1972 F-250 2wd to 4wd build

['84 Bronco II]

Nice to see the truck on the rocks

 

[rattle_snake]

 

[holdmypocket]

Is your MPG estimate the average of the whole trip? I’m surprised by that number with EFI, and OD. I would have hoped you would still get 10 on the highway.

 

[rattle_snake]

No just off-road. I get 8-10 on highway and about 7 in town.

Perhaps a gallon+ per hour is a better metric. Not sure it matters what speed or gear.

With 205 in low the trans controller isn't compensated. In low the RPMs are higher to go whatever speed. Going to try to enable the 4x4 input and comp in controller.

 

[FordFascist]

Ignition control will definitely help your fuel consumption. High performance engines benefit from lots of timing at low loads and need low amounts at high loads. Electronic control is the only way.

 

[Provience]

Ignition control will definitely help your fuel consumption. High performance engines benefit from lots of timing at low loads and need low amounts at high loads. Electronic control is the only way.

Vacuum advance does that, not so greatly

 

[FordFascist]

Vacuum advance does that, not so greatly

Fuel injection without spark control is a waste IMO.

On a stock engine with a 4500 RPM redline, an almost round camshaft and a 2 barrel, I agree. Any changes from that - not really. Vacuum advance is pretty shitty at dealing with low RPM cruise of an overdrive transmission. It was meant to augment a full mechanical advance / low load situations like a 460-C6 on the freeway at 3000 RPM pulling 20" of vacuum. When you're cruising in OD you are rarely pulling that high of vacuum, nor are you tripping the mechanical advance fully.

High compression Ford V8s are content with ~ 34-36° BTDC at full throttle above 3000 RPM at full load. They need about 16-20° to idle, ~40-50° to cruise, 50°+ on compression braking and less than 10° to start. Carb tuning simply ignores the cruise part because there is no way to accomplish it mechanically.

If you look at low speed ignition advance, cruising spark advance, and low load spark advance there's no comparison. Your average cruising spark advance ~20% load can get into the 50° advanced range. Not really possible with vacuum + mechanical advance. When you have a high performance engine, your fuel atomization does some weird shit at low RPM. You're running rich but your atomization is poor because the velocity is low so you tune it as if it were lean.

Load % and RPM are what you use to trigger advance changes in the timing curve. Almost all of your idle RPM control is ignition-based. Your off-idle performance is ignition based (<5% throttle "tip-in" is done with advance). Your low-mid RPM cruising is going to advance the shit out of your timing much more than you would be comfortable with if you were a carb tuner. If you have EGR you can add even more advance and open the IAC all the way. If you were reading the vacuum, load %, throttle position and advance it would probably look pretty foreign think like 8", 50% load, 15% throttle and 52° BTDC with a stoich of 16-18:1 on an engine cruising. Arguably, one of the hardest part of engine tuning is low RPM, low load ignition tuning.

 

[rattle_snake]

The fuel map doesn't use timing as an input, so I struggle to see how timing would alter fuel delivery.

Part of the issue is aired down tires driving in the sand hub locked turning everything.

 

[FordFascist]

The fuel map doesn't use timing as an input, so I struggle to see how timing would alter fuel delivery.

Part of the issue is aired down tires driving in the sand hub locked turning everything.

Simplistically, fuel is calculated by airflow and throttle percentage with the a preset stoich as the output. Spark is calculated by load, which is RPM, airflow and throttle position.

More spark, less throttle position. Less throttle position, less air, less fuel.


Here's a video from Sniper that may explain it more relevantly for your installation:

 

[mjlogan88]

With the sniper I think it’s speed density, fuel is by VE which is a function of manifold pressure (map) and rpm. Timing is also a function of map and rpm

TPS is used for accel enrichment (like a carb accelerator pump) and possibly other things

I think fordfascist is referring to a MAF based system. But he is correct on the fact that timing is based on load, there’s different ways to measure that

 

[Provience]

Fuel injection without spark control is a waste IMO.

On a stock engine with a 4500 RPM redline, an almost round camshaft and a 2 barrel, I agree. Any changes from that - not really. Vacuum advance is pretty shitty at dealing with low RPM cruise of an overdrive transmission. It was meant to augment a full mechanical advance / low load situations like a 460-C6 on the freeway at 3000 RPM pulling 20" of vacuum. When you're cruising in OD you are rarely pulling that high of vacuum, nor are you tripping the mechanical advance fully.

