Author: Dave roberts (---.milt-b-1.access.uk.tiscali.com)
Date: 05-19-05 17:51

We have a 740 Stanley and have been told that we should use Hexane instead of petrol as the latter cloggs up the jets. Is it possible to use petrol instead, as Hexane is extremely pricey?

Does anyone know of side effects associated with using petrol?

Dave



Edited 1 times. Last edit at 05/20/05 03:12AM by Jeff Theobald.

I've been informed that hexane is the fuel to use in the pilot fuel system only.

Leaded petrol does clog everything up with lead. I don't know what happens if you burn unleaded in a pilot, but I guess it clogs up with something else ese.

I donlt know what you should use in the main burner fuel tank in you car, I expect it was orginally built to burn kerosene as my Model 607 was. Its new burner is set up for a 50-50 (unleaded)petrol/diesel mix

Petrol is fine for main burner jets but tends to block small pilot jets. Petrol is designed to be atomised but when boiled tends to produce a nasty black treacle which can foul a pilot jet several times a day.

Hexane is expenseive but so is everything else associated with a steam car!

Another option is try Coleman fuel that is used in camping stoves. The Maxwell pilots that some Stanley's were made to use Coleman fuel. It not as cheap as gasoline but it is cheaper than hexane.

Alan

Author: Mike Clark (---.glfd.dial.virgin.net)
Date: 05-20-05 18:23

Hexane boils at 69 degrees C whereas petrol has some fractions in that need as much as 225 C. The point of this is that many pilots struggle to get the fuel to the jet at a high enough temperature to keep petrol vaporised and will only work properly with hexane. Coleman fuel is a more refined version of petrol - possibly has less of the high boiling point fractions in it - if it is the pilot you are thinking of then probably hexane is easiest but you will just have to try it in your car. If it is not vaporising properly the flame will be very yellow and smokey and you may hear the liquid fuel hissing in a wet sounding way.

Can only add to Howard's comment re main burner fuel by saying that the length of the vaporiser and probably how high or low it is mounted is important - mine is six feet long and about 1 - 1.5 inches above the burner plate. That works perfectly with 50/50 unleaded and diesel. If I go up to 60 diesel I have unburnt fuel going through into the exhaust flue and make lots of bangs.

Be very careful when firing up from cold not to force the burner before the stream of fuel through the jets has gone to clear gas - if you do you will get a pool of liquid, condensed diesel in the bottom of the burner which can lead to very exciting moments when it eventually catches fire! This is also a problem if you burn 28sec heating oil as some do.

Mike



Edited 1 times. Last edit at 05/21/05 03:54AM by Jeff Theobald.

oooh - I see my post in another place has migrated here - no problem for me but perhaps Jeff you should put such tranfers in quotes.

I can bore for England on petrol in pilots so will just comment that I've never used anything other than unleaded petrol but have had a lot of work to actually devise a pilot that really works well. I have now got there but want to put a few more road miles on it before I tell you how I did it - one for the Steamcar at the end of this season. The secret is keeping the fuel hot til it gets to the jet and making the pilot strong enough to reliably light the main burner - to achieve this requires a better way of entraining air than just poking a jet in a hole.

A good pilot should be just short of being strong enough to maintain boiler pressure while standing. This means running at 850-900 on the pilot tell tale - if it won't do that it's too weak. Maxwell pilots are good at keeping the fuel hot because it is all inside the burner but the vaporiser is just too small to produce enough heat and there is no way of boosting it up.

Pilots without a needle through the jet do tend to block but generally with detritus in the fuel rather than the treacley stuff Peter mentions. Carboning up is a source of blockage if the pilot vaporiser is too hot.

Mike

HELLO.
I have a io hp ex and i run the pilot on unleaded petrol
i have had no proplems at all in the last 500 mls.
all the best john.