Spigot Bush or Spigot Bearing

WKB · #1 (**permalink**) 08-25-2009, 05:09 AM

I am about to remove the gearbox to replace the throwout bearing. While everthing is out I am going to replace the spigot bush.
The question is do I replace it with another bush or use a bearing?

Warren

stephen low · #2 (**permalink**) 08-25-2009, 08:40 AM

In my day.......they were all bushes! Literally

But wouldn't it depend on your motor's specs?

I'd assume a precision bearing will always be better than a bush but it's whether one can be fitted.

Good luck!

Merv and Sharon · #3 (**permalink**) 08-25-2009, 03:10 PM

What motor Warren? I have the spigot bearing number if you need that.

Merv

WKB · #4 (**permalink**) 08-25-2009, 08:32 PM

The motor is a 1UZ Toyota V8.
As this motor came out of cars only fitted with autos there was no spigot bush or bearing. Both the bearing and bush are available to be used when a manual conversion is carried out.
The bearing that is used is a 6201.

Warren

Merv and Sharon · #5 (**permalink**) 08-26-2009, 02:05 AM

OK! Then I certainly can't help!

Cheers,

Merv

CHANMADD · #6 (**permalink**) 08-26-2009, 02:49 AM

There's no choice!.......... The bearing is the way to go!

Krait · #7 (**permalink**) 08-26-2009, 03:22 AM

Warren,

Bearings can get noisy real fast if conditions aren't right. We always used high quality bushes in rally cars. Maybe Scotty can advise.

BTW was it you talking to Roger Errington the other day?

Cheers

AC-460 · #8 (**permalink**) 08-26-2009, 03:54 AM

The biggest problem with a bearing is you cannot lock the centre of the bearing to the gearbox shaft. This can result in the shaft turning on the inside of the bearing and as the bearing is made of high carbon steel and the shaft of alot softer material you will wear the shaft on the nose. Stick with a Brass spigot it will cause you less problems

WKB · #9 (**permalink**) 08-26-2009, 06:23 AM

I have had a noise when the clutch pedal is pushed in. It sounds like a throwout bearing(the noise has been there pretty well from when the car was registered). The noise comes and goes, can be just audible to a horrible noise which sends a vibration through the gearbox, and goes away when in neutral and the clutch pedal is out. I am now thinking it could the spigot bush. But regardless what it is the gearbox needs to come out. To remove the gearbox the motor needs to removed from the car, so when it goes back in I want to 100% sure that the problem will not re-occur.
There is only one place I can get the spigot bush and I have one of these installed already.

That is my dilema, do I replace it with the same bush, or put a bearing in its place.

Quote:

Originally Posted by Krait

Warren,

BTW was it you talking to Roger Errington the other day?

Cheers

Geoff,
If Roger is an electrical engineer who has worked with you before, that was me.

Warren

Krait · #10 (**permalink**) 08-27-2009, 02:19 AM

Warren,

Sound like the throwout bearing is shot. If you have the gearbox out change them both. Bushes don't usually make a noise but if they're worn they allow the gearbox input shaft to flog about. My money would be on installing a new bush for all the reasons above.

Roger would have been masquerading as an insurance assessor. Big Holden fan.

Cheers

WKB · #11 (**permalink**) 08-27-2009, 03:03 AM

Quote:

Originally Posted by Krait

Warren,

Roger would have been masquerading as an insurance assessor. Big Holden fan.

Cheers

Geoff,
I was showing him the electrical areas of the power stations. As the assessor he was their electrical specialist. Didn't mention his Holden preferences.

I was going to change both when the gearbox was out. The part that annoys me the most is that the throwout bearing I bought was the "best quaility one available"(words from the bearing supplier). The one that came with the bellhousing etc had been in my cupboard for 6mths and I thought a new one was a good idea.

Warren

Krait · #12 (**permalink**) 08-27-2009, 03:26 AM

Warren,

If he knew me must be the same guy.

Yep, cars are fun aren't they

Cheers

speed220mph · #13 (**permalink**) 08-27-2009, 07:55 AM

Quote:

Originally Posted by AC-460

The biggest problem with a bearing is you cannot lock the centre of the bearing to the gearbox shaft. This can result in the shaft turning on the inside of the bearing and as the bearing is made of high carbon steel and the shaft of alot softer material you will wear the shaft on the nose. Stick with a Brass spigot it will cause you less problems

Rather than covering up the problem with the bellhousing not being centered to the crankshaft, dial indicate the bellhousing. If should be whether you use a bushing or bearing . . . I recommend the bearing, but either will work fine. If the bellhousing is off center, use off-centered dowels to center the bellhousing. They can be rotated to shift the bellhousing in the direction needed. If the bellhousing is not too far off, say 0.010 inch, retain the bellhousing with two bolt snugly tightened, then whack with a dead-blow hammer in the direction needed and repeat the dial-indicating process.

Keep in mind that an offcentered trans-to-engine will "wrench" on the transmission input shaft and bearing, causing the shaft to wobble. A worst-case scenario would be a transmission that jumps out of 4th gear.

RodgerH · #14 (**permalink**) 08-27-2009, 08:47 AM

Tom-

Maybe I'm wrong, but I read AC-460's statement to mean the transmission shaft is a slip fit into the pilot bearing with no way to lock the shaft to the bearing inner race. If the bearing starts to develop resistance, the shaft will start to spin in the inner race and it will either make a mess of the shaft tip, or worse case...."spin weld" the shaft to the inner race. You then end up prying the transmission from the bellhousing while trying to pull the pilot bearing out of the crankshaft. It's not too hard....the bearing is junk at this point and will pull apart...leaving the outer race still in the crankshaft. (Ask me how I know...but fortunately not on the Cobra!)

Although I'm using a pilot bearing with my TKO-600, I wonder if a bushing (like we used to run "back in the day") might be better?

BTW, your direction to dial-in the bellhousing is excellent advice. I preach the same sermon.

Rodger

Chaplain · #15 (**permalink**) 08-27-2009, 11:12 AM

I encountered this same question while replacing my clutch recently. I was advised that unless you have dead nuts concentricity go with a bushing because if there is any eccentricity the result will be poor shift quality. I went with a bushing. Car shifts smoothly now. Having both a bearing and a bushing prior to the install, I wondered the same thing previously mentioned. That is the hardness of the bearing versus the pilot shaft, and the fact that there was clearance between the two and any slippage that might occurr what would be the resultant effect. My advice.....go with a bushing.