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351 HO mechanical advance plate

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Eriksf250

351 HO mechanical advance plate

Good evening everyone, I have an 86 F250 HD (8,600 gvw), 2wd, 351 HO, t18, 4.10 gears. Would anyone know by chance what the mechanical advance plate specs would be on it? The distributor in the truck is not original, but it has the 10L/15L plate in it, set on the 10L side. I'm currently running it at 12° initial, 32° total. I was wondering if that's the mechanical plate that this truck should have or if it came with something different. I would like to be sure I'm getting the most performance out of it as I can with its current setup. The engine is pretty much stock other than the distributor being replaced at set at 12° initial, 32° total, smog deleted, 650 edelbrock, and currently in the process of installing long tube headers and 2.5" dual exhaust. What should the initial and total be at? I also did replace the heavy spring with a lighter one on my mechanical advance so the timing is all in at 3,000rpms. Any help is appreciated greatly

Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

Gary Lewis

Re: 351 HO mechanical advance plate

Administrator

Erik and I discussed this offline and I found a little bit about his situation in the documentation I have.

I looked at the calibration code information (Documentation/Calibration Info & Part #'s and then the Application To Parts List tab) & I find that there is only one calibration code for his combo: F250 - - M/T-O/8500 lb. GVW 5-76J-R17 522. The calibration code is the 5-76J-R17 bit and the 522 is the parts list.

Looking at the parts list, below left, I see that it used distributor E6TZ 12127—E. And then I found a list of parts for that distributor, below right, but that list doesn't include the mechanical advance plate. And that's where the trail goes cold. I can find no other reference to that part number in the master parts catalog, and no further breakdown of what is in it.

Does anyone have any other ideas of where to look?

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

85lebaront2

Re: 351 HO mechanical advance plate

Administrator

Gary, I found this on AllData:

The 351 HO is the 4 barrel version.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

Gary Lewis

Re: 351 HO mechanical advance plate

Administrator

Bill - Thanks. But how do you read that? I assume those are distributor degrees so x2 for the engine? But why a range on Total and Centrifugal? I'm missing something, and probably something quite obvious.

Gary, AKA "Gary fellow": Profile

FordFETruck

Re: 351 HO mechanical advance plate

For what it's worth. The distributor (that was a OEM distributor) that was in my 351W HO came with a 13L and 18L advance slot and so did my Cardone NEW replacement distributor ordered for my specific truck.

1986 F250 351W, C6, 10.25 Semi float 3.55 gear, 250K Miles

Eriksf250

Re: 351 HO mechanical advance plate

That does help out alot, thank you everyone for all your help, I greatly appreciate it.

Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

FordFETruck

Re: 351 HO mechanical advance plate

For a bit of a guide for yours I run 10 degrees base timing with 36 degrees total at 3000 RPM in my 351W HO truck. Runs fine with heavy loads on 87 octane. I also have aluminum heads, headers with 2.5" dual to 3" single exhaust but I ran this combo with the stock iron heads, intake and exhaust as well. Centrifugal starts to come in at about 1200-1300 and steps up progressively until it maxes out at 3000. I've experimented and it seems to work best for my engine. It does like more base timing running but 10 degrees is the max I can run before I encounter starter drag on a hot restart.

1986 F250 351W, C6, 10.25 Semi float 3.55 gear, 250K Miles

ArdWrknTrk

Re: 351 HO mechanical advance plate

Administrator

In reply to this post by Gary Lewis

It seems Scott gets $190 these days for a custom curved reconditioned DSII distributor with brass cap and rotor, to your door.
Or will work his magic Sun machine for $110 plus shipping on your core.

http://parklandautomachine.com/products

If you like to tinker and can weld slots, bend tabs and understand where the various spring weights will put you, you might just get a Crane Cams 99607-1 adjustable vacuum advance (if you can find one) and a pack of springs from MrGasket.
There are re-curve instructions on his site.
I think Gary may have archived them before the old RHP site disappeared.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Eriksf250

Re: 351 HO mechanical advance plate

In reply to this post by FordFETruck

Matthew, on your truck, do you have the sticker on your radiator support that tells you your factory timing and spark plug gap? Mine says 10° is my stock initial timing, but I have mine advanced to 12°. Anything higher than that like 14° I encounter the hard hot start you're talking about. With the distributor I have with the 10L/15L advance plate, I would have to advance my timing to 16° to get 36° total.

Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

ArdWrknTrk

Re: 351 HO mechanical advance plate

Administrator

You could just file the slot.
Scott's pages show the widths you need....

http://www.reincarnation-automotive.com/Duraspark_distributor_recurve_instructions_index.html

http://www.reincarnation-automotive.com/Duraspark_distributor_recurve_instructions_page-2.html

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

FordFETruck

Re: 351 HO mechanical advance plate

This post was updated on .

In reply to this post by Eriksf250

Yeah, my sticker says 10* BTDC base timing with vac advance unplugged and the sparkplug gap says .042-.046".

