Hi all,
I have been working on going through my 1991 hdj81 and could use some advice. Short story is i suspect that my turbo seals are leaking (long story below). I want to know what else I should check before rebuilding/replacing the turbo and also advice on turbo rebuild/upgrades.
It generally runs great, but has some minor white smoke (most noticeable when warm after a long highway run or when merging onto the freeway at night and looking back in rearview mirror. I am not sure if the smoke is white-grey (burnt oil) or white (raw diesel in exhaust). Smells like diesel to me. It also has consumed ~1.5 quarts of oil in 5000km. No leaks that i know of. Some blowby present when warm and removing the oil fill cap (it does not make the cap dance or blow like a steam engine). Mileage has been lower than i expect (17-20 mpg on freeway, running 60-70 mph). So i have been checking everything over.
Checked the turbine while on truck:
No signs of damage to the compressor wheel or housing. Some noticeable play in the shaft (more radial then axial). I tried to measure it on the truck using a dial indicator for axial and feeler gauges (measure the change in gap between the wheel and housing). Both measurements were suspect and real reliable but i got:
Axial ~4-6 mils (FSM spec <5.1 mils)
Radial ~10-12mils (FSM spec <7.1 mils)
I am not sure if it really is this far out of spec or if it is just my bad measurement setup. I would need to get it on the bench with access to both ends of the shaft and a dial indicator through the oil port to do any better.
Performed a compression check:
Cold: 1- 505psi, 2 - 500psi, 3 - 500psi, 4 - 505psi, 5- 510psi, 6 - 510psi
Cold test looked good (it can be a better sign of problems), ran out of time but will redo it warm when i get time. It is a pita because the adapter hose is a pain to get on and i have to remove the crosser pipe, glow plug rail, and injector return piping.
FSM spec:
Nominal Compression pressure: > 498 psi
Minimum pressure: 356 psi or more
Difference between each cylinder: 71 psi or less
Checked for oil in the intake. It was fairly wet between the air cleaner and turbo inlet, starting at the breather fitting from the valve cover. The crossover pipe also had some oil present (mostly around the turbo outlet/flex coupling and some at the manifold gasket. The breather tabs inside the valve cover were open to ~15mm, so bend them down to ~4mm gap and I removed breather and vented it into a open bottle temporarily. I cleaned the air intake and crossover pipe up with parts cleaner and wiped them dry as possible, put it back together and drove it to see if the smoke/oil in intake was coming from the breather. In the past 10 days since doing this i drove it maybe 5 times and the smoke did not change. when i re-opened the crossover pipe it again had some oil present (although less than before).
Also checked valve clearances (have not ordered new shims yet): A couple were outside the fsm specification range by 1-3 mils. Not sure how much of an effect this might have. My measurements may be 1 mil thin as i did not want to try to force in a shim that was too thick. Seemed like there was an oil layer that might affect it as well.
Intake ( spec 6 - 10 mil): 1 - 4mil, 2 - 5mil, 3 - 6mil, 4 - 6mil, 5 - 6mil, 6 - 5mil
Exhaust ( spec 14-18 mil): 1 - 12mil, 2 - 13mil, 3 - 13mil, 4 - 13mil, 5 - 13mil, 6 - 11mil
Below is a synopsis of what i have done so far:
It had low mileage (120,000km) and mainly had a few issues do to sitting (slow sticky power windows, corroded ac condenser, frozen transmission kickdown cable, bad shocks and inoperable fan clutch). It did great on my 2000 mile roadtrip from to bring it back from GA to Ca. So far i have done the following, as i go through the truck to make sure i can trust it for back country camping and long trips with the family:
I have been working on going through my 1991 hdj81 and could use some advice. Short story is i suspect that my turbo seals are leaking (long story below). I want to know what else I should check before rebuilding/replacing the turbo and also advice on turbo rebuild/upgrades.
