why do people recommend pilot bushing vs. pilot bearing?
#1
Race Director
Thread Starter
why do people recommend pilot bushing vs. pilot bearing?
I was surprised to see everyone recommend I use a bronze, fluted pilot bushing vs. a pilot bearing.
Pilot bearing typically used on heavy duty applications.
Anyone know why pilot bushing everyone here recommends the pilot bushing (vs. pilot bearing?)
Pilot bearing typically used on heavy duty applications.
Anyone know why pilot bushing everyone here recommends the pilot bushing (vs. pilot bearing?)
#2
I'm just guessing but I think the size of the input shaft would make a difference. The smaller the shaft you would need to go with bronze or brass. Very small needle bearings IMHO would not hold up very well. Anyone?
#3
Safety Car
I have had 3 pilot bearing failures, I have gone back to pilot bushings.
#4
Race Director
Pilot bearings hold up well if the input shaft is perfectly aligned with the crankshaft and will provide less friction between the input shaft and the crankshaft resulting in a cleaner, quicker clutch release. Unfortunately, not all bellhousings are perfect and a slight runout or misalignment between the tranny and motor can toast a bearing. The bushing is more forgiving in this regard.
#6
Race Director
Thread Starter
Pilot bearings hold up well if the input shaft is perfectly aligned with the crankshaft and will provide less friction between the input shaft and the crankshaft resulting in a cleaner, quicker clutch release. Unfortunately, not all bellhousings are perfect and a slight runout or misalignment between the tranny and motor can toast a bearing. The bushing is more forgiving in this regard.
Knowing that I havent had issues with pilot bearings, Im tempted to again use a pilot bearing.
#7
Safety Car
Clutch chatter. Upon inspection all the needles are missing. I beat (6000 RPM drag stip launches with a lightweight flywheel) my clutch hard and it appears to me that the pilot bearings cannot take the abuse.
#8
Melting Slicks
I've used pilot bearings without any issues...and yes it would seem to me that a bearing is more technically advanced than a bushing...but what I have read about is not the $20 bearing failure per se, but when the bearing fails, it can tear up your transmission input shaft which could be a much bigger problem.
#9
Race Director
Thread Starter
I drive my car hard too (though no 6000 rpm drop-clutch launches).
Im trying to figure out why your/my experience is different.
#10
You can hold & fit a pilot "bushing" in your hand and pretty much visibly determine it's quality. You don't want anything that's iron sintered just impregnated bronze. Fluted or not it would I believe be the preferred!
In this "pilot bearing" you've got the needles, the seal and the cage that holds the needles that can fail and lubrication is what's there. When any of these fail it takes out the other and without doubt will generally ruin an input shaft. Now you need to take into consideration who assembled your torrington pilot bearing - is it yet another Chinese sourced product?
A ball/roller bearing that's used for Pontiac, Buick, Olds and others including the larger diameters that are flywheel inserts vs crankshaft inserts are a different conversation entirely.
In this "pilot bearing" you've got the needles, the seal and the cage that holds the needles that can fail and lubrication is what's there. When any of these fail it takes out the other and without doubt will generally ruin an input shaft. Now you need to take into consideration who assembled your torrington pilot bearing - is it yet another Chinese sourced product?
A ball/roller bearing that's used for Pontiac, Buick, Olds and others including the larger diameters that are flywheel inserts vs crankshaft inserts are a different conversation entirely.
Last edited by WVZR-1; 03-18-2013 at 04:40 PM.
#11
Le Mans Master
Pilot bearings hold up well if the input shaft is perfectly aligned with the crankshaft and will provide less friction between the input shaft and the crankshaft resulting in a cleaner, quicker clutch release. Unfortunately, not all bellhousings are perfect and a slight runout or misalignment between the tranny and motor can toast a bearing. The bushing is more forgiving in this regard.
#12
Race Director
I've used bearings in the past with no problem, but I used a dial indicator to index the bellhousing and offset bellhousing pegs to make sure I had zero runout. If tolerances are within specs, a bearing will have less drag on the input shaft and shifting will be easier and quicker. The synchros won't have to work as hard.
#13
I've used bearings in the past with no problem, but I used a dial indicator to index the bellhousing and offset bellhousing pegs to make sure I had zero runout. If tolerances are within specs, a bearing will have less drag on the input shaft and shifting will be easier and quicker. The synchros won't have to work as hard.
Offset dowels don't catch much discussion these days. It's been quite sometime since I've heard them mentioned. They would be "new territory" for many here. It was very common to use these for nearly every MT bellhousing/shield install. Some are quite expensive!
We had the dowels available but there weren't bearings for the SBC "THEN" only for the Buick, Olds & Pontiac. A couple Pontiac/Olds guys actually used a pilot bearing that required the bore in the crankshaft be extended a little deeper and it allowed full support for the machined nose of the input shaft.
Last edited by WVZR-1; 03-19-2013 at 12:08 AM.
#14
Safety Car
I know (from reading your posts) that you are a very techincally savvy person, but could there be 'chance' that your transmission / bellhousing are not aligned perfectly - or that the pilot bearing went in slightly off-axis?
I drive my car hard too (though no 6000 rpm drop-clutch launches).
Im trying to figure out why your/my experience is different.
I drive my car hard too (though no 6000 rpm drop-clutch launches).
Im trying to figure out why your/my experience is different.
I have had good luck with the bushing and I guess I am not to interested in trying a bearing again.