[DeTomaso] Oilite Bronze Bushings - Marlin Jack?

[coffield at mchsi.com]

Whether its Oilite bronze, caged roller, or sealed ball bearing, it seems few people check the bell housing run out before installation. I’d contend the most important thing that can be done to assure proper pilot bearing operation and long life is to dial in the bell housing. I recently switched transaxles and the new ZF bell had .014” run out so I bought a couple offset dowel pins, mounted a dial on the crank, fiddled with it for a while, and was able to get it to the point where it indicated no worse than .003”TRO. Some manufactures say <.005” others <.010”. 

If you think about it, given their physical size and how many parts are interfacing, getting the bell and ZF input shaft centered compared to the clearance you would expect/desire between the journal and bearing of this size is really not that trivial. .005” per side is a lot of clearance for a bearing this size and chances are pretty good most bells that aren’t dialed are probably loading the input shaft/bearing on one side and leaving it unsupported without larger deflections on the other side….how much input shaft deflection is acceptable? .010-015” deflection isn’t a very comfortable thought to me.

All the needle bearings pilots I’ve ever seen are caged. I think a sealed ball bearing is fine but you still have to have clearance between the input shaft and the inner race because you can’t have a win fit and be perfectly concentric. If you don’t, you’re loading the bearing at install and that can cause premature failure and or cook the grease out. Also, not all sealed ball bearings are created equal. Many ball bearings are just shielded not sealed and even so, even excursions to 6k-7krpm can be a lot for many sealed ball bearings packed with grease to handle.
 
I had a caged roller in my car for the last 10 years and the ZF input shaft looked great. Big wheels, wide tires, hard launches. -I replaced it with the same. 

Best,
Kelly

----- Original Message -----
From: Mike Thomas <mbefthomas at comcast.net>
To: 'Julian Kift' <julian_kift at hotmail.com>, 'De Tomaso List' <detomaso at poca.com>
Sent: Sun, 29 Mar 2015 12:55:16 -0400 (EDT)
Subject: Re: [DeTomaso] Oilite Bronze Bushings - Marlin Jack?

I've got a needle bearing in right now, but will be pulling the ZF next
winter if the clutch chatter doesn't settle down.  Last poll had more
leaning to the Oilite, so I thought I'd stir the waters once again.

 

Mike Thomas

Pres., Panteras Northwest

Yellow '74 #6328

 

 

 

From: Julian Kift [mailto:julian_kift at hotmail.com] 
Sent: Saturday, March 28, 2015 8:56 AM
To: Mike Thomas; De Tomaso List
Subject: RE: [DeTomaso] Oilite Bronze Bushings - Marlin Jack?

 

I believe Marlin and some of the vendors sell them.
 
I was always an advocate of the oilite until I got my GT5; Coz had the ZF
rebuilt and it was fresh back from Dennis Quella, in fact Coz and I
installed it when I picked up the car from him and I then proceeded to drive
from Phoenix to Reno non stop (other than gas). The car wasn't shifting
quite correctly and we got Dennis to drive the car at the Pahrump track
during the Fun Rally, he agreed it was still not shifting correctly. I then
pulled the ZF and sent it back, Dennis went back though it and could find
nothing wrong, however he sent it back with a needle bearing and said try
that for the pilot. Low and behold that fixed all my problems, so now I'm a
convert to the needle bearing and never had an issue since.
 
It would be interesting to see if Lloyd Butfoy's opinion aligns with Dennis
on the needle bearing vs. oilite
 
Julian
YMMV
 

> From: mbefthomas at comcast.net <mailto:mbefthomas at comcast.net> 
> To: detomaso at poca.com <mailto:detomaso at poca.com> 
> Date: Sat, 28 Mar 2015 08:19:31 -0700
> Subject: [DeTomaso] Oilite Bronze Bushings - Marlin Jack?
> 
> Is it Marlin Jack that sells the Oilite bronze idler bushings?
> 
> Mike Thomas
> Pres., Panteras Northwest
> Yellow '74 #6328
> 
> 
> 
> 
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