I was curious what octane levels I could run in my MB 5500, eagle roller rockers, eagle rods, push rods, iron mountain heads, 42mm mikuni single carb, pistons, stock camshaft.

I am not sure what the compression ratio is on this engine?

What is the duration and valve overlap of a stock vanguard camshaft?

I am thinking of running a 92 octane with no ethanol and a additive made by Klotz that will raise my octane to 100, but i am not going to waist the money if it is warranted...If someone could tell me the compression ratio and the duration and valve overlap on my engine that would answer my questions about the octane!

Thanks For the Help!

that motor has a bps cam not a stocker. ? all you need is a dial indicator and a calculater to figure your cam specs.

I would think the specs on the cam could be found with a search on the MB forums or for sure a quick call to them tomorrow. Regardless I would think 92/93 octane should be fine. I've never heard of that additive before but just now reading about it the stuff does sound impressive. Helps control water in fuel, stabalize oxygenated and ethanol gasoline, protects from fuel breakdown for up to 18 months all in addition to raising octane numbers. Heck man if you can afford it throw it in with super and call it a done deal.

Russ

Plain ol supreme pump gas is good enough, but run the Stabil if yall have ethanol. That's all I usually run & never had any problems with it. Sometimes I'll throw in a lil octane booster for a lil extra kick, but it's minimal results from it.

Yall do know that Octane rating is the resistance it ignite right? It alone is not a power adder.

Yes, I know it does really add any power, but when it's 110 outside & you're only running pump gas, sometimes you'll have a lil engine run-on after you shut it off. Adding the oct boost helps to prevent the run-on in most cases.

^ you got it!

what yall run in a stock gtr?

Yeah I run the cheap shit. It's a lawn mower engine what would
You run in it. Modded out I understand higher octane but mine stock. If it starts running funny I put that carb and injector cleaner additive. Seems to to the trick I do put 21 gallons worth of additive in 6 gallons

I ran 87 and it dieseled after shut off. I witched to 93 and no more dieseling. Now with the stage 1 93 is a must to prevent preigniton.

Regular Unleaded should be fine in a stock motor.

If the gas is going to be setting for over a couple weeks and has ethanol in you certainly should add the marine stabil to it as well as a water seperator. Any form of Alcahol/Ethanol is highly succeptable to assorbing moisture out of the atmosphere. A water seperator won't protect a carburator that has been setting with fuel that is 10% Ethanol. If it sets in a carburator very long it will start to deteriate the aluminum due to the moisture it absorbs from the air. This is even worse if you live in a humid region.

In your 5500 I would run 92/93 octane. If you can find non ethanol fuel in your area that would be even better. If you have to use enthanol blended fuel then add stabil ethanol addative it is blue and you can get it just about any where. Mudbuddy use to put a sticker on the modded motors, above or below the key switch, that said to use 93 octane and let the motor idle for a minute before you shut it off to prevent backfiring.

Gator-Tail suggest 93 octane so thats what i run, i put 87 in it and didn't like it to much dieseling like Maxxis said, spit and sputter every once and a while, so its 93 for me

Every other tank i will put a half of a can of SEA FOAM and havent had any problems

Unless you are having issues with detonation/knocking there is no need to go to a higher octane. Just try good non-ethanol fuel.

Although we are now running E-85 in our stock car engines up here.