Build MNR 4600 class 2021 U4 Bronco

JR4X said:
I would love to have that thing as a buggy not a streetable vehicle. The Coyote and the 10 speed with the paddle shifters is psychotic. At the first meetup I got to be front and center for a full throttle no lift shift acceleration event and it actually stunned me. The RPM range that thing can maintain for 30+ hours doesn’t even make sense.
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I haven't been in a bronco, but my wife's 2020 mustang is a blast with that same set up and a little boost. I don't know what 10th gear is all about, but 155 is where I shifted into 9th.
 
Tryloff said:
I haven't been in a bronco, but my wife's 2020 mustang is a blast with that same set up and a little boost. I don't know what 10th gear is all about, but 155 is where I shifted into 9th.
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You could probably keep up with SLOWPOKE693 's old Camaro then.



:flipoff2:


JR4X , that is an incredible experience to have. :beer:
 
One continuous problem I’ve had with this thing is the drivers side ram end cap coming unscrewed and dumping the power steering fluid. We’ve built a couple different iterations of things to stop it from being able to unscrew but the ram is the only steer stops. So whatever we’ve tried has bent out of the way and let the dam thing unscrew anyway.

I didn’t know it but in the big crash in NorCal I bent the ram shaft really bad, like buckle spray metal bad. Between the bend in the shaft and hitting something hard enough to blow a tire and take the wheels to full lock left it did it again. Bent the finger out of the way that was supposed to stop it from turning far enough out to let the o-rings past the ram body and dump the fluid.



So I came up with another attempt to stop it from spinning entirely. I drilled and tapped the original holes for the spanner wrench and then drilled new spanner wrench holes. Built a spanner that now bolts on so that it can’t turn at all. If you’re wondering why I don’t just put the 4th ram clamp on there, it’s because I can’t. That end of the ram hangs out in the same space as the front differential mount.

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That’s just mockup, waiting for the bolts I ordered to show up.

Edit. We have spare ram parts on hand, I had a welded shaft/piston to build another ram sitting on the shelf. So tossed the bent one and built a ram with the old body and new shaft.
 
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This front third is the 4th of 5 third members I’m going through this year. Keep taking it apart expecting to find it needing something but it still looks like brand new inside. I got one smudge of super fine glitter consistent with normal gear wear off of the magnet in the drain plug, no glitter in the bottom of the case. Bearings are still tight and look new. This thing has only ran royal purple 90W gear oil in it.

Took some pics of the gear wear pattern. The 4 pin E locker and just some shots to show what it looks like. It’s already buttoned back up and ready to go in the Bronco again.

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Does that use a bigger bearing on the ring gear side of the carrier as well? I remember pulling a JL carrier for the first time and being slightly perplexed.
 
Byro said:
Does that use a bigger bearing on the ring gear side of the carrier as well? I remember pulling a JL carrier for the first time and being slightly perplexed.
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Yes. Like D60 size bearing on the back of the ring gear side and smaller D44 one on the pinion side.
 
What are the specs on that diff? Ring gear size, and axle shaft spline/Dia?

No disconnect in the middle either?

Do you have a chromo shaft for the diff to pass side cv? That's the part I worry about breaking the most on my 4runner ifs.
 
YotaAtieToo said:
What are the specs on that diff? Ring gear size, and axle shaft spline/Dia?

No disconnect in the middle either?

Do you have a chromo shaft for the diff to pass side cv? That's the part I worry about breaking the most on my 4runner ifs.
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This is the M210 which stands for 210 mm ring gear aka 8.25 inch ring gear diameter. It’s 32 spline and I’m still running the spicer 32 spline double spline long shaft. No CAD on this one. 32 spline pinion.
 
HYDRODYNAMIC said:
I was going to recommend the Bomber cylinder which was supposed to be the remake of the XR race cylinder which has locking end caps, but it looks like all they did was chrome it. :homer:
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i bet when hes on the limit on the driverside something is rotating unthreading the cap.

i looked through his pics but theres is a bunch of stuff in the way to really see things.
 
mobil1syn said:
i bet when hes on the limit on the driverside something is rotating unthreading the cap.

i looked through his pics but theres is a bunch of stuff in the way to really see things.
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Don’t you think it would try and unthread the shaft halves first? Obviously not all the way since the tie rod misalignment would limit it but I’d think it would work it’s way a little loose, at least enough to notice the indexing being off.
 
