1993 HiAce Firetruck Build Thread

[Lovetheworld]

Well as said, reliability shouldn't be hit to hard with a turbo when you don't change the fuel pump.
However, just always install one of those exhaust gas temperature sensors. They are cheap and come with beepers on thresholds. That way you will be ahead of any problems instead of experiencing them later on.

Yeah it is a unique van that we have. I am unsure about the price I am asking though. There is some rust. But the base of the car is very strong, so it just passes inspection and you could drive it way overland again. If I get too little for it, we will keep it.
We also have a Sprinter 4x4 now, very nice and comfortable, but already less reliable than the Toyota even though it is newer and didn't see any though roads haha.

If I get the chance, I will one day perhaps find a Toyota Himedic. Which is the ambulance version of our car with V8 and automatic.
That is if I didn't switch to something electric already.

 

[Fenderfour]

Beam Calculation

I’ve been busy and still need to finish a few things on the soft top. The door needs to be sewn, and a bit of material added to the door area to get it to hang straight. Since I didn’t have time to sew, I started sizing some elements of the camper design.



My camper design puts a full-size queen mattress lengthwise over the cab. This requires an 80" cantilevered beam from the camper that can handle the weight of two people + a little dynamic loading. There are many beams I could select that would be "strong enough", meaning it won’t break under loading scenarios. However, this camper needs to remain water tight and flexing of joints will lead to leaks, so I want to size the primary beam to minimize deflection (flex).

I used a free beam calculator. It’s a pretty easy to analyze a single element of a design. https://clearcalcs.com/freetools/beam-analysis/us. I chose this calculator because it allows more than one fixed support, others don’t.

We need to gather some information before we start:

Beam length: 13’

Material: TNutz 1545 T-Slotted Aluminum Extrusion https://www.tnutz.com/product/ex-1545-black/

Young’s Modulus: 10,000,000
Young’s Modulus is a property of the beam material. You can search for the specific material and “Young’s Modulus”. More info on Young’s modulus on Wikipedia: https://en.wikipedia.org/wiki/Young's_modulus

Cross section: 3.113 in2
Can be calculated, but is generally available on the material spec sheet. Engineering Toolbox https://www.engineeringtoolbox.com/ has cross section info If you are using standard profiles like square tube, i-beam, c-channel, etc… Specialized profiles like 80/20 will have info in the spec sheet.

Moment of inertia: 5.913 in4
Info on moment of inertia at Wikipedia: https://en.wikipedia.org/wiki/Moment_of_inertia
The 1545 extrusion has two values for moment of inertia: lx = 0.739in4 and ly = 5.913in4. lx is the moi when loading the flat side, ly is the moi for the long side of the extrusion. These are found in the material spec sheet or in Engineering Toolbox (link above)

Support locations:

• Fixed @ 13’
• Fixed @ 6.67’

Supports have types. A pin support is not attached to the beam. The beam is resting on a point. Roller supports allow the beam to move lengthwise as well as up and down. Fixed supports, are well, fixed… either bolted or welded, etc… Most designs will use fixed supports.
My supports are gray vertical beams in the drawing above.

Load: 600 lbs, distributed = 300 lbs/beam
Since the bed area is held up by two beams, we can halve the load to analyze one beam.
The distributed load is measured in lbs/ft, so we need to divide our load by 6.67 which is 44.97 lbs/ft

This is what the beam calculator looks like after all values are entered and the deflection calculated:




The resulting deflection is .323” at the end of the unsupported beam section. I think this will be ok, since I don’t have any skin panels on that section. I expect to see more than .323" deflection in real life since the mid-span support will deflect forward a bit toward the load.
We can also see the mid-span vertical support will need to handle ~1,000lbs. This hasn't been sized yet, but most extrusions will handle a lot of compression loading.

More complex constructions can be similarly analyzed if you break the calculation into singular beams and load scenarios. This isn’t the most efficient or best way to analyze a structure, but it will help inform some material sizing decisions, and how/where to add supports. It’s also free. Other methods will require expensive software or even more expensive college degrees.


Hope you found this helpful.

