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Discussion Starter · #1 ·
Hello fellow Planet Isuzoo-ians!

You may or may not have seen my post on New Member Introductions. Nevertheless, here is a dedicated thread about restoring a first gen trooper.

I bought this one through an estate sale company. It had one previous owner; seemingly used as the family soccer shuttle. The car had several stickers from various local Southern California universities. Mainly SDSU. It has 126K on the clock, and I bought it non-op for $2500. Now I know some will balk at that figure, expensive for a Trooper, but I can assure you this was the best specimen to show up Craigslist after about two months of searching. There were a few cheaper options in a 500 mile radius, but none of them had a body this straight or interior this clean, and the tow would have brought the cost to be about the same. Here she is getting dropped off at my house:









More to come...
 

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Discussion Starter · #2 ·
First step was to start with the fuel tank and work my way forward. The tank was... well, in need of some help:



Two times I ordered a brand new tank from the few OEM Isuzu suppliers. Both times I was emailed to inform me that it would take 6-8 weeks and was asked if I would like to proceed with the order. Both times I cancelled, because $750+ for a fuel tank was just too hard to swallow. So instead, I tried every home remedy to clean up the tank on my own. Vinegar. Rust remover. Shaking the tank with nuts and bolts to remove all the gunk and rust. What I was left with was an uncomfortable amount of dirty run-off water that I captured in 5 gal. buckets, and a tank looking like this:



Not bad, not great either.

I tried applying Red Kote to this, and in the process, destroyed the little rubber flap that sits in the center bowl of the fuel tank. I figured this to be not ideal and decided to test my luck at the local pick-a-part. Now, most yards in my area punch a hole in the gas tank making them all unusable. Somehow I found the one yard that doesn't do that, and there was a trooper there that must have just had its fuel system overhauled. Here's what the tank looked like using my snake camera/endoscope (saves a lot of time at the junkyard):



So, yeah, struck gold.

Fifty bucks later I was taking this puppy home, and getting it ready for installation. I ordered new rollover valve grommets from JLEMOND.

New Bosch fuel pump from eBay (EDIT: turns out this was the wrong pump. It was for a V6 and not usable on the 4ZE1. See Page 3 for an update)


After cleaning and sanding


Fresh coat of paint, new fuel pump, grommets, and fuel level sender installed


I installed the tank with all new fuel lines, and a new fuel filter. Finally I could see if the engine would maybe turn over.

No dice. Compression was just two low on two of the cylinders, which I was told about at the time of sale, but I was hoping against hope there might be just enough to get a brief idle.

More to come...
 

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Discussion Starter · #3 ·
A couple months after rebuilding the fuel delivery system, I finally had time to dig into the engine and look into the compression issues I was having.

Memory serves that the figures were as such:

Cyl 1 : 0 psi
Cyl 2: 0 psi
Cyl 3: 180 psi
Cyl 4: 160 psi

After pulling the head, cylinders 1 and 2 were readily explained:


I wiped off Cyl 1, and you can clearly see the gasket blowout between 1 & 2.
 

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What a clean truck, worth keeping. It's an LS to boot. If you have to have a automatic at least you have a good one. It is an Aisin and they are good ones. I would look at doing a fluid change once you get this little puppy running. Jerry also has a modified cam that will make this engine run even better. Look at upgrading the exhaust to a 2 1/4" down the line. It was one of the best mods I did on my SpaceCab.
 

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X2 on the good looking truck. An LS with a 4 cylinder and automatic! I might even be tempted. Dennis
 
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Nice looking Trooper. I wouldn't regret what you paid. Some may think it's absurd, but paint and interior work is quite expensive and since you can do most of the mechanical work yourself, you'll be better off. I only paid $700 for mine, but as of right now, I've got over $3,000 invested in it and the interior is in decent shape but not perfect and the paint is shot. However, I plan on using it off-road and wouldn't want to scratch a good paint job.
 

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as far as the price you paid to obtain this diamond in the rough, doesn't matter what anyone else in the forum, thinks..it's your choice..and if you feel comfortable with paying $ 2500, then more power to you....You can't put an price on pleasure...do the math, tally up more or less what you will spend to get your baby up and running,..and sit back, admire your ride....and ask yourself, what type of similar vehicle, could you obtain...for the monies spent.....not much out there..AND ESPECIALLY finding a very clean first gen..no less...after going thru the drive train, suspension,re do the 4 cyl, keep an eye on the floor pans, and frame...and with your replacement gas tank and new fuel pump, problems that usually crop up due to gunky gas tanks, and gummed up fuel pumps, won't be knocking on your door..

Always LOVED the LS series..nicer carpet, and the seats, not only looked better than the original tweed seats, but were far more comfortable..and once you get the body washed and waxed up, that white really does look good, and stand out..

congrats on your recent find...may you have many happy hours, of motoring fun...
 
