Turbo 1hz Big End Bearings

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Jan 17, 2012
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Thought i might as well share this with everyone, Hopefully others will catch theirs before it goes pear shaped., Grab a beer before you start reading.

My car is a 2000 vintage, 79 series complete with 1HZ and DTS Turbo setup (Mitsubishi TD05), 2.5" dump pipe out to 3" exhaust with a hotdog on the end. 366000 ish Kms, and had the turbo for over 100000kms i believe. I have only owned it for the past 30000 ish so do not know the complete history but the previous owner was a builder and lived in Toowoomba. I imagine the turbo went on to get up the range a bit quicker. He installed the turbo with his brother and seem to have done a pretty good job. Except when it came to mounting the exhaust but thats another can of worms.

My understanding is the bottom end of this engine is almost identical to the 1HD-t. Same bearings, crank etc. I figured that the bottom end of mine would be under the same load or greater and would suffer similar issues with the bearings.

A few hundred dollars later and a month or so i had all the bits i needed. The con rod bolts are the proverbial wooden horse poo of brisbane.

Jacked it up from the frame, blocked the suspension up and removed the sway bar to give myself enough room to remove the sump.

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Happy snap of the business end of the engine.
Some may note the piece of metal sitting in the oil strainer. The oil drain line for the turbo seems to have been just drilled and threaded into the side of the sump, leaving sharp bits of metal hanging off the hole. This is one of them. (Cleaned all this up when i reassembled.)

Went through and did cylinders 1(worn) and 6(Nasty), 3(Nasty) and 4(worn), 2(worn) and 5(nasty) as they came to BDC together... easy enough, checked the oil clearance with some flexi gauge which showed they were all between 0.054mm and 0.076mm. Good enough as i'm not going to be pulling the crank to have it machined and still below the limit of 0.100mm the manual specifies. The crank itself was in great condition, No scratches, grooves, nothing.

These are the bearings i pulled out. Top shells are on top and bottom on bottom.
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Close up of carnage on shell 3-Major pitting and evidence of where flaked off material has been hammered into the shell.
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Close up of Shell 5 - Major scoring around the centre line and well worn.
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Close up of Shell 6 - flaking and impressions where it has been hammered and ejected from the side, and what appears to be the beginnings of it flaking on the top shell.
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Put the sump back on, filled with Castrol J-maxx twice (forgot the sump plug the first time... :bang:). Disconnected the fuel cut off, Cranked it for a bit, let it cool, cranked it for a bit, let it cool, cranked it for a bit, let it cool, cranked it for a bit, Checked oil level (dropped from full mark to low mark and the sump plug was in so refilled), Cranked it for a bit, let it cool, cranked again, reconnected fuel cut off and fired it up.

Built oil pressure as it normally did from cold. Seemed to misfire/stutter twice. once almost enough to stall it but has been good ever since, Im thinking this was just a bit of air in the fuel system somewhere...somehow.

So thats part of my story. Also fixed an exhaust leak from the join on the 2 piece manifold, cleaned the turbo up, flushed coolant, replaced top radiator hose (bottom is not a stock one so need to find a suitable replacement, it has a longer radiator installed.)

I recommend anyone with a turbo 1hz, After 100000kms or so, Change the bottom end bearings, same as the 1hd-t owners do.

For anyone still reading, Now for question time.

1. Listening to the injectors with a stethoscope, 4 of them make a high pitched click sound, 3 and 5 make more of a resonating tong sound. I think this may have something to do with 3 and 5 having really bad bearings, doesnt explain bearing 6 though...Thoughts? (im getting recod injectors this weekend.) After a bit of a drive, when i pull up, there is a distinct deep knock sound, this was present before i changed the bearings and is still there. Could this be these odd sounding injectors?

2. This did get rid of what i believe to be the 1hz tick (Angry little man with a hammer at 1500rpm) for about a day then it came back. any thoughts?

3. Last compression test i did a few months ago showed 540, 570, 540, 520, 520, 510. This was with a $100 ebay gauge so am a little suspect of the results. 570 seems WAY too high (over factory spec). For the sake of conversation lets assume it is correct, what would this point to that would leave the bearings in reasonably good nick?

Thats all i can think of... for now..Cheers.
 
disagree,
you do have some delaminating on bottom of 3 and a start on 6
but
i have seen worse on the B series engines with the same mileage.

i would recommend checking the BEB on any engine if you are going to turbo it.
i would not waste my time doing the BEB on a PZ or HZ unless i had to pull the pan for another reason.

to me, that looks like extended oil change intervals more than bearing quality.
 
Fair enough, My reasons for changing the bearings seem to be flawed but after seeing what came out i am glad i did. On top of that, it was a bit of fun anyway.

I expect something to go south in the top end of this engine next. hopefully its a few hundred thousand ks away.

I dont know what the previous owner did in the way of oil changes but it got done as soon as i bought it and has been done every 5-6000kms since and seems happy.
 
5000km is the interval to change, especially with a turbo on it.

Some think 10k is ok, but it is not.

It's a good idea to check the bebs before adding a turbo.

You have to drop the pan to fit the oil return properly anyway. (not the dodgy drill and tap as seen here ;) )
 
If your going to turbo your 1hz your going to take your oil pan off for the return drain. Change your bearings and bolts while your there.

The 1hd-t had harmonic issues which resulted in oil cavitation at the 2000-2200rpm range if I remember correctly.

Change your engine oil every 5000km. In my eyes it's not worth pushing it for the little bit in oil savings.
 
5000km is the interval to change, especially with a turbo on it.

Some think 10k is ok, but it is not.

Why is that? Oil sampling picking up problems past 5,000km or just paranoia?

My diesels have factory 16,000 and 20,000km oil change intervals.
 

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