Tractor overhaul project

[cathead]

The Isuzu engine(4FA1) in my tractor starts hard and as far as I can tell has low compression. Parts are seemingly hard to find.
I was able to find an overhaul kit from Alibaba so ordered one. The cylinder sleeves need to be bored to fit the pistons so it is
going to get interesting. Maybe the existing sleeves in the engine are usable but maybe not. It was my hope that I could just
pull the head and pan and install rings, bearings and rework the valves. If I need to utilize the sleeves, the engine will have
to be removed from the tractor so I can bore out the cylinders to fit the pistons. I would guess that one needs to bore the cylinders
while they are mounted in the block. So, anyhow in the meantime, it runs and plan to use it this spring and rip into it later in the year.
As long as I have this whole kit, my thinking is that it would be best to disassemble the thing down to the block and work on it that way.

I have time to think about a plan of action. It appears to me that if I want to use all the parts and do a first rate job, I need to
pull the engine. The project is somewhat complicated in that there is a loader installed on the tractor making splitting off the
front end more difficult. Now that I think about it, it might be best to pull the head, install new valves and guides and measure
on the bores. Then either do a top overhaul or rip into it if it is too far gone.

 

[Alcap]

I think once you pull the head you’ll be able to come up with a plan . Hopefully the bores are not worn too much and just reringing is all that’s needed . Are you getting a lot of blow by ? Have you checked any starting aids ( glow plugs , intake heater ) Might pay to do a compression test so you can make a better decision. I recently had to make a choice with the engine in my chipper 4 cylinder Ford . The engine was left uncovered and water filled #4 cylinder causing the block to crack . I contacted a automotive machine shop . I asked for a rough estimate once I brought the bare block to him , cleaning , sleeving #4 cylinder bore and hone pistons I would have provided would have been around $500. I figured even though a complete overhaul kit was under $500 the head would have needed a few valves were rusty so an unknown amount was there too . I decided to find a used motor and roll the dice lol .

 

[cathead]

I think once you pull the head you’ll be able to come up with a plan . Hopefully the bores are not worn too much and just reringing is all that’s needed . Are you getting a lot of blow by ? Have you checked any starting aids ( glow plugs , intake heater ) Might pay to do a compression test so you can make a better decision. I recently had to make a choice with the engine in my chipper 4 cylinder Ford . The engine was left uncovered and water filled #4 cylinder causing the block to crack . I contacted a automotive machine shop . I asked for a rough estimate once I brought the bare block to him , cleaning , sleeving #4 cylinder bore and hone pistons I would have provided would have been around $500. I figured even though a complete overhaul kit was under $500 the head would have needed a few valves were rusty so an unknown amount was there too . I decided to find a used motor and roll the dice lol .

The glow plugs were tested with an ohm meter and are fine. The compression is 300, maybe more as I was using a tester for
a gasoline engine. The intake sucks up the blow by so need to check that out. Heat in the intake doesn't seem to help and ether
doesn't seem to help, strange. It generates a lot of white smoke and fires, just doesn't pick up. I think you are right that I need to
remove the head and see what can be determined. Machining services are expensive so will have to figure it all out on my own.
Once it gets running, it seems fine and has plenty of power.

 

[ddillman]

I would check the fuel delivery system and timing

 

[Nutfarmer]

I checked glow plugs with an ohm meter and they all showed ok. When I changed them out the engine started fine. Don't understand why they would show good on a meter and not be ok. Those selves don't look like wet sleves. You may have to bore the engine block to fit. If you have the parts and have to take apart the engine I would go through the whole engine. By the time a diesel engine looses enough compression due to wear in the piston and cylinders it usually starts burning quite a bit of oil. If it runs ok once it starts I .would change the four glow plugs before taking the engine apart. It's less than an hour job and if you rebuild the engine you would probably change them any way . One last thought is put a bolt meter on the glow plugs and make sure they have voltage when they are supposed to. If it's hard to start but runs fine the first thing is change the glow plugs. It's a lot cheaper than to rebuild the engine

 

[Alcap]

Did you happen to take a voltage test right at the glow plugs while there were on ?

 

[Karl_T]

I've rebuilt a tractor four or five times over the years...

Always got sleeves to fit the pistons, never heard of having to bore a sleeve. that's the whole idea of a sleeve, change it out and you are like new.

 

[cathead]

Did you happen to take a voltage test right at the glow plugs while there were on ?

Yes.

 

[Firebrick43]

I've rebuilt a tractor four or five times over the years...

Always got sleeves to fit the pistons, never heard of having to bore a sleeve. that's the whole idea of a sleeve, change it out and you are like new.

Wet sleeves don't require honing/boring at all. However many engines are dry sleeved. These engines have no orings, no coolant contact, and have a significant press force into the block. They are typically thinner sleeves as well. If you beat them in they typically will crack, and even if pressed with good care and tools will distort depending on the manufacturing tolerances that the machinist and many heat cycles the engine has had. So you press the sleeves, measuring with depth mics to positively ensure the sleeve is to depth, and hone with a 4 stone sunnen brand/type hone.

Internation was probably the largest manufacture to use this type of sleeve, even they switched to wet sleeves later on.

Also parent bore engines, that either have damage( as alcap mention) can have cracks fixed or severe wear that is over limit fixed by putting in custom dry sleeves. These engines are bored to an over size, dry sleeves press fit in, and then bored and honed back to factory new bore size.

 

[Nutfarmer]

The sleeves have me scratching my head too. The only thing I have seen that comes close is some of the Ford's had a thin wall sleeve you had to chisel out. A lot of the new tractor engines don't use sleeves anymore. The are like a gas engine and you have to bore them out. Have not worked on an Isuzu though. The only thing close is a couple of Yamars. They didn't have sleeves. Would not surprise me if their is a member who is an expert on Isuzu.