Questions about '86 F250

[TheKing86]

I went home from school this weekend and took a better look at some things on my truck so that when I can actually work on it in May, I'll already have some parts already ordered. I have been trying to soak up as much information as I can but I do have a few questions regarding different areas of the truck.

First up is the rear axle and I am not sure what assembly is above it. Maybe the rear brakes proportioning valve? I've tried to look for documentation as to what it is and haven't been able to find any info anywhere.


Next I've got a question about the engine plate for the 460/T19. It has an opening on the bottom and I wondered whether or not it rolled off the lot like this or was "custom" from the PO.


Next I've got some engine related questions. The goal for the motor is to have good low end torque and be fairly driveable as well as be able to haul some heavy loads. I plan on keeping the E5TE (I think) heads and having everything machined, but I am not sure about what to tell the machinist, as well as what other parts should be kept/replaced/upgraded. I've been reading a lot, but I'm just not familiar with engine building. If anyone has good recommendations, I'd love to hear them, as well as anything you notice in my engine bay besides the dust. And I'll try to make a write up on how to open the hood from the outside on '86's since there is the antitheft cover in the way.
 

Also if anyone has just general advice about what I should and shouldn't do and what I ought to look out for, that would be much appreciated.

[grumpin]

Yes, it looks to me like the rear proportioning valve in that picture. More rear brakes with more weight.

On the engine bay, there’s something there I don’t often see. Those two air pumps. If you don’t use them please don’t toss them. Something someone trying to register a truck that needs all the emissions stuff on it would like to have.

I don’t remember,  but do you need to pull the heads? Might it run ok without tearing into it?

Good engines, low end torque and drivability are natural to it. MPG, no!

[TheKing86]

I'll be sure to keep whatever I pull out, and it is certainly possible that the engine doesn't need to be torn apart. I was told it ran like a top when it was parked, but I figured if I am going to put a cam in it, and paint the block, and check it from top to bottom as I believe it has 225k miles, I ought to just pull it and get to learn. Part of it is just peace of mind too.

I looked at some diagrams and I am pretty sure it is the rear proportioning valve too.

As my dad says, it's not miles per gallon you've got to be worried about, it's gallons per mile My '10 F150 isn't much better on gas so I'm pretty familiar with the drinking issues these big motors have got going on.

Thanks for the info Dane

[85lebaront2]

Other than the 4 speed your drive train is what Darth came with, 460, C6 and 3.55 open rear. The valve linked to the rear axle is a load sensing valve. Ford warns not to remove the linkage from the valve as it can't be adjusted and would need to be replaced. When I changed to a newer limited slip, I took the bracket off the axle and just lifted it out of the way. If you do remove the air pumps, see if you can locate some exhaust manifolds with no external piping, that way you won't have to mess with plugging the holes. On the back of the heads are two more holes, if you follow the air pipes you will see that one set goes to the manifolds and the other to the back of the heads.

If you do pull the heads, be warned, (a) those 9/16-12 head bolts will be tight, 130-140 ft-lbs, then being run for 33 years, the outer row will be the worst, (b) they are heavy and if you plan on pulling them, leave the exhaust manifolds on as they are a pain to get to the bolts with the heads on the engine. I have found removing the inner fenders helps with access. If the heads are off, have them surfaced as much as the shop says they can do without having to machine the intake, every bit of compression helps.

Cam, go for an RV (torque) cam as these, in stock form don't enjoy being spun up like a 302, they were designed to move a heavy (near 3 ton) luxury barge away from a stoplight quickly. Timing chain, the stock timing set retards the cam 4° an aftermarket, or 1988 up factory set is a double row roller and straight up.

The factory DS-II ignition is a reliable unit and easy to fix, The site owner has a DS-II tester, DO NOT try to stuff a Chinese GM distributor in it, it won't clear things! Carburetors, if you do not need emission certification, a 650 cfm 4 barrel, Carter (now Edelbrock) or Holley is a good match, if you happen to be able to score a 1969 428 CJ 735 cfm Holley, it is a great match for one of these engines. Long term suggestion from several on here who have 460s, a ZF5, wide ratio will do wonders for power and help the economy a bit. 10 is about average for these, be glad it's not a Chevy 454, 6-8 is normal for them. I have gotten as high as 12.5, but that is with MAF/SEFI and an E4OD, same 3.55 gear and running 70-75 on the interstate.

[ArdWrknTrk]

I don't see that anyone addressed the louver in the chin of your engine spacer plate, but yes, that is meant to be there.
I'd assume to be an indicator or rear main seal leaks, or just to let the oil out so it doesn't get onto the clutch?

Bill says to mill the heads, but reality is that stock pistons are too far down the bores to have any effective quench.
A better approach would be to zero deck the block, as a normal head gasket is .040-.044" (compressed) anyhow.
Increasing CR without quench only exacerbates the octane problem in my experience.

