spark plug choice

[blown&0chevelle]

I have a 69 c10 with a 350. It has a mild cam. edelbrock intake manifold. 600 holley and headers. Just original heads what would my best bet be for spark plugs. Much appreciated.

[CST10]

R44TS gapped to 0.035" is what I used for years without any issues.

[CST10]

AC Delco plugs that is.

[cdowns]

I like to go for the ones marked on sale

[leftybass209]

I use autolite. There's all kinds of information about spark plugs and some are better than others but it's an expensive venture. Your spark is only as good as your distributor, coil, wires, and the quality of incoming voltage to those components. Best of luck!

[Chucks72Longbed]

I was taught to use AC-delco on GM, auto lite on fords, champion on Chrysler and ngk or Bosch on anything foreign. For some reason I never forgot. Just like 18436572, chevy v8 timing order. Man, I AM weird!

[Stocker]

Originally Posted by Chucks72Longbed

I was taught to use AC-delco on GM, auto lite on fords, champion on Chrysler and ngk or Bosch on anything foreign.

FWIW, I almost always use Delco in my K20, never had a problem. Also had Autolites one time and those were good too. Only bad plugs I ever ran was Champion and they were junk, never bought them again after that.

[mrjankins]

Just some information on your spark plug choice. I am by no means an expert. The lower the number the hotter the plug. I had a problem with burning up ignition modules in my truck and so i upgraded all the things Leftybass209 talked about. i still had the problem until i went to the e3.40 spark plug a hotter plug(I have no idea why this fixed my problem). The R44TS the CST10 mentioned is the plug that came with the truck. These tend to work just fine but remember that these trucks came with points. When Chevy went to HEI distributors they opened up the gap in the plugs to .045. So if you're going with a standard plug pick one from a mid 80's Pickup that had an HEI distributor and use the gap setting from that truck or just open the gap on the R44TS. I also agree with Chucks, try to use AC Delco on anything GM.

[wbc409]

I worked in auto parts over 10 yrs. How the number relates to heat range changes based on who manufactured the plug. For AC plugs if the number is higher it's a higher heat range. A R43 plug is colder than R45.

[skeeterbug]

I have been using ac delco r45's for years in my drag truck with great success. Impressive to me that a pretty much a stock application plug works so well in a fairly stout drag motor.

[70cst]

Informative thread all.

[mrjankins]

Originally Posted by wbc409

I worked in auto parts over 10 yrs. How the number relates to heat range changes based on who manufactured the plug. For AC plugs if the number is higher it's a higher heat range. A R43 plug is colder than R45.

I did a little research and WBC409 is correct for the most part. Here is a chart comparing several plugs.


Maybe this is for my own clarification but here is a quote from http://www.ngksparkplugs.com/tech_su...3.asp?mode=nml

NGK Spark Plugs Heat Rating

The spark plug heat range has no relationship to the electrical energy transferred through the spark plug. The heat range of a spark plug is the range in which the plug works well thermally. The heat rating of each NGK spark plug is indicated by a number; lower numbers indicate a hotter type, higher numbers indicate a colder type.

Engine Speed and Load

If the engine is to be operated at high RPM, under a heavy load, or at high temperatures for long periods a colder heat range may be needed.
Conversely, if the engine is to be operated at low speeds or at low temperatures for long periods, a hotter heat range might be needed to prevent fouling."




Like i said this may be for my own education but i assumed that a hotter plug meant a better spark. Apparently the heat range indicates how well the plug dissipates heat. This allows the plug to stay in it's optimum operating heat range. An example would then be that if you are have a hot plug but mostly do highway driving or are always pulling a trailer the plug may get too hot and not function correctly. Conversely if you have a cold plug and mainly cruise and sit in traffic the plug may may be too cold to function properly.



Its all about staying in the optimum operating range of you plug and will vary by engine and engine usage. There is a long list of symptoms to diagnose if your plug is too hot or too cold.

If this is news to anyone else let me know and I post more sources and articles.

[Longhorn 70]

I don't know if it's my seat bottom dyno or my self back patting but here it goes. I like Autolite plugs. I have sold them and run them for many years. I have tried several different brands AC, NGK, ND, Champion, and Bosch as well with mixed success.

Some, NGK and Bosch I can feel the engine produces less power. This was backed up by loss in fuel economy with Bosch on a Suzuki Samurai by 10%. Switched back to Autolite in it, baddabing. The power (HA) came back and economy went back up too.

I can also feel it in my Corvette and same fuel economy changes with NGK. I changed back to Autolite and VAHROOM...

I have tried Champion as well. The insulators used to be so soft if you dropped a plug, the insulator would break. AC and Autolite you had to slam down just right or hit with a hammer to break the outside insulator. PLUS I have seen black streaks up the external insulator on Champion plugs MANY times. The insulator to shell bond is fragile on them and they leak compression. I don't even use them in my lawn mower.

