1984 Bronco build thread

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Re: 1984 Bronco build thread

StraightSix
Rob- thanks for the input of my "issue" in second. Im sure it would creep off from a stop in 2nd without any trouble, that would just be poor etiquette in traffic I think. Feathering in the gas definitely prevents any issues. Looks like you have quite the 300 set up btw!
1984 Bronco, mild built 300-6, Np435, 3.55 gears, 8.8 rear with Eaton TrueTrac, D44 TTB front, 31" tires, Duraspark II, Offy C, EFI manifolds, Holley 390, No AC, 3G alternator, front receiver
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Re: 1984 Bronco build thread

ArdWrknTrk
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I'm pretty sure that you advance the timing to max vacuum, and retard it a bit if you're worried about knock, or find rattling at cruise.

Crane Cams has very detailed instructions that come with their adjustable vacuum advance kit.
You can get the PDF from Jeg's online documentation.
Just look up the 99607-1 unit.

This will help you set your static timing, but obviously you can't change the limit slot, springs or vacuum profile.

Also note that the I-6 distributor rotates opposite to the V-8 engines. So advance-retard is opposite to them as well.
 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.
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Re: 1984 Bronco build thread

StraightSix
Thanks Jim! Ill look up that bulletin and see what I can learn.

I just got back from a 40 mile fuel economy test drive. I used the same pump before the drive as I did after. It was mostly rural highway driving, so about 55 with the occasional stop or slowing down for someone turning up ahead. 55mph is about 2200 rpm for me. I came in at 17.3 mpg! Im completely flabbergasted. I know that a test over a longer distance will be more accurate since My drive only consumed about 2.3 gallons of gas, but still, I thought Id be lucky to make 15mpg on pure highway miles. That alone makes all of the work worth ut to me, but the added performance and potential for a much more reliable engine definitely rank pretty highly as well.
1984 Bronco, mild built 300-6, Np435, 3.55 gears, 8.8 rear with Eaton TrueTrac, D44 TTB front, 31" tires, Duraspark II, Offy C, EFI manifolds, Holley 390, No AC, 3G alternator, front receiver
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Re: 1984 Bronco build thread

ArdWrknTrk
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That's awesome!  

Congratulations! I'm so happy for you....  

It's always rewarding when all the effort pays out.
 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.
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Re: 1984 Bronco build thread

Gary Lewis
Administrator
In reply to this post by StraightSix
Yes, that is awesome!  Glad it is working out so well.  
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

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Re: 1984 Bronco build thread

Sac79
In reply to this post by StraightSix
Yes, that's a small sample size, but still an excellent return. I haven't managed to get past 15MPG yet. We have very similar setups, only different in ignition, carb size and you have a lower gear in the diff. Maybe that Bronco has better aero efficiency... Bottom line, your tune can't be terrible with that fuel efficiency.

More than 4 years lapsed between driving my truck in it's 'stock' form and now with the upgrades. So I can't say for certain that it's a night and day difference, but I definitely don't remember ever being impressed with my truck's performance before... And it's no slouch now. Not that I drive it or want it for performance. But as you say, it's just nice to know that all the work and money isn't just for show...
Rob

Eddy Myrtle '84 F150 300-6, Offenhauser C series intake, Edelbrock 1404(500cfm manual choke), EFI exhaust manifold, HEI dizzy, custom Painless harness, NP 435, NP 208, D44, 8.8"/3.08, 1.5" leveling coils, 265/75/16 tires.
Toyopet (Daily driver) '86 Toyota Pickup
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Re: 1984 Bronco build thread

StraightSix
Well, Im off work this week and will be driving the bronco criss cross around the state, so hopefully I can get a more accurate idea of the milage. And hopefully you guys wont be getting any frantic road side messages from me!

