1984 Bronco build thread

[StraightSix]

Hi guys. I need to sit down and write out a full update for you guys. The news is all good, the bronco went on its first mountain fishing trip in over a year last weekend.

My type 9 mirrors are floppy. Is there a consensus on which replacement mirrors are the "good ones"? A particular brand or telling feature, perhaps?

Thanks!

Hi Guys!

Sorry its been so long. Family health issues, work stuff, and life outside the four walls of my garage have kept me busy.

Here is where it sits - No additional tuning changes. it seems to run fine on 87, though Id be tempted to top it off with high grade if I was going to tow a trailer with it. Im running 14 degrees of base timing. Cruising AFR floats from 13.8-15 depending on load and moon phase, but spends almost all of the time between 14-14.5. Idle vacuum is still about 16inhg on my faulty gage which correlates to about 20 in reality. It no longer goes lean in 4rth (as in leaner than stoich at WOT) but I wouldn't mind it being a little richer under that specific condition. it will get down to 13-13.5 but it may take it a minute to trend that way.

the engine now has about 1300 miles on it. I replaced my thermostat gasket and I am not losing water any more.

I drove it up to the mountains a few weekends ago for an off road fishing trip, one expression of the vehicles ultimate purpose. It did great on the highway, I think all of the head work and oversized valves really helped with accelerating from 65mph (2600rpm) to about 75 rpm. I consider that to be a major safety upgrade for the purpose of defensive driving, even though I seldom drive the vehicle that fast unless Im trying to avoid getting smacked by a honda. Off the pavement, the bronco is great. It will power up any hill in 2nd and its happy to pull hard and sling gravel in 3rd so long as you keep it above about 1000 rpm. because of how Im geared the 10-15 mph gravel road sweet spot straddles 2nd and 3rd so I end up shifting a lot but thats not the engines fault. If anything, the generous wide useable torque band 1000-3000 rpm helps compensate for my wide gears. Skinny 33" tires may be coming next time I need new tires, that may help a slight bit.

the bronco made 14.6 mpg on the way home, a drive consisting of about 80% interstate miles at 65-70 and the rest local highway driving at around 55. this is the same drive where I made 15.9 mpg a little over a year ago. I think the engine was probably running really lean back then though, I upsized about 6 jet sizes once I got the AFR running. While I would love for it to make better fuel economy, thats hard to complain about for a carbureted 4x4. I think it made closer to 10 mpg on the gravel. Perhaps there is still a little bit of tuning work that can aide in fuel economy. Also, the transmission and Tcase were rebuilt at the same time as the engine. the rear axle is fully rebuilt only 600 miles before that, so all of the bearings may still be tight? who knows. it might get better, but I wont be heart broken if it doesnt.

I think Ill rebuild my carb next time the forecast goes to rain for a week. I doubt it can hurt, and it will make me more confident in my tuning work. A new vacuum gage is in the works, but I need to be mindful of how much cash this vehicle has sucked down. there are other more pressing things like side view mirrors that dont point right or a filler neck/cap that leaks gas when you park on a grade. it feels good to be back in a spot where I can make gradual improvements to the vehicle as I have time and cash, without having to leave it disabled long term.

I ordered some new type 9 mirrors from JBG, Ill report back on their quality and function once I have a chance to install them. For this week, life is all about my girlfriends final exams this week, work, and prepping for a 5 day backpacking trip in the prettiest place this side of the Mississippi, great smokey mountain national park.

[Gary Lewis]

Hi Guys!

Sorry its been so long. Family health issues, work stuff, and life outside the four walls of my garage have kept me busy.

Here is where it sits - No additional tuning changes. it seems to run fine on 87, though Id be tempted to top it off with high grade if I was going to tow a trailer with it. Im running 14 degrees of base timing. Cruising AFR floats from 13.8-15 depending on load and moon phase, but spends almost all of the time between 14-14.5. Idle vacuum is still about 16inhg on my faulty gage which correlates to about 20 in reality. It no longer goes lean in 4rth (as in leaner than stoich at WOT) but I wouldn't mind it being a little richer under that specific condition. it will get down to 13-13.5 but it may take it a minute to trend that way.

the engine now has about 1300 miles on it. I replaced my thermostat gasket and I am not losing water any more.

