Classic cars forum & vehicle restoration.

[oldtimer]

I have long believed these engines were invariably lubricated by a fuel/oil mixture but I met a chap very recently who claims that a British firm designed an engine where the fuel and lubricant were not integrated in this way.He further believed it had stepped pistons and,having been a motor cycle buff in his youth,that it may have been a motorbike maker that conceived this design but was unsure whether such an engine ever made it into production or off the drawing board or in fact if it ever existed !
I had a vague recollection of mention of "Stepped pistons" sometime in the past but in what context I can't remember and I have racked my two remaining brain cells in vain.
So I have recourse to you chaps as usual to sort fact from fiction in the longsuffering way you have always done previously.My thanks in anticipation.

[Penman]

Hi
This is a quote from:
http://en.wikipedia.org/wiki/Two-stroke_engine.

If it doesn't answer your question maybe the rest of the article might.

[oldtimer]

Hello Penman,
My thanks for your reply and information.It very much looks as if this was no more than the figment of someones imagination or a sort of Holy Grail
that was searched for but never found.
John

[roverdriver]

I am sure that I have read of a 2-stroke motor cycle, pre 1920, that used a separate tank for the oil, and that oil was somehow inducted into the crankcase. I have got rid of all my motorcycle history information, so unfortunately can't look it up for you.
_________________
Dane- roverdriver but not a Viking.

[Jim.Walker]

[Keith D]

Jim,

I think the motorcycle with two pistons in parallel cylinders was the Puch.

In the 1970's, the Jawa used a separate oil tank. However, I always used a pre-mixed fuel in mine! That way I knew I wouldn't seize the motor up!

Keith

[Jim.Walker]

[RotaryBri]

The German motorcycle with the stepped piston was the TWN (Triumph Werke Nurenberg) and made in 125 to 350cc sizes in the 50s and 60s.

The Pre-war British two stroke with a separate oil tank was the Velocette GTP, 250cc.

There was a prototype two stroke British engine with stepped pistons, in the 70s I believe, designed by Bernard Hooper when at Norton Villiers in Wolverhampton and was called the Wolf. It never went into production.
_________________
Keep Torqueing,

RotaryBri

1976 NSU Ro80

[oldtimer]

Hello Rotary Bri,
I feel sure your submission is right on the money and ties in with the assertion that there was a British input as an attempt to tackle the problem of separating fuel and lubricant in two strokes.It also seems likely that the attempt came to nothing,for whatever reason,if it never reached production. My thanks to you and all the other chaps.
John

[roverdriver]

The Excelsior 2-stroke 2 1/4 h.p. motor cycle of 1916 is listed as having- 'petrol tank capacity 1 3/4 gallons, oil tank capacity 1/2 gallon.' Obviously not a machine that used pre-mixed fuel.
_________________
Dane- roverdriver but not a Viking.

[oldtimer]

Hello again Dane,
I probably did not make it clear at the outset that my query related to an engine which not only fed the engine and lubricated it from separate tanks initially but continued to keep them separate on a continuing basis as is the norm in normal four stroke setups.Apologies for any confusion I have inadvertently caused.

[roverdriver]

Thanks Oldtimer, now I understand what you mean. Rather like some of the 4-stokes that had a 'total loss' lubricating system!
Seems to me that it would be possible, although the oil would end up burned anyway. Should such an engine have existed, it would be interesting to know the engineering theory and reasons for doing so.
_________________
Dane- roverdriver but not a Viking.

[Jim.Walker]

[Inglewood]

Google: Doppelkolbenmotor

[Churchill Johnson]

Ref the Zundapp twostroke engine's they did not make any two piston engine's, i still have a 70cc engine from a late 50/60s Zundapp moped,it was the Puch that used a charging piston,known as the split single.