Dodgy oil? This could be expensive.....

[StarCruiser]

Good luck with it Rodge. It is, after all, your one chance to get it right.
I don't envy you the job mind.

 

[frank rabbets]

Plastiguage will tell you if you have the correct journal clearances with the new shells.

 

[clivehorridge]

Mains replacements will be the only way to sleep easy, but I'm still unsure how they were damaged so quickly in the first place.

OK some aerated oil got pumped through, but it never suffered from oil starvation.

Unless there were some contaminates in the oil...?

Those BEBs don't look bad, but they will look better with new shells

 

[Towpack]

On a plain bearing crank as in the 1H series (and most other) engines oil aeration is bad news. Yes, some oil gets through but not enough to maintain film strength and prevent metal on metal contact. Some engines, particularly high performance or race engines use roller or ball bearing bottom ends. The crank bearings on my dirt bike are roller not plain as a precaution against oil aeration which can happen under severe use. Roller bearings can survive on an oil 'mist', hence their use in 2 stroke engines, unlike plain bearings which require a constant pressure feed.
The cranks in the Kawasaki Z1 engines in the Z1/Z900/Z1000 bikes were all roller bearings. Massively over engineered for road use but gained a reputation for being unburstable no matter how much you tuned them. The down side is the extra weight of the crank/rod assembly.

 

[Roger]

Mains replacements will be the only way to sleep easy,

A mechanic friend giving me the same advice via a text message said:

".........Verses staring at the oil pressure gauge for eternity followed by a potentially ruined weekend and a 2k bill"

 

[clivehorridge]

On a plain bearing crank as in the 1H series (and most other) engines oil aeration is bad news. Yes, some oil gets through but not enough to maintain film strength and prevent metal on metal contact. Some engines, particularly high performance or race engines use roller or ball bearing bottom ends. The crank bearings on my dirt bike are roller not plain as a precaution against oil aeration which can happen under severe use. Roller bearings can survive on an oil 'mist', hence their use in 2 stroke engines, unlike plain bearings which require a constant pressure feed.
The cranks in the Kawasaki Z1 engines in the Z1/Z900/Z1000 bikes were all roller bearings. Massively over engineered for road use but gained a reputation for being unburstable no matter how much you tuned them. The down side is the extra weight of the crank/rod assembly.

I suppose it all depends on how hard the engine was revved/loaded at the time of aeration.

On idle I'd imagine very little problem, but if it was under full load and/or high revs, metal to metal would be very destructive.

 

[Dave2000]

Agree, location of seals being a very valid point - decision made, lump out

Way to go IMO

regards

Dave

 

[karl webster]

Jmo Roger.
Seen many engines with worse bearings and not had the mains changed. I had a rebuild on the first engine I had big end bearing issues with as it had taken the crank too far.

I still wouldn't change the mains personally if I changed the bebs.

If you would sleep easy knowing the mains were done though, then all good. Nice to be able to drive a motor and have the feeling that it won't let you down. It will always be in the back of your mind if that's how you feel.

 

[frank rabbets]

TP this happened to my 1933 International Norton in 1962. As you can see it is a roller big end bearing with aluminium cage which melted then stopped the rollers turning. The outer race turned in the con rod and the engine still ran but with clouds of smoke from the breather. I had run out of oil after riding it back to my house from Morton Valance aerodrome where I had getting it up to top speed. Just as in the photo. No number plates, insurance nor tax, loud exhaust etc etc. Straight through the middle of Gloucester.

Other MC engines I'd worked on had "crowded roller" big ends with no cage.

 

[clivehorridge]

As said, rollers are commonplace in 2-strokes as well. I bought a Suzuki twin 190cc 60hp outboard motor for my boat, it was totally stripped down and the bits were chucked into three cardboard boxes. The guy promised it was all there

It had been in his shed like that for goodness knows how long.

The bores had surface rust which I honed off, but I was very unsure of what to do with the big end rollers.

Clearly they were rusty, but I could turn them by hand - just. I cleaned them in paraffin, then oiled them. They felt a bit crusty, but as far as I could tell, the rollers didn't look pitted. Put it all together and it ran as sweet as a nut for 5 or 6 years before it was sold on.