I drove it up to the mountains a few weekends ago for an off road fishing trip, one expression of the vehicles ultimate purpose. It did great on the highway, I think all of the head work and oversized valves really helped with accelerating from 65mph (2600rpm) to about 75 rpm. I consider that to be a major safety upgrade for the purpose of defensive driving, even though I seldom drive the vehicle that fast unless Im trying to avoid getting smacked by a honda. Off the pavement, the bronco is great. It will power up any hill in 2nd and its happy to pull hard and sling gravel in 3rd so long as you keep it above about 1000 rpm. because of how Im geared the 10-15 mph gravel road sweet spot straddles 2nd and 3rd so I end up shifting a lot but thats not the engines fault. If anything, the generous wide useable torque band 1000-3000 rpm helps compensate for my wide gears. Skinny 33" tires may be coming next time I need new tires, that may help a slight bit.

the bronco made 14.6 mpg on the way home, a drive consisting of about 80% interstate miles at 65-70 and the rest local highway driving at around 55. this is the same drive where I made 15.9 mpg a little over a year ago. I think the engine was probably running really lean back then though, I upsized about 6 jet sizes once I got the AFR running. While I would love for it to make better fuel economy, thats hard to complain about for a carbureted 4x4. I think it made closer to 10 mpg on the gravel. Perhaps there is still a little bit of tuning work that can aide in fuel economy. Also, the transmission and Tcase were rebuilt at the same time as the engine. the rear axle is fully rebuilt only 600 miles before that, so all of the bearings may still be tight? who knows. it might get better, but I wont be heart broken if it doesnt.

I think Ill rebuild my carb next time the forecast goes to rain for a week. I doubt it can hurt, and it will make me more confident in my tuning work. A new vacuum gage is in the works, but I need to be mindful of how much cash this vehicle has sucked down. there are other more pressing things like side view mirrors that dont point right or a filler neck/cap that leaks gas when you park on a grade. it feels good to be back in a spot where I can make gradual improvements to the vehicle as I have time and cash, without having to leave it disabled long term.

I ordered some new type 9 mirrors from JBG, Ill report back on their quality and function once I have a chance to install them. For this week, life is all about my girlfriends final exams this week, work, and prepping for a 5 day backpacking trip in the prettiest place this side of the Mississippi, great smokey mountain national park.

It is awesome that you have it running so well. And that MPG is nothing to be sorry about. But, if you are running at 14.0 - 14.5 most of the time you can gain a little bit by leaning it to 14.5 - 15.0. The reading I've done says that max MPG is at 15.6 but that there's not much difference between 15.0 and 15.6, so the high 14's are good.

But if you are running 13-13.5 at WOT you are leaving torque on the table. Best torque is at 12.6 and it won't hurt to be a little lower than that. So I think if you got the carb to provide more fuel when getting into it you might find that it pulls a bit better at 1000 RPM. And that may help with the 2nd/3rd shifting.

And these things can be some of those "gradual improvements".

 

[StraightSix]

It is awesome that you have it running so well. And that MPG is nothing to be sorry about. But, if you are running at 14.0 - 14.5 most of the time you can gain a little bit by leaning it to 14.5 - 15.0. The reading I've done says that max MPG is at 15.6 but that there's not much difference between 15.0 and 15.6, so the high 14's are good.

But if you are running 13-13.5 at WOT you are leaving torque on the table. Best torque is at 12.6 and it won't hurt to be a little lower than that. So I think if you got the carb to provide more fuel when getting into it you might find that it pulls a bit better at 1000 RPM. And that may help with the 2nd/3rd shifting.

And these things can be some of those "gradual improvements".

Thanks Gary!

In 2nd/3rd @WOT it quickly gets on down to 12-12.5 afr. However, at ~2000 rpm, 4rth gear, WOT, It often floats around 14.-14.5 and then gradually makes its way down to 12.5-13.5. that may take a few seconds? its not great, because that's generally what happens when I shift into 4rth while accelerating to highway speed. Im kinda hoping that a rebuild might help some, but I dont have any good reason to think that would be true beyond hoping. as for leaning out the main jets, Im open to it for sure but Id want to wait and get a better idea of how the engine runs. As overplayed as this statement is, Id rather waste some fuel than damage my engine or shorten its working life. once Im positive I know whats going on, I may try shifting down a jet size or two. Id rather fix the 4rth gear bog 1st. it has occurred to me that I may be up against the tuneability limitations of my beloved 2150. If so, that's fine. I wanted a simple carb and I have one.