It generally runs great, but has some minor white smoke (most noticeable when warm after a long highway run or when merging onto the freeway at night and looking back in rearview mirror. I am not sure if the smoke is white-grey (burnt oil) or white (raw diesel in exhaust). Smells like diesel to me. It also has consumed ~1.5 quarts of oil in 5000km. No leaks that i know of. Some blowby present when warm and removing the oil fill cap (it does not make the cap dance or blow like a steam engine). Mileage has been lower than i expect (17-20 mpg on freeway, running 60-70 mph). So i have been checking everything over.
Checked the turbine while on truck:
No signs of damage to the compressor wheel or housing. Some noticeable play in the shaft (more radial then axial). I tried to measure it on the truck using a dial indicator for axial and feeler gauges (measure the change in gap between the wheel and housing). Both measurements were suspect and real reliable but i got:
Axial ~4-6 mils (FSM spec <5.1 mils)
Radial ~10-12mils (FSM spec <7.1 mils)
I am not sure if it really is this far out of spec or if it is just my bad measurement setup. I would need to get it on the bench with access to both ends of the shaft and a dial indicator through the oil port to do any better.
Performed a compression check:
Cold: 1- 505psi, 2 - 500psi, 3 - 500psi, 4 - 505psi, 5- 510psi, 6 - 510psi
Cold test looked good (it can be a better sign of problems), ran out of time but will redo it warm when i get time. It is a pita because the adapter hose is a pain to get on and i have to remove the crosser pipe, glow plug rail, and injector return piping.
FSM spec:
Nominal Compression pressure: > 498 psi
Minimum pressure: 356 psi or more
Difference between each cylinder: 71 psi or less
Checked for oil in the intake. It was fairly wet between the air cleaner and turbo inlet, starting at the breather fitting from the valve cover. The crossover pipe also had some oil present (mostly around the turbo outlet/flex coupling and some at the manifold gasket. The breather tabs inside the valve cover were open to ~15mm, so bend them down to ~4mm gap and I removed breather and vented it into a open bottle temporarily. I cleaned the air intake and crossover pipe up with parts cleaner and wiped them dry as possible, put it back together and drove it to see if the smoke/oil in intake was coming from the breather. In the past 10 days since doing this i drove it maybe 5 times and the smoke did not change. when i re-opened the crossover pipe it again had some oil present (although less than before).
Also checked valve clearances (have not ordered new shims yet): A couple were outside the fsm specification range by 1-3 mils. Not sure how much of an effect this might have. My measurements may be 1 mil thin as i did not want to try to force in a shim that was too thick. Seemed like there was an oil layer that might affect it as well.
Intake ( spec 6 - 10 mil): 1 - 4mil, 2 - 5mil, 3 - 6mil, 4 - 6mil, 5 - 6mil, 6 - 5mil
Exhaust ( spec 14-18 mil): 1 - 12mil, 2 - 13mil, 3 - 13mil, 4 - 13mil, 5 - 13mil, 6 - 11mil
Below is a synopsis of what i have done so far:
It had low mileage (120,000km) and mainly had a few issues do to sitting (slow sticky power windows, corroded ac condenser, frozen transmission kickdown cable, bad shocks and inoperable fan clutch). It did great on my 2000 mile roadtrip from to bring it back from GA to Ca. So far i have done the following, as i go through the truck to make sure i can trust it for back country camping and long trips with the family:
- LubriMoly flush of fuel injectors/pump
- Replaced all fluids/filters, shocks, tires and wheels (17" from 2005 seqouia)
- Checked/greased all wheel bearings, u-joints, birfs, and replaced axle seals
- Replaced Timing belt/tensioner
- Replaced cooling water houses, thermostat, and fan clutch
- Replaced AC condenser, drier and compressor (had leaky o-rings and some corrosion)
- Replaced turbo water and oil hoses (going to replace hard lines also when i have it off as i already have them)
- Cleaned up contacts on Neutral start switch, hazard switch and 24 V isolater relay
- Replaced passenger window regulator
- Swapped in shoulder strap seat belts for the lap belts
- Plan on replacing Big End Bearings this weekend if possible (i have a wife, 3 year old and 2 month old daughter that get jealous of my time)
- Check injector timing, pull injectors and service if needed
- Larger disc brakes, Lockers, Lift/coil springs, 3" exhaust, EGT probe and gauge, install 3rd row seats
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