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Re: your blown head gasket, it's most common to see that between cyl 3 & 4 but, there ya go! You'll have to at minimum get the head surfaced. These do have issues with burnt exhaust valves so I'd highly recommend, at minimum, you pull all the valves out of the head and check for valve burning/seat recession. The intake valves will probably look really good and may only need a slight lapping-in with fine valve compound. Depending on what you see on the exhaust side, maybe the same. Or it may need the valves ground. Have the head pressure-checked as well.

For best results, use an Isuzu OE head gasket. They are less prone to blowing out. El-Cheapo gaskets will likely blow out the fire rings within a few thousand miles. Jerry Lemond (JLEMOND on this site) can provide one of those.

If you get a chance, post a pic of the firewall side of the head. We need to see the casting number. Lower numbers are more prone to cracking, especially after an overheat.

Change all of the cooling system hoses or I guarantee, one day they'll blow out. Then it's Goodbye, Head! Check the radiator for proper flow and install a new, 180-degree thermostat with "jiggle" air-bleeding valve. Put the rig on ramps, or jackstands, or point up a hill, to bleed air out of the system. Entrapped air that doesn't "burp" out will cause overheating.

Nice, low-miles Trooper! Very clean.

HTH & G'luck with the repairs.............ed
 
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Discussion Starter · #9 ·
Thanks for all the encouragement everyone! I've had a few weekends now to dedicate to working on the Trooper.

Ed Mc. asked about the casting number of the head and it is a "2" and it looks like it maybe has a crack right along the casting line. The valves and valve guides looked rusty on cylinder 3 where there was a visible calcium build up:

Cast number "2'


Calcium build-up and rust in exhaust port of Cyl. 3:


My dad was in town who's rebuilt a few engines in his time, and we checked out the con-rod and crankshaft bearings. We thought they looked pretty good:


Going back to Cyl 3, the walls of cylinder had some light pitting that I could feel with my fingernail, and some obvious rust coloration. It was hard to capture it with a picture:


For comparison, here's Cyl 4, which had perfect compression:


So, the current plan is to get the engine dipped, and cylinders honed. I also discovered that where the head gasket blew out between Cyl 1 & 2, there was maybe a .001-.002" gouge on the top surface between the two cylinders, so I'll probably have to have the engine block resurfaced as well.
 

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Yeah, #2 casting wasn't the greatest (#3 and #4 are better), usually the cracks aren't external but found in the combustion chamber of the cyl head, or in the ports. What you see on the outside is probably just sand-casting "flash".

Better go over that head with a fine-tooth-comb. You might consider getting a new casting, because they are an improved design with better water flow, stronger, more reinforced metal and much less prone to cracking. That being said, if your head passes all the visual crack tests and pressure-tetsing, too, it might be OK.

But you've got to consider the machine shop cost of all that testing, then surfacing the head and doing a valve job. They ain't as cheap as they used to be, for sure! I had a rude awakening last time I did a valve job, I could have spent a bit more and bought a new head. Fortunately the head worked out and she ran for a long time.

You might consider getting a "jerry cam" while you've got it all apart. This special-grind cam from Jerry Lemond (JLEMOND here at the Planet) will really wake up the engine's mid-range and top-end. A worthwhile investment. You can P.M. Jerry if you're interested in that.

The ZuZu 4-cyl bottom ends are very stout, with one Achilles Heel: the crankshaft thrust bearing rings. They are 2-piece, so if they get a lot of wear they can fall out. Then the crank thrusts against the block and wears both parts out, to a non-repairable state. Not Good!

Might not be a bad idea to take a real close look at the thrust bearing rings and consider replacing them. Can't hurt, that's for sure.

Sounds like a good course of action with the block, carry on! :thumbright:

Oh, and a few eBay heads (check with Jerry, he sells 'em too):

https://www.ebay.com/itm/Isuzu-2-6-SOHC ... 0005.m1851

https://www.ebay.com/itm/NEW-ISUZU-2-6- ... Swd~RZOtsT

https://www.ebay.com/itm/Isuzu-2-6-SOHC ... 0005.m1851
 
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Discussion Starter · #11 ·
So I decided to clean up Cylinder 3 a bit before I take it to the machinist just to see what would happen, and it looks like a simple honing isn't going to cut it.

About halfway down was some major pitting.



I was reading DSUZU's space cab thread, and it seems like the thing to do is to get the cylinders bored +.020", and then get newer style oversized pistons. Sound about right? Would those newer style pistons pair better with a specific style of cylinder head? DSUZU had some heart shaped combustion chambers on his.
 

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If you go with the newer-style pistons, it'd probably be better to also go with the newer-style head with smaller combustion chamber. I'm wondering, though, if a mix of old-style flat-top pistons and the smaller combustion chamber might give a beneficial boost in compression ratio.

Maybe Jerry Lemond can chime in on recommendations for a mix-n-match...........ed

p.s. I reached into my archives and found a blurb from Jerry saying that the small-chamber head on an older 2.6 was a "very worthwhile upgrade".

His son's 2.6 automatic Trooper has the cyl head upgrade, and he found it ran well with timing set at 6 degrees BTDC. Depending on the particular quality of regular gas used, on occasion it might ping a bit, but a tank of mid-grade settled it right down.