High compression Ford V8s are content with ~ 34-36° BTDC at full throttle above 3000 RPM at full load. They need about 16-20° to idle, ~40-50° to cruise, 50°+ on compression braking and less than 10° to start. Carb tuning simply ignores the cruise part because there is no way to accomplish it mechanically.

If you look at low speed ignition advance, cruising spark advance, and low load spark advance there's no comparison. Your average cruising spark advance ~20% load can get into the 50° advanced range. Not really possible with vacuum + mechanical advance. When you have a high performance engine, your fuel atomization does some weird shit at low RPM. You're running rich but your atomization is poor because the velocity is low so you tune it as if it were lean.

Load % and RPM are what you use to trigger advance changes in the timing curve. Almost all of your idle RPM control is ignition-based. Your off-idle performance is ignition based (<5% throttle "tip-in" is done with advance). Your low-mid RPM cruising is going to advance the shit out of your timing much more than you would be comfortable with if you were a carb tuner. If you have EGR you can add even more advance and open the IAC all the way. If you were reading the vacuum, load %, throttle position and advance it would probably look pretty foreign think like 8", 50% load, 15% throttle and 52° BTDC with a stoich of 16-18:1 on an engine cruising. Arguably, one of the hardest part of engine tuning is low RPM, low load ignition tuning.

Oh sure, if you want to get technical. But now you've switched for low rpm low load, crawling/camping to highway cruising in overdrive


Just jump right to the weakness in the almighty vacuum, why dontcha

 

[FordFascist]

With the sniper I think it’s speed density, fuel is by VE which is a function of manifold pressure (map) and rpm. Timing is also a function of map and rpm

TPS is used for accel enrichment (like a carb accelerator pump) and possibly other things

I think fordfascist is referring to a MAF based system. But he is correct on the fact that timing is based on load, there’s different ways to measure that

Since we are getting pedantic, I would consider a modern SD system with a closed loop wideband O2 sensor and a MAF system comparable. The difference is how each calculates the air mass entering the engine (VE vs lbs O2). Both systems switch the fuel requirements (idle, cruise, accel, full throttle, decel) via load calculations which also have direct implications to the timing control.

 

[rattle_snake]

I still don't think timing through EFI is going to make a noticeable difference in fuel usage on the trail. It's a 6000# pig with 466 inches to feed at all times.

At some point I plan to lock dizzy and do timing through sniper but I expect gains to be minimal over the custom curved and already optimized distributor. I left learning on way to long and has a shitty tune for awhile and fought idle surge due to timing swing, which is the same concept discussed, they interact. I was able to fix the tune and that removed short term need to go EFI timing. Off idle tip in is crisp and lights the tires up.

 

[FordFascist]

I still don't think timing through EFI is going to make a noticeable difference in fuel usage on the trail. It's a 6000# pig with 466 inches to feed at all times.

At some point I plan to lock dizzy and do timing through sniper but I expect gains to be minimal over the custom curved and already optimized distributor. I left learning on way to long and has a shitty tune for awhile and fought idle surge due to timing swing, which is the same concept discussed, they interact. I was able to fix the tune and that removed short term need to go EFI timing. Off idle tip in is crisp and lights the tires up.

This is what I think you're missing - there is no comparison between a mechanical and an electronic control. There will be a noticeable difference at low throttle input and less fuel usage in low range.

Timing idle swing is easy to cure as well. You merely need to adjust the idle up / down range to match your camshaft profile. I did it on my GPW.

Otherwise, sweet build. I look forward to you coming to the dark side and welcoming Skynet to control your distributor!

 

[reptillikus]

I cant help on the engine tuning, my 466 is a thirty pig as well and i still have tuning issues to resolve on mine too. Yours does look good on the trail though

A doubler would still be nice.

This is surprising since you have the 6R80 in there. I dont remember what your axle gearing is? I love my 203/205 doubler with 5.13s, but i do wish i had OD for the road trips. Here i was thinking the 6R80 would remove the need for the 203 range box and i could get a longer driveshaft in there.

 

[rattle_snake]

I'm running stock 4.10 gears. Just takes a bit of throttle to climb obstacles, then it's too much and on the brakes.

 

[rattle_snake]

Replaced the dented diff cover with one from Ruff stuff. 3/8", 16 lbs.

Used a lube locker gasket instead of sealer.

Has a beefy look. Tie rod just contacts at full lock left so hit it with a flap wheel.

