[davidpaul]

Does any one know where the oil cooler fit's into the oil system,  is it under pressure from the oil pump before it lubricates the engine, or is it before the pump ?

[NMKawierider]

Does any one know where the oil cooler fit's into the oil system,  is it under pressure from the oil pump before it lubricates the engine, or is it before the pump ?

Its after the pump and I think also after the filter. There is a flow chart I think in the manual.

[davidpaul]

Ok yes I've had a look at that but's it's not very clear, as my engine has been out for a few weeks I have noticed not a drop of oil has come out of the cooler pipes, and as mine seemed to take a bit longer than I would like to build oil pressure I wonder if the non return valve is faulty allowing the oil to drain back into the sump. Would this have lead to my big end failure ? if each time she was started it took a little longer to get good oil pressure.

[NMKawierider]

Ok yes I've had a look at that but's it's not very clear, as my engine has been out for a few weeks I have noticed not a drop of oil has come out of the cooler pipes, and as mine seemed to take a bit longer than I would like to build oil pressure I wonder if the non return valve is faulty allowing the oil to drain back into the sump. Would this have lead to my big end failure ? if each time she was started it took a little longer to get good oil pressure.

I didn't know they had an anti-drain back valve but..if the cooler was drained each time and it took more then a few seconds to fill and get pressure, I would say yes, it would have an effect on the big-end or rod bearings. But...if it did, then the oil pressure warning light would also stay on for that period too. Ever notice it on for more then 2 seconds after starting?  Heat has been the #1 killer on these. Poor quality lubrication #2.

[davidpaul]

There's a ball in the top banjo fitting, as it does not have a spring what would stop the oil draining in the direction of flow,  the draining oil could lift the ball off the seat so overnight all the oil could drain back to the sump.
Now I'm thinking is that why when she broke down and I checked the oil level and it was off the stick, I checked the oil the week before after she had been standing for a few days and it was fine, no oil in the air box or any sign of leaking and no smoke

[davidpaul]

Would anyone like to run their Z8 and check the oil level just after stopping the engine ??

[NMKawierider]

Would anyone like to run their Z8 and check the oil level just after stopping the engine ??

I will for you. Its been sitting several days so if the cooler does drain back it should have by now. Mine is a hair over filled though so I'll see if there is any difference.

[davidpaul]

Would anyone like to run their Z8 and check the oil level just after stopping the engine ??

I will for you. Its been sitting several days so if the cooler does drain back it should have by now. Mine is a hair over filled though so I'll see if there is any difference.

Thank you

[NMKawierider]

Ok, the difference was about 2mm. So I guess the cooler shouldn't...or doesn't normally drain back.

[davidpaul]

Ok thanks, does your oil light go off quickly when starting up ?

[NMKawierider]

Ok thanks, does your oil light go off quickly when starting up ?

Yeah about 1.5 seconds when cold...that is right now at about 85 degrees. Half that after warmed up. A little longer in the winter but I keep it in a warm shop.

[davidpaul]

I thought I may have been on to something there, I may do more tests when mines back together.

[bezerk1]

My light takes about 3 seconds to go off when cold.  I feel like it stays on a little longer than is should. Just long enough to catch your attention.

[davidpaul]

Mine was longer than I felt comfortable with, my one way valve doesn't seem to seal fully so I will be testing it when I've rebuilt my engine.

There was also something odd going on with the rear cylinder (other than the big end failing) the piston is scored and the cam chain guides on the rear cylinder have gone a deep brown colour as if they've been over heated so I will be checking the thermostats as well.

One quick update on the big end shells, my man at the engineering shop has matched the shells to a Toyota car, I will confirm which model when I know.