Outer Limits 4x4 Board

Just bought the young bloke a hzj75 1996 tray ute, just had all the services done, and clocked up about 700kmhs,
All going great we decided to head bush, We are not far from the Avon wilderness (east Gippsland Vic) there are some awesome tracks,
With some pretty knarly hills,
We were tackling one such hill which was made even more difficult with drizzely rain which had been going for most of the day,
On the first attempt going up we probably took it a little slow, so we went back for a run up, i was in my 4x4 with a mate, followed by my son and my mates son, I made it and got out to watch them come up, well they also made it, but the smoke belching out of the cruiser almost covered the side of the mountain, And all i could here was the cruiser reving of tap and smoke still bellowing out the exhaust, i yelled at the young bloke for F#%^&K sake turn it off, he said i have!!!!, i checked sh#$$T why is it still running, it probably ran for another couple of minuts at red line, before coughing rattling and eventually finally dieing,
seems it was running on fumes after blowing a piston
After about fifteen minuts trying to work out what had just happened we decided to try and restart the cruiser as we were in very remote and dence bushland, we finally got the thing restarted less one cylinder and decided to make the treck home,
We decided to call it a day and camped over on the Saturday night as we new we had a big journey ahead as the longest way was the easiest, even though we had over 180kmhs and in some places a meter of snow,
About midday Sunday (and a pretty big hangover from the night before drowning the sorrows) we made it to the town ship of Locola,
After putting a couple more litres in the old girl we finnaly made it home about 6pm Sunday evening,
Dont really have a moral to the story other than one of those Father Son things that didnt go quite to plan and old cruisers keep on goin on no matter how tough it gets,

i am guessing you just replaced the oil in the motor and it was just a little over full and what happened is that the motor was running on sump oil and the best thing you could have done was to have your foot hard on the brakes and in gear and stall it then try to safely get the car back down to the bottom of the hill then restart it there. i know all about this from experience as it happened to me in my diesel 80 series

here is a link to what happened to me (page 2)
http://www.outerlimits4x4.com/ftopic146 ... ht=yandina

X 2 this is a common thing with toyota desiels espesially on a steep hill when giving it sum as said above through it in 5th gear and stall it back down the hill and then start it, will cough and splutter for a few minutes sump oil leaks into the intake and the runs away on that "Revs out"

Yeah both are exactly right, i guess the young bloke panicked a little and was unsure what to do, the mate i mentioned that was with us at the time is a mechanic, and when we retried the hill (now on five cylinders) the cruiser did the same thing, but this time around we did what was mentioned (and stalled the ute), it never did it again but the damage was done, also should mention its running a Safari Turbo,
My mate just rang and tells me theres a hole in number 5 piston and it looks like its also scored the bore,

mate sounds like a good time to pull that 1hz out and do it up a little!

Yes i think your right, also looks like the other pistons are on the way out, apart from rebuilding the engine, has anyone got any ideas how to prevent this re happening, eg is there any engine mods i should do as it seems like it may be the fault of the turbo and im a bit new to these deisels,
the motor was aprox 180kmhs old completely standard, with the exception of a 3inch mandrel exhaust, any help would be appreciated, or if anyoneone out there knows of a good engine for sale

and give me the turbo kit

what boost are you running? maybe need to run an intercooler to keeo the heat down, also run an egt to monitor temps. A mate did his 1hz towing a small boat up a hill, major piston damage as a result of to much heat caused by to much boost, over fueling and no intercooler

In the bush id be very suprised if you could stall a 1hz even dropping the clutch in 5th and jumpin on the brakes, even on the bitumen would be a big ask.

berad wrote:In the bush id be very suprised if you could stall a 1hz even dropping the clutch in 5th and jumpin on the brakes, even on the bitumen would be a big ask.

um......ok then

it is easy to stall it. i was in 2nd low when i had to stall mine. but mine only reved out for a couple of seconds before i stopped it

sounded like an exciting day

Hi Paul
we have had this happen on our winch comp truck
what we did is cut the breather hose from the top of the rocker box and where it goes into the turbo and block both ends, this is beacause when on extreme up hill climps the oil flows to the back of the motor and fills up the back of the rocker box then it flows into the tubo and thats what keeps it running, after we did this no problems

80series chris wrote:Hi Paul
we have had this happen on our winch comp truck
what we did is cut the breather hose from the top of the rocker box and where it goes into the turbo and block both ends, this is beacause when on extreme up hill climps the oil flows to the back of the motor and fills up the back of the rocker box then it flows into the tubo and thats what keeps it running, after we did this no problems

So how does it breathe now?