Very forgiving those rollers, if they keep rolling.

 

[Dave2000]

The research Ive done seems to point at its much easier to do the mains when the lump is out but according to the Max Ellery manual it can be done in situ - works been manic busy this week, hoping to get cracked on during boxing day! Will report back.

Max Ellery also states front wheel bearings should be torqued to some ridiculous figure, and called done, which is obviously wrong, so check the figures with the FWM.

regards

Dave

 

[Grimbo]

Looking at your pics then yes do the mains , I don't think your oil was aerated ....I think it was contaminated by water , in the pic of your crank and block I can still see what looks like milky white oil , this would definitely cause the damage you see to the bearings as the film strength would have been very weak.
If it was me I would strip the whole engine and for the few extra quid do the rings and check the valve seats and small ends , also if that has happened to the BEBs then the Turbo has been fed with the same oil .

 

[Dave2000]

Unless the dipstick was out of it's hole or the oil filler cap was off, then the engine should run ok under water, snorkel assumed to be fitted.

If water had been ingested then I would have expected a hydro locked cylinder?

regards

Dave

 

[Grimbo]

I tend to agree Dave but the crank going round won't aerate the oil to the degree described , the only other way this can happen is if the oil pump pickup was sucking air ...... we see this on Hydraulic systems when the oil is low or when say tipping a trailer with big multi stage rams....this will produce the described frothy oil very quickly but we are talking of pumps at 160 litres a min .... if the water entered via the crankcase breather then the engine wouldn't hydraulic......personally I'm going with aeration via the pump pickup being starved of oil

 

[Dave2000]

The crankcase breather is via the rocker direct to the air intake to the turbo IIRC? This is why I thought no water into the crankcase. Going back to the post I made earlier, I think the engine oil became overheated, started to froth and allowed air into pickup, or there may have been surge issues, and there would be no indication on the dashboard.

regards

Dave

 

[frank rabbets]

It's impossible to check the main bearing clearances on any engine with the block in the vehicle. It needs to be up side down, the crank placed in, then the plastiguage then the main bearings and caps bolted down. Then dis assembled and checked. If the clearance is not there the engine may not turn over but if it does it may melt the bearing. If the clearance is too big the oil pressure may be compromised. Even with a brand new block, shells and crank the clearance must be checked. Otherwise it's just an assumption it's ok.

It's several days work even not taking the head off. In comparison a Rover V8 can be done completely in couple of days.

 

[nathanrobo]

Agree, location of seals being a very valid point - decision made, lump out

I'd agree with doing the mains... good news (so far) is that you'll get away with a polish on crank.

 

[Roger]

And back in the game - I needed to park the thing up and let it fester for a couple of months to wait for the enthusiasm to come back....... it finally has!

This weekend saw the lump coming out and a full strip down ready for a rebuild. Some interesting findings, namely that other than the Big End Shells being ruined, their is no other damage, 200k miles and it looks like new inside!

This is a double edged sword, I've done a lot of work just to find that the only thing that needed replacing was the BEB's - there were two people who knew and advised this; Karl Webster and Julian Voelcker, they both said just change the mains, the rest will be fine. They were right, everything seems to be well in spec from the crank to the oil pump.

That said, I have peace of mind and I am fitting an uprated clutch and turbo whilst sending the injection pump off for a birthday along with the re-assurance of all new gaskets and seals - should be good for a few more 100K miles. Head and valves getting a tweak as well.

Having only worked on LandRover engines in the past, all I can say is working on this Toyota lump has been bliss, bolts just undo and dont snap!

Anyway, a few pictures to back up the words.

 

[clivehorridge]

It's hard to press 'like' with pics of shagged BEBs, but it's good to see the job is worthwhile.

I changed my BEBs at 230k km and the old ones would have been good for another 230k km, I'm sure. Still, it's good insurance against a disaster...

 

[Towpack]

I changed my BEBs at 230k km and the old ones would have been good for another 230k km, I'm sure. Still, it's good insurance against a disaster...

Not an issue you need to worry about on the 1HZ Clive. Maybe not the most powerful variant of the 1H series but probably the most reliable. Can't recall reading about any serious issues with a standard 1HZ motor anywhere. All the 1HZ needs is a 7 figure odometer.