Side view mirrors -

my JBG type 9 mirrors came in, and frankly it was really disappointing. They seem to be equivalent to the absolute junkiest mirrors on amazon. The housings are plastic instead of metal, the boomerang shaped bar and brackets don't fit up to the bronco and the part they sold me as a "passenger side" mirror is identical to the driver side meaning non concave. At $100+ shipped I wasnt really too pleased especially considering that products of similar construction and quality can be had on amazon for about half as much. Fortunately, the rep at Jeffs agreed to refund the parts. Unfortunately, they did not agree to refund the shipping or return shipping even though the parts dont fit, and the passenger side mirror, in my opinion, does not meet that qualification. Not to mention the obvious cost/quality issue. So thats the end of that. I hate to complain, but I feel defrauded and dont want that to happen to you guys.

At this point, my plan is to either repair or rig the mirrors I have which appear to be aftermarket themselves. The easiest option would be to epoxy them in place. I suppose that there is probably an epoxy that could be removed later down the line chemically, or with heat?

I know that the general consensus is that these are "non reparable" but has anyone had any success with tightening up that ball joint so the mirrors dont flop down in the wind?

Another option might be to hunt down originals in the JY.

[ArdWrknTrk]

Thanks Gary!

In 2nd/3rd @WOT it quickly gets on down to 12-12.5 afr. However, at ~2000 rpm, 4rth gear, WOT, It often floats around 14.-14.5 and then gradually makes its way down to 12.5-13.5. that may take a few seconds? its not great, because that's generally what happens when I shift into 4rth while accelerating to highway speed. Im kinda hoping that a rebuild might help some, but I dont have any good reason to think that would be true beyond hoping. as for leaning out the main jets, Im open to it for sure but Id want to wait and get a better idea of how the engine runs. As overplayed as this statement is, Id rather waste some fuel than damage my engine or shorten its working life. once Im positive I know whats going on, I may try shifting down a jet size or two. Id rather fix the 4rth gear bog 1st. it has occurred to me that I may be up against the tuneability limitations of my beloved 2150. If so, that's fine. I wanted a simple carb and I have one.

Side view mirrors -

my JBG type 9 mirrors came in, and frankly it was really disappointing. They seem to be equivalent to the absolute junkiest mirrors on amazon. The housings are plastic instead of metal, the boomerang shaped bar and brackets don't fit up to the bronco and the part they sold me as a "passenger side" mirror is identical to the driver side meaning non concave. At $100+ shipped I wasnt really too pleased especially considering that products of similar construction and quality can be had on amazon for about half as much. Fortunately, the rep at Jeffs agreed to refund the parts. Unfortunately, they did not agree to refund the shipping or return shipping even though the parts dont fit, and the passenger side mirror, in my opinion, does not meet that qualification. Not to mention the obvious cost/quality issue. So thats the end of that. I hate to complain, but I feel defrauded and dont want that to happen to you guys.

At this point, my plan is to either repair or rig the mirrors I have which appear to be aftermarket themselves. The easiest option would be to epoxy them in place. I suppose that there is probably an epoxy that could be removed later down the line chemically, or with heat?

I know that the general consensus is that these are "non reparable" but has anyone had any success with tightening up that ball joint so the mirrors dont flop down in the wind?

Another option might be to hunt down originals in the JY.

You might consider wicking in some Loctite.

That tightened up my mirror heads enough that they would not budge from wind or slamming the door but still allowed me to move the head around (with two hands)

If you really wanted to glue them in place I'd think cyanoacrylate (Crazy Glue) would be better than epoxy.

Acetone or MEK seems to dissolve it.

 

[StraightSix]

You might consider wicking in some Loctite.

That tightened up my mirror heads enough that they would not budge from wind or slamming the door but still allowed me to move the head around (with two hands)

If you really wanted to glue them in place I'd think cyanoacrylate (Crazy Glue) would be better than epoxy.

Acetone or MEK seems to dissolve it.