I bet that 500 cfm carb really opens up the top end. Ive noticed that mine is now much more useful above 2500rpm. Before, it would spin faster than 2500 but nothing great really happened up there. No reason to do it unless you were in top gear and wanted to go faster. Now, it makes good power (by the calibrated foot test) up to atleast 3250 which is the highest Ive pushed it. Before I always shifted at about 2500 regardless of what gear I was in, now I find myself shifting 2nd to 3rd aroud 2500 and then 3rd to 4rth at about 3000-3200 which lands me in 4rth at 35mph and 1500 rpm. It seems sorta spun out in 4rth below about 1500. Overall driveability is significantly better
1984 Bronco, mild built 300-6, Np435, 3.55 gears, 8.8 rear with Eaton TrueTrac, D44 TTB front, 31" tires, Duraspark II, Offy C, EFI manifolds, Holley 390, No AC, 3G alternator, front receiver
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Re: 1984 Bronco build thread

ArdWrknTrk
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The 300 was never a high revving engine (Frenchtown Flyer may disagree) but I'd think EFI manifolds are doing more for you than a 500 cfm carb.

I gave Josiah Thorngate a 435 cfm 4160 for his truck a few years back, and it seemed more that enough with his cam, EFI manifolds, Walker Y-pipe (opened up) and Offy intake.
Sometimes smaller primaries give better signal even with annular boosters.

Anyway, we're all looking forward to your report after next week.  
 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.
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Re: 1984 Bronco build thread

Gary Lewis
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In reply to this post by StraightSix
Yes, looking forward to the report.  And, hopefully, no calls for help!
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

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Re: 1984 Bronco build thread

Sac79
In reply to this post by StraightSix
Yeah, I don't know if the bigger carb does anything other than drink more gas(which probably just goes out my tailpipe)... But the intake and EFI manifold combo does the trick I believe. If you watch the Powernation build, the stock engine achieves peak power at around 2500 and torque falls off steeply from 1500(the start of their graph). With all the improvements peak power comes around 3500 and torque at 2500... And I can believe that from driving my truck.

Before the rebuild I never got above 2000Rpm in anything other than 4th. Now it will happily pull up to 3500 in 3rd at which point I chicken out, not the truck. I don't really push it in 2nd and in 4th the limiting factor is the wall of air I'm trying to push through at 80MPH!

Enjoy driving the Bronco this week!
Rob

Eddy Myrtle '84 F150 300-6, Offenhauser C series intake, Edelbrock 1404(500cfm manual choke), EFI exhaust manifold, HEI dizzy, custom Painless harness, NP 435, NP 208, D44, 8.8"/3.08, 1.5" leveling coils, 265/75/16 tires.
Toyopet (Daily driver) '86 Toyota Pickup
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Re: 1984 Bronco build thread

ArdWrknTrk
Administrator
Carbs meter gas to air.
There's no reason for a bigger carb to be more thirsty.

I'm sure the 4V carb helps on top!
I'm just saying the improvement over stock manifolds is helping more (before you chicken out)
X litre = X00 CFM is a formula that works for most street applications.
But the easygoing nature of the I-6 with its perfect primary balance means that you want it to pull really cleanly from low rpm's
Getting a good signal with that little flow it's sometimes advantageous to give up a bit on top (where you are.. only rarely)

Or use a spreadbore, like the huge boats of the 1970's

But it is working for you, and that's all that counts!
Bill is the carb guru.
Perhaps he can better explain.
 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.
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Re: 1984 Bronco build thread

FuzzFace2
17 MPG I hate you

I hit 15 MPG once most are mid 14's and I am all stock other than EFI exh. manifolds. Thats shifting at or just below 2000 RPM as I dont see the need to run it up much higher. It does still pull up to 3000 RPM but again don't see the need to.
With the over drive even on the high way at 70 MPH I am spinning 1800 RPM.
Pushing the wind out of the way at 80 MPH is 2200 RPM.

I have been looking at making a AFR meter but everything I find on line don't show how it gets wired so maybe Santa will bring me one. I would like to see what the AFR is before I go making any changes so I know where I started at.

