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P55 Magneto problem , help please!

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chris beale
Member
Username: chugger

Post Number: 5
Registered: 06-2008
Posted on Monday, October 27, 2008 - 05:56 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Some time ago I posted the story of my P55s.
Since then I have got them home and had a play, but I seem to be a hopelessly stuck getting the magneto to work.
After removing it and drying it out, I cleaned it and set the points to 10 thou and there is now a healthy spark but only on one of the leads. Both leads are wire not carbon and have continuity,there are no suppressors. I have 2 identical SR2 from these engines so have interchanged caps and leads in every variation/combination I can think of.
Each component works fine. So the leads are good and the connection seems fine but no spark on one side.
Swapping leads makes no difference despite there being a continuity reading on my meter. I have washed the caps in industrial alcohol and there is no sign of HV leakage from terminal to case.
It is just one side and strangely applies to both the magnetos.

Help please!!!

Also I would appreciate some help in identifying these engines as 2 of the 3 are marked as P55 CY which does not appear on any list.

Your help would be greatly appreciated.
tia,
Chris

A more detailed outline; http://www.thenewcafe.net/members/stuartturner/restoration2.htm
The overall story is on http://www.thenewcafe.net/members/stuartturner/index.htm
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Peter Ogborne
Senior Member
Username: peterogborne

Post Number: 278
Registered: 09-2002


Posted on Monday, October 27, 2008 - 02:35 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Chris from what you say you have tried all manner of things .The constant is the magneto itself .By that i mean the breaker points .Have you checked to see that the points open twice during each revolution of the rotor .Could be that one is not opening enough .Have you tried spinning the magneto and seeing if you have a spark from each lead . Use a battery drill with a socket to drive the magneto.
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chris beale
Member
Username: chugger

Post Number: 6
Registered: 06-2008
Posted on Thursday, October 30, 2008 - 11:45 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

I have tried posting 2 replies so this is a test. please ignore
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chris beale
Member
Username: chugger

Post Number: 7
Registered: 06-2008
Posted on Thursday, October 30, 2008 - 11:51 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

For some reason my previous replies have not shown up so appologies for delay.
I have checked and there is a clear gap in 2 positions when rotating the mag. Both appear to be about the same 10thou
I have put both mag and cap in a warm place to see if that helps. Just don't know what else to do.
I have done an HT leakage test to check for any miniscule cracks.
Any other ideas please? This really is a puzzle
Thanks
Chris
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Todd Vidgen
Senior Member
Username: todd_vidgen

Post Number: 93
Registered: 03-2008
Posted on Thursday, October 30, 2008 - 04:51 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Do you have the same magnetic pull at both points?
Is The armature grounding at any point?or touching
the magnet?Are any of the wires from the coil,points
condensor too close to the armature,points spring
and at some part of the rotation being earthed?
Todd
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chris beale
Member
Username: chugger

Post Number: 8
Registered: 06-2008
Posted on Thursday, October 30, 2008 - 05:49 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Fortunately I have had time tonight to follow this up.
As I said I have 2 mags off the engines. The one that has given the biggest spark has been the one I have concentrated on, however it may well be that the armature is touching as there are 2 places where it is more difficult to turn, this doesn't feel like a magnetic cogging effect but more like a mechanical catching somewhere. I can't see where, obviously if I remove the plate carrying the points/condenser it is not going to be in bearings one end so is it possible to check with the plate in place?
There is a metal shim between the main body and the plate carrying the points/condenser, what is that for? I have cleaned on and under that to ensure good contact. This meant undoing the fixing screws, so it may be that when I re-assembled it the bearing was out of line which would result in the armature not running true. What is the gap between armature and rotor?

The other mag is much smoother so perhaps I will try spinning that one in the lathe tomorrow.
Once I have narrowed down the possible causes I can pick-and-mix between the two mags if necessary.

Thank you for your suggestions, I am learning as I go. It may well be that when the mag problem is solved it will be the start of the next ............... your help is much appreciated.
Regards,
Chris
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Todd Vidgen
Senior Member
Username: todd_vidgen

Post Number: 94
Registered: 03-2008
Posted on Thursday, October 30, 2008 - 11:09 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

The aluminium plate is a shim to allow for the
variences in machining etc,you should only have
001' end float,you may have more than one shim
and they may be of varying thickness.
The clearance between the body and armature is
.004'.You can measure this by removing the coil.
Make sure there is no rust on either surface of
body or armature,also clean surfaces where coil
mounts against the iron anvil.
Sometimes the bearings have wear and have to be
replaced.Caution!! Their is a "paper" insulator
under and around the outer race,DO NOT LOOSE,
DAMAGE THIS as all the spark will run away.
Sometimes the lower ball race derails and
the same thing happens.
Another point of note is not all maggies are
set to run in the intended direction,then you
have to reset the timing of the magnetic pull
to your points and cam assembly
Happy hunting
Todd
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chris beale
Member
Username: chugger