 

[Fenderfour]

If you need to calculate the moment of inertia for different shapes, this calculator seems to work well: https://calcresource.com/moment-of-inertia.html

 

[Fenderfour]

It's been a long time since I posted here. I've been working on a bumper that integrates tail lights and the license plate so I can remove the bed and leave it off as I build the camper box on the back.


I want something simple that works with the lines of the truck. It was pretty easy to model the final design in Fusion 360 and turn it into flat pieces.



I had Keith at 2K Metal Works in Seattle cut the parts. He had it done in two days, and at a good price.



this is 10g mild steel, .132" thick. I know lots of folks go with .1875 material, but it's not really required if you are careful about internal bracing and alignment of recovery points. I will be adding a crossbar between the frames to support the hitch. I plan to carry a bike rack back there and I need to support the fatigue loads of the bikes + carrier.

I still don't know how It will get attached to the frame. There is a lot of extra junk welded to the end of the frame of the truck to support the firetruck step bumper. I need to get that cleared away and work out a solution to extend the existing frame about 14", making the camper just a little shorter than the current step bumper.

 

[KiwiMtnClmbr]

I still don't know how It will get attached to the frame. There is a lot of extra junk welded to the end of the frame of the truck to support the firetruck step bumper. I need to get that cleared away and work out a solution to extend the existing frame about 14", making the camper just a little shorter than the current step bumper.

I also need to have a rail extension of about a foot added onto mine. Watching to see what you come up with.

 

[Fenderfour]

Made some progress welding up the bumper. I know the welds are ugly. It's been a while since I did any welding. I'm a pretty good grinder. It's all 10g mild steel, mic'ed to about .132" thick.

The receiver was pre-heated to ensure good penetration from the welds.



There will be some recovery eyes welded in-line with the frame extension, along with a square bare across the back between the frame and welded to the top of the receiver. The main purpose of the receiver is to carry a bike rack so I want it to be able to manage the fatigue loads of ~150 lbs bouncing back there.


Lots of grinding and filling before its "done"

 

[Fenderfour]

My truck came with 5.13 gearing in the diffs. Combine this with a 4200 rpm redline and well... it's a slow truck that has a top speed of 62 mph at almost 3500 rpm. 30mph also sits at a weird spot in the gears, just between 3rd and 4th. it makes city driving a bit irritating.

I've been looking for someone to re-gear my HiAce, but most of the big shops won't touch it. They were willing to work on the diffs if i removed the carriers, but I don't have space to store my rig on blocks. I needed Drive-in, Drive-out service. A 4x4 company in Utah posted a video on a HiAce Firetruck regear.

It's also tough to figure out what equipment is needed. I've done a lot of online research to sort this out. First thing is decoding the stock transmission. This link has the diff codes, and this wiki page has the transmission info.

My ride has the R351F transmission, which is the very common R351 with 4WD. The reat diff is G152, which is the very common Toyota 8", with 5.125 final gearing, 2 pinions, and an open diff. FYI - 4 Pinion Diffs are referred to as "Turbo" and seem to have been specific to the Supra.

Transmission info is important to calculate the projected speed to RPM changes for the re-gear. There are lots of calculators online, but I used an excel spreadsheet.



Now I know I want to switch to 4.11's. I still have to sort out what parts to use.

There are multiple options for the stock differential. Do you have the V6 or 4 cylinder transmission? Is it turbo? High Pinion?
This page has great info on identifying your Toyota diff.

Unsurprisingly, I have the super-common 4 cyl Toyota 8" in the rear. My front diff is another very common Toyota 7.5 IFS (independent front suspension). This is all the same equipment as found on a Gen 2 4Runner or a Hilux Surf (international 4Runner equivalent), which is very convenient since these parts are readily available in the states.

There is another thing in the rear diffs that might need to be changed, the carrier. This diffs have a "carrier break" at 4.88. This means that all diffs with 4.88 and numerically higher gears use a different internal carrier than diffs with 4.56 and numerically lower gears. My regear will require a new carrier as well. The carriers seem to run $300-400. This carrier is replaced by any locker or limited slip differential you may want to add in the rear. I decided to add a Torsen/helical limited slip diff to the rear (Detroit TrueTrac). it's ~ $700, but provides better traction and handling in the snow.

