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Member postings for IanH

Here is a list of all the postings IanH has made in our forums. Click on a thread name to jump to the thread.

Thread: Seal selection
19/10/2021 19:15:22

Hi Noel,

i remember at the time a discussion with the folk at Luminition about the size of the chopper. I recall that the leading edge puts power on the coil and it is the training adage that triggers the spark. The width of the chopper then determines the dwell angle and the duration that the coil is powered up. Too long a dwell angle could lead to the coil overheating. The Morgan engine is pretty slow revving by comparison with modern stuff so a small dwell angle would be fine. We decided to start with the chopper shown in the photo and then reduce it if we hit problems. It never got changed!

the electronic magneto has a 180 degree dwell angle, even more extreme. The reason for trying 180 degrees was that if it worked, we could reverse the direction of rotation of the magneto with the same 180 degree ring magnet. Reducing the dwell (bringing the N and S poles of the ring magnet close together) would mean that the ring magnet would have to be turned upside down if the mag was to run backwards. I ran the mag on the lathe at low revs for half a day in the warm workshop to see if it did overheat - it seemed fine so we are road testing with the 180 degree dwell.


19/10/2021 09:08:26

4e33493d-6163-4959-8e44-dddb45aa370e.jpegHere is the contact breaker housing with the Luminition through beam units installed. The 4 core cable heads off to the control unit under the bonnet and the coils.

18/10/2021 17:12:18

Hi Noel,

I converted my own 1933 coil ignition Morgan to electronic ignition something like 20 years ago. The set up I used was from Luminition and was based on a kit provided for Moto Guzzi motorcycles. The through beam infra red units fit neatly to the contact breaker housing, I made one IR unit fixed and arranged for a bit of adjustment on the other to fine tune the timing on No 2.

The magneto contact breaker housing is smaller and I suspect you would struggle to get the hard wired Luminition through beam units in. If there was a PC board mounted equivalent through beam unit it would be a nice solution. Do you know of a suitable component?


18/10/2021 09:04:39

There is a cover for the bevel gears and oil pump drive, here is a close up. You can also see the mag end cover in place.


17/10/2021 20:02:53

There are plenty of magnetos around where the defunct magneto becomes simply a housing for a set of points. You then you have coils, or a double ended coil tucked away somewhere under the bonnet. The original magneto HT leads are either removed or tucked away somewhere, and the working HT leads from the coil(s) emerge from under the bonnet. This works but loses something in terms of authenticity.

The objective of this project was to develop a magneto that was indistinguishable from the original instrument. This means that the magneto HT leads must be real. The unit must be completely self contained, there can be nothing mounted remotely, and you can only have one wire (the original only has an earth wire) going to the magneto. The original cable advance/retard control must operate as normal. An extra rule I added in was that the double ended coil/wasted spark approach would not be used - it has been associated with carb fires on these engines.

So we have two separate coils inside the magneto body, the secondaries essentially hard wired to the HT pickups - so no distributor and no carbon brushes. There is also a PC board tucked away inside the magneto body with two more or less independent ignition circuits. A relatively small diameter shaft driven by the standard bevel gear passes between the coils and through a hole in the centre of the main PC board. The shaft terminates in the points housing.

The single wire is used to provide 12 volts from the ignition circuit.

Inside the points housing is a dummy cam ring which provides a mounting for the trigger PC board. The manual advance retard control engages with the dummy cam ring in the normal way. The trigger board provides mounting for two Hall sensors, one for each circuit. Each sensor has an associated LED indicator light to allow you to time the magneto. The Hall sensors are mounted on the PC board, separated by an angle chosen to suit the V angle of the engine. On the end of the shaft is a taper on which is mounted a component with a ring magnet that presents N and S poles to the Hall sensors.

To time the magneto, you mount it on the engine without worrying about timing, you just engage the bevel gears. You set the manual adv/retard to max advance and then turn the engine to the appropriate firing point for No 1 cylinder. You then rotate the ring magnet until it just fires No 1 (the LED indicator facilitates this). You nip the ring magnet holder up on its taper, fit the cover and then drive off 😃.

Happy to have a chat about your set up - send me a pm If you would like to have a natter.


16/10/2021 22:50:46

The mag will be lucky to see 3000 rpm on this sidevalve, and would most likely only see it momentarily before something catastrophic happened 😬, but some or the more exciting ohv engines will rev up to 6000 rpm and even a bit beyond. A rev limiter can be programmed into the mag if required to look after the engine.

The electronic mag is designed to run clockwise or anti-clockwise, and by changing the discrete timing board mounted in a dummy cam ring, it can handle different engine types with different V angles.

16/10/2021 18:21:24

Just for interest, here is the magneto on the test car, a 1930 Family Morgan 3 wheeler. Yet to fit the cover over the bevel gear drive and fit the points cover.


15/10/2021 14:08:08

That makes me wonder about using a separate seal at all - maybe just let the sealed bearing do its job?


15/10/2021 12:28:50

I have recently finished a conversion of an ML magneto to coil ignition. This involved squeezing a pair of coils into the magneto body along with some electronics. I have tested the magneto on a car (Morgan 3 wheeler) and the results are very encouraging.

This is very much a prototype, and I am beginning to think about longer term testing and a version 2 with some improved weather protection. I have replaced the original magneto bearings with standard sealed bearings, but I would like something outboard of the sealed bearing to keep water (rain - the magneto is very exposed on the front of the car) out of the magneto body. I thought about a lip seal but wondered about how it would manage with no lubrication? In dry weather it would be running dry. An option might be to remove the seal on the bearing on the lip seal side anticipating some grease from the bearing lubricating the seal.