I use this rule for my cars.

Get what the plug manufacturer calls for for my vehicle UNLESS it has been beefed up. If it has higher compression or hotter cam, one step colder. If it is beefed up and I run it hard, 2 steps colder. If there is no Autolite listing, go AC. This has worked for me for over 40 years.

[blown&0chevelle]

Thanks guys. I still have the old point system if I was to change to hei is their anything I would need besides the distributor?

[Longhorn 70]

You'd want to run a heavier wire in the place of the resistance wire....14 gauge would work. You'd also want to run a bit wider gap .045" is where mine is.

[Stocker]

Originally Posted by Longhorn 70

You'd want to run a heavier wire in the place of the resistance wire....14 gauge would work. You'd also want to run a bit wider gap .045" is where mine is.

Agreed as to the wire and the gap. 12 ga. wire also works well. You'll also need heavier plug wires to handle the higher voltage. IIRC, points-type ignition uses 7mm wires and HEI requires 8mm wires.

[snipescastle2]

Ditto on the delco R44/R45 ts resister plugs.
Ben

[Sicklajoie]

I've always used Autolite 24's.

[swamp rat]

Originally Posted by Chucks72Longbed

I was taught to use AC-delco on GM, auto lite on fords, champion on Chrysler and ngk or Bosch on anything foreign. For some reason I never forgot. Just like 18436572, chevy v8 timing order. Man, I AM weird!

I thought you said Wired for a sec...

[1967chevy c10]

I like accel sorty plugs. There good if you have headers do to tight space.

[Acorn]

This is useful to keep a copy in your tool box

http://www.78ta.com/HTAF/index.php?topic=6782.0

[mechanicalman]

Originally Posted by leftybass209

I use autolite. There's all kinds of information about spark plugs and some are better than others but it's an expensive venture. Your spark is only as good as your distributor, coil, wires, and the quality of incoming voltage to those components. Best of luck!

X2, autolite copper core and plain Jane HEI never let me down. For me, more would be over-kill.

[mechanicalman]

Originally Posted by Stocker

FWIW, I almost always use Delco in my K20, never had a problem. Also had Autolites one time and those were good too. Only bad plugs I ever ran was Champion and they were junk, never bought them again after that.

I've had similar experiences with Delco and Autolite. However, I've heard Champion is now a good plug but as long as Autolites are available I'll stick to them.

[Legolas894]

These discussions can go on for ever. I've found with various cars and trucks that it's usually better to stick with what was in it from the factory. In my 67 GMC, I've got Champion right now with an old points set up and it runs great when I'm driving to the grocery store. If I was racing, I might think about a different plug but then again, I would be changing everything else too (carb, ignition, cams, headers etc). So with a stock setup for normal driving, in my opinion only, there is little to be gained performance-wise just changing a plug.

I remember having bad luck with Champions in the 1980s-plugs that didn't spark right out of the box. But Champion has made plugs for probably 100 years so almost every manufacturer has changed over the years as far as quality goes and well it's pretty hard to say "Champions are junk" without saying maybe "Sometimes they were junk".

I was working on a 1999 Sunfire with AC Delco plugs in it and snapped one of the plugs off a couple of weeks ago. That was the first plug I've ever snapped off so should I say "AC DELCO are Junk"? Maybe I was using too much torque.

Now let's start talking about brands of oil filters...LOL.

[mechanicalman]

Originally Posted by Legolas894

These discussions can go on for ever. I've found with various cars and trucks that it's usually better to stick with what was in it from the factory. In my 67 GMC, I've got Champion right now with an old points set up and it runs great when I'm driving to the grocery store. If I was racing, I might think about a different plug but then again, I would be changing everything else too (carb, ignition, cams, headers etc). So with a stock setup for normal driving, in my opinion only, there is little to be gained performance-wise just changing a plug.

I remember having bad luck with Champions in the 1980s-plugs that didn't spark right out of the box. But Champion has made plugs for probably 100 years so almost every manufacturer has changed over the years as far as quality goes and well it's pretty hard to say "Champions are junk" without saying maybe "Sometimes they were junk".

I was working on a 1999 Sunfire with AC Delco plugs in it and snapped one of the plugs off a couple of weeks ago. That was the first plug I've ever snapped off so should I say "AC DELCO are Junk"? Maybe I was using too much torque.

Now let's start talking about brands of oil filters...LOL.

Right on! I agree with everything you said.

I think that at some point auto manufacturers and spark plug manufacturers played games with the actual heat ranges in order to sell their plugs to their people and to make Champion look bad as I don't recall them being standard equipment? Not sure. But I think with the many brands of cars now available, heat ranges are a bit more honestly portrayed?

No, let's NOT talk about oil filters, manifold vacuum vs ported vacuum, PCV valves, etc.