Chevelles were straight up drag cars. Tow to the track types. Nobody around here ran race gas, there just wasn't any, and plenty of guys had drag cars.
I agree, race gas is a better option than Avgas LL100, but it will work fine and for many years/runs if tuned properly.
Yeah, that's a BIG if. Not something I would do. I wonder if Ben will run it again. I remember Jason telling me he would get it at the airport for his 1971 GS with 12:1. He said the pump asked him for a tail number, he put in 71GS455.
I'm guessing you had a chance to tear one of these motors down.......did the pistons wipe clean very easy. I had wanted to try and tune and run 110, never made enough passes to get around to it. On my ladt 464 it slowed down on race 110, but never made enough passes to full get a tune for it. I had often wondered if the engine speed being 2x of an air plane might cause an issue.......I do know I had to add more jet than ppl though I needed to run
You can have your tune off on vp just as easily as any other fuel, so they're all a BIG if. Doesn't matter what you're running, plenty of guys burn things down on actual race gas. It's not an insurance plan that covers a lean mix or too much timing if it isn't tuned properly. Just ask John Force....I have to put the tail number in as well. I just put some randomness in. Usually just a 1 or whatever because the guys at the airport don't care.
Ben, my Cleveland had a normal carbon pattern, but it had 50k miles or more on it.. The only reason that engine let loose was because Lucas forgot he had the 250 hp jets in it and held it open for over a mile, and the head broke off a Manley intake valve at 7800 rpm on the way back to his 10 year class reunion.. Now I can tell you on the massive amount of 2 strokes I've ran and run on avgas that everything had wiped clean very easily. They usually have a white coating from the lead that wipes off with a rag leaving everything clean, even in the expansion chambers, and two strokes are a lot "dirtier"....just glanced this thread over as I said. My question that you may have answered already is, did just the one bad cylinder come clean? Is it possible maybe a headgasket let loose? It does seem like you had some pre ignition in that cylinder, but why just the one? I've had engines let go because of ignition passing between two cylinders that were next to each other, the one 2nd in the firing order getting damaged. Obviously coolant leaking into that cylinder can also make it clean and ping itself to death.
You got 7 cylinders looking good, right? That's not a tune issue. Something happened in just that one. And yeah, sometimes things just break unfortunately. Read my pucker factor thread for example. Parts fail.
They all wiped clean the same way....#4 took a little more force, but I had a valve seal or guide issue on that cylinders exhaust valve........that piston was slightly stickier in the carbon coating..... But still just dry rag. The only bearings damaged were 5 and of course 6 sitting right beside it.....the other bearings as seen in pictures are almost new looking
The only other thing I noticed that I cant figure out was on #3. You can see the spot in the center lower......its a little bump and it had no carbon on it when it came out. I took pictures from several angles I'll add the piston from #2 on zoomed in on the picture and see what jim thinks he sees......from the picture it looks peppered and pitted on the surface........in life its not....its a reflection from my new led lights I was holding it under........
This is what thought too, if I beat 1 bearing to death so bad what wouldn't some on the others show some sign of the same thing happening? Its nice to hear someone not instantly say the fuel is junk ass garbage. I agree there is better options out there......just not sure the gas is a junky as some think. I never had to give a tail number, just show up and pump......hell at Norwalk they have a 24/hr self serve pump......I've run out there b4 and taken the golf cart to the airport and bought a couple jugs
I'd say them wiping clean is a combo of lack of run time and the lead coating the parts as I stated. No, avgas isn't the devil, I've heard that for years and I also know that plenty, as in thousands and thousands of guys, have run it way more than anyone on here has probably ever run their cars without issue. Saying "well I seen a guy blow his engine up on it" isn't an excuse. I've seen more guys blow things up on "good" race gas, and that doesn't mean it's bad ...something happened in that one cylinder, and that one alone. The fact that the others are OK is common sense proof of such, and I'm assuming you ran avgas in the previous engine with no issues for many runs before. The fact that your car slowed down when you added more octane proves it doesn't need more octane, unless you could've thrown more timing at it to make it up. For the quickest times you want to run as low of octane as you can get away with because it burns faster, then run a little more for safety.... Need to figure out what mechanical issue happened or just an unfortunate parts failure, despite using good pieces....unless, that is, that all BBB engines pre ignite on cylinder number 5 and only number 5 first as a rule....
I've been running it for about 20 years, when I got my prosystems carb I did have the change the jet sizes front and rear about 6 or 7 numbers up. I've found I've had to run bigger jets than most feel I should. I assumed that could be a big reason why my last motor slowed down on race fuel.......it very possible couple had been very very rich.
Lucas, if you want to run aviation fuel in your cars, go right ahead. All I'm saying is aviation fuel has some differences from automotive fuel. Aircraft operate at altitude where conditions are very different. If you tune for it in your cars, and run it all the time, and it works for you, that's great. Not my choice for other reasons, not the least of which is, it isn't that accessible for me. I think it might work for my 10.5:1 engine, if I tuned for it, but it might have cost Ben his engine. Not sure we will ever know for sure at this point. The bottom line is if you detonate an engine on a continual basis at sustained WOT, you will hurt it. This applies more so to a BBB thin wall casting block that was never designed for the power and especially the RPM that we sometimes run them at. My engine runs great on 93 octane unleaded fuel. If I go to WOT, it is momentary at best on the street, but at the track, it's easy enough for me to add in some leaded race fuel for the insurance it gives me. Is it too much octane? Does it slow me down? Maybe, but I couldn't care less. I've run the car enough to know what it runs, and I have the time slips to prove it. My enjoyment is mostly street driving. I realize that others may have different priorities. Aviation fuel isn't worth the trouble to me. Jim Weise built my engine, and I followed his recommendations as far as oil and fuel goes. From his posts (starting with post #7) in this thread, I gather he isn't a fan of using 100LL Aviation fuel. People blow up engines on all kinds of fuel. I know that. Years ago, at Cecil, one of our club members was running his Edelbrock headed BBB. I kept seeing him re jetting the carburetor, and when I inquired, he told me he was leaning it out because every time he did, the car would go faster. I said to him, yeah, lean is mean, but if you go too far, it will detonate. I asked if he was running some race gas in the mix. His response was, "Race Gas?, this is a pump gas motor". I said OK. At the end of the day, I saw him pushing the car back on the trailer. He told me it was pissing coolant from between the block and head, head gasket. Weeks later, after replacing the head gasket, the engine started blowing the freeze plugs out of that side of the engine, diagnosis? Cracked block.
With the help of Kenny Betts setting it up, I plan to ship my failed part to molnar for them to look at.......I've been crazy busy this week and haven't gotten around to it yet, be interesting to hear what they have to say too
And there is a good chance that my cheapness cost me the motor, but there is 5 dollars a gallon in price in it. Everything in this setup was speed to me using this fuel when it was built......so its not like I made my mind up after the fact, the information was given when the motor was built.....
I have to ask Jason what the price for 100LL is/was on Long Island. Is that what you pay, 5.00/gallon? Definitely cheaper than Race Gas.
I haven't bought any this year, I had 20 gallons left over from last year......I was all set to go race in KY in oct till my wife got covid.....when I bought then it was around 5 buck per gallon plus the special taxes they charge for it. Every little air port around here has and sells it no issue, just bring your jug and they pump it.....
I know it can be 30* out and you can spill it on the concrete and the stuff will evaporate in very quick order. It has some unique properties for sure
