Hi,
I haven't been happy with my continued destruction of the #8 spark plug boot. I have headers on the late 1986 454. I was thinkin.... Racers have to have an answer for this problem of clearance between the spark plug and the header. It turns out there are shorter spark plugs made. They are made by Accel, Autolite, and NGK.

From what I read on other wegbsites, the first two brands are generally 6/32" shorter than stock, and NGK is a little shorter than that.

I think I'll pick out an NGK and see what happens. http://www.ngksparkplugs.com/docs/product_list.pdf

Anyone try this or get recommendations for or against? I figure more clearance is a better first step instead of trying to come up with barriers which will further cut down on clearance.

Matt

quote:

Originally posted by BarthBluesmobile:
Hi,
I haven't been happy with my continued destruction of the #8 spark plug boot. I have headers on the late 1986 454.

What headers do you have?

What plug wires do you have?

Do you have the later GM right side splash shield/air flow director?

Do you use the OEM steel heat shield on the plug?

Do you use a sock on the boot?

Do you let the engine idle for a little while before shutting down?

Do you have an electric fan that runs after shutdown?

Matt,

You could also try an exhaust wrap for those headers. JCWhitney has one that is called black exhaust wrap with claims of reducing engine compt heat by 50%. A lot of race cars use this-- just an idea.

Jim

I don't know if this applies to other brands, but my Thorley lifetime guarantee is invalidated if the headers are wrapped.

All my plug boots were protected by a 4 1/2" length of Thermo Tec sleeving, http://www.thermotec.com/thermo-sleeve.html which are foil and fiberglas.

Seven of them are doing well. On number 8, the foil aft gang aglay. That boot now sports a Taylor 2524 space-age boot protector which I have wrapped with several layers of heavy aluminum foil. I replace the foil when it starts to break down from heat and ocean salt air. Amazon has the best price.

Install the OEM heat shields for each plugs and you wont melt the boots. I also installed "lightning wires."

If ya'll don't mine me asking which brand and series of spark plugs/wires are you using.

quote:

Originally posted by Tommy&Evelyn:
If ya'll don't mine me asking which brand and series of spark plugs/wires are you using.

I use AC plugs because they are easy to spell. And that is what came in the new engine.

I use Accel Super Stock spiral hi temp yellow wires because they were new when I bought the coach. For boot protection, in addition to the OEM metal shields, I installed Thermo Tech foil and fiberglass sleeves. Number 8 gets extra protection from a thick Taylor sleeve with my own foil added.

If I were to buy new wires tomorrow, I would probably buy the Accel 9000 series with the ceramic nipples. I would still use the OEM heat shields, and slip some Thermo Tech sleeving over the boots and a coupla inches of wire for extra heat protection. Marketers make a lot of noise over the boots being heat tolerant, but the first few inches of wire have high heat exposure, as well.

I use an MSD 6A sparker-upper because it makes all spark plugs work better and it has improved the performance of every engine where I have used it. It also forces an engine to run in situations where it would not otherwise.

An example is when my carb overflowed due to crud in the inlet. The engine, of course, ran horribly rich, but still ran, allowing me to drive to a safe place to stop and do the carb thing. This was both a safety and expense thing. Also time.

Another reason I like the MSD 6A is that it allows use of the MSD adjustable spark timer. Forgot its number. This allows me to adjust my timing with the turn of a knob, tailoring my advance for the temperature, load, incline, quality of gas, throttle position, etc. The result is more power, and better fuel economy. I grew up on cars and motorcycles with adjustable spark, and just can't help myself.

If any diesel guys are reading this.... see what yer missin'?

quote:

MSD 6A

Thanks bill h, I knew that I could count on you to help.

quote:

Originally posted by Tommy&Evelyn:

quote:

MSD 6A

Thanks bill h, I knew that I could count on you to help.

Despite my enthusiasm for the 6A, the OEM HEI is pretty good for most people. In a stock engine, the 6A doesn't really do much for you unless something is wrong.

My boat, on the other hand, is so rasty that it won't run between two and three grand without loading up. Over-cammed, over carbed, over-manifolded, puddling, etc. Unfortunately, no-wake zones require using that rpm range. The MSD took care of the problem. I had a dune buggy that ran rich over the whoopdies, owing to poor float bounce control, and MSD saved the day, again.

quote:

Another reason I like the MSD 6A is that it allows use of the MSD adjustable spark timer. Forgot its number. This allows me to adjust my timing with the turn of a knob, tailoring my advance for the temperature, load, incline, quality of gas, throttle position, etc. The result is more power, and better fuel economy. I grew up on cars and motorcycles with adjustable spark, and just can't help myself

One has to take into account, however, that the other 99o/o of us would just screw it up and blow the whole thing to kingdom come

quote:

Originally posted by Danny Z:

One has to take into account, however, that the other 99o/o of us would just screw it up and blow the whole thing to kingdom come

LOL.... Without my hearing aids, I can't hear too much advance as well as I used to.

quote:

If any diesel guys are reading this.... see what yer missin'?

What's a "spark plug"? Sounds like it's used to keep sparks from coming out of a hole.

quote:

Originally posted by Rusty:

quote:

If any diesel guys are reading this.... see what yer missin'?

What's a "spark plug"? Sounds like it's used to keep sparks from coming out of a hole.

You got it Rusty... It's also called a "Knock out seal" in the field..

I had Findlay RV in Las Vegas service my Barth. They did not reinstall the OEM steel heat shields and 150 miles from Las Vegas I melted the boots on a majority of the spark plug wires. Of course this happened on a Sunday morning and it took me 30 hours to drive from Las Vegas to Amarillo. After locating additional heat shields and installing them I never had this problem again. I also have Doug Thorley Headers and I use AC R44T's.

Back at it. It turns out that NGK doesn't have a resistor style short spark plug. I didn't want to mix resistor and non-resistor plugs, thinking that it would muck up the relative spark timing between cylinders.

Accel does make a shorty plug, that is a resistor type, 0576S. S is for shorty. The Accel 0576 (no S) corresponds to the Delco R44TS. I am running the Delco R44T. The S on the Delco plug is for "extended tip". I think it is 0.080" inches longer.

GM did use the R44TS in the 1971 Corvette with a 454. I don't know if it was the 365HP or 425HP variant. One had flat pistons, one had domed. Lots of 402 big blocks for various models of 1971 also had the R44TS instead of the R44T.

In my 1986 454, there was a flat top variant piston used, and a dished piston used.

So unless the head castings moved the plug depth, I think I am going to be OK with the Accel plug. Head gasket thickness is a concern also. I've read that racers will use washers of certain thicknesses to "index" the spark plugs, to get the plug to point in a certain direction. This is also going to retract the plug as well.

So, I'll give the Accel plug a try. I'll turn the engine over, and check if any plug damage occured before running it. I think I should get 1/4" more clearance for the spark plug boot from the header tube on that #8 cylinder.

see you later,
Matt