Ruston and Hornsby PT

I've just been given this Ruston and Hornsby PT, my wife's uncle bought it 20 years ago at a farm sale he'd had far to much to drink that day and the engine has sat in a dry shed and not turned a wheel since. I'm looking forward to getting her going but the first challenge will be getting her from the farm to my garage. If anyone can help me date her it'll be much appreciated. Thank you.

If anyone can help me date her it'll be much appreciated. Thank you.

 two is company 3 would be a crowd

nice looking engine - I am sure a bit of petrol and a clean plug and it will be running in no time.

Looks complete enough. Shouldn't take much to get her running. Make sure the magneto isn't seized up, turn her over slowly with the valve spring cover off to make sure the valves are moving as they should. Clean out carb, check for spark (personally I would take the mag off & give it a basic service: make sure the bearings have old grease taken off & some new grease on them, clean it all up, change the condenser, clean up points with very fine wet & dry/emery (P500 or finer) or use a diamond file, re-set the gap then check for a spark), clean the spark plug, or get a new one, make sure it is gapped to no more than .020", preferably around .016"-.018" (16-18 'thou, which is around 0.4-0.5mm) then have a go at starting her up.

As far as the engine is concerned: Make sure the oil is good (replace if necessary, & it will be necessary for anything longer than a quick test run), but I think the main thing which could give you problems will be the magneto. A little care & attention on it now will pay off in the future. A new condenser can be bought from any car spares shop & should go in this type of mag quite easily (ask for one off a Morris Minor or an old Mini). I recently had a magneto seize up on me, so it's made me more wary of it now. Condensers are a recent obsession of mine as well, since replacing ones which "worked" only to find they were causing all sorts of lumpy running problems due to internal breakdown of insulation. Even a knackered one will give you a spark.

Anyway, all pretty straight forward stuff.

Looking on the darker side of possibilities: Check for any frost cracks to the water jacket. hopefully it'll be fine (dry storage helps a lot). Never run an engine with no water in the hopper, fill to at least above the head bolts (even for a test run), wind it over & check in the hopper for any bubbles from the head gasket joint. It should be fine & even if it isn't it's not the end of the world.

Best of luck.  (sorry, can't help you with date).

Thanks very much for that, I got a date for it, 1941 it was sold to Balgownie Engineering and Dairy Supplies in Aberdeen. Which ties in as my wife's uncle was staying in Aberdeen at the time he bought it from the farm sale apparently it was used to power a milking machine. So I'm heading over today to collect it, the fun starts here. 

I have a 1942 Lister D that went to Balgewnie Engineering and Dairy Company Aberdeen, same company?


Untitled by LewizMacRae, on Flickr



Untitled by LewizMacRae, on Flickr


lister D by LewizMacRae, on Flickr

Yes Lewis it certainly seems like the same company. They're still going this is from their website; Balgownie started trading as an engineering company in 1907 in sheet metal work and tank manufacturing supplying to shipyards, farmers and the food industry diversifying into manufacture and supply of dairy equipment.

It's great when you can get some history for these engines. It kind of completes the picture & goes down very well on the engine info sheets with a rally display.

Even better when the company is still going. 

Nice engine you have there, they run sweet once you sort them.

Good luck,

Stu.

Some more interesting history: Before the war, PT's were painted Ruston's "Deep Bronze Green". During the war, only War Office Grey was available.  When Rustons ran out of green paint, early in 1941, they used up old stock of Hornsby "Bullock Maroon" from their paint store before having to use the War Office Grey. 



I've not had a spark yet after trying all the suggestion above but a friend is going to have a look at it over the weekend he's apparently a whizz with mags. So I've spent the week making a new gaskets and replacing missing bolts. 

Nice engine mate am doing one of these up myself at the moment, mine had been done in burgandy but the orignal colour was deep bronze green which is what its getting returned too mines dated at 1947

Abes wrote:Nice engine mate am doing one of these up myself at the moment, mine had been done in burgandy but the orignal colour was deep bronze green which is what its getting returned too mines dated at 1947

Thanks Abes, I got a weak spark out of the mag this morning so that's progress, I've decided it wouldn't be as much fun if these things started first time. 

Have a go at testing the magneto coil. If you have a multimeter put one lead on the magneto body (earth) & the other on the little brass button/nib on top of the coil, where the HT lead contacts (you can try to read it through the HT lead, but for the preliminary tests you're best off testing at source).


Your reading should be somewhere in the thousands of ohms (Kohms range) around the 5k mark (but anything from around 4k to 10k will be fine). The reading should also be stable.


If this test proves successful then you need to replace the condenser (which should be done anyway) & perhaps replace the HT lead & check everything is nice & clean both inside & out (for a good earth return path).


If you get no reading (open circuit) or a reading in the meg-ohms range which won't settle down then the coil has had it. It may still give a weak spark, as the electricity will be jumping a small gap deep inside the coil, or working it's way through the moisture in the coil. This spark won't last for long I'm afraid, & may not be strong enough to start the engine.


