong with the carb.

Also are you sure you have the right timing mark on the crank pulley and can see the numbers on the plate.
IIRC there were 2 marks on my pulley so make sure you have the right one and it is at TDC and has not slipped.
Dave ----

 

Vacuum advance disco and carb fitting capped for this. I'm trashing an otherwise perfectly good new carburetor because the one (and only) vacuum fitting is set into a blind hole... l'm taking that up with the vendor. But, yes... l'm using ported vacuum for the distributor.

I try to keep the idle speed under 700 rpm for base timing. TDC was verified (several times, just to be sure) by manually turning the engine over at the crank bolt and checking the position of the #1 piston. Factory timing mark was dead nuts on 0 or, what l ​​​​​​think is 0°... there was rust on the timing tab that left some pitting when l scrubbed it off making the actual numbers illegible. For good measure, l re-marked the tab and balancer to reflect New Zero. I'm using the tab on the passenger side of the engine and the timing mark on the balancer, not the little mystery notch.

I got it back to some semblance of normalcy last night but didn't take the truck out for a drive. It would still like a ridiculous amount of advance at idle, but l won't give it... stubborn that way.
Unfortunately, l won't be able to test drive until next weekend... aaahhh... the glamorous trucker life. We have a cold front coming in, snow in the passes.. Winter ain't done here in PNW. Should be a fun week.

 

I would have to dig up my notes from when I was messing with the dist. timing curve but the only reason I used the light was so I could plot the curve.
If it was not for pinging I would have just advance the timing till I got pining or kick back on start up.

If you have a vacuum gauge use it to set timing for the highest reading but not get kick back when starting cold or hot or pinging.

Also this high timing is this base and what is the number again at idle and hose off & plugged?
Last few days have been in the mid to high 70's herein NC
My plumb tree has flowers on it already.
Dave ----

 

My vacuum gauge was reading 17-18 inHG when l had the timing advanced to the moon. The idle speed also was much too high when l achieved maximum steady vacuum. I didn't bother trying to adjust the idle down because l wasn't going to leave the static timing at 35° BTDC, no matter how strong the engine looked and sounded.

Right now I'm set at 13° static, add 16 for mechanical (<the 20 l had before) and another 15-20 from vacuum (much less that the 50° total l was showing last week. Numbers are fuzzy, the work was done a few days ago) and idling at 690 rpm. Here, vacuum is down to 14-15 inHg... not great but it does start easily, idles on it's own right away, and drives. I used my digital timing light for this because it has a tach setting, and because going for maximum vacuum readings had me all up and down the scale (carb settings, timing advance, and idle speed... l can't trust my ears anymore) l needed to verify everything at least twice. Smoke from the exhaust is close to nil, just little puffs of condensation, no smell of gas or other burning fluids. I haven't opened the valve cover, but l don't hear any valvetrain noises. *

Its a looong way from optimized, it ain't even close. I wanted it in tune before l jumped into the exhaust/intake manifold/gasket(s) R&R, a good baseline to tune back to. There has to be something I'm missing.

We were looking at Wrightsville Beach or maybe Oak Island for a little getaway later this year. Pretty sure we've decided on Virginia Beach instead because it's several hrs closer to where l have family. Dad's over 80 and I'd really like to get a visit in soon.

Edit
* l just reread my first post and realized that I'm right back to where l started. My most recent frozen Sunday afternoon tuning session got me nowhere.

 

Do you know the RPM that the mechanical starts at?
You said the idle RPM was pretty high with the vacuum at 18 hg maybe it was high enough to kick it in?
What RPM dose the vacuum start at?

What needs to be done with them? If the gaskets are leaking, between head & manifolds? then what you are doing is all going to change when the vacuum leaks are fixed.
Dave ----

 

Mechanical advance was all in at 1800 rpm. Vacuum advance came on at 2500 rpm or so.

