So can anyone tell me if running a 10:1 350 on a steady diet of 100LL avgas will hurt it in the long run?Avgas does have lead in it and i was curious if the lead would build up and cause damage to the engine?I work a an airport and basicly can get all i want for free

 

yeah i have a friend with a 78 nova that has the same set up, and he wants to know if it will hurt his motor as well.

 

I would think if you are not running cats or 02 sensors , probably wouldn't hurt anything . Lead was used as a lubricant in the older engines requiring leaded gas. One thing that has been said by some racers to me is avgas is not as good as racing fuel because it has de-icer that knocks down the octane rating . I don't know how much truth there is to that.

 

The local 100 octane low-lead AV gas that we have been useing tested to have a higher octane than the Sunoco 115 race fuel by a fuel density tester that we have for testing the local circle track racers.

 

you can run it.. but you are wasting your time and money with only 10:1 compression

 

how is he wasting his time or money he gets it for free.

 

AV gas is rated as a MINIMUM octane. It will generally test much higher than that (the suppliers play it safe). I remember reading somewhere that it wont produce as much power as race gas because it is formulated for high altitude flying. I ran it in my 12:1 406for a couple of years with no problems.

 

Yeah, i wouldnt run it in a 10 - 1 motor.

 

x3....No reason...but wont hurt it. A couple guys around here have used it for years.

 

Well all i was wanting to know is if it would hurt it to run it all the time.I have noticed that it starts up easier with the avgas and runs much smoother than on 93 auto gas....as i said i can get it for free and i know it will run just fine on 93 octane,but hey if its free why not?!

 

totally un-necessary. 10.1 is pump gas friendly lllll day long. higher octance just burns slower to keep your pistons cool and help prevent detonation. i wouldnt waste your time. or you could get the fuel free. sell it by the barrell to the local ricers and tell them its the cool thing to do. then pay for pump gas =)

 

it would be wasting his time if he went to all the trouble selling it to ricers and then taking the money and buying 93 when he could just put it into his car and save himself alot of trouble. i know he doesnt need it for his car , but thats not what he wanted to know he wanted to know if it would hurt his motor running it.cuz he can get it for free and i guess he is getting it pretty easy with him working at a airport and all.

 

I would use the hell out of it if i was spraying the engine.

 

Well for what it is worth. I had an 11-1 355 mild cam with mondo duration. 2500 stall th350 and 4.11's besides the white deposits it left on the plugs and the higher rpm stutter. that was on an av gas mix. When i ran straight 92 (mainly because that is the octane they had) Those problems were not there and it ran much better. gasoline is rated the research and motor way av gas is not. So if you like your car to not run as good sure go for it.

 

Nah it shouldnt hurt a thing. That av gas is more similar in quality wise as gas ur 98 oct back in the 60s, thats why there were so many engines with 11:1-12.5:1 compression back then. They remove lead from gas nowadays cause of the epa crap

 

It doesn't matter long term, as he won't be able to get it for more than a few years. Rumor has it that EPA is illegalizing the use of Leaded fuels in aviation.

Reasoning is not many new planes require leaded fuels anyway and some people with recip engines have already got Supplemental Type Certs. to run auto gas anyway. The only planes that still need leaded fuel's are the WWII warbirds and earlier using 2800cid+ supercharged radial engines. Those planes doing airshows and such will probably end up using racing gas after this law takes effect.

 

yeah that is very true stroker ss....the EPA is gonna make the aviation industry use a diffrent fuel for piston engine aircraft.I refuel aircraft and i see alot of the aircraft with lower performance and low compression engines with STC's for mogas...the aviation fuel industry is already looking for a replacement.they actually are looking towards developing a new fuel thats very simliar to racing fuel but they having to get the other additives to blend with it for aircraft use......but until the im gonna run all the 100LL i can get.

 

The av-gas will be fine, it burns a little dryer, so to remedy that issue i put a little Marvel Mystery oil in it, just enough to tint the color of the gas. I have run it for years with no adverse effects, and it does even better with the addition of the oil. Any motor can use a little extra octane in my opinion, even if it don't neccessarily need it, it sure cant hurt.

 

http://www.idavette.net/hib/fuel/page2.htm

a steady diet will kill the catalytic converters and ruin the O2 sensors. So if your engine does not have those then you aren't really going to hurt anything. But if you're fuel injected and the computer runs in closed loop mode off O2 sensors you will get major performance problems when the O2's fail.

 

Very true on the converters and o2s, i am speeking from more of a carburated perspective.