Thanks Jim! I hadnt thought about Loctite. any ideas on which loctite would be best? regular red or blue? I just read something on another site about using spray glue in a similar way. I have also come across people dimpling the balls with spring loaded punches or electric engraving tools.

[ArdWrknTrk]

Thanks Jim! I hadnt thought about Loctite. any ideas on which loctite would be best? regular red or blue? I just read something on another site about using spray glue in a similar way. I have also come across people dimpling the balls with spring loaded punches or electric engraving tools.

Loctite offers a green formula meant to wick into already assembled fasteners. (this is different from the green bearing retainer)

But if your mirror socket is super loose I would imagine red or blue would seep in there if you set it up so gravity is on your side and you swiveled it around to work it in

I didn't realize you could swing the mirror enough to dimple the ball in order to tighten the fit.

I have done that with spun bearing pockets but always used an anerobic in conjunction with punch marks.

I need to go see what these type mirrors look like.

[Gary Lewis]

You might consider wicking in some Loctite.

That tightened up my mirror heads enough that they would not budge from wind or slamming the door but still allowed me to move the head around (with two hands)

If you really wanted to glue them in place I'd think cyanoacrylate (Crazy Glue) would be better than epoxy.

Acetone or MEK seems to dissolve it.

I think Jim is right about Loctite. Some blue should work well.

As for the AFR, you aren't far enough off on cruise to worry about, but that 4th gear WOT is pretty lean. I'm not sure why it wouldn't go rich in 4th like it does in the other gears since I would have thought it is predicated on vacuum and not air flow. And I would expect the vacuum to go low even at lower R's.

Do you have a vacuum gauge on it while driving? It would be interesting to know how low the vacuum goes at different RPM/throttle combinations.

[StraightSix]

I think Jim is right about Loctite. Some blue should work well.

As for the AFR, you aren't far enough off on cruise to worry about, but that 4th gear WOT is pretty lean. I'm not sure why it wouldn't go rich in 4th like it does in the other gears since I would have thought it is predicated on vacuum and not air flow. And I would expect the vacuum to go low even at lower R's.

Do you have a vacuum gauge on it while driving? It would be interesting to know how low the vacuum goes at different RPM/throttle combinations.

Ill try the loctite trick. if it doesnt work, Im out nothing.

I have a vacuum gage permanently installed but its not very accurate. I checked it against a fluke vacuum pump/meter and its really pretty dismal. At 20 inhg on the fluke, my gage reads 16 inhg. I dont have any other points, so Im not sure if that relationship tracks linearly down to zero. An upgrade to a more accurate (and backlit) gage is in the works.

when I had my shop vacuum gage (very accurate according to the fluke) zip tied across the hood I observed that it was very easy to achieve vacuum readings in the 0-2 inhg range in 3rd and 4rth.

[Gary Lewis]

Ill try the loctite trick. if it doesnt work, Im out nothing.

I have a vacuum gage permanently installed but its not very accurate. I checked it against a fluke vacuum pump/meter and its really pretty dismal. At 20 inhg on the fluke, my gage reads 16 inhg. I dont have any other points, so Im not sure if that relationship tracks linearly down to zero. An upgrade to a more accurate (and backlit) gage is in the works.

when I had my shop vacuum gage (very accurate according to the fluke) zip tied across the hood I observed that it was very easy to achieve vacuum readings in the 0-2 inhg range in 3rd and 4rth.

I think you can use the gauge you have to do the tuning since you know that 16 is actually 20". You really don't need all that much accuracy for vacuum, just repeatability.

So I'd be trying to figure out why your AFR goes down into the 12's for the lower gears but not in 4th. And the question would be if there's a difference in vacuum for the gears.

[mat in tn]

I think you can use the gauge you have to do the tuning since you know that 16 is actually 20". You really don't need all that much accuracy for vacuum, just repeatability.

So I'd be trying to figure out why your AFR goes down into the 12's for the lower gears but not in 4th. And the question would be if there's a difference in vacuum for the gears.

in my thinking anyway. the greater the load the lower the vacuum will be leaving air flow to do the work of drawing fuel. velocity through the venturi being the mechanism. that would explain the difference in higher gears at least until the vacuum dropped enough to work the power valve.