Replacing odd-ball sized bearings from 1989.
Replacing odd-ball sized bearings from 1989.
(OP)
Dear Gentlemen,
I've been rebuilding the supercharger from 1989 Toyota MR2. Here in the States, the car is officially an antique. The supercharger is an OEM factory (Toyota SC12), self contained unit which has a pair of flat roots-type paddles. I am having trouble finding replacements for the oddly dimensioned front bearings that measure 17mm bore, 45mm outer diameter and 14mm in depth. It's the 45mm outer that is absolutely impossible to find... off-the-shelf items tend to be 40mm or 47mm. If this were a money-no-object project, I could order custom bearings. Cheaper yet, I could bore the mounts to 47mm but I'm trying to avoid those expenses, if I can. I was wondering if the problem could be solved by pouring a hard setting compound around smaller 40mm bearings. Liquid Metal is advertised as being pretty tough. I was also considering the use of a high-temperature binary plastic called Novolac 555. Is it likely either of these compounds would adequately hold a 40mm bearing placed inside a 45mm mount? Does anyone know of a company that stocks odd-ball sized bearings?
Walter Carter, Palm Springs, CA
I've been rebuilding the supercharger from 1989 Toyota MR2. Here in the States, the car is officially an antique. The supercharger is an OEM factory (Toyota SC12), self contained unit which has a pair of flat roots-type paddles. I am having trouble finding replacements for the oddly dimensioned front bearings that measure 17mm bore, 45mm outer diameter and 14mm in depth. It's the 45mm outer that is absolutely impossible to find... off-the-shelf items tend to be 40mm or 47mm. If this were a money-no-object project, I could order custom bearings. Cheaper yet, I could bore the mounts to 47mm but I'm trying to avoid those expenses, if I can. I was wondering if the problem could be solved by pouring a hard setting compound around smaller 40mm bearings. Liquid Metal is advertised as being pretty tough. I was also considering the use of a high-temperature binary plastic called Novolac 555. Is it likely either of these compounds would adequately hold a 40mm bearing placed inside a 45mm mount? Does anyone know of a company that stocks odd-ball sized bearings?
Walter Carter, Palm Springs, CA





RE: Replacing odd-ball sized bearings from 1989.
Failing that, I presume that the shaft needs to be held accurately in alignment in order to maintain the proper clearances between the supercharger rotors and their housing. That ain't gonna happen if you have the shaft loosely in place and pour some sort of liquid crap around it. Plus, if you ever have to change the bearing again ... ! ! !
Choice 1, accurately (!) machine the housing to accept a 47mm OD bearing. Choice 2, machine a sleeve that fits around a 40mm OD bearing which in turn fits into the 45mm hole.
RE: Replacing odd-ball sized bearings from 1989.
http://www.trdusa.com/
Rod
RE: Replacing odd-ball sized bearings from 1989.
RE: Replacing odd-ball sized bearings from 1989.
If that seems like a major effort you really should stick to new cars still in warranty.
Regards
Pat
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RE: Replacing odd-ball sized bearings from 1989.
Either way getting the proper spare part is worth it whatever the cost, compared with machining.
The smaller bearing will only have 80% of the load capacity, given the original part has shagged out I am rather averse to replacing it with a weaker part. Might be worth thinking about a needle roller instead.
Cheers
Greg Locock
I rarely exceed 1.79 x 10^12 furlongs per fortnight
RE: Replacing odd-ball sized bearings from 1989.
RE: Replacing odd-ball sized bearings from 1989.
Regarding the shell idea to get a smaller bearing installed, I wouldn't know where to begin. I would guess one would want to start with 47mm O.D. aluminum stock or heavy tubing. For me, that would be like finding the hey stack needle. And as Mr. PontiacJack pointed out, the smaller bearing would be weaker. I plan on calling TRDUSA today. Maybe they have the OEM bearings.
RE: Replacing odd-ball sized bearings from 1989.
I'm about 98% sure it is their "TX12" model, though it may have been updated since 1986 when it was first sold on the MR2: http://w
Might be worth trying to contact the company for replacements. I haven't yet had an opportunity to dissect the blower on my supercharged MR2 so I'm sorry I can't be more help :)
RE: Replacing odd-ball sized bearings from 1989.
A sleeve, as a previous poster suggested, barring an original replacement, might be the best way to go. If you start boring out housings, you've got to watch for oil channels or other features, not to mention weakening it. A smaller bearing will have less load capacity, true, but may have a higher rpm rating which would equalize the difference.
My 2 cents. Good luck!
RE: Replacing odd-ball sized bearings from 1989.
Thought from the past---------
7mm OD X 40 mm ID X width
Heat shrink on available 40 mm X 17 mm bore
At 74th year working on IR-One2 - - UHK PhD - - -
RE: Replacing odd-ball sized bearings from 1989.
load bearing capacity, machine a sleeve to
to fit the housing. This would be much better
than machining the housing and losing rigidity.
Use Loctite on the sleeve depending on the
housing material.
The more you know, the more you
know you don't know....
RE: Replacing odd-ball sized bearings from 1989.
http://www.usatolerancerings.com/
Russell Giuliano