chris_barry

Bearing failure is most likely started by oil surge. You may find that the G forces you were hitting on slicks was enough to push the oil away from the oil pickup. The problem is not the lack of oil, more the rush of air the pump sucks blowing the bearings free of oil.

There is a device nicknamed the Apollo tank that the Caterhams use in England. Its an oil/air separator that runs at full engine pressure. It separates any air the pickup sucks from the oil so there is less chance of blowing the bearings dry.

You may want to look at baffling the sump and running it a little over full.

The best setup is a dry sump. I'm in the middle of a dry sump conversion at the moment and mounting the pump was a real pain. Honda didnt leave any spare bolt holes on the block.

Bearing wise, I'm not sure of the F20C, but most Jap engines main bearings have one bearing shell with a groove, and the other flat. Running two grooved shells helps oil flow to the rod bearings.

Depending on the damage you may be able to linebore the main journals. This will move the crank slighly closer to the head. The crank girdle has steel inserts which should be robust. Not sure of the block side of the journals.

Best of luck with the rebuild.


Speedracer.

honda9krpm

thanks chris
I was hoping that you found this thread.

I have not open the engine yet so I still don't know how extensive the damage is
Teh F20C cylinder is elliptical. Do you know of anyone in Australia that can sleeve them? Expensive?

Do you know if the f22c crankshaft and rods fit the f20c engines? Someone said that Honda made them similar to the toda 2.2 stroker kit.

Jason00S2000

Spun the crank bearing??


Ok, like the other guy above me, isn't that an oil issue?


Has anyone else heard about a bearing failure like this? With or without a supercharger? I can't say for sure, but do you think that it would've happened without the Vortech?

beroznikmal

I think Wicky had his bearings spun....

Mee

well. u spun the conecting rod bearings, crank shaf bearing are usually called mains. when a bearing is spun the engine usually seizes, or in most cases i shouls say, and damage to the crank is done. make sure that the cylinder walls are not scored towards the bottom of the motor. sometimes the conecting rod tends to hit the side of the block. all will be reavealed when the motor is apart. spun bearings are rarely caused by oil issues, due to the fact that the bearings are oiled conestantly when the crank hits the oil in the pan. if ur paranoin baffles can be added to keep the oil level constans

chris_barry

Mee,

Not sure how much engine work you really do, but the splash oil is not enough to lubricate the rod bearings. Oil pressure is required so there is cool film of oil flowing through the bearings. The film of oil is what stops metal to metal contact.

In the case of oil surge, the oil pump sends pressurised air through the oil system and blows the bearings clean. They then run mostly dry till they overheat and spin.

In my experience in the majority of cases spun bearings are caused by oil problems.

Speedracer.

Windscreen

Grooved lower bearing shells have DRAMATICALLY reduced load carrying capability. You do not want to reduce the load capacity of the bearings in this engine, as the inertial loads at 9,000 rpm are huge. Also, a grooved lower shell only helps oil flow to the rod bearings (crank pins) if the crankshaft is not cross drilled. I'm quite sure the F20c has a fully cross drilled crank.

[QUOTE]Originally posted by Mee
spun bearings are rarely caused by oil issues, due to the fact that the bearings are oiled conestantly when the crank hits the oil in the pan.

Windscreen

[QUOTE]Originally posted by honda9krpm
Teh F20C cylinder is elliptical.

Mee

[QUOTE]Originally posted by Windscreen

honda9krpm

[QUOTE]Originally posted by Windscreen