Dating JAP 600 Sidevalve

[ColinF]

Just got hold of a 600cc JAP sidevalve engine with the intention of making a vintage looking special around it .For the record, i'm not a hipster and it wont be a "brat-tracker " or a "beard -racer"!
I managed to find the engine number which is     UCZ/W 80359/4  and i understand that u=600cc,C=sports engine,Z= dry sump and that W=year ( 1930 or 1950 ) and believe the last digit refers to any deviation from std.
I know these things were fitted to large rotavators etc ( Howard Gem etc).
So what i want to know is.......
  Does the sports engine denote what it might have been used in?
  Is there any way of telling if its 1930 or 1950 ?  When was this engine first built?
  Is the fact that the cooling fins on the head run front to back significant ?  I've read of other people changing to this type of head from rotavator ones which had transverse fins.
Any help would be appreciated.

[R]

What does it actually look like ?

https://s3-eu-west-1.amazonaws.com/lot-images.atgmedia.com/IB/264/5168/916-201379154735_original.jpg

https://farm6.staticflickr.com/5055/5409498093_9d682144c9_b.jpg

There seems to be a whole industry out there making such things these days....

[cardan]

A photo would help distinguish between 1930 and 1950.

I suspect we might find that "C" in this context is not "Sports", but let's have a look first.

Leon

[cardan]

https://farm6.staticflickr.com/5055/5409498093_9d682144c9_b.jpg

There seems to be a whole industry out there making such things these days....

Nice one R: it would be funny, except that in the Facebook age few can differentiate between the "NUT dirt track racer" and the real thing. Not really a problem with the NUT, but fake racers (Rudge, Norton, American board trackers, etc.) are reaching a level of sophistication able to fool even the one-make clubs.

Leon

[chaterlea25]

Hi
The 1930 engine would have a one piece casting for the cylinder and head (non detachable)
Also I do not think the dry sump system became available till mid thirties

The industrial engines usually have the engine / crankcase mounting lugs as wide or wider than the crankcase itself

John

[33d6]

Well my J.A.P. engine chart does confirm UCZ as being a 600cc sidevalve sports engine and W as being of either 1930 or 1950 manufacture. As mentioned above a photo will sort that one.
I think the J.A.P. idea of a sidevalve sports engine dates from pre 1914-18 First World War days and was a little dated even by 1930 standards cos' sporting it ain't. But that depends on your idea of sporting doesn't it.

Back in my yoof I went through a lengthy sidecar phase and have fond memories of various 600cc outfits. VB Ariel, Big 4 Norton and a Big Pussy. None startling fast, max 55-60mph but would do it up hill or down hill, loaded to the gunwales or empty. I find the idea of a 600 sidevalve sporting solo dull but same engine in a sporty outfit? Brilliant!
As JFerg of this parish will confirm, outfit owners are always welcome in any riding group cos' guess who gets to carry all the peace of mind necessaries and godwot. No one wants to haul extra weight if there is an alternative.
Outfits are fun. Old thumper outfits especially so.   

[john.k]

I d bet a weeks pay that its a 600cc mk III,type 5......which is good in one way because it has a ball bearing d/s main.......the 600cc mkIII,type 3 has loose rollers in a cage ,a la HD/Indian.........if it has a detachable head ,it aint 1930........commonly seen here are from the railways....not railcars with big rorty 1323cc twins.......but things like Autotrucks on the stations,and lots of mobile machnery with the engines as starting motors.....the Ruston 6 VPH had a 600cc,wheras the Dorman 6DL only needed a 500.

[john.k]

I also believe the C stands for a customer order,not sports................if you cant do a pic.....the Howard engine has a large flange around the D/S crankcase......the others are motorbike crankcase type........some rail ones have a crankhandle dog in the timing case.....and in the past,i have left this type for scrap......not now ,obviously.

[ColinF]

Thanks chaps for the quick replies. I do realise it's not a sporty engine, that was just what i got of the engine codes online.I have modern classics for sporty riding and just wanted something fun to build and to be able to collect random parts that look right at autojumbles. I will post pics when i've cleaned it a bit. Be warned, it is in pretty much "as found" condition" but it does turn over ( it was local and i didn't pay a lot for it ) .It is missing carb and mag, also the timing gear ( available 2nd hand online) and cover. It does have separate head so 1950?  Any idea what the last digit ( No 4 ) means? Not really bothered about age as it will still be more 30's style.Thanks all for the input.

[john.k]

Colin,have a look at the Autotruck forum,and I also found a proper manual for the motor online..........search for  600cc Mk 3 type 5,and you will find a repair manual,easily............if its been a starting  engine,it will have badly brinnelled mains.......incidentaly ,the starting engines are impressive,you get in the back of say a RB54,big as a house,start up the JAP,and give it a bit of throttle,apply the clutch lever ,and the big Rustons just turns over and starts,no need to lift valves ,the JAP just plonks away,the white smoke turns to black,and the 6VPH starts firing evenly.......incidentally,the JAP is started by a belt.....a workmans belt ,that held up his dungarees........never lost,always available.

[ColinF]

Cheers, i'll have a look at that. Will attempt to post pics so stand by......
Right, well that didn't work. I could select the image from files okay and you can position it with the insert image function but i can't see any way of actually applying it. Am i missing something or is it just my +#x! computer?

[chaterlea25]

Hi Colin,
That;s an identical engine to the Howard Gem rotovator engines I have/ had, except for the head finning direction
Wide crankcase lugs and 90 degree inlet manifold are  identical, that deep crankshaft nut is just like a spare one sitting on my workbench 
It should make an interesting thumper

John

[john.k]

Incidentallly,the inlet pipe has a fine (26tpi)...LEFT hand thread.into the cylinder.

[ColinF]

The inlet isn't very sporty, think that will get a straight one.I was surprised to see the pictures up because i couldn't preview them so thought they didn't upload.I managed to download the manual mentioned by john.k and had already bought a Howard engine manual (paper one) off ebay. hadn't undone anything yet so left-hand thread noted! Plenty of penetrating oil on it now,especially on the exhaust thread. I know everyone has their favorite penetrating oil or cocktail of solvent and oil to shift things but the best by far that i've come across is Kano Kroil . It's not cheap but it really does work.It was the only thing that managed to penetrate all the crud on a splined pto shaft that wouldn't move on a tractor mounted cement mixer so i could replace the chain.
I was at Newark autojumble on Sunday and had a look at a couple of girder forks and a few gearboxes. I have to confess to never having had a "British bike" on the road ( have had British framed Scrambler and have got British framed speedway bike ) so my knowledge of British bikes isn't as good as it should be but i have partially restored/recommissioned a '37 500 MSS Velo, rebuilt an Le Velo and building BSA A10 engine for a friends custom bike. So with your combined experience what sort of gearbox would be suitable? of all the pre-unit boxes i looked at  about half looked too small ( off lightweight Villiers etc ) some looked too chunky tho. It's not like it has massive HP but i'd like a neat "old looking" box with the primary on the correct side, also how many gears to be useable ?      Any ideas?

[chaterlea25]

Hi Colin,
A Burman CP or BSA early B or M series would be robust and give 4 speeds
earlier hand change boxes are harder to find
Sturmey Archer boxes seem to be made of gold 

John