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Overhauling a Diesel

PostPosted: Sat Oct 14, 2006 9:41 am
by Taziiy
dani4JB1T wrote:Hi guys....

Im overhauling my engine. It`s a 1991 Isuzu 4JB1T 2.8 td. The head cylinder was removed last saturday. I found water inside (sulphated areas plus water drops), lots of heat spots and soot around the liners and piston heads. Maybe the water drops leaked when i removed the head cylinder. I have to check if the head cylinder is twisted or not.

Next stage is take off the cyl block, and have a deep look inside.

That should be a piston head. Notice the water drops.
Some sulphated zones
the head cylinder

Interesting fact is it was running very strong....problems were too much oil consumption (only on highways, around 4 liters each 1500 km), too much blow by and a weird knock sound.

This is my first diesel overhaul, so any tips/comments will be very handful. Image


dani4JB1T wrote:According to the book I had a B grade head gasket (second from 3 grades options). What`s the meaning ??...the engine was overhauled before or it is just a factory option...??



Patrolden wrote:you will probably find that all you need is new rings and maybe new liners..... mine was getting a bit of blow-by, but it wasn't using any oil at all. Maybe the headgasket grade relates to the amount of boost you are running? Anyway, if you want to fly over, you can have my engine pretty cheap :lol: :lol: :lol: going to be hard to get it back in your hand luggage though!!

coelux wrote:you need to use different thickness headgaskets depending on how much your piston protrudes from the top of the block


PostPosted: Mon Jan 15, 2007 10:55 pm
by Adskia
hi mate , the b is the thickness of the head gasket in relation to the amount of piston projection out of the block. if you were planing on running higher boost levels then the thickest gasket will be the best. hope that helps. cheers.

PostPosted: Wed Oct 15, 2008 8:59 am
by Leedo
hey guys,

I'm new here and this is my first post.

yesterday while coming off a roundabout my 96 rodeo died for no apparent reason. it could crank over but not start so i was thinking ok nothing major.
upon closer inspection i found a busted coolent line near the fire wall and an all but empty radiator. with the help of my diesel mech' mate we discovered i had snapped 3 rockers and bent all 8 push rods. i know stuff all bout diesels and any info from Deo owners out there would be great.


PostPosted: Wed Oct 15, 2008 6:51 pm
by nig
Sounds a bit strange - the camshaft on a rodeo is gear driven, and so cant get out of phase with the crank. But the broken rockers & bent pushrods sound like valves hitting pistons:confused:

As for the heater hose - that would have drained the engine & not neccessarily caused the temperature gauge to go up, in fact it more than likely dropped when/if the water ran out.

I think you need to get the head off and see what goes up & down when the crank shaft turns

PostPosted: Thu Oct 16, 2008 3:32 pm
by Leedo
head is off Nig,
all the pistons are ok and move freely when cranked and the bore and sporting hone marks that i assume were done before i aquired the deo'.
picked up full rocker assembly and push rods from the local wreckers for $150 and have noticed the rods are a little thicker which may be a good thing.

the head and valves are ok and the new gasket is on its way.
not sure on vavle tolerences as i dont have a manual.

any info would be a massive help mate.


PostPosted: Thu Oct 16, 2008 7:44 pm
by nig
Valve clearance is .4mm or .016 inch

The other one you might want is head bolts are torqued to 5 kg/m +or- .5 (36.2 ft/lbs +or- 3.6) and then tighten them all 60-75 degrees twice - going round in the tightening sequence (sounds bizzare, but that is what the manual says).

BTW - you can get a manual online via Clubisuzu - go to and follow the instructions - you are not interested in the UBS stuff - that is for Jackaroos, but drag down the TFS stuff and you are in business

PostPosted: Sat Oct 18, 2008 7:02 pm
by Leedo
the deo is almost done, been put on the shelf over the weekend while we build a 360ci 8banger which we just got back from the machine shop (and sadly its not goin into the deo..but ill keep dreaming). i downloaded the manual nig and its been handy, next step is pull the timing cover off and check the gears for damage and thats pretty much it. really missing my car and getting sick of the loner im driving cause its an excel that sounds like a swarm of sick angry bee's lol.