isuzu 4BD1T swap?! (1 Viewer)

[astr]

. . . The Isuzu gearboxes use the gearbox bellhousing as part of the front case which includes the input shaft seal. They are removable and swappable, but expect them to dump all the oil on the floor when unbolted.

You are absolutely correct. I looked in the manual and see that the front seal and the sleeve that the throwout bearing slide on are part of the gearbox bellhousing. That being the case, it probably will be next to impossible to mate a TLC gearbox to the Isuzu gearbox bellhousing as I suggested in one of my previous posts.

 

[belaw]

I just got off the phone with David at "isuzuswapper" he just told me that up till 85 4bd1 (b4 they were turbo) engines came with chevy transmissions and they were "SAE" housings. In 85 they change to Japanesse automatic tranmissions and these took different flywheel housings. So, if you can find an older 4bd1 engine you can get a ring and bolt up what ever domestic tranny you like.

Dieseltim

This is a great thread; I've been following it for awhile, and finally have to jump in with a questions that I'm unclear on after reading the whole thing a couple of times: do the pre-85/pre-turbo gearbox bellhousings with a SAE pattern really exist? I found a reference on another site (http://cruisers.shoumatoffmedia.com/4bd.html) that Isuzu used to make an adapter that allows SAE #3 bell housings to be used (gearbox bellhousing, I assume)- is this the same thing? Wouldn't this simplify things greatly if you wanted to use a GM transmission?


Also, the discussion about whether body lift is necessary is a little fuzzy to me; assuming you want to keep the engine off the firewall, how much lift would you need for oil pan clearance? (I'm not a big fan of body lift, so less is better!)

Finally, are engine mounts commercially available, or would they have to be fabricated?

 

[Dougal]

This is a great thread; I've been following it for awhile, and finally have to jump in with a questions that I'm unclear on after reading the whole thing a couple of times: do the pre-85/pre-turbo gearbox bellhousings with a SAE pattern really exist? I found a reference on another site (http://cruisers.shoumatoffmedia.com/4bd.html) that Isuzu used to make an adapter that allows SAE #3 bell housings to be used (gearbox bellhousing, I assume)- is this the same thing? Wouldn't this simplify things greatly if you wanted to use a GM transmission?

The SAE flywheel housing is only fitted to the industrial engines (excavators, compressors, generators etc), no model year relation. I have a few threads on www.4BTswaps.com which are dedicated to sorting out that particular rumour.

 

[RHINO]

rumore or not if you find an SAE isuzu you still need to adapt it to a tranny.

lift : its not the depth of the engine, its the fact that to clear the starter you need to favor the passenger side of the truck, where the pumpkin is. also, the higher you place the engine in the bay the less lift you'll need, i kept mine a bit low for center of gravity since i have all kinds of axle clearance. from looking at mine i'd say you could simply notch the oilpan a bit to clear with no lift at all, or i think a 2-3" lift would work ok. the oilpan will hit the pumpkin right on that oil return "hump" on top, but only the edge. maybe an inch, so a oilpan notch would be doable.

 

[Dougal]

lift : its not the depth of the engine, its the fact that to clear the starter you need to favor the passenger side of the truck

The stock starter is a geared item that can get in the way.
On my engine it's been replaced with a direct drive one which is more compact but draws a much higher amperage to start. Roughly 200 amps on 24V to crank over a recently rebuilt engine.

 

[RHINO]

good to know for clearance, but i'm pretty sure all of us in the USA got the gear reduction 12v units. better starter for the application cause its keeps things simple. i have about 20mm clearance on both sides with the parts that stick out the most, starter on one side of course and the power steering pump hard line on the other.
its a tight fit in the frame w/o mods to the frame but its fine and nothing hits. i really wanted to clock the starter but the 3 mounting bolts are not equal.

 

[Dougal]

good to know for clearance, but i'm pretty sure all of us in the USA got the gear reduction 12v units. better starter for the application cause its keeps things simple. i have about 20mm clearance on both sides with the parts that stick out the most, starter on one side of course and the power steering pump hard line on the other.
its a tight fit in the frame w/o mods to the frame but its fine and nothing hits. i really wanted to clock the starter but the 3 mounting bolts are not equal.

Sure about the 12v thing?
All our truck motors are 24 volt, some of the industrial engines were 12.
You'll know when you try to start it the first time.

My truck has the chassis rail notched even for the direct drive starter. Lifting the engine 2" more would have cleared it, but then you'd be reshaping the transmission tunnel and bonnet (hood).

 

[astr]

So far I've found all the US Isuzu NPR trucks and GM/Chevy derivatives are 12V, including the 4HE1 and the current 4HK1 engines. They all come with dual 12V batteries but are wired in parallel.

Personally, I would prefer a 24V system from the performance standpoint, however, it is a real PITA from parts availability and compatability with towing and accessories, at least here in the US.

 

[RHINO]

Sure about the 12v thing?
You'll know when you try to start it the first time.

well since i've been driving it for the past 2 weeks i hope i'm sure.

 

[Dougal]

So far I've found all the US Isuzu NPR trucks and GM/Chevy derivatives are 12V, including the 4HE1 and the current 4HK1 engines. They all come with dual 12V batteries but are wired in parallel.

Personally, I would prefer a 24V system from the performance standpoint, however, it is a real PITA from parts availability and compatability with towing and accessories, at least here in the US.

