Stuart Turner P4 750 Watt

[Engineslune]

Bought this P4 a couple of months ago now with no water tank and fuel tank, luckily had just what I needed already here, I made up some fuel tank brackets using my R2 ones as a guide and the straps were from a Villiers MK 20, the water tank is an old one that was on a Bamford SV3 so adapted it to fit the P4 and plumbed it in to feed the water pump then into the block/head then back into the tank at the top, made up a pram trolley out of some recycled wood and ply but had to make the top removable to have access to remove mag drive/water pump housing, someone had already replaced the brushes on the generator and with help from Noel Aucott have now got it producing power from the control box, although its rated at 1200 RPM for it to produce 50-70 volts I need to run it at around 950 RPM, today gave it a good long run and am very pleased with it, just waiting for my bulbs to turn up and then will make up some light boxes/box for displaying next year plus just had the coil rewound on the N1 which needs to be rebuilt and put on, will try and upload a vid of it running today.












https://youtu.be/EIulX1KFavU

[listerdiesel]

Nice pictures!

You may want to put something flexible in that bottom water connection.

Peter

[wolseley phill]

Nice lighting set, you have probably seen the thread on the restoration of my one. I'd lost the enthusiasm for it a bit in recent times and moved onto a couple of other projects which I'm enjoying.... why rush these things!


Yours differs from my set in that it's rated 250 watts higher capacity and has a water pump. How is the pump driven from the timing case?

Is there any possibility you could measure full resistance across the rheostat please? That would really be a great help.

Cheers,

Phill.

[Engineslune]

Hi Phill, indeed have been following your P4 and was hoping to get some tips.
As for the water pump when I remove the back plate and drive gear for the pump to fit the N1 mag I will take some images for you on how its put together, hopefully have measured the resistance on the rheostat for you as well, setting he multi-meter to ohms at 200 with nothing attached I am getting a reading of 43.2 and with rheostat raised have a reading of 42.4 hope this helps, also have a question you may be able to help me with, mine is 750 Watts and 50/70 volts at 1200 Rpm, when I run it at 1200 RPM I am getting nearer to 85 volts and have to decrease the RPM to get the 50/70 volts to around 850 RPM will it be ok to run it at this if its rated to 1200 RPM or should I just get a voltage control unit for my light box as wanted to use 50v bulbs, Thanks Richard

[wolseley phill]

I'll be interested to see what's in the timing case. I've found with mine, it's very easy to try and fill the chain case with oil via the filler provided and it will give a false reading. I took the cover off a few weeks ago and there was hardly any oil in there, but it was showing up to level! Might explain the things I've had to put right with it.


Thanks for taking the resistance reading, mine is U/S and I have an old rotary type which should be suitable given that reading.

It sounds like your rheostat isn't doing anything though, you should be able to use that to control the voltage at rated speed, increasing the resistance during the charging process to maintain the correct charging voltage. There were lots of dodgy looking insulators on mine, might be worth checking those around the spindle the wiper contact is attached too, make sure nothing is bypassing it or to see that the wiper is making proper contact with the wire. You obviously have a complete circuit, I think I'm correct in saying you wouldn't get an output if the rheostat it's self was open circuit.

It will work as you say, but it's better for the dynamo if you can properly control the voltage.

Phill.

[Engineslune]

Hi Phill, I have taken some images of the timing gear etc, the dipstick sits in a small trough which when filled gives a incorrect reading I have put the rebuilt N1 back on and filled with oil but found that I had to put a lot more in and was still getting the correct level on dipstick, so I filled until it went just over the max marker, I now have a problem with the guvnor not working properly so have to take it all off again to see what is going on there. not that I have been anywhere near the guvnor when I changed the mag. The rheostat is working and today re checked the RPM and at around 1000 RPM I am getting 77 volts max and around 50 volts with rheostat turned down I might have another look at the voltage regulator as its continuously closed I may need to adjust the spring a little tighter to get it to release sooner, ( hopefully you understood that ) again have been surprised what a decent mag does in helping to start it one swing with the handle and its off, where before I was using a starting rope, I am going to set up some lights and see what happens when bulbs arrive have spares as well just in case I blow some as they are 50v may have to go for 100v if that happens.

[wolseley phill]

Thanks, interesting to have a look inside. Looks a bit like a speedometer drive.. interesting to note the extra bearing on the back, makes getting at the governor a bit of a pain.

Before you try and extract the governor weights, have you checked the pivot adjustment? There is a bolt on each side with a ground points, the bell crank lever sits between them.

One is adjustable, tightening up and backing off 1/16th of a turn should be about right.

I can see where that fitting should be in the first photo, the little lump in the casting next to the pipe union but it looks to be missing? Perhaps it's on the mag side because of clearance issues with the pump?

Phill.

[Hornet 6]

These pics are before you set the magneto chain tension, yes ?

Neil.

[Engineslune]

Hi Neil, I was in the process of taking the Wico mag off when I remembered that I was going to take some pics for Phill. Regards Richard

[Hornet 6]

Ok, still a bit jealous of your magneto sprocket though

Neil.