I started talking to folks and calling around my area. I found a shop that was highly recommended. They quoted me $4200 for the regear and LSD installation. It will take two days. I'll report back when it's done.


I've been told to just put bigger tires on the ride; a "poor man's regear". While that does effectively change the final drive ratio, it also sucks an immense amount of power out of moving the truck and into moving the tires, not to mention adding stresses to all parts, engine, transmission, suspension, etc... To get a 20% increase in final drive, I'd have to replace my 30" tires with 35" tires. This might make sense on a burlier truck with power to spare, but it's a terrible idea for small trucks with little engines. It's also not cheap. 35's cost 400-500 each, and would also require new wheels. It's not really less expensive, but your truck will look cool.

 

[rruff]

Not having driven it... but I have had a very overloaded '84 Toyota PU, 22re, 5spd, 2wd... which supposedly made ~115 hp, and I think your gearing and tire size are just about the sweet spot. Max power of 75hp comes at 4000 rpm, which would be 83 mph with current gearing. Redline is 4800 rpm, or 100mph.

Is there a reason why cruising at 62mph and 3,000 rpm is a problem? The motor should be happy I think. I ran mine over 3,000 rpm most of the time, just to get down the road without constantly shifting for every little change of grade or gust of wind. Little engines like to rev, and they need to. I realize it's a diesel which is a little different, but not that much.

BTW, people way over estimate the weight effect of tires, when it's really the gearing change that they feel. In acceleration the inertia of the tires is ~1.6x the weight elsewhere. Unless you go crazy, it's too small to notice.

 

[Ozarker]

View attachment 736006

Making a tent like this takes some CAD skills to create the surfaces then flatten them to make a pattern. Luckily, I've been doing this work for around 25 years.

View attachment 736007

That might be all well and good, but I've been looking at folded tents and Bimini tops for more than 50 years and that ain't no bed cover illustrated above, that will almost be a cone putting those edges together.

The frame used is nearly irrelevant so long as it supports the arched canopy, pretty much like an Army duce and a half and the tarp is rectangular without any tapered cuts. Two flat pieces make the front and back. Use a zipper or lace the front and back walls. You could also sew the front and back walls on and simply fold the top forward like an accordion, stored against the back wall of the vehicle.

Hope you haven't cut the material yet.

 

[Fenderfour]

Not having driven it... but I have had a very overloaded '84 Toyota PU, 22re, 5spd, 2wd... which supposedly made ~115 hp, and I think your gearing and tire size are just about the sweet spot. Max power of 75hp comes at 4000 rpm, which would be 83 mph with current gearing. Redline is 4800 rpm, or 100mph.

Is there a reason why cruising at 62mph and 3,000 rpm is a problem? The motor should be happy I think. I ran mine over 3,000 rpm most of the time, just to get down the road without constantly shifting for every little change of grade or gust of wind. Little engines like to rev, and they need to. I realize it's a diesel which is a little different, but not that much.

BTW, people way over estimate the weight effect of tires, when it's really the gearing change that they feel. In acceleration the inertia of the tires is ~1.6x the weight elsewhere. Unless you go crazy, it's too small to notice.

My truck has a 2L (2.4 liter) diesel. It wasn't common in the US. The manual says redline is 4200 rpm, online resources say it's 4800. Peak HP is 3200 rpm (85bhp), peak torque at 2800rpm (120ft-lbs). It's all a bit slower and lower than the 22re.

It feels like 3,000 rpm is fine for mid-term bursts, but seems high for hours on end. Someone on Instagram was running their hiace with a very similar engine at 3200 rpm while crossing the country. They blew a head gasket and warped a head. Sure, that's anecdotal and we don't now anything about other factors that can lead to this, but it's a little bit of data.

My experience with increasing tire size has been different than yours. I did a mild increase in size/width and tread on my Subaru. It had a large impact on gas mileage, noise, and power. Granted, the stock tires are optimized for reduced weight/increased mileage.

 

[Fenderfour]

That might be all well and good, but I've been looking at folded tents and Bimini tops for more than 50 years and that ain't no bed cover illustrated above, that will almost be a cone putting those edges together.

