Bottle says "don't be fooled by misleading advertising. It takes 10 octane points to equal 1 octane number." It also says it treats up to 25 gallons. It doesn't say how many points it increases the octane. But I see where you are coming from. I've been buying cases of the booster, the big bottles from napa. My Napa guy gives me a great deal on it, $78 for 12 bottles. They sell the bottles $11.99 retail and its $143 for the case retail. I'm able to divide the bottles up each fill up so they last longer. Yeah it's kind of annoying I have to do that but it's not too bad. I always keep the bottles in my trunk and have plenty with me before I go on a trip. Do you think the booster is bad for the engine? This Lucas oil booster seems to work great, I've tried other boosters and it didn't do anything. Engine still continued to deisel. Never does it with the Lucas booster.

I have not checked to see if the carbs are jetted correctly, I can look into that though. They seem to be pretty good, engine is very responsive when I stab the throttle. Plugs are reading good as well, all of them are brown. But they could possibly still need some fine tuning. Cause we were told with my set up, all the engine parts I had and compression ratio that I should be able to get away with running high octane pump gas. But it doesn't want to run on just normal high octane pump gas.


I can't remember exactly all the timing specs, I was planning on going over to my grandfathers tomorrow and use his timing light to check all of that. I do remember that total advance is 36 degrees and it's at 16 degrees at idle. We talked to one of the techs at Clay Smith Cams where I got my cam from and he said that's where it should be. He knew exactly what cam I had in the engine and everything.

I do have domed pistons, they are forged. I got everything from john mummert, he put the whole kit together and said all of those parts would be great and etc. I'm using a WC T-5. It deiseling is never a common problem. In the past when it had desieled, it's because my fuel mixture was off, added some of the Lucas Oil Octane booster, never did it again. Plugs aren't showing any signs of it being lean at all. I've been wanting to run some racing gas through it, but unfortunately it is a little difficult to get it around here. Have to travel atleast 20-25 miles to get some.

Thank you for the advice!

there is one other  thing that could cause " dieseling" upon shutting the eng. off, and that is that the idle may be to high. what I mean by that is that the carb throttle plates may not be completely closed. this can cause the problem. Just another idea that I am sure you have not over looked, but I thought I would throw it out there.

Yes, re check your timing.. Also what Distributor are you using? If by chance it's a 1957-58 distributor, John Mummert says they have too much centrifical advance built in, as the intention those years was to use only about 3* initial. He recommends using the later didtributors with a cammed engine, because of the need to run more initial..


Paul

Hm that's a thought about the carb plates not closing all the way. When it's idling it's at 1,000 rpms. Which is where it likes to be considering the cam I have. But maybe sometimes the carb plates don't close all the way and is allowing fuel to get in the cylinder walls and then ignites it since it's hot? Is that what you're thinking?

I'm running a '62 distributor

If the distributor is only providing 20 degrees of mechanical advance then it is not configured to any factory spec so it is probably not providing too much advance.  It might be possible that it is advancing too quickly, though.

If the carb plates are hanging open, you would know because the idle rpm would be higher in that situation.  If it is always 1000RPM, then that is not happening.  On many entry level carbs, 1000rpm may be too high for the typical method of adjusting idle speed and requires a different method.  what happens is that it will idle of of the main circuit rather than the idle circuit.  I don't know about Holley 2110,s so I do not know if that actually could be a problem with those.


Lawrenceville, GA

Back in the late 60's I had a 0.40 over 312 with 11:25 : 1 Jahns pistons and an RPM300 Isky cam. It required the "white pump" scrubron fuel, guaranteed to be 102 octane, but generally ran around 105. It was before unleaded fuel and comparable to Sunoco 260 or something. Mainly race fuel for the high compression muscle cars. That was a 900-1000 rpm idle, and it would diesel and knock like hell on any lower grade premium. Much like you describe. I could clutch it dead since it was a stick.

I've had limited success with octane booster on an OT supercharged motor. But it only knocked under heavy continuous load in warm weather, after you built some real heat in the aluminum head. Taking 2 degrees of initial timing out of it had the same result. It's a comparable experience, but not a comparable motor.

Check out Charlie's comments on the mechanical advance, that might help.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Miker made me think of a possible band-aid fix.  There are timing controls that allow you to adjust timing on the fly.  That might help you adjust to different fuels.  However, it will be at the expense of performance and given the cost of timing controls, it could be more expensive than simply addressing the issue and fixing it correctly.


Lawrenceville, GA

usual to hear valves banging closed with pipe headers.



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