THE ATTEMPTED “RESTORATION” OF A TARPEN 2 STROKE ENGINE AND AN ATTEMPT TO RE UNITE IT WITH A TARPEN DYNAMO
PART 1 – FIRST ATTEMPTS
Those of you who have read the previous pages on the evolution of the JAP powered unit might now realise that I have two Tarpen 400w Dynamos in my possesion. The original Dynamo from the JAP “0” series unit and the one that got put away as it “gave up the ghost” as it were .
The one ( now working ) on the JAP gas powered unit is the above previously not working unit,that I internally rewired (and changed the direction of rotation in the process,by reversing the brush connections)
and is now working once again very well .
The other Dynamo ( the bought on ebay one) I had the wonderful idea of at some stage trying to re unite it with a Tarpen engine ,not necessarily as a complete original Tarpen generating set but as something more akin to showing,IE on its own trolley .
This is its ongoing story .
So back in 2019 I came across a Tarpen 2 stroke engine from a type 40 Tarpen generator for sale on ebay . As coincidence would have it ,it was the same seller as I had just bought my 1933 Type 13 Lister D from ,so off I went back to the same guy and bought the Tarpen engine .
This got put into storage for a while as I concentrated on the Lister ,then shortly after this years Paddock Wood crank up in March, the lockdown started and it was now a good as any opportunity to start on the Tarpen engine.
The ” in development” Picture below gives an idea of what I had in mind for the final “look” of the set and once restored cosmetically I thought it would look quite good – but as this story unfolds it will become obvious it was just not to be
The set is actually running in the picture above but that was not the whole story – It ran like a pig ! and needed lots of further work
Also note the oil on the ground below the trolley .
The next picture actuallly shows the set generating succesfully
Part 2 describes the previous stages and what happened next !
PART 2 – FIRST ATTEMPTS
The Tarpen 2 stroke engine was developed and made by Tarpen themselves (in house) specifically for their generating sets
The Dynamo units are really well made and solidly constructed ,work and last well and are a really nice piece of kit .I am sure Tarpen did not manufacture them in house but “bought then in ” as they are so far
unlike the 2 stroke engine which is a cheap and nasty construction that uses that horrible useless alloy “MAZAK” for its drive train
(crumbly useless metal that is no good for anything ! ) than is possible .
The Tarpen 2T engine has no “fan” blades on its magneto ,therefore it requires a seperate fan to pass air over the cooling fins ,without this flow of air the engine would quickly overheat and seize up .
Now if you look closely at a photograph ,you will see the large fan drive pulley is actually on the driveshaft of the Dynamo and directly on the engine ? IE it is on the wrong side of the drive coupling .
Tarpen Fan Unit
Note that when fitted the small fan drive pulley is a good 6 inches away from the engine, in the photo below it is the casting right up close to the pulley and the small pulley is directly inline with the belt .
Driveshaft Details – the pulley on the left is on the Dynamo and drives the fan belt (literally)
Now on the engine as bought the driveshaft coupling was missing and the prvious owner had simply bolted the two drive flanges together , extended the drive with a seperate driveshaft bolted into the left hand flange and attched the pulley accordingly – hence no way of driving the dynamo .
Not a problem says I – replace the drive coupling and keep it as it was designed –
So original rubber drive couplings do not exist -stock ran out years ago
chances of getting one – zero,short of buying a complete generating set with one still useable which is a total waste of the rest of the set ETC ETC
so make your own !