Hi all, Sharing an observation ... not sure why. A buddy has a dune buggy powered by a Corvair engine with oversize cylinders and the factory carbs which he rebuilds and is really familiar with. He started running av gas in it around 15 years ago. The thing he noticed when running av gas is the accelerater pump diaphrams would rot out and he would have to replace them regularly. Some guy told him to add a bit of tranny fluid to his fuel and that stopped the problem. About 5 years ago he decided to use Marvel Mystery Oil which looks and smells like the same thing. Any theories, whether its MMO or tranny fluid, why this stuff seems to stop the rubber deteriorating? I am running a fuel line which is supposed to have a very short life with todays fuels and I'm not seeing any deterioration yet. When guys installed rubber fuel lines that deteriorated from new fuels how fast did this happen? Probably had to remove the line to see the damage or could you feel the hose swelling or getting soft? cheers
The old timers, flying Cessnas with rubber fuel bladders, such as the 195, say that a little Marvel Mystery Oil in the aviation fuel keeps the rubber supple and free from cracking. I think the mix is 4 oz. of MMO to 10 gallons of 100LL aviation fuel.
Install Dave Helms' fuel line kit and never worry again, never spend any $$$ on additives. It's that simple!
There's other reasons I run MMO ... one of which is my motor compression is close to 13:1 and it helps prevent detonation and heat with street gas. I back the timing down to 32 degrees and no detonation. Whenever I put race gas in and bump the timing back up it's insane. Also, since I engineer and manufacture my own EFI bits I think Dave's kit only has one hose that will fit my car . Thanks for the post about the airplane guys. My dune buggy buddy will be glad to hear someone other than him thinks it has a benefit. cheers
The aircraft industry has been successful in keeping the alcohol and other additive's out of their supply chain due to sound arguements regarding things falling out of the sky. Adding oil to protect those bladders is based on logic that eludes me. I have aircraft rubber bladders from the early 70's in my old CanAm race car that only see's race fuel, to this day they remain supple and leak free. As both MMO and ATF are high detergent oils there may be added benefits of one kind or another in keeping the chambers clear. Strange as it sounds I am doing some on going testing with the old 1950/60's Castrol R, two cycle race oil, the Original "Green" oil. If it fails to do what I hope it will at least the smell brings back fond memories of the track many years ago. Regardless, oil mixed into the fuel effectively lowers the octane rating and that must be watched closely. The problem with the rubber degradation is far more pronounced when the fuel is allowed to sit and serperate, usually starting around the 30 day mark. Using the car on a regular basis keeps the seperation from occuring thus lessening the chances of that failure. Dont let this lull you into a false sense of security, the degradation starts on first contact and we have whitnessed hose failures within 20 mins on new hose just off the spool. I have a few Ferrari customers that are Chemical Engineers who have attempted to help me identify a 'mechanic in a can' solution to protect the rubber and/or delay the seperation of the gas from the alcohol/water/additives. As of yet we have been unsuccessful in that quest and have not found anything that lives up to the claims. That effort started before we designed the fuel hose and continues to this day.