The frame used is nearly irrelevant so long as it supports the arched canopy, pretty much like an Army duce and a half and the tarp is rectangular without any tapered cuts. Two flat pieces make the front and back. Use a zipper or lace the front and back walls. You could also sew the front and back walls on and simply fold the top forward like an accordion, stored against the back wall of the vehicle.

Hope you haven't cut the material yet.

Cut and built.



Could be tighter, but it doesn't flap much on the highway.

just as you said, a top like this can be designed and built to disregard the frame. That's not how I built mine.

 

[rruff]

Strange that specs are all over... but even if peak is at 3200 and max at 4200, I don't think it changes things. RPM isn't what killed that engine, unless the engine is a defective design. They have a rep for reliability and a lot of vehicles with your ratios will be geared lower because of smaller tires, so they will be revving on any highway trip. Thoroughly check with people who have experience with the engine and see what you can find.

I put larger and fatter AT tires on my truck (>2x the weight) and MPG improved. Very good ATs for rolling resistance, and the stock street tires must have been crap. They make more noise, are a little firmer, and I could tell a small acceleration difference, but it's a V8 with 400hp... and I love the tires for everything else. You already have ATs anyway, so the negative aspects of that are already present.

But I doubt increasing the gearing is necessary and may even be a bad move. Have you done any long trips in varied terrain to get a feel for practical speeds?

 

[Fenderfour]

Strange that specs are all over... but even if peak is at 3200 and max at 4200, I don't think it changes things. RPM isn't what killed that engine, unless the engine is a defective design. They have a rep for reliability and a lot of vehicles with your ratios will be geared lower because of smaller tires, so they will be revving on any highway trip. Thoroughly check with people who have experience with the engine and see what you can find.

I put larger and fatter AT tires on my truck (>2x the weight) and MPG improved. Very good ATs for rolling resistance, and the stock street tires must have been crap. They make more noise, are a little firmer, and I could tell a small acceleration difference, but it's a V8 with 400hp... and I love the tires for everything else. You already have ATs anyway, so the negative aspects of that are already present.

But I doubt increasing the gearing is necessary and may even be a bad move. Have you done any long trips in varied terrain to get a feel for practical speeds?

I have, but it depends on what you mean by "long". 3+ hours over hill and dale to get from Portland, OR to Seattle, WA, multiple trips to Snoqualmie pass in the cascades at 3,000 feet, 1.5 hours away, trips around a hilly city.

I agree that regearing isn't necessary. Nothing in this forum is necessary. We are all just playing with toys.

How would regearing be bad?

I don't think I will have any more struggles over passes or in a headwind than I already do.

 

[rruff]

Can you keep up with freeway traffic? Would you be able to with a load?

After some more searching, I think you should have the 2L-II which lists as 84hp at 4200 rpm. Unless all the places online have the wrong specs for 2L I don't think it's possible that your hp peak could be 3200 rpm. That would take a completely different engine, since hp drops like a rock past its peak. At 4200 rpm in 5th you'd be going 87mph which is plenty fast IMO, and likely faster than your 84hp could carry you on flat ground; and definitely faster than you could go with a loaded camper.

The regear would be "bad" if you spent the time and money and found out it didn't help anything, made acceleration more sluggish, and made 5th gear so tall that you drove in 4th most of the time on the highway.

 

[allochris]

chiming in here...about the rear 8" 3rd. Do the Hiace rear 3rd member (with the carrier contraption) share the same bolt pattern (onto the diff housing) as the common 4.10 rear 3rd from a 4cyl. 22re?

If it's directly bolt-on, why not just buy (for a few hundred bucks or less ) a used 4.1 3rd from a junker to try it? That way you can keep your hiace one unmodified as a spare original.

back in the day not that crazy long ago, all the 4cyl 22re guys were dumping their 4cyl-4.1 ratio-2 pinions, ring and pinion for the V6 4 pinions 4.88 or aftermarket 5.29 ratio, just so they can run bigger 33"-35" rubbers. (I poor's man "regeared" mine from 4.1 to 4.88 (commonly found on v6 auto 4runner) myself to run from size 235/75r15 to 33"s).