IMHO the deep-dished pistons are gonna reduce compression ratio over flat-tops. From what I understand, the real reason for this change was emissions. So it would seem there's no clearance issues when putting the small-chamber head on a flat-top-piston lower. Coupled with a "Jerry Cam" and freer-flowing exhaust, it should give a significant boost in performance.
 

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Honestly, I never saw any real difference between the early head / piston combo and the later combo when I changed mine. For power, IIRC, you would use the early pistons and the late head (again, IIRC, the late heads have a smaller combustion chamber).
I definitely advise contacting Jerry for parts. Jerry really took good care of me. As long as you are dealing with Jerry, don't forget the (4 maybe?) small coolant hoses that go from the intake manifold and molded heater core hoses. Now's the best time. Dennis
 
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Discussion Starter · #15 ·
OK... So I got the .020" oversized pistons from Jerry, took my block to the machinist, and after all that there's still a small band of pitting that wasn't able to be removed with the .020" overbore.



The band sits just above the piston at bottom dead center:



I gotta say after all that I'm a little disheartened and am seeking advice on where to go next.

From what I was able to google, people say that if you have pitting in your cylinder, this is the best place to have it, at the bottom of the stroke. It really is pretty minor, though I can definitely feel it with my finger. I'm a little ticked off because the machinist I took it to said the piston doesn't touch that part of the cylinder when it obviously does. I guess he just eyeballed it. :cyclopsani:

My inclination is to run it as is, as I think in the grand scheme of things it probably won't make that big of a difference, but on the other hand, I've done all this work already. "Do it right, do it once" kind of thing.

For the pistons and all the machining, I'm about $450 in. So I see my options as being:
  • run it as is [/*]
  • Get the block rebored to .040 over and order set of .040 pistons [/*]
  • Get a block from the local pick-a-part and just start over[/*]

Thoughts anyone?
 

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I would look for another block.
 

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takemehome4LOroads said:
OK... So I got the .020" oversized pistons from Jerry, took my block to the machinist, and after all that there's still a small band of pitting that wasn't able to be removed with the .020" overbore.



The band sits just above the piston at bottom dead center:



I gotta say after all that I'm a little disheartened and am seeking advice on where to go next.

From what I was able to google, people say that if you have pitting in your cylinder, this is the best place to have it, at the bottom of the stroke. It really is pretty minor, though I can definitely feel it with my finger. I'm a little ticked off because the machinist I took it to said the piston doesn't touch that part of the cylinder when it obviously does. I guess he just eyeballed it. :cyclopsani:

My inclination is to run it as is, as I think in the grand scheme of things it probably won't make that big of a difference, but on the other hand, I've done all this work already. "Do it right, do it once" kind of thing.

For the pistons and all the machining, I'm about $450 in. So I see my options as being:
  • run it as is [/*]
  • Get the block rebored to .040 over and order set of .040 pistons [/*]
  • Get a block from the local pick-a-part and just start over[/*]

Thoughts anyone?
You could run it that way, and probably not notice any difference. However you should never buy pistons nor bearings, before the machining is done. The machinist should have told you that when you took him the block.
 

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Discussion Starter · #19 ·
mudoilngears said:
You could run it that way, and probably not notice any difference. However you should never buy pistons nor bearings, before the machining is done. The machinist should have told you that when you took him the block.
Unfortunately this was an expensive lesson for me to learn. I was a little confused on when he said he needed the piston before he could do the boring, I thought he could just measure it and know it was at the right diameter. I don't think he measured it at all, he just bored it until the piston fit in there, and when there was still pitting he passed it off as "the piston doesn't go down that far anyway."

On the bright side, I snagged a gas tank from a 82 short bed PUP yesterday to do an auxiliary gas tank mod. There's something to be happy about.

 

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Discussion Starter · #20 ·
Ed Mc. said:
If you go with the newer-style pistons, it'd probably be better to also go with the newer-style head with smaller combustion chamber. I'm wondering, though, if a mix of old-style flat-top pistons and the smaller combustion chamber might give a beneficial boost in compression ratio.

Maybe Jerry Lemond can chime in on recommendations for a mix-n-match...........ed

p.s. I reached into my archives and found a blurb from Jerry saying that the small-chamber head on an older 2.6 was a "very worthwhile upgrade".

His son's 2.6 automatic Trooper has the cyl head upgrade, and he found it ran well with timing set at 6 degrees BTDC. Depending on the particular quality of regular gas used, on occasion it might ping a bit, but a tank of mid-grade settled it right down.

IMHO the deep-dished pistons are gonna reduce compression ratio over flat-tops. From what I understand, the real reason for this change was emissions. So it would seem there's no clearance issues when putting the small-chamber head on a flat-top-piston lower. Coupled with a "Jerry Cam" and freer-flowing exhaust, it should give a significant boost in performance.
Thanks for the idea Ed. I've read many of your helpful replies on other threads and I shudder to remind you I live in CaLiFoRNia. Do you think that combo of early pistons+late head+Jerry cam would cause issues for the Smog test? I wonder if anyone else in CA is running that config.
 
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