Author Topic: Born again timing bushes  (Read 1556 times)

Online orabanda

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Born again timing bushes
« on: 09.09. 2009 16:50 »
I have "recovered" some old timing bushes, by removing the worn inner sleeve, and replacing with white metal. They are all a couple of millimeters undersize, so plenty of "meat" to suit a crank which has been re-ground more than once.
http://i302.photobucket.com/albums/nn82/orabanda/P1010137_resize.jpg

http://i302.photobucket.com/albums/nn82/orabanda/P1010138_resize.jpg

http://i302.photobucket.com/albums/nn82/orabanda/P1010139_resize.jpg

Richard

Offline MikeN

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Re: Born again timing bushes
« Reply #1 on: 09.09. 2009 17:02 »
Thats interesting,Can you describe how you do it please? How do you tin the outer part so the white metal "sticks" ?
Mike

Offline trevinoz

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Re: Born again timing bushes
« Reply #2 on: 10.09. 2009 03:37 »
Richard,
               I am curious as to whether white metal is up to the job. I know the early engines used it but at some time lead bronze was substituted.
Could the change be due to cost or is bronze a superior option?
 Trev.

Online muskrat

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Re: Born again timing bushes
« Reply #3 on: 10.09. 2009 08:44 »
NICE job Richard, I had one done years ago by a OLD engine man. It outlasted two bores and big ends. As long as you keep the oil clean or replace every couple of thousand, no worries. How much would secure me one ?
Cheers.
PS spoke to Josh last night, he speaks very highly of you and your abilities.
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online orabanda

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Re: Born again timing bushes
« Reply #4 on: 10.09. 2009 09:55 »
Muskrat,
$70 Aus.
I require your old bearing in exchange. the ID will be whatever you require.
Regards,
Richard

Online orabanda

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Re: Born again timing bushes
« Reply #5 on: 10.09. 2009 09:56 »
Muskrat,
Don't forget, Josh is a pilot!!
Richard

Online muskrat

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Re: Born again timing bushes
« Reply #6 on: 10.09. 2009 10:31 »
I think he must have vertigo. I will hunt around for an old one to send over.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline coater87

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Re: Born again timing bushes
« Reply #7 on: 10.09. 2009 16:08 »
 Nice job Richard!

 I managed to do my own with some 660 bronze, and I think they will be OK. What exactly is this "white metal"?

 I sure wish there was a way to have two identical bikes, each running one of each. Then with good oil change and care, we could compare the two bushings in about 30,000 miles. One of the main reasons I went the route I did was because all that was available was phosphor bronze. Now with you making that good looking bushing, there is once again a proper choice!

 Lee
Central Wisconsin in the U.S.

Online orabanda

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Re: Born again timing bushes
« Reply #8 on: 10.09. 2009 17:12 »
Mike,
The process I follow is to press out the original inner bearing material, thoroughly clean the steel shell, polish the inside, then de-oil with a prep solution.
I then tin the shell with a solder prep solution, then also apply a CIG tinning flux.

I have formed a mold which the shell is set to.

The melting point of the metal is 420 degrees C.

After pouring, it is allowed to cool which takes around 20 minutes.

The machinability of the material is excellent.

I use a tin based alloy which conforms to British Spec DTD214. The maker claims that it is the highest grade standard Tin Base Alloy manufactured anywhere.

It has been designed for fatigue resistance and is particularly suited for diesel engines, and all other types of internal combustion engines.

They list the applications as:

Diesel, Aero, Marine, Oil Steamship,, Gas Engines, Automotive bearings and air compressors.

The material is 'OTL' C.I.E

"A tin Base Alloy containing Cadmium, and harder than other alloys which conform to Spec DTD214. Specially designed for users preferring an alloy containing Cadmium.

Application: Compression Ignition Engines (Diesel). Alternative to 'OTL' AERO A where white metal bearings are specified"


I noticed that one of my old bearings already used white metal, whereas another three used the bronze - lead - whatever else insert. I don't know why they went for the bronze based bearing; was it cost?

Thirty years ago I used to pour and machine large (12" bore" split bearings for crushers), and thought why not do it on a mini scale for the BSA bearings?

Previously to this, I have been machining my own one-piece bearings out of phosphor bronze.

Offline BSA_54A10

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Re: Born again timing bushes
« Reply #9 on: 11.09. 2009 10:54 »
Funny you should say that .
The original A7 motor had a solid con rod with a cast in situ white metal bush.
The big problem with cast in bushes is a nasty reaction which can generate stibene gas which is extreamly toxic.

For those who find the term "White Metal" confusing we are talking about a "Babbit" type bearing and if you Google the word Babbit you will find out more than you ever could want to know.

I do worry about using babbits in old bikes that do not get used very much as there is always the worry of the bearing running dry and for this reason I principally recommend 85:5:5:5 leadded gunmetal ( oft called 3 5's) for the wear side of the bush
Bike Beesa
Trevor

Offline fido

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Re: Born again timing bushes
« Reply #10 on: 11.09. 2009 12:48 »
I had heard that the early engines had a white metal timing side bush but don't know when they changed to bronze.

Offline Josh Cox

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Black 1953 Golden Flash Plunger