Gernby

I adjusted my clutch pedal the other night to remove some of the free play at the top of the pedal stroke. I took out just a little too much of the play, so when the fluid heated up, the fluid couldn't expand back into the reservoir. Pressure built up, the clutch pedal got really firm, and the clutch started to slip at full throttle.

I didn't have any tools with me, so I continued to drive it until I could readjust it at home. At the time, I just thought I was putting excess wear on the throwout bearing, but it didn't occur to me that I was also putting wear on the thrust bearing inside the engine. I don't really know how the thrust bearing gets its oil, so I'm hoping I didn't just wear the sucker out by oil starving it for 20 miles.

Any thoughts? Is there an easy way I can check the thrust bearing without pulling the oil pan?

marcucci

I would be more concerned about having roasted the clutch with slippage. The thrust bearings seem to handle a fair bit of abuse, not going out of spec until a good 70k to 100k of hard street/track/autox abuse. Much longer on a daily driver with only spirited driving. I think you will be fine there.

The release can't take a log of abuse, but if you are only talking about 20 miles then I think everything should be OK. You get the equivalent of 20 miles of clutch part wear in just months of city traffic driving, I would guess. I definitely wouldn't sweat the thrust bearing.

The clutch release bearing gets no oil. It's a sealed bearing.

You can't check the thrust bearing without pulling the pan and probably the girdle as well.

SpitfireS

The thrust washers are 2 half-moon rings so I doubt they create any kind of oil pressure by turning like crank journals.
I don't know if they get pressurized oil or "just" oil that splashes around and/or runs down from the head.
As long as the engine is running they DO get oil... somehow.
(if anyone has a picture of the crank or any other part that shows this.. please share )

Have someone press the clutch - engine running! - and look at the front pulley.
If it moves back any more than 0,45mm (and that's not much) when the clutch is pressed = bad news.
IOW you're looking for crank walk.

OEM pressure plate?

Gernby

I do have a stock clutch. The slippage was just for about 2 seconds, and the engine only rose probably 1K RPMs above the transmission. It didn't start slipping until I hit peak torque at 6500 RPMs. After adding some slack back into the pedal, the clutch is strong again. I didn't even smell anything from it.

I was just concerned that the thrust bearing relied on "slack" to get oil. I figured it would squeeze the oil out after a few seconds, then start burning up.

Robert O

The thrust washers are positioned around #2 main.It appears to me as if they get lubrication from the return off of #2 main bearing.

Gernby

Thanks for the input!

crank

i have some pretty nice pics up in a thread i made maybe it can help you out....

https://www.s2ki.com/forums/index.ph...pic=835518&hl=

engine had 112k miles and the thrust bearings were fine

Gernby

I couldn't find any pictures in that post that looked like a thrust bearing / washer...

SpitfireS

The top pic I found online, its not an F20 but (IIRC) a B-series.
The 2nd pic is a cut out of a picture from crank's post
Its about the principle.

In the first pic its kinda clear the thrust gets its oil from whatever runs out of the main crank bearing, on both sides, so it is pressurized oil to some extend.
(like Robert O mentioned)
The half moon thrusts are tapered at both ends and have 2 slots deviding the area in 3 parts, allowing oil to enter there between the crankshaft and the bearing, creating an oil film because the crank *rotates.
As far as I understand the oil enters at 3 spots, at a tapered end and through the 2 slots.
It is not fresh oil from an oil gallery but "used & hot" oil from #2 crank main.

I guess this is where the HTHS of an oil does the job.

* another reason not the start the enigne with the clutch in.
Especially not with aftermarket, stronger PP's.
The time it takes for the #2 main bearing to get pressurized oil and get enough to "leak" into the thrust, the thrust is running without oil.

In the 2nd pic I could not find any direct oil channel to the thrust so it "must" be like was mentioned above.



edit: typo's

Gernby

Great info! Thanks.

Any idea why they would not put the thrust washers at the rear of the engine, just on the otherside of the flywheel? Putting it at the front of the engine means that the clutch pedal is effectively trying to stretch the crank.