Services for Brough Superior motorcycles and their contemporaries
KTOR engine replica page
Just a brief specification of the 1927 KTOR JAP v-twin engine:
What do we need to build this engine?
|Starting at the bottom, a pair of crankcases. First of all we need a set of good castings. As this proved to be a problem, I have made a page exclusively dedicated to this topic.||
|Next, these castings will have to be machined. I found this is not an easy task if you want to achieve some accuracy. I say I have a deep respect for the brave men who did this successfully in the 1920's, with tool machines that were quite primitive by our modern standards!|
|Then, a crankshaft to revolve within the latter.
I will deal with that later.
And a pair of connecting rods (Carillos?) to attach the pistons to.
1/2006: I have now, after a few iterations, succeeded in persuading Carillo's to make me a pair of rods to my liking.
2/2007: I have spent much thought on how to
make the flywheels. And I have spent even more thought on
how to balance them.
|03/2022: Another post-up: I have started to make the crankshaft during the last 12 months. A friend and keen mechanic in Austria came to help CNC machining it.|
|oh yes...pistons! I think I will use BSA Gold Star pistons. They have a crown height of 32.5mm plus a 10mm dome. To my knowledge the original ones have the same height, and a slightly higher dome, which is slightly smaller in diameter. The 3/4" gudgeon pin should be o.k.|
|A pair of cylinder barrels to give the pistons a good home.
I had already started to make my own pattern, but I tell you it is not easy to find a foundry who will make these castings. Usually they tell you to use half as many fins and make them a bit thicker....
But now (8/02), after much pleading from my side and a few problems, MFC
(They are at www.japbits.co.uk ) have
come up with these very nice KTOR barrel castings, thank you Mark and Mike!
|And a pair of heads on top of them,
I have already ordered a pair of castings from MFC.
(They are at www.japbits.co.uk ) Meanwhile (9/02) I have taken delivery of a pair of head castings, and I am very pleased with them!
Click on the pic and see how I machine these!
|Inside the timing case, we need some camshafts.
These came from John Holleren of Morgan fame. I have, of course, not tried them yet, but they look very good.
You can contact John at firstname.lastname@example.org if you are lucky or give him a ring: +44-161-3303304.
|And we need a lot of small stuff to actuate the valves,
some of which will hopefully be supplied by MFC (again).
|Plus a number of small things: valve springs and collets, pushrods and
their return springs, bearings, an inlet manifold, a breather valve, lots of
nuts and bolts, and we will need an oil pump and a carburettor....
I am sure I have forgotten about a thing or two!
|Yes, valves - we need to close those ungainly holes in the heads!
As usual, I looked at the readily available car engine valves and found a good one, but had to machine the spring cups and collets of course.
|4/2004: Well, things are coming together slowly. The engine is still empty, but it is at least taking shape!|
|6/2004: Now I have machined an inlet manifold. The casting was courtesy of Brough Superior Club.|
|10/2004: After looking out for a correct AMAL 6/022 carburettor for a long time I have decided to help myself. I have now started to build one out of a rather scruffy 6/024 (flange fitting) body...|
|12/2004: I have finally got around to finishing the overhead rockers I'd bought from MFC and to fit the bearings for this.|
|1/2005: Now I have made some progress with the valve actuating stuff: I have got the rockers and their bearings ready, and I have machined a set of cam followers|
|3/2005: I have, after a good two years of
pestering a friend in England, obtained a pair of castings for the exhaust
cooler. I found that machining these
is not a job for a spare hour in the evening.
5/2007: I have recently got the castings for the rear coolers (which had been temporarily out of stock...) and have machined these. Nothing exciting, but I also made the missing threads on the front coolers which was a bit exciting!
|6/2005: And I have at least started to make the valve lifter bits...|
Well, that is all for the moment, but I will carry on!
Any kind of feedback to
(sorry, this is not a clickable 'mailto:' hyperlink. If you want to write me, please type my address in your mailer. )
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