carb damper oil

[Lord Flashart]

What's everyone using in the top of their carbs?

I use 20/50 but I recently read one of the classic car mags that said use the lightest machine oil that avoids spluttering.

Are there any performance advantages to a lighter oil?

 

Flash

[Don Elliott]

Paul - Back when you could only buy single grade engine oils, all TR owners talked about using the oil that we were using in the engine. That is, in the summer I used SAE 30 weight and in the winter, I used SAE 10 engine oil.

 

In the last 10 or 20 years, special oil has become available and is labeled "Oil for SU dash-pots" - or something like that.

[Lord Flashart]

Cheers Don,

 

I`ve seen the SU oil in my local parts shop, but the bloke behind the counter swears that it`s a gimmick and 20 50 is the best stuff. I was just wondering what others opinion was on this matter.

 

Paul

[Dazzer]

As an ex BL mechanic of the era, always used 20/50 or whatever you put in the engine

 

If you use an oil that is too thin it will not dampen the upward movement of the piston, which in simple terms will weaken your mixture off and give you a flat spot or hesitation.

 

Unless of course you run over rich.

 

Cheers

 

Darren

[vivdownunder]

What I think Don is referring to is Penrite SU Carburettor Dash Pot Oil which comes in a 125mm plastic bottle, and is a fairly lighweight oil that suits the SU carbie very well for everyday use.

 

I used to mix my own by diluting SAE 30 gearbox oil with light machine oil, to get around SAE 20, and the Penrite dash pot oil is about that viscosity.

 

As an aside, the late owner of Penrite, a friend and fellow TR3A owner, built a huge global business supplying the best possible lubricating products for vintage, veteran and classic cars. His analytical research and practical testing of new products was legendary. (no commercial interest)

 

Outside his family and business, John D's passion was historic racing cars, and his collection and workshop, where he reposed every day for lunch, was something to behold.

 

Regards,

 

Viv.