Have fun on your MPG drive
Dave ----
Dave G.
81 F100 flare side 300 six / AA OD / NP435 / 2.75 gear
http://cars.grantskingdom1.com/index.php/1980-Ford-F100?page=1
81 F100 style side 300 six/SROD parts truck -RIP
http://cars.grantskingdom1.com/index.php/1981-Ford-F100
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Re: 1984 Bronco build thread

ArdWrknTrk
Administrator
Sometimes optimal power is not at lazy rpms.
That's why CVT's were banned in racing.

But now we have crap like mandatory pit stops and sub-optimal tire changes.
I'm done....
 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.
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Re: 1984 Bronco build thread

FuzzFace2
ArdWrknTrk wrote
Sometimes optimal power is not at lazy rpms.
That's why CVT's were banned in racing.

But now we have crap like mandatory pit stops and sub-optimal tire changes.
I'm done....
Even with out the over drive and not lugging I was getting the same MPG.
I believe it is the carb that the PO messed with the high speed rod that can be adjusted.
I hate the CVT in the wifes Subie

I could not tell you the last time I watched a race because of that crap that's not racing!
Dave ----
Dave G.
81 F100 flare side 300 six / AA OD / NP435 / 2.75 gear
http://cars.grantskingdom1.com/index.php/1980-Ford-F100?page=1
81 F100 style side 300 six/SROD parts truck -RIP
http://cars.grantskingdom1.com/index.php/1981-Ford-F100
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Re: 1984 Bronco build thread

ArdWrknTrk
Administrator
Carbs are cheap and fun to tinker with....  
 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.
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Re: 1984 Bronco build thread

StraightSix

Hey Guys!

Fuzzface – unfortunately based on some intermediate fillups I have done recently, I doubt that Im really making 17 mpg. I need to fill up after my 200 mile return trip from the mountains which should be a good representation of highway driving as 65mph and 2600 rpm with very little deviation for the entire trip. Ill post that trips MPG once I get to a pump.

 As far as my trip to the mountains – it was great! I made about 200 miles on various national forest roads and other dirt back roads through a beautiful chunk of the north Ga mountains. I have been blessed to be able to travel safely to the western US twice this year including a cross country driving trip from Arizona to Georgia. My main take away from it all is that we are so lucky to live in such a beautiful country, and I am grateful to live in such a pretty part of it. Anyhow, the bronco does great work on steep mountain grades and gravel roads. I found myself mostly cruising in 2nd and occasionally hitting 3rd on long straight stretches where 20-25 seemed reasonable. It engine brakes to a degree that is very practical for this kind of driving as well. From 2nd it will sling gravel when the clutch engages, and in 3rd it has no problem building speed with confidence on a steep grade from about 1000 rpm. Just a low grunt and then youre pushed into the seat. I have removed the back seats and built a wooden frame to fill the rear seat floor board. I keep things like jumper cables, my hi lift, spare hoses, etc under the wooden frame. I cut 7” off of a bed matt for a F150 and rolled it in. so now I basically have a 6 ft “bed” right behind the drivers seat. This allowed plenty of space for gear and sleeping quarters.

 

 It turns out that the bronco is an awesome choice for a do it all camping rig. Im superbly pleased with it to say the least.

 Before I left for my trip I built a mounting bracket for my winch and got it installed. This should allow me to take the winch off (its mounted to the front receiver) for the majority of the time when I wont need it. Gary and I discussed options for making/breaking the electrical connection between the winch and the Battery in my previous alternator upgrade thread. We discussed using battery cable plugs, or just hard wiring the winch. Im inclined not to trust the plugs for reasons that are probably foolish and ungrounded. What I eventually decided on was that I would permanently route the cables in the bronco without any plugs. I used size 2 wire and the hot cable has a 500A fuse that is only about 2” away from the battery + terminal. The cables have been routed down from the battery to the frame, then on to my front receiver. When the winch is not installed, Ill remove the cables from the winch, pull the extra length of the cables back through the bumper, zip tie them to the receiver to secure them, and pull the fuse from the hot cable so I don’t have 12V running around through a size 2 wire. It may add 5 minutes to the process of installing the winch but I don’t have to worry about snaking wires in and out, and I don’t have to worry about the plug failing.