How about installing a catch can on the hose wich is basically a cylindrical can with 2 hose fittings and filled with stainless steel scourer pads to catch the oil before it gets to the air intake and still alows the motor to breath

Well firstly thanks for the replys, and yes the second time it happened we did stall the engine no dramas, foot on brake dumped clutch etc,
as mentioned earlier i think the young bloke panicked a little and was unsure what to do seeing he had turned the key off and it was still reving flat out,
probably if we could have had our time over perhaps a differant out come,
but prior to reaching the top and reving flat out the thing may have already lunched the piston as the smoke was bellowing out the exhaust all the way up which he hadnt noticed,
And with the steepness of the hill and no doubt by now heeps of crankcase pressure pouring out through the whole in the piston and the turbo on full boost just added to its downfall,
My mechanic mate said theres a hole in number 5 piston as well the other pistons also appear on there way out, its also scuffed the bore on #5,
im unsure on the boost pressure but we will have it checked, as mentioned we have only had the ute a couple of weeks,
But its looking more like detination perhaps due to the turbo maybee to high in boost, funny though the car only fealt normal to drive definatly nothing out of the ordinary, (nothing like my mates 06 100 series turbo)

what precautions should we take to stop blowing holes in pistons,
Lower the boost, thicker head gaskets to lower compretion, can you buy turbo pistons to suit etc etc??????????
Any help in the right direction would be great

Are you assuming the holey piston was the cause of the uncontrolled revving or a result of the uncontrolled revving?

Exhaust Gas Temp gauge will keep combustion temps in check. If the probe is installed pre turbo max safe temp is around 750degC, if post turbo around 550degC. Engine damage is more likely to be caused by high combustion temps rather than compression - leave the compression ratio alone unless you want to get really serious.

High exhaust temps could be down to poor tuning or an inefficient turbocharger (resulting in high intake charge temp).
An intercooler will also help to bring temperatures down.

I'd suggest the cause of your problems could be overfilled oil, a dodgy crankcase breather setup dumping fuel into the intake or a combination of the two.

-Stu

we did the cutting of the breather as a short team thing, i should have completed my run down when we got back we ran a catch can from the hose from the rocker box and put a breather on it and left the hose going into the turbo blocked off you just have to check the catch can now and again thats all

catch can is the best idea. These do this whether turboed or not, mine did it with turbo, my mates did it without a turbo. Both in the same scenario, steep hill at high revs. Like others said the oil pools at the back of the rocker cover on steep uphill angles and the breather feeds it straight into the intake. Engine will keep revving til it runs out of oil supplying the intake, and has no governor controlling max rpm either obviously... Worst thing mine was on a muddy hill so once stalled I slid to the bottom all locked up and then kicked up on 2 wheels...pinched a few holes in the seat that day. Both of ours started again with no probs after a bit of coughing and farting. Bad luck yours got damaged mate, thats a bugger.

Yes, the son was a little dissapointed being his first car and all,
and it was only our second trip,

So reading all the posts, do you think this damage (hole in piston) would have been caused even if we didnt have a turbo?????,
i understand it would add to it as the engine makes more power, but we are worried if we rebuild or replace the engine it may be the turbo weeekening the pistons,
We are not so worried about the full rev on the hill (as we will know how to control that now),
But more so if the turbo had anything to do with it

I put a turbo on mine at 290K and didn't do a thing except set it up properly. Didnt change pistons, bearings or anything. And then abused it for years after that with no worries. That was 93 model HZJ75.
My suggestion would be once rebuilt, fit a boost and pyro gauge, but also check your pump timing. This can melt pistons if its wrong. If for some reason the pump has been removed it may not have been timed properly when it was refitted. Or an injector with a poor spray pattern can cause it.
Good luck with it mate, hope you can pin point it, wouldnt be much fun having it happen again.

I find it strange that noone has thought of turbo seals blowing and the engine running on the oil. Could this be a possiblity?

thewayitis wrote:I find it strange that noone has thought of turbo seals blowing and the engine running on the oil. Could this be a possiblity?

it would be happening all the time then wouldn't it not on steep up hills

thewayitis wrote:I find it strange that noone has thought of turbo seals blowing and the engine running on the oil. Could this be a possiblity?

it would be happening all the time then wouldn't it not on steep up hills