It's entirely possible that the advance weights were kicking out in idle when it was revving so high... that's something l thought of at the time but didn't pursue it because even if that was the case, it would still mean my initial advance was crazy-high like, around 20°. At that point l retarded it until it reached 12 or 13 degrees, adjusted the idle speed down to under 700rpm, and turned the mix screw in about 1/4 turn.

I know l have tons of exhaust leaks but haven't been able to find any vacuum leaks at the manifold.... they're both coming off for the installation of the EFI manifolds I've been sitting on since last summer. I realize that things will change somewhat with the new gaskets, manifolds, etc, but l wanted to get a decent baseline beforehand and take it from there, eliminate as many variables from the equation as possible. If it's running wonky before l do that work, it's harder for me to tell which system needs adjustment.

 

Ok I can see doing it that way then.

Have you put the timing light to it now that the idle is below 700, vacuum hose off & plugged?
I ask because it sounded like you set it to 12 13 with the idle speed still high.

When you do the manifolds are you going to use a factory Y pipe or something else?
If Y pipe look down in the pipe from the manifold end where the pipe is welded to the other.
The hole on some Y pipes are really small and need to be open up to get flow.
Mine was ok and did not need to be open up.
Dave ----

 

When l turned the distributor back (retarded) the idle came down on it's own quite a bit. I set it at 13° BTDC and readjusted the idle and mix screws... the 13° was an arbitrary number, but seemed to be in the ballpark of normal.

Since Ford conveniently placed the timing tab on the opposite side of the engine as the distributor, adjusting advance while simultaneously monitoring the timing light and marks is a pain, not to mention trying to keep the cord out of the fan. My son will be over this weekend and I'll divide the labor, put him on the light and I'll monitor the vacuum gauge and twist the distributor.

I have the Walker Y-pipe and yes, it needs to be grindered-out some at the flange. They do a pretty poor job putting those things together.

 

I find when doing the timing I will see where the timing is, put the light down and move to the dist. side.
I take a small hammer, remember it is only tight enough so it will not move on its own, and depending what way it needs to move I give it a little love tap then check with the light and adjust from there if needed.

Just note the idle RPM and if it goes up to much lower it, you dont want the weights to kick out, and check timing with the light again till you get it where you want it.
Dave ----

 

I had to be away for a few days, we had a bit of an emergency here. Without all the gory details, I'll just say that it involved a Life Flight trip to Portland and me scrambling around to get there myself. We're all back home now.

I drove my truck around quite a bit yesterday, including a couple of short (4 or 5 mile) blasts down the highway (55-60 mph) to get my son's truck (85 F250) started and running*. We also replaced his ridiculous 650 Edelbrock carb (on a stock 302) and it's stacks of adapters/gaskets for a Motorcraft 2 bbl. The short story is... multiple short trips to various parts stores and longer highway miles to his place and back makes me think that there's still some tuning to be done as it's still not optimized, but if l didn't know better, I'd say it's a pretty good running old truck (mine is... now his is too).
Being someone who people count on ain't the worst thing in the world, but it sure can keep you busy when the crisis stack up.

*His problem was quickly diagnosed as cruddy coil terminals/connections. The carb swap was planned, but for another day.

 

Sorry to hear about the emergency and hope all is getting better.
I been home from work for 4 weeks taking care of my wife, got a new knee.
She had issues with pain when in hospital and issue with her hart so over night stay turned into a week.
We also cant get a aid to come to the house and why I am home.

On your truckI would say dont worry about the timing light and make adjustment and drive it to see how it is till you get it where you like it.
I found on my truck anything more than 14* BTDC it would ping badly. I do have a little pinging and may back it down to 12* BTDC for summer but I like the power it has.
Dave ----

 

May be a silly question but given the potential for your timing marks to slip if the harmonic balancer gets wonky - have you verified that your timing marks are accurate and that TDC really is?

 

After determining TDC of #1 cyl l re-marked the timing tab. There may have been some slippage of the balancer, but not very much because the "new" TDC mark ended up dead nuts center of the timing tab. The marks and numbers on the tab were unreadable due to some rust pitting.