isuzu 6bb1 5.4 litre truck engine in my 80 series

[PIP]

K5 these are medium duty engines and rubies won’t underpowered and unreliable. They turbo well and will be way more powerful than any light duty old I-6’s. They have a lot of parts that interchange with 6 and 4bd series engines. Got to 4btswaps.com and check out the Isuzu diesel section. You can find most parts for them still. 6bd1t would be easier to find.

That doesn't align with my experience. They do not turbo well. You can rebuild one with turbo pistons and oil squirters, but if you put a turbo on an N/A Isuzu it won't last long. The upper ring lands are just plain aluminum with straight sided rings. Turbo pistons have steel inserts with keystone rings. The N/A piston's ring lands will be beat to death by a turbo. Lots of blowby in a short period of time.

I have seen lots of these swaps. There were a bunch done back in the day and most got a turbo added at some point which led to failures shortly thereafter.

If it works, great, drive it. What transmission does it have? That has a lot to do with the drivability of these old things.

 

[K5blazer]

That doesn't align with my experience. They do not turbo well. You can rebuild one with turbo pistons and oil squirters, but if you put a turbo on an N/A Isuzu it won't last long. The upper ring lands are just plain aluminum with straight sided rings. Turbo pistons have steel inserts with keystone rings. The N/A piston's ring lands will be beat to death by a turbo. Lots of blowby in a short period of time.

I have seen lots of these swaps. There were a bunch done back in the day and most got a turbo added at some point which led to failures shortly thereafter.

If it works, great, drive it. What transmission does it have? That has a lot to do with the drivability of these old thingsa

 

[PIP]

My initial research has backed that up. It started easily after 20 years of sitting. I'm not planning to turbo, tweak or upgrade. My goal is to keep it simple and in good order. The fun is in its obscurity stateside.

These were a very popular conversion into pickups in the NW in the late 70's. They may be rare now, but they sure weren't a couple decades ago. A friend of mine has a 1979 F-250 4x4 with a 6BD1 with turbo added that was done by a local upfitter in the early 80's. It is on it's 4th engine and I don't think it has 100K miles on it. Another friend had a 6BD1 1985 K30 crewcab 4x4 that he went through the same stuff with. He eventually put a real 6BD1T in it and adapted an NV4500. It was a good truck once it was all sorted with the turbo engine and OD trans.

 

[mjosoba]

I’ve driven several N/A turboed. They last fine. That’s mind blowing, I don’t think I could kill that many engines if I tried. He must be doing something wrong.

 

[K5blazer]

Some form of 5 speed. It's big. Might be Isuzu.

 

[mjosoba]

I bet it’s one of the non O/D’s. There’s a lot of info on all that in here. Isuzu 4BD1T/2T - https://www.4btswaps.com/forums/isuzu-4bd1t-2t.16/

 

[K5blazer]

This was a NW truck. Engine

These were a very popular conversion into pickups in the NW in the late 70's. They may be rare now, but they sure weren't a couple decades ago. A friend of mine has a 1979 F-250 4x4 with a 6BD1 with turbo added that was done by a local upfitter in the early 80's. It is on it's 4th engine and I don't think it has 100K miles on it. Another friend had a 6BD1 1985 K30 crewcab 4x4 that he went through the same stuff with. He eventually put a real 6BD1T in it and adapted an NV4500. It was a good truck once it was all sorted with the turbo engine and OD trans.

I’ve driven several N/A turboed. They last fine. That’s mind blowing, I don’t think I could kill that many engines if I tried. He must be doing something wrong.

My guess is when you up the pressure you up the problems. If total performance was my goal I'd bypass to a 12 valve 5.9 Cummins. My goal is to see it living and working.

 

[PIP]

I’ve driven several N/A turboed. They last fine. That’s mind blowing, I don’t think I could kill that many engines if I tried. He must be doing something wrong.

Same guy with the 6BD1 F-250 has a 93 diesel stickshift Dodge he bought brand new in 93. His Cummins is essentially stock and runs like new with 380K on it. He's not hard on stuff and in all seriousness, anyone who would own a rig with an old Isuzu diesel in it probably didn't buy it to run it hard or try to blow it up. You know, common sense says you'd do a little research and plan to live with it's limitations before you'd commit to buying one. His old F-250 is full of gauges inside, EGT, boost are there and he always watched them close.