I would also go with a towing cam, rather than an RV cam.
This engine is the second time I've made that mistake.  

Also be sure to install the cam 'straight up' (tooth directly above crank keyway)
The '88 and up EFI engines used a straight up double roller timing set, but the Cloyes #3079 is only $42 on Amazon or Summit.
Taking out the 4° cam retard really wakes these engines up.

If you're doing away with EGR (and even if you aren't) recurving the stock DuraSpark distributor will help with power.

An Edelbrock Performer intake (with or without EGR) helps add a bit of flow while not having big runners that destroy bottom end.
It will also shave 50 lbs or more off the engine weight.

Plugging the heads in the rear takes a pair of .666" welsh plugs, just like the front.
Or you could simply tap the holes for shortened bolts.

I have my exhaust manifolds plugged (capped)
My advice is to be sure you have oxy-acetylene torch to get the injection spider manifolds off.
The caps can be bought in a pack of 10 at NAPA.

[kramttocs]

Everyone's already given you the good info so I'll just say that your load sensing valve looks really good. Most I see around here are a rusted chunk.
Also, when you go to remove the air pumps and related components/lines you'll be surprised just how much stuff that is or at least I know I was.
Like Dane said, try to remove it all carefully as there are people that need it. I shipped all of mine off to another member.

[ArdWrknTrk]

It's a ton of stuff Scott!
.... well at least 60lbs.

Consider getting an aftermarket alternator bracket. 💡
The stock airpump/alternator bracket is massive and you'd have to hack it to pieces (making it no good to someone who really needs it!)

I know I used an L&L bracket with my 3G alternator when I finally ditched the Thermactor system.
Car brackets from 429/460 applications will not fit an '80's truck.

[kramttocs]

Good call Jim - I second both the Performer intake and the L&L bracket. I think you and I both ran into shimming issues with the bracket but nothing a couple washers didn't fix.

[TheKing86]

If/when I remove the egr system, I'll likely put on new headers, performer intake and obviously I've got to get a new carb anyways as the current one got swiped years ago. I'll probably only pull the heads if I'm going to have to whole engine worked on, so I'll have a little bit better access than reaching out over the fenders.

Regardless of rv/towing cam, being installed straight up and have a double roller set and recurving the DSII should help it out a lot. I know there is some difference of opinion regarding Carter/Edelbrock vs Holley carburetors, but if I go with a performer intake, does it matter which brand it is? something around 750 cfm sounds about right? And would I need a spacer as well?

I've started to keep my eye out for a ZF5, but I'll have to see how it drives and how the T19 is for my usage. I get 12-14 on my truck now, so 10 isn't all that bad. Would a 4.10 and adding the sway bars help it tow/haul much better?

[TheKing86]

I'll be sure to be careful in removing the air pumps and system so that someone who needs it can have it. The rust all around isn't too bad and only has some real rust in the area between the bed and cab, as well as in the upper area of the footwells surrounding the tranny hump.

Thanks for the warning about being careful during removal, I might have just ripped everything to shreds

[TheKing86]

When I first saw the louver I was a little confused as to what was going on but now it makes sense. Probably just to be an indicator or help with heat.

Is there a big difference in lift and duration between the RV and towing cam? I'll definitely be doing a double roller and recurving the distributor as I've seen recommended and done many times. I've heard Scott/TheMadPorter is the go to guy for this stuff.

I should have access to about anything I could ask for so the oxy-acetylene should be quite helpful.  

[kramttocs]

Sometime run a water hose through the cowl and watch inside. Leaks up there are one unfortunate cause for rust at that seam.

[ArdWrknTrk]

Not a 'big' difference, but you might have a more aggressive profile or slightly more lift with a towing cam.
RV's don't really need to get anywhere quickly and their aerodynamics mean they are pushing harder the faster they go.
With 3.55's running out of top end shouldn't be as much of an issue for you as it is for me.

These gearboxes have a deep enough first gear that it shouldn't be an issue getting a load moving.
If I was towing heavy and had to start on a hill with a car behind me at a light, I might be glad I have the 4.10's I do.
As it is I only use 1st a couple of times a year.
Sometimes just to show someone I can walk faster than it idles along.  

I have had both 4160 and AVS carbs on my truck.
While Gary may have a personal, and long outdated bias against Holley.
Blue bowl gaskets and Powervalve blowout protection have been a standard feature since 1991.

I don't think you'd ever want a mechanical secondary "double pumper" in a heavy truck.
Didn't even prefer one in my '85 Mustang.  

In Edelbrock I have a slight preference for the Air Valve Secondary over the Aluminum Four Barrel.
But this is mostly down to how it meters, and ease of adjustment.

Those flare nuts on the air injection are very likely frozen.
But not even corroded steel is frozen when it's molten. 😉
Get them glowing good and work them forward and back, they will usually come off in one piece.