You don't need to take the coil out for this test, just remove the cover of the mag.


Best of luck 

Awesome Thanks Nutts. 

Give us a shout if you get stuck. You can PM me or ask here on this thread. 

I just got text from my friend saying he's got the mag sparking nicely and I should be getting it back this evening. Which leads to my next issue, I've read the thread about TDC mark and the spark mark on the fly wheel, the only mark on my fly wheel is as seen in pic below. (which could mean anything or nothing)



The large cog in the timing gear has 2 different marks on it, when the mark on the fly wheel is TDC this is the position of the large timing gear cog.



This pic shows the other mark. I'm guessing this could be TDC as it seems a more solid mark?



Do you think the marks on the fly wheel and the timing gear cog are related? The small cog that turns the mag also has 2 small mark only a tooth or 2 apart, pic below shows the marks on the timing gear cogs.



I hope you can shed some light on this, thanks guys again.

Usually the marks on the cogs are related to valve timing. Can I ask, what is the magneto drive system? Is it keyed or just a blind taper? In other words is the timing fixed when the mag is coupled to the cog?


I usually don't bother much with timing marks on flywheels as they're not an exact science (depending on angle of sight you could be quite far out), I usually go by a TDC tool down the plug-hole, or a finger down the plug hole or with the head off or even mount up a proper timing disc.


The other way is to make your own marks on the flywheel, get the piston to TDC (feeling in the plug hole) then find out how far away the ignition mark should be, mark this distance & you have your own timing mark. Personally I would set up something like a small screwdriver shaft or piece of stiff wire, clamped to the engine, resting just over the flywheel (almost touching) so you know it's accurate, & make your marks with Tip-Pex or something similar (a small touch-up paint thingy works well). But you'll have to ask someone what the distance is between the 2 marks on the flywheel.


Of course you could just do it roughly where it should be & it'll probably work fine. I'm a bit anal about timing (as if you couldn't tell )

Thanks Nutts, it's a blind taper. So do you think the marks on the timing gear cogs are irrelevant? Once I've found TDC how do I find out where the spark mark should be? Sorry about this.

If it's a blind taper then the marks on the cogs will be irrelevant.

When you find & mark TDC on the flywheel the ignition timing point will be an inch or two behind it (remembering the engine fires just before the piston reaches TDC). If someone here has a PT, & it still has both marks on the wheel, they could measure the distance between the 2 marks for you. Then when you mark your TDC, you simply measure back from that & set your timing there. 

It's probably about 1.5" to 2" before TDC on the flywheel, which is a pretty good place to start. A retarded spark (late spark, IE closer to TDC) is probably slightly better than advanced in as much as advanced spark will cause an engine to run hot (OK so will a retarded spark, but it has to be pretty damn retarded to make it run hot, whereas it doesn't have to be very far advanced to run hot). Also, it's advanced timing that kicks back on starting & causes injury. Retarded timing will give easier starting, so start with an inch or so if you can't find the proper measurement.

The other way is to feel down the plug hole, get the piston to TDC then wind it back until it's about 1/4"-1/2" down & set the timing there.

If you can find out what the actual timing is in degrees you can set it with a dial. It's just a circle, usually cut from thin plastic, with a hole in the centre & degrees marked around it from 0 to 360. You secure a marker somewhere on the engine, pointing at zero when the piston is at TDC, then wind it back to the correct amount & set the timing there. I have one here which my dad got free with one of his classic bike magazines, they really are that cheap. You could stick it to the crank shaft with blue tack if you had to, just make sure it's roughly central.

So there you go, several ways to set your timing. Don't forget the fag paper between the points, the thinner the better (blue Rizla), give it a tug, as soon as it becomes loose is your exact firing point.

Or just do it by eye, so it looks about right & you'll probably get away with it (like the majority of people probably do, I don't know many people who go to these lengths, & we all have engines that run. But I rarely have to set timing twice . Of course I could be wrong, I don't know what lengths others here go to TBH, I just know they usually fire up pretty quick when I start them & I haven't broken my wrist yet).

Can measure mine if you want

Thanks Nutts, I poked my finger in the hole and the double mark on the fly wheel is TDC and at that point one mark on the timing cog is TDC and the other is at the point where the 2 cogs meet. 
Abes that would be great if you could, thank you.

5 mins and ill go and check for you

Gary.B wrote:Thanks Nutts, I poked my finger in the hole and the double mark on the fly wheel is TDC and at that point one mark on the timing cog is TDC and the other is at the point where the 2 cogs meet. 
Abes that would be great if you could, thank you.

Gary sorry took a bit longer than i thought could not find a measuring tape, right from TDC mark to the SPARK mark is 85mm

Abes wrote:Gary sorry took a bit longer than i thought could not find a measuring tape, right from TDC mark to the SPARK mark is 85mm

Perfect thank you. 

Blimey, that's a bit further than I expected. 

Nice one Abes 

Finally we got her going after a getting a loan of a friends mag.  
Thanks for all the advice guys.