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JP2 woes


Proper Job

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Lay a straight edge along the flywheel taper. If it is worn there are specialists who can spray the taper with metal then turn it off on the lathe to the correct taper profile.

 

 

If the crank taper is worn the female taper on the flywheel will want looking at too.

 

N

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Looking at the picture I see the JP2 has only two main bearings- I would have expected there to be one between the two cranks. You learn something every day!

 

Are there any other common vintage engines like this?

 

N

The JP2 also had a reputation for breaking crankshafts.

 

The JP3 has a lot more support for the crank as it has mains in between the big ends

 

If the crank taper is worn the female taper on the flywheel will want looking at too.

 

N

The machine shop is checking the taper and it looks like the flywheel will be taking a visit as well so that they can be paired up and made sure of a good fit.

 

A straight edge, torch and feeler gauges on the flywheel taper shows nothing obvious, but running your finger along the taper, I'm sure I can feel a slight 'shoulder'.

 

It needs to be clamped properly and a DTI run along it at the correct angle. Some thing that's not easy to do in a dark, cold engine room ;)

 

Happy days :)

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<snip>

 

Some thing that's not easy to do in a dark, cold engine room ;)

 

Happy days :)

 

Pah! A bit of plate glass, some engineer's blue, a file, a scraper and a bit of emery cloth is all you need. I don't know, youth of today, no stamina...

 

:P

 

Richard

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On the old 1275 Mini Cooper race cars the flywheels used to come loose on the taper. We used to lap the flywheel and crank together then assemble

flywheel hot, crank cold, big hammer.

 

Yes I know its not a marine motor but the principal is the same?

 

Mike.

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On the old 1275 Mini Cooper race cars the flywheels used to come loose on the taper. We used to lap the flywheel and crank together then assemble

flywheel hot, crank cold, big hammer.

 

Yes I know its not a marine motor but the principal is the same?

 

Mike.

The principle could be the same. I'm not sure I'm up for manhandling a hot 3 cwt flywheel though :unsure:

 

Especially if the big man has a big hammer :blink:

Edited by Proper Job
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On the old 1275 Mini Cooper race cars the flywheels used to come loose on the taper. We used to lap the flywheel and crank together then assemble

flywheel hot, crank cold, big hammer.

 

Yes I know its not a marine motor but the principal is the same?

 

Mike.

Except that the mini flywheel weighs several pounds, whereas the JP flywheel weighs several hundredweight!

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The principle could be the same. I'm not sure I'm up for manhandling a hot 3 cwt flywheel though :unsure:

 

Especially if the big man has a big hammer :blink:

Actually, I think the JP2 has a heavier flywheel and it's nearer 4 cwt.......

 

Either way, it's bloody heavy!

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  • 2 years later...

Well.........

 

It's out and off to the have a polish and new bearings:

 

gallery_1645_261_223621.jpg

 

The journals are all good but the mains were showing a bit of cracking in the white metal.

 

Jesus..... it's heavy!

Hello,

 

Can you please tell me how did you remove the balance weights?

I am working on a Lister JP1 (9-1) that needs grinding.

There are some kind of locking pins in the sides of the weights, do they have tread?

Do I have to drill them out?

 

Kind regards.

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