Well that sure is interesting.
The Isuzu NPR's here are all 24V, both batteries are wired in series.
They have warning stickers on the cigarette lighter socket, even my glowplugs are stamped 23V.
Don't know what they did with the stereo though, that's gotta be 12v.

My truck has 24v starting, everything else is 12v. Has a series/parrallel switch taking up a lot of space under the bonnet.

 

[acy76]

I have a question on transmission choices, if I may:

Let's suppose someone wanted to use a 5-speed manual transmission that was made for the chevy V8 with this conversion (eliminates the need for additional adapters), along with a common passenger-drop transfer case, something like a Dana 300, BUT did not want to deal with the expense, weight or low 1st gear of the NV4500. Is there a stock combination that would work? Something from a 1/2- or 3/4-ton Chevy pickup? Or is the NV4500 the only game in town?

 

[astr]

What did you get for a rocker cover gasket?
The factory one is shaped to fit and looks right. The aftermarket kit I had was simply a long piece of oring rubber. I was not impressed.

Here is a photo of the gasket set that I purchased from gaskets4less for around $100 for my 4BD1T. It seems to be quite complete and includes crank seals, valve stem seals, a multi-layer steel head gasket and a molded valve cover gasket. The label on the package says Isuzu 4BC2, which, from your previous post is a 3.3 L engine whereas the 4BD1T is 3.9 L. The headgasket seems to fit perfectly, so I have to assume that the difference in displacement is due to a difference in stroke. I would feel better isf the label did say 4BD1T

 

[RHINO]

acy, chevy has non NV4500 5 speed trannies no problem there. but i dont know what all they can adapt to, an adapter for something like a D300 would most likely be needed but since the "other" GM 5 speeds are not being used much for conversions i would have no clue what is available, i would start by contacting advance adapters to see if the offer anything or can give you any info.

 

[Dougal]

Here is a photo of the gasket set that I purchased from gaskets4less for around $100 for my 4BD1T. It seems to be quite complete and includes crank seals, valve stem seals, a multi-layer steel head gasket and a molded valve cover gasket. The label on the package says Isuzu 4BC2, which, from your previous post is a 3.3 L engine whereas the 4BD1T is 3.9 L. The headgasket seems to fit perfectly, so I have to assume that the difference in displacement is due to a difference in stroke. I would feel better isf the label did say 4BD1T

I'm afraid that none of your timing gear gaskets will fit.
The 4BC2 doesn't have the powersteering pump integrated into the front gear train.
Those exhaust port gaskets are also bad. The genuine ones are stainless steel with a beads rolled into them. I'd reuse the old ones.
Other items of concern looking at that is the intake manifold gasket. The factory item is moulded rubber and steel, again I'd reuse the factory one if it doesn't need disturbed or damaged.
The large sump gasket is completely different too. Factory is a two layer rubber sandwich, that is a single layer paper item.

 

[astr]

I'm afraid that none of your timing gear gaskets will fit.
The 4BC2 doesn't have the powersteering pump integrated into the front gear train.
Those exhaust port gaskets are also bad. The genuine ones are stainless steel with a beads rolled into them. I'd reuse the old ones.
Other items of concern looking at that is the intake manifold gasket. The factory item is moulded rubber and steel, again I'd reuse the factory one if it doesn't need disturbed or damaged.
The large sump gasket is completely different too. Factory is a two layer rubber sandwich, that is a single layer paper item.

Actually, I'm just trying to get the engine running well enough to allow me to evaluate what I am going to do next. The engine had two bad (partially-melted) pistons and the head gasket was bad. Not sure which happened first. The cylinder walls in the cylinders with the bad pistons look fine. I picked up a couple of good used pistons with rings from 88tlc that I will use. I pulled the whole head with intake and exhaust attached so I don't need those gaskets. I prefer to use RTV silicone rubber for oil pan so if that pan gasket doesn't fit its no big deal. I do need the valve cover gasket as the old one was damaged pulling the cover off.

My objective is to get the engine running well enough so that I can drive the truck around a bit and see how well I like the engine and the MSA5D tranny. If I like the combo well enough, I'll try to address the shifting issue and the T-case adapter issue. If I decide that I want to move forward with installing the combination in my FJ62, then I will rebuild the engine properly.

Parallel to this effort, I still want to evaluate the A440F/A450 hybrid automatic transmission. If I can come up with a workable solution, then I'll go the 4HE1 route.

All I need is more hours in a day or less projects to make some progress on the FJ.

 

[RHINO]

does the 4BD1 have a low oil shutdown? i dont see anything of it on the FSM i have.

 

[Dougal]

does the 4BD1 have a low oil shutdown? i dont see anything of it on the FSM i have.

I don't think so.
The engine has an oil pressure switch, for the light on the dash. That's all I'm aware of.

It also features an old fashioned dipstick, by far the most reliable indicator of oil volume.

 

[RHINO]

dipstick?? your crazy man, everbody knows a dipstick is another term for a drongo.

 

[astr]

Dougal: MSA shift pattern ?

Dougal: When you converted your MSA tranny to top shift, what shift pattern did you end up with?

 

[Dougal]

Dougal: When you converted your MSA tranny to top shift, what shift pattern did you end up with?

It wasn't me (honest). It was done about 15 years ago using Austin Allegro parts.
The resulting pattern is
R24
135

Most vehicles here have reverse by 5th, but the Toyota Dyna light trucks at work have the same shift pattern.