Clearly the OP's K5 has been driven a lot. There's a healthy enough oil crust under it to suggest it's seen some miles. It probably will do some more without much effort. I was hoping my suggestions would come across as being realistic, like don't turbo it and tow stuff over the mountains as opposed to pessimistic. It's just my opinion, take it or leave it.

 

[mjosoba]

Same guy with the 6BD1 F-250 has a 93 diesel stickshift Dodge he bought brand new in 93. His Cummins is essentially stock and runs like new with 380K on it. He's not hard on stuff and in all seriousness, anyone who would own a rig with an old Isuzu diesel in it probably didn't buy it to run it hard or try to blow it up. You know, common sense says you'd do a little research and plan to live with it's limitations before you'd commit to buying one. His old F-250 is full of gauges inside, EGT, boost are there and he always watched them close.

Clearly the OP's K5 has been driven a lot. There's a healthy enough oil crust under it to suggest it's seen some miles. It probably will do some more without much effort. I was hoping my suggestions would come across as being realistic, like don't turbo it and tow stuff over the mountains as opposed to pessimistic. It's just my opinion, take it or leave it.

I hope I didn’t come off as antagonistic, just genuinely surprised. That’s the only time I’ve ever heard anything along those lines.

 

[K5blazer]

I hope I didn’t come off as antagonistic, just genuinely surprised. That’s the only time I’ve ever heard anything along those lines.

Not at all. Regardless, with an old, obscure engine I'd prefer to try to get it going again before it becomes too far gone and ends up in the scrap heap. Lord knows there is a 350 SBC on every corner to convert back to stock if desired.

 

[deisel 80]

Well havnt you lot been chatty since I’ve been gone i can give an honest long time review if anyone is interested???

 

[deisel 80]

Shes been everywhere and not with out it’s troubles i may ad. But never failed to get me home ever. Until a week ago bastard thing

 

[mjosoba]

Uh oh! What happened?!

 

[deisel 80]

Well lets just say dont build enginges with parts from china. It all started out well then it blew a head gasget. So i put a new one on and that time i torqed it up to turbo specs. That went well for about 12 months then it decided to crap a piston.. so opon tear down i reliised that there was too much slack between the pistons and cylinders. At this point i was ofered a rebuilt 6bd1 not a t motor though. I know the guy who built it. So i jumped on it. Turns out that i am a dick head. I didnt retention the head to suit the turbo..... so away goes the first head gasget. By now im really anoyed. Since then i have been daily driving this thing and i have relied heavily on it for work. Id had started a new job that requires my to travel a hell of a lot some times up to 20k ks a fort night wich is insane. Any how because of this i have to service this thing and shoot if to work i the blink of an eye. Soo every 12 months goes by and it does a head gasget ??? I spoke with professionals and most said head must be bent. Id finally got the chance to take the head to be machined. The bloke said its bent like a bannana. He showed me and to be honest i think that was an ununderstatement. So head was fixed and id decided id buy head studs while i was at it. This tim id bouht a new car to take its placed as i had honesty had enough. Well gues what its gone again this time barely making it home. I thought beautiful it'll show me exactly whats wrong now as it was reallyhard to tell where it was blowing before. So far i haven't pulled it out. But after having a conversation with some one that knows these old girl's it turns out that i may have a bent block and this will cause the liners to be out there for not seal. Well thats the bad crap out of the way as for the good the thing pulls like a freight train and its done a heap of kilometers from.the out back of aus to the Victorian high country literally sipping on fuel. Its actually bitter in fuel than my nephew's factory turbo while towing a camper mind you. And for this i think that i will get to the bottom of what the issue is now that it just lives in the shed and only a weekend rig. I will eventuallyget back with pictures and information.

 

[PIP]

Thanks for the update. Sounds shockingly similar to my experience with them.

 

[PIP]

I wanted to add that I do not believe Isuzu diesels are a bad engine. My opinion is that the non-turbo versions, the 4BD1 and 6BD1 are more available than the turbo versions so they get pushed into turbo duty leading to failures when they are used past their limitations. At the same time, the isuzus are a very complicated design with liners. Most people believe (mistakenly) that the liners are a great thing in a small engine like this, but my experience says otherwise. The liners require a lot more knowledge and skill during an overhaul. 4 out of 5 Isuzu diesel overhauls I have been involved with have needed deck machinework and subsequent machinework to fix liner protrusion followed by a thicker headgasket. This is very expensive work to do correctly.