Byro said:
Don’t you think it would try and unthread the shaft halves first? Obviously not all the way since the tie rod misalignment would limit it but I’d think it would work it’s way a little loose, at least enough to notice the indexing being off.
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Some of the XR shafts are welded to the piston.
 
mobil1syn said:
i bet when hes on the limit on the driverside something is rotating unthreading the cap.

i looked through his pics but theres is a bunch of stuff in the way to really see things.
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It does rotate slightly due to the wobble stopper which as you know doesn’t actually stop wobble but controls wobble.
Byro said:
Don’t you think it would try and unthread the shaft halves first? Obviously not all the way since the tie rod misalignment would limit it but I’d think it would work its way a little loose, at least enough to notice the indexing being off.
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All our ram shafts are tig welded to the piston by a hydraulic shop.
 
HYDRODYNAMIC said:
Some of the XR shafts are welded to the piston.
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I don’t know if they still do it but PSC used to offer that as a service. You could order a ram with the shafts welded. My ram is limited internally. Since I have to open it anyway we just have it done locally
 
Waiting on race car parts so we’re working on the really important stuff in the meantime. This is the “Hog”. A 1950’s Montgomery Wards mini bike that dad bought for us boys for $50 bucks. Meant to have a 3 hp Briggs and Stratton in it, Kevin shoe horned a way to big for it 8 horse Honda and it’s been a lot of fun, a lot of crashes. We killed the engine by crashing it, caving in the pull start housing which busted all the fins off the flywheel, quit moving air. Think we bent the crank etc.

These are old vids of its glory days.




So the logical next step? For us, is to put more power on it. Kevin was scrolling for Black Friday deals and found the Predator Ghost engine on sale. So we pitched in 3 ways and bought us one.

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New tires. New race engine.

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JR4X said:
Waiting on race car parts so we’re working on the really important stuff in the meantime. This is the “Hog”. A 1950’s Montgomery Wards mini bike that dad bought for us boys for $50 bucks. Meant to have a 3 hp Briggs and Stratton in it, Kevin shoe horned a way to big for it 8 horse Honda and it’s been a lot of fun, a lot of crashes. We killed the engine by crashing it, caving in the pull start housing which busted all the fins off the flywheel, quit moving air. Think we bent the crank etc.

These are old vids of its glory days.




So the logical next step? For us, is to put more power on it. Kevin was scrolling for Black Friday deals and found the Predator Ghost engine on sale. So we pitched in 3 ways and bought us one.

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New tires. New race engine.

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Hell yeah :smokin:
I was thinking the other day a mini bike project should be built if a guy owns a tube bender.
This suspension seat makes it even easier doesn't it.
 
CarterKraft said:
Hell yeah :smokin:
I was thinking the other day a mini bike project should be built if a guy owns a tube bender.
This suspension seat makes it even easier doesn't it.
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The newer Montgomery Wards bikes from the 60’s up have a swing arm instead of the suspension seat. I guess it would be harder to retrofit anything on them with that suspension.
 
My buddy and I had a really similar JC Penney mini bike when we were kids, we got hurt a few times with a 3.5hp Briggs flat head on it. I gave the frame back to him a couple years ago, supposed to be getting a mildly built 212 eventually.
 
TrikeKid said:
My buddy and I had a really similar JC Penney mini bike when we were kids, we got hurt a few times with a 3.5hp Briggs flat head on it. I gave the frame back to him a couple years ago, supposed to be getting a mildly built 212 eventually.
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Not enough fathers keeping them running for the kids these days. When I was a kid our dad tried his best to keep something around for us to ride and work on. But it’s easy for kids to burn up air cooled engines that run good so eventually we tapped him out.
 
One of my favorite days doing KOH prep. Putting new Milestar Patagonia MT02’s on our Racelinewheels. Who doesn’t love the smell of new tires, a whole body workout, and being one step closer to race day. Muddnuttracing 4531_pit_crew doing all the hard things.

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