Technical > Matt Shaff's Engine Shop

Time for a rebuild?

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gasserx:
Again, thanks a lot for your input Jon. This is great information for a rookie like me!!
I learned a bit about reading plugs from a very experienced guy on my second weekend out. He and is son is running a Alcohol dragster (wich i believe has had the european record for several years).
He told me the exact same thing as you, that NGK`s are easier to read (i had Autolite). They also indexed the plugs so that the gap pointed towards the exhaust valve on all plugs, that way they got more correct reading for comparing each plug. He also told me if i did changes to the pills, change at least one plug to get a new reading. He also teached me a little bit on fuel.
They lean until they get burned on the first or second thread, but as he said: do you want to go fast or go safe - fast can be expensive! (The next day they got a window in their block.. but he said no big deal).
Im running 38 of timing (Vertex mag), and it seems to be working good.
Waiting for my engine stand to get back from a friend before i remove crank and rods for inspection. Crossing my fingers all is good.

I am absolutely sure i would have been into the 8`s at the next race with everything i have learned since last time. Higher idle and perfect temp on engine sounds like the little extra i need to get there!

THIS IS FUN!  8)
Thanks again! 

novadude66:
This is a great site with lots of valuable information!!! You can learn so much by reading all these posts!! With my set-up 427 cu. in. SBC, brodix aluminum heads and Enderle hat on a tunnel, I cant get my plugs to burn any of the plating off the base of the plug, am I too rich still? I run a .75 pill with an enderle 80A .5 pump that is new.

JrFuel Hayden:
You are welcome Gass, it is a bit disappointing when I give, asked for advice, and they don't take my advice.
Is your alcohol dragster buddy racing NHRA Top Alcohol racing blown alky or injected nitro ? Blown alky is a different game. i agree with his advice to put one new plug in your motor with any tune-up change, matter-a-fact I suggest a new plug every round. As an example, Q-1 could be early in the morning, at 1200 DA, and Q-2 could be around noon, which could have a density altitude of 3000', well your tune-up just changed because you will have less good air going in your motor, it just got fatter.  So I suggest in Q-1 new plug in #1 cylinder , Q-2 new plug # 2, etc, that way it's a little easier to keep track where your new plugs are, plus after 8 runs [ ya I know that might be more than 2 events] you will have a new set of plugs in your motor with only a few runs. At $3.00 each it's not allot of money.
When I 1'st started helping my partner, Bud Hammer he was indexing plugs also, but that goal was to keep the high piston dome [ 16;1] from smashing the plug ground strap closed. When I was doing that I kept trying different plugs until the strap was between 10;00 and 2;00, without using plug washers, I think  the washers changes the heat range. But when I built my 1'st RR SBC we cut with a porting tool a "fire slot" in the dome, with the idea it would help the flame front go over the dome, but also not have to index the plugs. I always try to keep our car simple, less likely to have a crew member put the wrong plug in the wrong hole. Also when I ran my motor in a Comp elim [ B/ND] and he had help from the Autolite rep, I asked him now that I cut the fire slot, would it be any advantage to index the plugs 180° from what I was doing, he said Autolite tried that and the dyno test didn't show any difference. 
You are right it costs more to go fast , "speed cost money, how fast do you want to go ?" But I know allot of SBC injected alky racers running 8.60's,[NE-2] and 7.60's [NE-1] with bowtie blocks, OEM forged cranks,  off the shelf pistons, shifting at no higher than 8500.
Your Vertex is fine until you up your combustion pressure with higher compression and higher fuel flow, and even then you can have Spud hop-up your Vertex, or go to a Mallory Mag. I run 20 amp MSD, because i run around 16;1 compression, 220-230 fuel flow and 10,000 rpm.  Your 38° timing looks about right for a non-raised runner heads, but I have helped some JrFuel cars at the Bowling Green  Reunion when they had a ton of water grains in the air, you can't burn water, so we kept leaning the fuel and upping the timing to as high as 42° to try to get some heat in the plugs. He would have won, except he red-lighted. 

Jon

JrFuel Hayden:
Dude66, what are you running for timing ? Are you using NGK plugs ? With no heat showing on your plugs try a .80 main, then a .85 etc until you get some heat. Also the more timing you run the more heat you'll get, but look at your plugs after each change, look for tiny black or silver spots on your plugs, they could be detonation = too far. You can also just fatten her up a bit to cut down on the detonation. AS I've said before look for ground strap discoloration, if you get a blue ring at the bend that's a good but safe timing.
I don't know what your alum heads want for timing, but the iron non-raised runner SBC motors like 36-38°, my iron RR SBC motor likes 29-32°, and I think some of the iron 14° heads like as low as 27-28°. It seems to depend on combustion shapes. So again listen, and look  to what your motor is telling you it wants.

Jon, 805-444-4489

novadude66:
Hey Jon,, im running 38 degrees, with just a 6AL box,, NGK 5671-8 plugs

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