Spark Plug indexing

[George]

I am considering trying spark plug indexing . I have read several online articles and not sure it's worth the hassle. What's your opinion?

I have a 13.4 : 1 SBC ,355 CID, Dart 230 cast iron heads, Hilborn stack injection, alky, MSD 12LT mag. I have no interference problems with spark plug to piston. Running NGK 8,gapped at .018.

Thanks . George

[Frontenginedragsters]

George:
 If you have no interference problems now, I doubt that indexing would provide any improvement.
In the old days when we ran stock 461 castings on a small block, we had to index.
It was typical to angle mill those heads .125" to .150".
This brought the spark plug right to the deck. I found that if you indexed 180* from the normal - meaning you
pointed the ground strap up, the combustion chamber could "see" the spark plug.
I believe your Dart heads have the spark plug slightly higher than the old Chevy castings and you dont have to cut them so much.
By the number posted in your personal box, your little small block hauls ass!
Tell us more about your combo. Whats it run in the quarter mile?

Matt

[masracingtd1167]

Here is something we found . I am not 100 percent shure this worked but I would like to share it with you guy's . I run injected alcohol with a tunnel ram manifold . When I started spraying it with Nitrous we would sometimes burn the side electrode off of a plug ! The funny part was that it would be different plugs every time . I always index my plugs but between 3 and 6 o clock was good enough or so we thought . Even with a safe tune up It would burn a plug but never the same cylender . Finally we tried indexing the plugs very carefully so the open part of the gap was facing toward the intake valve . From then on we never burned another side electrode . I guess the cool air and fuel would keep the electrode from burning . I would be interested to see what you guy's think about this.

[George]

George:
 If you have no interference problems now, I doubt that indexing would provide any improvement.
In the old days when we ran stock 461 castings on a small block, we had to index.
It was typical to angle mill those heads .125" to .150".
This brought the spark plug right to the deck. I found that if you indexed 180* from the normal - meaning you
pointed the ground strap up, the combustion chamber could "see" the spark plug.
I believe your Dart heads have the spark plug slightly higher than the old Chevy castings and you dont have to cut them so much.
By the number posted in your personal box, your little small block hauls ass!
Tell us more about your combo. Whats it run in the quarter mile?

Matt

Matt, It's been on the dyno making 640 hp. It's got Hilborn 327B 2 7/16", Waterman 400, 16As nozzles, usually start with an 80 bypass. Heads have been ported, no welding or putty. Scat std. weight crank and Callies rods. Ross pistons 13.4:1. It's been very reliable. It has only been on the 1/4 at Bowling Green Ky. That was the HHRR 2010. We were just figuring thing out and with the help of Scott Parks we got it to run 8.32 @ 155 mph. At that time we were running a Hoosier 12x29 tire. We soon changed to the Goodyear 2585 and went from 1.12-1.15 60' to 1.06-1.10 . We also bought a Race Air and got better with tuning.( Notice I didn't say good) Also improved the engine heads, compression and cam last year ( was 607hp).   I would guess we could get it into the low 8s now?

The reason I am considering spark plug indexing is we tend to run best when it's rich and we are getting what I think is too much fuel in the oil, even with a vacuum pump. I'm thinking if I index toward the exhaust valve it might help. Don't know but I'm looking for others to share their tune ups?

Thank for your input. George.

[masracingtd1167]

George it may not be too rich . How hot are you getting it? and how much dose the temp increase durring a run?

[George]

George it may not be too rich . How hot are you getting it? and how much dose the temp increase durring a run?

I have a themocouple in just one cylinder and it will only give me the high temp. So after 1/8 mile run I see 1000-1100F. I have seen hotter temps BUT it may have been caused by alky burning in the upswept zoomie.

[masracingtd1167]

George I have never had much luck using E.G.T's for tuning mine . Like you said fuel burning in the pipe can cause high readings even if it is too rich . We were getting milky oil and thought that we were too rich and went slower and still had milky oil! I wasn't paying much attention to engine temp we would warm the car in the pit's and tow it to the lanes . One day I looked at the temp guage at the end of a run and it was only 140 degree's ! We started driving the car to the lanes to build heat in the motor and it worked well for us . I try to stage at around 160 to170 degree's and at the end of the track it's around 180 and bingo no more milky oil . If you are going 1.06 at the sixty ft. that is really good and 5.08 at the 1/8 you can't be too far off on your tune up . Sound's like 7 second potential too me! If you have some time read some of the articles that Spud Miller has posted on this forum .Very interesting stuff ! Good luck with your racing this year . and post some pictures of your car !

[George]

I may try bringing  the car up to the staging lanes with the engine running. It's for sure the engine runs better with a good heat soak. I installed a heater in the oil pan and made thermocouples for both the transmission and engine oil. They are installed in the drain plug locations. Before we start the car , I try and get the oil warm and turn the engine over with the block mounted starter . I crank the engine wo/ ignition until the oil pressure comes up. I have helped with a car running a dry sump and I think that's the ticket for pre-warming the oil and getting it circulated without starting the engine.

Oh, do you run coolant in the engine? We do not.

Thanks for your input. George

[ricardo1967]

Great discussions guys!

[masracingtd1167]

Thank's Ricardo This forum is a great place for us to share information with each other . Most of the other forum's like Bracket Talk and Yellow Bullet are not really geared for what we do . Racing a F.E.D. is much different than a R.E.D. After seeing what George is going on his 60ft's I am thinking about going back to those 12x31 Goodyear's if I can get a set.

[George]

Checkout the Southwest Junior Fuel Forum.   http://www.angelfire.com/tx/fuelcarfan/jrfuelers/results.html

There is a thread on the purchase of the Goodyears. Last set I bought used from Scott Parks. Too bad someone else doesn't make a lightweight grow tire.

Good racing. George

[ricardo1967]

Thank's Ricardo This forum is a great place for us to share information with each other . Most of the other forum's like Bracket Talk and Yellow Bullet are not really geared for what we do . Racing a F.E.D. is much different than a R.E.D. After seeing what George is going on his 60ft's I am thinking about going back to those 12x31 Goodyear's if I can get a set.

Thank you Bill and everybody else here for sharing precious knowledge with FED rookies like me.

[coupemerc]

I will have to index the plugs on my deal because I'm shooting for a max compression piston dome. But I would index anyway. Why not? If you don't do it, the guy in the next lane will. All it costs is some time. 

[George]

I will have to index the plugs on my deal because I'm shooting for a max compression piston dome. But I would index anyway. Why not? If you don't do it, the guy in the next lane will. All it costs is some time.

It will take tapered washers for my deal or a lot of spark plugs. How is the plug indexed in relation to the intake valve? Injection ? Fuel ? Compression ?

What's it worth on the dyno and/or track?

[coupemerc]

I'm shooting for the spark plugs having the open side of the gap somewhere between facing down towards the piston top and the intake valve. It's on a Kinsler 2.875" stack injector, methanol and CR will be around 16:1 (maybe). I have no knowledge on what indexing is worth on the dyno or track.