Crankshaft timing pinion - will it or won't it?

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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Crankshaft timing pinion - will it or won't it?

Postby Greybeard » Mon Nov 30, 2020 2:57 pm

Hello, folks.
I'm in the process of rebuilding a 1955 16MS that has been 'converted' to trials trim. I bought it simply to use for the odd green-lane jaunt rather than anything serious. It was bought as a non-runner though has obviously had some brass chucked at it - brand new monobloc carb, a rather nice stainless exhaust, new chain etc etc, but I dont think it has been run since much of that was spent. Whilst coming across quite a few jobs that need doing to get it as I want it I am completely stripping the engine (as well as everything else in due course).
One task needing attention is to repair a crack around the oil outlet pipe - due to the usual overtightening by some cack-handed gorilla - I am at the point where I'm separating the crankcases and a possible stumbling block is whether the timing pinion (017195) will actually pass through the timing side bush. I'm pretty sure that on my 61 G80 it did, but that was 25+ plus years ago when I did that engine!
With this one, whilst it looks as though it should and the cases come apart so far - allowing the pinion to go about 1/8th inch through the bush - everything then goes solid and I don't want to force it naturally. If the pinion does have to come off it would mean buying a 50 quid puller as the only puller I have won't give it enough beans to pop the taper, or I run a Dremel disc down it and split it off. As this is likely to be the last AMC engine I work on (I have two other 500 singles and two twins) it seems that 25-30 quid on a new pinion is financially more tempting than a puller ;)
Any other suggestions would be appreciated - the oil pump plunger is already out of the engine.

Steve

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Re: Crankshaft timing pinion - will it or won't it?

Postby 56G80S » Mon Nov 30, 2020 7:21 pm

On my 1956 G80S the pinion goes through the bush.

But it was an interim year and I reckon that measuring the size of the bush will tell you. I don't know the dates but there was a change to the size of bush and axle and the earlier arrangement didn't allow the pinion to go through the bush.

Someone will come along with better info.

Johnny B

PS Spriddler posted about this recently:
"There's a ref to the larger axle dias. here: http://www.jampot.com/article_read.asp?id=159

There is some narrative ref. the changes to c/cases and timing side axles and bushes if you scroll to 'History and changes' in the 'Tech. Articles' which may help to clarify:

http://www.jampot.com/article_showall.a ... me=Engines

and more about changes here:

http://www.jampot.com/article_read.asp?id=28
I poke badgers with spoons.....from 2 metres."

The middle (and I think damaged) link sets out the the larger axle and bush was used from 1954 but always wary of this as PO may have changed things.

Johnny B

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Re: Crankshaft timing pinion - will it or won't it?

Postby Greybeard » Mon Nov 30, 2020 7:51 pm

Thanks for that, JB. A bit of reading to do :)

Steve

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Re: Crankshaft timing pinion - will it or won't it?

Postby clive » Mon Nov 30, 2020 11:04 pm

Steve PM sent
clive
if it ain't broke don't fix

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Re: Crankshaft timing pinion - will it or won't it?

Postby Greybeard » Thu Dec 03, 2020 7:07 pm

A bit of an update - Yes, it will. Or rather yes it would have done :headbang:
I was sent a dimensioned drawing of the puller and set to making one yesterday. It helped me pass nearly 4 hours anyway. It took a fair amount of effort to get the pinion off and I'm rather pleased that my welding held.
It didn't help with parting the cases though - I found that a burr on one edge of the bush was holding the crank and I had to resort to a bit more pressure to get them apart. At least there appears to be no damage to the bush surface. To add insult to injury I also found that the pinion would have passed through the bush easily. I'll know for next time :roll:

Steve

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Re: Crankshaft timing pinion - will it or won't it?

Postby dave16mct » Thu Dec 03, 2020 7:22 pm

That's a very nicely shaped exhaust pipe on your bike. By the way how about putting that drawing in the Tech Articles for us. Sounds like a useful thing to make.
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Re: Crankshaft timing pinion - will it or won't it?

Postby Greybeard » Thu Dec 03, 2020 8:28 pm

I think the pipe was made by Den at Alldens in Lincolnshire. Hes done the pipes on my Panther and made a superb job. Reasonable prices too.
https://m.facebook.com/Alldens-Exhausts ... 524635747/

Ill have a go at uploading the jpeg of the tool later.

Steve

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Re: Crankshaft timing pinion - will it or won't it?

Postby Greybeard » Thu Dec 03, 2020 8:53 pm

Im not sure whether Im being a bit dense but couldn't see a way of uploading a PDF onto the tech articles, so here it is. If anyone wants to transfer it to the 'Articles' please feel free.

Steve

Timing pinion puller.pdf
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Re: Crankshaft timing pinion - will it or won't it?

Postby dave16mct » Thu Dec 03, 2020 9:51 pm

Thanks for that Steve. I have got one that works but it looks like Frankinstein's monster knocked it up in his lunch break! :D
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Re: Crankshaft timing pinion - will it or won't it?

Postby clive » Fri Dec 04, 2020 9:40 am

Greybeard wrote:Im not sure whether Im being a bit dense but couldn't see a way of uploading a PDF onto the tech articles, so here it is. If anyone wants to transfer it to the 'Articles' please feel free.

Steve

Timing pinion puller.pdf


I have had a try too but it defeated me. Seems too good an image not to have it in the tech articles. Can Eamonn or anyone more computer savvy than me do this please?
clive
if it ain't broke don't fix

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