 



 I also have a good bit of work planned for the near future. 2 gallons of redline mt-90 should arrive in the mail today for the transmission and I purchased new ATF for my np 208. I have a new volt meter from rocketman as well as an ice blue LED light kit from that fellow on ebay. The needle paint and relay for the volt meter are in the mail. So, hopefully I get away with the volt meter, needle paint, and new LEDS all in one shot. On the relay for the volt meter – any recommendations on placement? I plan to use the relay to interrupt the ground wire. My first preference would be for the relay to live under the dash somewhere out of the way but still accessible for replacement incase it fails. Perhaps near the fuse panel? My second preference would be to mount it next to the starter solenoid.

 I had a bear of a time with cold starts on my trip. When I got home and started messing with the choke I discovered that my vacuum choke pull off was probably pulling the choke open 3/8” or even more. I adjusted the choke pull off with a 3/16 drill bit and it cold starts much better now. I may go back and try 1/8”.

 I despise my coolant reservoir, and it seems to be leaking. I would really like to be able to replace it with the 90s style reservoir like the one from my 1990 bronco and my 1995 F150. It looks like you can still buy one brand new for $40. I would want to mount it in the stock location. Has anyone tried this? At a glance it seems like it should work. Thanks Guys!
1984 Bronco, mild built 300-6, Np435, 3.55 gears, 8.8 rear with Eaton TrueTrac, D44 TTB front, 31" tires, Duraspark II, Offy C, EFI manifolds, Holley 390, No AC, 3G alternator, front receiver
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Re: 1984 Bronco build thread

ArdWrknTrk
Administrator
Thanks for the trip report.
Sounds like you had a great time!

You can swap reservoirs with a Bricknose truck but I'm pretty sure you need the bracket that holds it to the fender as well.

Overflow and washer tanks are reversed, I believe.
 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.
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Re: 1984 Bronco build thread

grumpin
That’s great! Should try my Bronco for camping. Only problem would be getting my crippled up self in and out!
Dane
1986 F250HD SC XLT Lariat 4x4 460 C6-Sold
1992 Bronco XLT 4x4 351W E4OD
1998 GMC Sierra SLE K1500 350 4L60E
Arizona
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Re: 1984 Bronco build thread

StraightSix
Fuel economy report- 15.9 mpg
Roughly 140 miles at 65mph/2600 rpm with no stops that I can remember and then another 60 miles or so driving on secondary highways at roughly 55mph/2200 rpm.

Its not as good as I originally though, but still seems pretty good to me!

I think its a little lackluster on the low end now that Im back home compared to how it drove in the mountains. I was about 1000-1500 feet higher in elevation up there. Any chance that the elevation played a part and Im jetted a little lean for home?

Thanks Jim! Ill order one a let you all know how it goes.

Dane, crawling over the center console and into the driver seat first think in the morning is the only notable problem. I think its a great camping rig, I highly recommend it!

On another side note, Ive pretty much lost all desire to have a zf5 for the bronco. Initially I thought I would just have to have an OD gear. Now, 65 seems like plenty for highway cruising. And the NP435 seems to do incredible work off road and is also an excellent around town cruiser. Maybe those guys at Ford did know a thing or two..
1984 Bronco, mild built 300-6, Np435, 3.55 gears, 8.8 rear with Eaton TrueTrac, D44 TTB front, 31" tires, Duraspark II, Offy C, EFI manifolds, Holley 390, No AC, 3G alternator, front receiver
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Re: 1984 Bronco build thread

ArdWrknTrk
Administrator
Not only Fords engineers, but the guys at New Process too.  
You have to remember what happened with the oil embargos of the '70's.

The 55 mph limit and Claybrook mandated 85 max speedometer.
Now the manufacturers had to optimize for the federal speed limit.
Gasoline seemed expensive and emissions laws had crude solutions that strangled performance.
 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.
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