I have just switched my dragster over from gas to alcohol (methanol). I have a couple of questions about timing and spark plug choice. The engine is a 572 with 440-1 heads, Ross Flat top pistons, 14:1 compression, APD alcohol dominator carb on a 440-2 indy intake.

The timing that I found to be about optimum for 110 race gas was around 35 to 36 degrees.

When on alcohol, do I leave the timing in this range or do I increase or decrease it?

I have been running NGK -8 plugs for 110 race gas. Do I run a hotter or cooler plug for alcohol?

Thanks

bob Spelic

Indy told me to run Champion C59CX plugs in mine. They seem to work well,also I have run my timing @ 35 degrees so far. I am still learning how to run alcohol,but so far its been great.
There are a lot of others on here that hopefuly can help you a little better.
Maybe we can compare tune ups as we both get our set-ups right.

sure, once I get done with the carb and the rest of the tune we can compare notes.

I am hoping someone can share some timing information. I talked with guys at the track and they say add timing to your gas setup and others say take 4 degrees out of the timing. Right now i let the timing the same as my gas setup and that is 35 degrees.

I just assumed I should run a heat grade colder plug, but I couldn't find written advice so I thought someone here might be able to share that they found out that works as far as plug heat ranges.

Any experience would be appreciated.

Bob Spelic

I am looking for the same answers,so far the best plug is two steps colder than ar13. My timing is at 33 but this weekend i am going to run 35. I will report results. I am running a rons terminator,last time out gained .03 by indexing the plugs and running a shorter reach plug (was too close to the dome)egt also dropped.

When I swithed from gas/carb to alky/Toilet a few years back I kept the #8NGKs in and left the timing at 38degrees and it ran great, Combo; 500" w/ IndyEZ-1s. Since then I have switched to NGK#9s with no noticable difference and run my timing at 35-36degrees. best of luck with it.
Curtis

you can almost always add more timing over a gas set up, id use 38 deg. some chevy guys on L/M dirt cars use as much as 44 deg on alcohal but wouldnt dare try it with any grade of race gas

In my experience with motors that size take out 3-4 degrees on alky. I prefer to run a -9 or -10 plug. NGK r5671a-9 is a good choice or autolite ar3933. I have been running ar 3932 which is a -10 heat range cut back electrode with great success also.

The Mopar engines seem to want more fuel than the Chevy's. James Monroe says he has Chevys that make HP and take less fuel than mine.

Had been running 33. This weekend tried 35, engine temp came up quicker which is good and egt dropped slightly to 1100 picked up acouple of hundreds to 330,but hard to compare as it was 95 degress and marginal track. Then went to 37,engine temp up noticeable and egt way up,1250/1300. So I will probably stay at 34 which is about the same as is i was running gas.I parked next to a super comp olds running off the stop 8.30,says he never goes above 35,this is a 622 chevy.I am only at 440 cu,around 775 hp,15/1 720 roller,so the answer is eeach engine has different needs based on a lot of factors ,i would be conservative and err on the side of caution.

I raced this Thursday at a test and tune, and I started at 30 degrees and 177 jets. Bad miss past the 1/8th mile marker. Increasing to 188 jets and miss went away and performance was a 8.15. Went to 196 jets and no miss but slowed to 8.18. Changed to 35 degrees and car slowed to 8.20. I could not get over 160 degrees with just running the water pump.

Saturday I left timing at 35 and lowered jetting to 192, Different day and different weather, performance was a 8.18, and 8.14 then an 8.20....no consistency! Sunday tried again with no changes, 8.18, 8.14, 8.17. I still cannot get any more than 160 degrees even with a lean out valve. I still think it's moving around too much and not generating any heat has me concerned I'm still way off in tuning.

Do you think I should go to 188 jets and leave timing alone or mess with both?

Thanks for all that responded!

Bob Spelic

Bob the best thing to do is leave the timing alone and play with the jetting. I would say timing at 32*. Put the 188 jets back in and give her a rip.

After that I would lean on it a bit to 182s and see if you have any performance change.

Not getting over 160 seems a little cool to me which would indicate you may be a bit rich. However in talking with some guys on Methanol their cars run the best with the temp staying low around 160-165.

What HSB/Intermidate Bleed/Idle bleed to you have in it?

I do fell I am beginning to make a little progress. It's slow and hard to do on race day, and having no previous knowledge with methanol I do want to be careful.

The current setup is .062 idle, .045 intermediate and .023 high speed air bleeds, jetting at 192 and timing at 35.

AJ, thanks for the tip. I will try the racing this weekend with the timing at 32, jets at 188. If it still doesn't make any heat I will try .182 jets. I know that .177 missed at higher RPM, but I just took a guess that the miss meant the same as with gas....lean!

Bob Spelic

I cant reccomend a carb tune, but I did run a very similar combo in a digger also. Same heads, intake a hair more compression 20 or so less cubes.
My engine was very sensitive to plug gap..Note that if I increased gap to .040+ the car would slow near a tenth.
I ran a old self modified Toilet injection. The car was a easy mid to high 7 second car in the middle of July.
So there should be a little more left in your combo.
My engine/drivetrain was thrown together by me with swap meet parts and self tuned. Pretty large learning curve but I overcame most. I really felt it should have been a half a tenth faster though..
The converter I was using was all wrong, which it was a friends made custom for his small block Chevy car @ about 3000 lb car.
It worked OK. The car 60ft in the 1.06-1.07 range, no matter what track I took it too. The last pass it went 145+ in the 8th down at the Clay City Ky Mopar Southrn Classic show...
Anyways.
The temps is a good tuning tool for a alky car. The car should gain about 6-8 deg in temp from the launch to the stripe. As soon as you let off the throttle it will cool.
My car would burn 2 1/2- 3 gallons per pass from the pit to pass back to the pit, depending on where I run..Like clay city has a long return road etc.

My 440-1 heads ran the quickest on "gas" at 35 - 36 degrees.

Switched to a Terminator on meth, and on the Dyno the best power was at 36 degrees...

They tried 34 and lost a bit, and tried 38 and it was about the same as 36, so no sense stressing the bottom end,

440 Jim did some timing testing at the track, so maybe search for his post.

Good luck!

Arnie