Not on this truck, but the distributor for my 64 galaxie I have filed the advance slot to get what I wanted, and if you go slightly too far the thickness of a piece of heat shrink seems to take off 2* of timing (I have a few layers of heat shrink built up) if you heat shrink it over the limiting pin like this.

This is a points distributor but the centrifugal advance is the same as a DSII distributor.

1986 F250 351W, C6, 10.25 Semi float 3.55 gear, 250K Miles

ArdWrknTrk

Re: 351 HO mechanical advance plate

Administrator

Yep, pretty much the same distributor body with a points plate on top instead of the reluctor and magnetic pickup.

The $20 MrGasket spring kit comes with a brass bushing to go over the limit pin.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Eriksf250

Re: 351 HO mechanical advance plate

Jim, you wouldn't happen to have a part number for that spring kit do you? The one I got only had 2 springs in it. I appreciate all the help and wealth of knowledge on this topic for me, thank you all very much. Once I get my truck back, I will have try going into it and see what I can accomplish. The guy I work with who is doing my header and exhaust installation said it's running and performing alot better with the carb he put on for me.

Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

ArdWrknTrk

Re: 351 HO mechanical advance plate

Administrator

Embarrassingly, the kit I bought shows as 'for Delco distributors'...

I didn't want "all in between 2,000-2,800 rpm"
So I just bought the Mr. Gasket 928G Advance Curve kit

(link didn't work) https://a.co/d/bETRRzc

Back before stuff like this was available we used vacuum tube or brass tubing from the hobby shop, but I don't see any reason why heat shrink wouldn't work.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

FordFETruck

Re: 351 HO mechanical advance plate

In reply to this post by Eriksf250

I've only ever bought the Mr gasket 925D kit and used either both of the springs, one of them with the factory medium and or factory heavy spring already in the distributors. It depends on how the spring ears are tweaked but I found two light springs typically have max advance in at 2500-2700 RPM, one light and one medium 2800-3000 RPM and one light and one heavy is all in at 3200-3400 RPM. As you can see in my photo I have it set up, so the heavy spring does nothing until about 50% advance slot travel then holds it back at a bit at higher RPM. That was my trick to keep my high compression 390 from pinging under certain conditions at mid-range to higher RPM but I still get plenty of advance off idle-2000 RPM for good response. Typically, the heavy spring is discarded but they do occasionally have their uses.

1986 F250 351W, C6, 10.25 Semi float 3.55 gear, 250K Miles

ArdWrknTrk

Re: 351 HO mechanical advance plate

Administrator

Yes, you can use one (or both) lighter springs.
But as you say, you get a dogleg in your curve. (In your case that seems exactly what you needed!

)

The instructions that come with the Crane Cams advance unit are good.
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.jegs.com/installationinstructions/200/270/270-99607-1.pdf&ved=2ahUKEwiL9uvAvaz9AhWUFlkFHf6YDi0QFnoECBgQAQ&usg=AOvVaw3dp7550K0OkXiQxo_8TLw3

Without something like a Sun machine you don't have hard data to back up what you perceive is going on under hood.
Not to mention pulling the distributor apart is a real PITA if you have to do it multiple times. (though this is more about getting the last tenths than driving a pickup down the road)

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Eriksf250

Re: 351 HO mechanical advance plate

What would you guys suggest the best total timing should be for a 351HO? I was thinking 36°, and if that is, I might go ahead and try to open up that 10L slot to get the extra 4° I need. 12° initial is the highest I can go before I get the hard hot start, so the 10L will only get me to 32°

Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

ArdWrknTrk

Re: 351 HO mechanical advance plate

Administrator

36° centrifugal + static works in most cases.

You also have to be mindful that you can still get considerable amounts of vacuum advance in 'cruise'.

My truck will 'nibble' on tip-in on midgrade gas, so 91 it is.
Honestly, I think I should have welded my slot a little tighter or should open up the dizzy and bush the pin.
Because I don't want to back off the initial timing and the vacuum can is spot on.

I didn't build or tune your engine. I don't know what gears you have, and I don't know how you drive or what you haul.
The PDF instructions I linked above spell it out, but you have to follow them step by step.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Eriksf250

Re: 351 HO mechanical advance plate

Jim, my engine for the most part is stock, other than emissions deleted, a 650 edelbrock, and headers with 2.5" pipes, x pipe and chambered mufflers. It has 4.10 gears, I drive pretty low key, not too fast because of the t-18 and no overdrive, so I usually stick to the speed limit.

Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

ArdWrknTrk

Re: 351 HO mechanical advance plate

Administrator

With 4.10's and 1:1 you should be spinning pretty good on the highway, so depending on your tire size maybe tip-in won't be any problem.
2.73's in a huge boat like my grandmother's '76 Country Squire would be a different story. Man! Did that thing just move out...

I think 36° @ 3K might be fine for you.
You might like it with faster on the bottom as described above.

If you get knock slowly accelerating on a highway hill try backing out some vacuum advance (if yours is adjustable)

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.