E: Engine Main bearings

Bill Thomas

Well Known and Active Forum User
VOC Member
Does Martyn tell you to grind the centre out of the old bearing a nats, So it will slide on and off easy.
Good Luck. Bill.
When you get your new puller, Try and grind the middle edge of the tool to as thin as you can,
To get behind the bearing.
 

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
Bill,

here is just part of the article I wrote in OVR #18
"
Using whatever means at your disposal, dismantle the old bearings then open up the internal diameter of the inner race so that they are an easy slide fit on the main shafts and Vola! You have a set of spacers. You may need some professional assistance to open up the ID but once you have done so – you have a spacer set for life.
"

Martyn
 

davidd

Well Known and Active Forum User
VOC Member
The Comet flywheels are easy to fit, but with the twins I have seen the pins and the nuts are all too wide to fit in a Vincent. I believe that is what Steveo is worrying about in the near future. What do the twin builders do when the big end pin hits the bearing race?
Vin_crank_bearing_installation_006.jpg

This is a Maughan flywheel a friend received. All the Comets are close to flush and the Comet and twin flywheels Terry builds are near flush as they have no nut.

David
 

greg brillus

Well Known and Active Forum User
VOC Member
Bearings are dead easy to remove if you use a heat gun like I suggested earlier in this post..........Just heat the bearing up some and it will slide off with a pair of screw driver blades diagonally behind. The end of the pin sticking out from the nuts, just grind it away, sometimes even need to grind some of the nut as well, you only need a small gap to clear everything. Sometimes the ET 77 spacer can be different widths, so this does not help at times........Unfortunately when cases have been reclaimed in some area's there is little room for everything.
 

stu spalding

Well Known and Active Forum User
VOC Member
As regards removal of bearings from shafts, with a pressed steel cage it is possible to get a small screwdriver behind the rollers and pop them out of the cage. It is then relatively easy to get a puller on the inner track. Afterwards the rollers are replaced and the cage dressed back to its original shape. Tony Maughan taught me this one so it must be OK. Cheers, Stu.
 

Chris Launders

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VOC Member
I don't know if this would apply but when building my JAP engine on which I had machined the casings myself from castings I made some accurate replica bearings from engineering plastic with fractionally more inner and outer clearances so they were a light push on the shafts and in the housings so the crank could be fitted and clearances measured and adjusted without any force or doing damage to anything.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
As Greg says, after all these years anything could have been done,
There was a bit some years ago, Where the Crankcase faces were ground/reclaimed, And nothing fitted because the Cases were now too narrow.
I had a problem with my L/ning, After the gearbox was welded at the top, The top face was all over the place,
But I just use silicone, Which won't do any harm, It's only the gearbox.
They were scrap from Africa, So I had nothing to lose.
 

SteveO

Well Known and Active Forum User
VOC Member
Bill, does the bearing have to go on a certain way round then? There is a thin side and a wider side? I hadn't noticed this, I put them on with the engraving facing out, is this wrong?
 
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