Lots of mechanics and individuals that work on smaller diesels like these aren't familiar with liner engines so they don't take the care to do the job correctly. This ends up in a cycle of repeated head gasket failures.

Not so much on the early 4BD1/6BD1 engines, but the 4BD2T's and all subsequent 4.8/5.2 big 4 cylinders from the NPR's have very porous block castings. It's like the iron is an improper grade or something was amiss in the casting process. I have seen a ton of 4BD2T's with sunken liners where the step in the block has been eroded away from the liner moving. The corrective action is usually more than the engine is worth. The later engines are a bedplate design where the upper and lower block are split at the crankshaft centerline. Theses engines are notorious for the bedplates walking around leading to spun main bearings.

Additionally, the 4BDx/6BDx engines also have a design flaw where the oil pump is driven from a helical gear on the camshaft. These gears are usually heavily worn requiring a new camshaft and drive gear when the engine is torn apart.

 

[deisel 80]

I wanted to add that I do not believe Isuzu diesels are a bad engine. My opinion is that the non-turbo versions, the 4BD1 and 6BD1 are more available than the turbo versions so they get pushed into turbo duty leading to failures when they are used past their limitations. At the same time, the isuzus are a very complicated design with liners. Most people believe (mistakenly) that the liners are a great thing in a small engine like this, but my experience says otherwise. The liners require a lot more knowledge and skill during an overhaul. 4 out of 5 Isuzu diesel overhauls I have been involved with have needed deck machinework and subsequent machinework to fix liner protrusion followed by a thicker headgasket. This is very expensive work to do correctly.

Lots of mechanics and individuals that work on smaller diesels like these aren't familiar with liner engines so they don't take the care to do the job correctly. This ends up in a cycle of repeated head gasket failures.

Not so much on the early 4BD1/6BD1 engines, but the 4BD2T's and all subsequent 4.8/5.2 big 4 cylinders from the NPR's have very porous block castings. It's like the iron is an improper grade or something was amiss in the casting process. I have seen a ton of 4BD2T's with sunken liners where the step in the block has been eroded away from the liner moving. The corrective action is usually more than the engine is worth. The later engines are a bedplate design where the upper and lower block are split at the crankshaft centerline. Theses engines are notorious for the bedplates walking around leading to spun main bearings.

Additionally, the 4BDx/6BDx engines also have a design flaw where the oil pump is driven from a helical gear on the camshaft. These gears are usually heavily worn requiring a new camshaft and drive gear when the engine is torn apart.

Yerp i agree with every thing you say. I was thinking ill find a turbo motor and rebuild that but non to be found at any truck wreckers in aus at the moment. But ill keep an eye out for one as the car isn't used as a daily any more so im in no rush. The thing is that in Australia they used these engines in race truck with great success. The 6bd1t that is. So i do have a question do you know of any one that has machined for the oil squirters successfully??? May be a reasonable opinion to fit those along with turbo pustons and turn the heat up a bit well just a tiny bit any way.

 

[PIP]

Yerp i agree with every thing you say. I was thinking ill find a turbo motor and rebuild that but non to be found at any truck wreckers in aus at the moment. But ill keep an eye out for one as the car isn't used as a daily any more so im in no rush. The thing is that in Australia they used these engines in race truck with great success. The 6bd1t that is. So i do have a question do you know of any one that has machined for the oil squirters successfully??? May be a reasonable opinion to fit those along with turbo pustons and turn the heat up a bit well just a tiny bit any way.

The material is there, but nothing is machined for the oil squirters. I remember looking at doing it to a 6BD1 block, but the turbo block (4BD1T) I was looking at had different regulators in the oiling system. Machining for the nozzles would not be a difficult job with the bare block as long as you have an example block to take the dimensions from, but the oiling systems are actually slightly different from non-turbo to turbo. I didn't complete the machining because I wasn't sure the oiling system would work correctly.

I believe a turbo engine is the way to go. 6BD1T's sure seem to be the hardest Isuzu diesel to find when you need one though.