Does anyone have any recommendations for this application? Probably looking at 3000 rpm, shaft diameter 15mm.



Thread: calling 254 Myford owners
20/06/2021 08:22:14

Hi, I think I have one of those, it has a 12 tip thread on the big end and is tapped for a draw bar at the other.


Thread: Spiral adjustable reamers
20/05/2021 15:57:45

Hi Oily Rag,

A picture of the Triumph broaches would be interesting thanks.


20/05/2021 08:36:43

Just to clarify, these are old JAP engines and we are not dealing with wear, just two different approaches. One supply organisation uses dead size valves and gets the clearance in the guide, the other uses dead size guides and gets the clearance on the valve stem. What we are doing is mixing the two systems, we want to use the dead size valves from one outfit in the dead size guides from the other, hence the need to open up the valve guides.

There is a good reason behind wanting to do this by the way....we want the valve head sizes of one engine in the other. The valve guides are not interchangeable between the engines.

We are machining new head castings so could more or less easily make custom valve guides, but it would be a quick fix if we could easily and reliable open out the dead size valve guides to suit the non standard valves.

I should also add that like many home workshop enterprises we are cheap always looking for low cost solutions, so had discounted the lovely but expensive adjustable diamond hone. Buying two new reamers is probably affordable.


19/05/2021 20:40:59


Chatting with a friend about IC engine valves and valve guides, there are two approaches in play.

One is to have the valve guide reamed dead size and to achieve the clearances with reduced diameter valve stems. The valves are specified and purchased with the appropriate stem diameters to give the required clearance - 2 thou on the inlet and 4 thou on the exhaust.

The other approach is to have the valves dead size and achieve the clearance on the guide. The problem comes when mixing things up and then the need to open out an 11/32" valve guide by 2 or 4 thou to suit a dead size valve arises.

The normal parallel blade adjustable reamers seem to be very hit and miss and can be hard to get turning smoothly in the bore. This may be a quality problem with the reamers I suppose but I spotted adjustable spiral shank reamers on Ebay. Unfortunately the Australian supplier is reluctant to ship as he has struggled with stuff getting lost in the past. I would like to give one of these things a try, but I can not find a source in the UK.

Does anyone know where such devices can be sourced in the UK?

Unlike the usual type of adjustable reamer they only have a range of 0.010" so OK for valve guides, but probably not too useful generally. Any other ideas also gratefully accepted, the valve guides may be iron, or one of the bronzes and have a working length of over 2 inches.


Thread: Hall Toledo Orbital Valve Seat Grinder
30/04/2021 07:29:03

Thanks for the info, I have an email on the way to them now.


29/04/2021 18:00:59


I have come across a Hall Toledo orbital valve grinding machine that I bought years ago on spec and forgot about. This is a clever machine that is mounted on a pilot fitted in the valve guide. It rotates the grinding wheel at something like 10k rpm, and the clever bit is that the grinding stone then orbits the valve seat at 10 rpm. I would like to get this machine back in action.

Having stopped the motorised unit blowing fuses, I have set about making the missing stone dressing unit.

There are some very tired looking stones with the unit and I could do with finding some replacements. The unit is designed for large valve seats I think, so the stones I need would be at the bottom of the size range and ideally 45 degrees plus or minus 15 degrees. I have emailed Hall Toledo in the US but so far no response. It is a bit of a long shot but does anyone have any stones kicking around that they would part with?

I also need an 11/32" pilot. I am thinking I could make one of these but if anyone has one floating about I could find a use for it.



Thread: Myford 254 Plus toolpost type
14/04/2021 09:32:25

I also use the Greenwood tools parting off system. Like you I have never had a problem with it letting go despite doing some fairly extreme parting off.

What a pity Greenwood Tools have finished.


14/04/2021 08:24:38


Here is my 254 with PeWe Tools size AS.

personally I wouldn’t bother with a rear tool holder for parting off, can you not just modify the tool to suite the tool post?


Thread: How does this temp trip work?
11/02/2021 21:40:15

Thanks for that, that explanation makes sense. I will examine the trip more closely and see if I can identify the PTCR device.

Thanks again,


10/02/2021 17:34:21

I also have a small portable fan heater that I use in the garage sometimes and we also take it away in the caravan. This has two settings, 1kw and 2kw suggesting two separate heating elements. If you leave it on, eventually when the room warms up it will switch itself off (elements and fan), then it switches itself back on when things have cooled down.

If I took this one to bits I expect I would find a bimetallic temp device that resets with power on acting as a thermostat. In addition I would hope to find a thermal fuse, a one time device designed to protect against overheating following fan failure for example.

This was what I was expecting in the dodgy heater, but instead found just the mystery device. The instructions say that if it shuts down you should turn it off, wait 5 mins and then turn it on again. If it trips out a second time call an electrician.

I think the device does have a heater on board to keep it tripped under power, I just can't see where the neutral is! I will see if I can get a photo....

10/02/2021 12:52:28

I have been investigating the failure of a fan heater....don’t shout, it is just a lockdown diversion. It has what looks like a bimetallic type thermal trip fitted such that if the fan fails for example, the heater overheats operating the trip. The trip is on the incoming live and goes open circuit, so once tripped nothing works. The fan motor and heater elements are downstream of the trip.

I assumed that once it cools down it will reset, but it won’t do this whilst the unit is still switched on.

I think the trip is generating a bit of heat which keeps it open circuit? If you turn the unit off (isolate it from the mains), it resets after a short period.

How does the trip manage to not reset whilst still connected to the mains? I imagined that to generate heat it will need to pass a small current, but once tripped it is isolated from the neutral.

Have I forgotten/missed something simple?


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