1940 J.A.P. Model 4/3 Restoration
Preparation
When I bought it - the engine wasn't in too bad condition. It had obvioulsy not been touched for a long time, and hadn't been run for ages, but overall, it wasn't in bad condition. The big plus was that everything was there!! Even the old style Oil Bath Air Filter that is almost always missing from these things. It was however, pretty dirty, greasy and grimely.
It turns over - happy days!! Even better - it's got spark. And it seems to happy pretty good compression as well. As long as the valves are OK - this thing shouldn't be too hard to get going I think. Obviously, the carby will need a good stripping and cleaning, don't they always??
This is how it looked before I did anything to it.
10 May, 2022
So first job - degrease and power wash. Here's how it looks after the clean.
The photos don't show much difference really, but there is quite a bit. At least now I will be able to start stripping it without getting covered in grease and oil.
I've only got a few more days left here before I head back home to Sydney, so I might strip a few things off it to take home with me and work on at home.
So - off came:
- Exhaust
- Carburettor
- Cowl
- Air Filter
- Governer
- Magneto
- Drained out all the oil (pretty black - but not too bad)
- Sump Plate - Surprisingly clean inside the Crankcase - I think someone has been in here before.
- Back Pulley
- Head - Bore is in wonderful condition
- Fuel Tank and Supports
So overall - pretty good. I get the impression that someone has had a go at it before. The thick red paint is a real giveaway, but even that seems to be quite old. The condition of the bore shows it hasn't done a great deal of work, and the condition inside the crank case makes me thing that someone has had it open lately and flushed it all out. Either that or it is just quite clean because this engine has had an easy life. Given the condition of the bore, and the condition of the oil here's what I reckon.
Someone bought this engine new, many years ago - possibly 1960. They used it a little bit, and took good care of it while it was in use. Then, for some reason, they didn't need it any more, and it fell into disuse. So since then it has been sitting in the back of somneone's shed just corroding away externally. SOmeone decided to freshen it up with a thick coat of paint, but with little care or preparation. They maybe used it for some time, but once again it fell into disuse and into the back of perhaps a different shed. Over the years the paint started flaking off and the underlying, exposed metal started to rust. And that brings us to today.
I bought it off a chap in Forbes, who says he inherited it off his father.
12 May, 2022
I made a crank handle for it today. wasn't quite sure how this was going to work, becauseif I put any length at all into the handle, it would be too long and hit the ground while cranking!! In the end I ended up making it too long to work if the engine was sitting on the ground, but it would work fine if the engine was sitting up on a Skid or Trolly.
13 May, 2022
So back to Sydney tomorrow - and these parts will be coming with me.
- Magneto
- Carburettor
- Air Filter
- Exhaust
- Governor
15 May, 2022
Air Filter first.
So the Air Filter is an Oil Bath style filter. It's pretty grotty. Loads of gunk inside, and some of it quite hard, so it has been doing its job over the years, perhaps that's one of the reasons the bore looks so good - no crud getting into the engine itself.
Its covered in a thick layer of red paint, and it looks like black pain beneath that - the black is probably the original colour, but I will be redoing it red again, to match the rest of the engine. I tormented over that - I very nearly did it black.
Anyway - the whole thing was cleaned out with degreaser. Then stripped with a wire wheel on my angle grinder. Both the tub and the top came up quite well.
Exhaust got a bit of a wire brush to remove dirt, rust etc, and came up OK. There are a few dents in it, and they won't get fixed. I don't care too much about this exhaust, after all, it's not the original one - it looks like a Briggs and Stratton Exhaust. But it will do until I find an original one, and that will get fixed up nicely.
16 May, 2022
Red - Black - Red - Black - Red - Black - right - Black.......no!! Red.
I use VHT paints for most things I paint - even if they don't need heat protection. I use them because onced cured (baked) they have pretty good resistance to enginey type things like petrol and oil.
So - after the wire wheeling - it became apparent that there were a few spots of corrosion present, so they were treated with rust converter/sealer and left to dry. After that, all the parts got a couple of coats of Red Oxide Primer. Followed by a couple of coats of VHT Engine Enamel Grey Primer and a couple of coats of VHT Bright Red Engine Enamel. And 2 coats of VHT Engine Enamel Gloss Clear.
I left them to dry for 24 hours.
16 May, 2022
Into the oven for curing. 1 hour at 90 Deg Celcius (200 Deg Farenheit)
I reckon they came up pretty darn good.
So now it's onto the carby over the next couple of days. I like doing carburettors :)
18 May, 2022
Slight change of plans - I'm going to attack the Governor next.
AS usual with the old J.A.P.s, the Governor is all stuck and gummed up, so the plunger isn't plunging, and the little piston is stuck in place, so there's no chance of it working. But unusually, the plunger, spring and all the other bits are still there, which is a real plus.
Here's a picture of it still in place on the Engine. This is after the whole engine got a Jet Wash, so it doesn't look too bad, but you can see the Adjuster Screw and Lock Nut are corroded. What you can't feel is they are seized in place and the Oiling Hole in the end is completely filled with gunk. The piston and spring are also seized in place, so the governor arm that adjusts the carburettor doesn't move. All in all, its a gunked up mess internally.
Now here are a few photos of it after having removed it from the engine. By this stage I had removed the Piston and Spring, which came out surprisingly easily. And you can see from the internal view, it looks quite nice and clean. Once again, I think someone may have cleaned this out at some stage, but I guess they must have left the Piston/Spring alone - I can't think of any other reason they would be so corroded/gunkled up while the rest of it is quite nice and clean.
And now after a degrease, paint stripping and a wire brushing, although my OCD did get the better of me and I picked off those few remaining bits of paint with some dental picks. Ready for new paint.