Post Number: 9
Registered: 06-2008
Posted on Thursday, November 06, 2008 - 09:03 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Thank you for your replies and suggestions,sorry to be so slow getting back to you.,this has been my first opportunity to sit in front of the computer and reply.
Having spent most part of the weekend trying out all the variations and possible combinations imaginable using the 2 magnetos and getting nowhere, from one side a beautiful spark but from the other side absolutely nothing.
I followed up on the various suggestions and checked the appropriate settings then reassembled all to no avail.
I am getting splinters in my fingers from all the head scratching I have been doing!
It was obvious that I would have to undertake a fair amount of work to get these engines going again as they had been sitting around for so long but I had not anticipated spending so long on just the magneto side. It may be that there are serious problems with the rest of the engine, which will only show up once I get Sparks on both cylinders.
It is not as though I can be sure that if I connected an external car type coil and just used the distributor part of it that that would solve the problem, but that would at least show that it is not the magneto and coil
assembly that is at fault. This may be my next line of investigation but I cannot see that if I am getting a spark on one why it should be the coil or the condenser and I have double checked that the points are opening in closing at the appropriate times in 2 positions.
In desperation/frustration I am waiting to get an EHT probe and I will be able to then use an oscilloscope and see if that gives me any indication of where the problem is, it would show how consistent the voltage is out of
the coil and if the points are interrupting on the two high points.
Unfortunately my "playtime" is very limited and this side of it has taken up a lot longer than I had thought. This weekend being Remembrance Sunday will be out so it looks like my next opportunity may not be for a fortnight or so, if anyone can come up with any other suggestions I would be most grateful.
Regards to all and thanks for your help,
Chris
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Todd Vidgen
Senior Member
Username: todd_vidgen

Post Number: 101
Registered: 03-2008
Posted on Thursday, November 06, 2008 - 03:26 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Send them to me and I will have a squiz at them
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neil r jones
Member
Username: senojn

Post Number: 12
Registered: 08-2006
Posted on Sunday, November 09, 2008 - 01:00 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Hi Todd,
Chris appears to live in England so it would be an expensive exercise to send two maggies to you for a 'squiz' (look) in Australia.
Kind regards Neil (Sydney)
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chris beale
Member
Username: chugger

Post Number: 10
Registered: 06-2008
Posted on Monday, November 10, 2008 - 05:34 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

As Neil has said I am in the UK but thanks Todd for your offer (I have emailed him ,for a few days I have had email access but no net).It is hoped that a friend can come down in 2 weeks time and have a "hands-on" look.
I had expected a challenge but the time just this one aspect has taken has been suprising, I hope it is not a sample of what is to come whenI start looking at the engine itself.
Real life restricts playtime unfortunately.

My thanks to all for the help,
Chris.
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Peter Ogborne
Senior Member
Username: peterogborne

Post Number: 280
Registered: 09-2002


Posted on Monday, December 01, 2008 - 04:20 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Chris ....I have had a friend contact me .He is having exactly the same problem as you are experiencing.....If you have resolved it would you please contact me jopeter@omninet.net.au
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chris beale
Member
Username: chugger

Post Number: 11
Registered: 06-2008
Posted on Monday, December 01, 2008 - 06:51 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Unfortunately I have had no time to go into the problem any further. It had been arranged for a friend to come down and spend the weekend but that had to be postponed . If necessary we were going to convert it to coil ignition but that would still mean that the distributor part of it would have to be working.
It is interesting that someone else is having this problem, I was beginning to wonder if I was missing the obvious or had the only 2 magnetos in the world to display such baffling symptons.
I may well have to shelve the project until after Xmas but would be interested in your friends progress.
Or I might just bite the bullet and buy a replacement.
Regards, Chris
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Peter Ogborne
Senior Member
Username: peterogborne

Post Number: 281
Registered: 09-2002


Posted on Monday, December 08, 2008 - 04:45 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Chris as I told you a friend was having the same problem as you are experiencing.I suggested that he take off the head .Sure enough head gasket blown .I have not heard back from him yet but I would say that with a new head gasket it will be firing on both cylinders .....could be the solution to your problem.
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Peter Ogborne
Senior Member
Username: peterogborne

Post Number: 282
Registered: 09-2002


Posted on Wednesday, December 17, 2008 - 04:55 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Chris ,as i previously said my friend was having the same problem as you .We thought it might be that a head gasket was blown and wetting the plug .Seems that this was not the problem
A suggestion I made to him earlier was to check that the contact breaker points were opening enough .The points open twice on each revolution of the magneto . Turns out that this was the problem .He has cured it by increasing the gap which now allows for enough opening to provide adequate spark for both cylinders.
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chris beale
Member
Username: chugger

Post Number: 12
Registered: 06-2008
Posted on Friday, December 19, 2008 - 05:01 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Thank you Peter for your suggestions. In my case the magnetos are off the engines and I have been testing them using the lathe to spin them.
On both I have checked the gaps and increased/decreased the gaps but there is no spark from one side.The points open twice on each revolution of the magneto . When I can I will put them on an EHT probe and get an oscilloscope on them.
It will be after Xmas now before I have a chance to even look at them again.
Regards and thanks for the suggestion,
Chris

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