 

[rattle_snake]

Started on the 2nd, left side, bedside toolbox project. Cut box off old bed

Chopped hole in truck, cut width smaller.

Threw the cutout back on the donor bed to make it complete.

Used some painters tape to make a more accurate template cut, some fitting and booger welds.

The liner needs to be the mirror image. 1st was to move the recess for the bed cross member

Cut and swap sides.

Then a slight notch for the forward spring hanger.

Next step is body work and paint. Need to buy some more paint. Door is in good shape, but missing the latch which is not a standard size.

 

[Steve300xcw]

I bet that was a hard cut to make

 

[F***roads]

Started on the 2nd, left side, bedside toolbox project. Cut box off old bed

Chopped hole in truck, cut width smaller.

Threw the cutout back on the donor bed to make it complete.

Used some painters tape to make a more accurate template cut, some fitting and booger welds.

The liner needs to be the mirror image. 1st was to move the recess for the bed cross member

Cut and swap sides.

Then a slight notch for the forward spring hanger.

Next step is body work and paint. Need to buy some more paint. Door is in good shape, but missing the latch which is not a standard size.

that is brave cutting up a beautiful truck. I know you will make it look beautiful again, but wow!

 

[rattle_snake]

I bet that was a hard cut to make

Haha, sort of. Easy cut with grinder but hard to commit to cut location. Only get one shot at it, then more scabs.
I cut the box out of the donor bed first, and made a tape template to place on the green bed.
The hole in the red bed is larger by 2 cut widths.
Cut came out OK. Fitting went quick, and fit well.
There was a fuel tank filler hole above that is sunk in, so have to deal with that again. And the corner seam of wheel well section job sunk a bit and this patch is in basically same location. Trying to use minimal filler as possible but this area is the worst.

that is brave cutting up a beautiful truck. I know you will make it look beautiful again, but wow!

Not going to lie, I procrastinated awhile. Had a little liquid courage and went to work.
After doing the whole truck a single panel doesn't seem like too much.

 

[Steve300xcw]

I just meant making yourself make that first cut. I'da had a hard time doing that

 

[rattle_snake]

cut into fairly new paint? ya... Driving through the brush and trees last trail run helped make it less new looking.

Bough more irate green paint today, only $100 a quart. Probably $200 all in to do this job.

 

[Steve300xcw]

Probably $200 all in to do this job.

We'll see about that

 

[rattle_snake]

We'll see about that

Jesus you sound like my wife







Ok well I already had the other $300 worth of shit needed. And I bough some tools to make the job easier.

 

[rattle_snake]

Puttering along on the bodywork as I have time. Ended up getting into the old hackery from fuel fill and wheel well enlargement patches as I work the area. My skills and expectations have improved over the last 4 years.

Fully welded the box liner and scraped off all the old dried out seal sealer in prep to reseal the whole thing. I want it tight to keep the content dry. So far the other side has sealed very well.

 

[rattle_snake]

Any ideas on slider/rocker protection design for a long bed fool size?

 

[holdmypocket]

Any ideas on slider/rocker protection design for a long bed fool size?

Every time your thread updates I excitedly check-in to see if you came up with a solution for sliders, damn't.

For my truck I want to keep it full bodied and maintain as much of the original look as possible. For the sliders on my truck I'm contemplating 2x2x.250/trailer-stock right under the rocker (tied into the frame of course) and then I was planning on being able to bolt on something to that which would stick out more to protect the driver's door and act as a step, and maybe another one in front of the rear wheel. That way I can remove it the 90% of the time I'm not wheeling trails.

 

[LScout800]

On mine was planning a box tube for the length of the truck tied to the frame, then bending up some tube u's to weld to it under the door for a step, and one at the front of the bed for a step like the newer trucks have. Probably weld some expanded metal to those tubes to keep your boots from sliding off. Definitely putting some protection behind the rear tire, my brick nose is beat to shit right after the rear tire after dropping off of ledges and boulders, lots of bed behind the rear tires.

 

[rattle_snake]

90% bodywork and paint job. The last 10% is 90% of the effort. Minimal filler over perfectness. Etch, high build, sealer.

2 coats Urethane single stage, blend at wheel arch.

Slicked up the liner welds and applied seam sealer. Had to fill and redrill several mounting holes. Just need to fit in truck and add back one more back mount.

Door with no latch. I painted the latch on the other door green and plan to do same when I find one.