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Caballerokid 10-22-2012 04:33 AM

Help reading spark plugs
 
3 Attachment(s)
I am running a set of Delco R44TS plugs in my sbc. I've done tons of looking and can't find anything on this that is real definitive. The porcelain is clean on one half and brown on the other. Is this due to the air/fuel flow in the chamber, is it bad, is there not enough swirl in the chamber?... Also, what do you all think about the coloration. I think I'm good on the heat range, rich and maybe some slight detonation??? Would I be right or am I off?... Thanks!

Caballerokid 10-22-2012 04:37 AM

3 Attachment(s)
Hopefully these are larger pictures. Also... these were after 3 hard pulls on the dyno with a 160 degree thermostat. I want to go to a 180 thermostat. Would I need to go down to maybe an R43TS?

67Mustang Al. 10-22-2012 04:46 AM

Spark plug reading

Wide open throttle and then killing the ignition will give you a reading at that speed. The linkabove will give you some info on this subject, blackish could indicate a rich mix or the heat range could be a little cold and not burning off the carbon on the outside edge. For racing bikes we used to hit the kill switch after WOT and then coast to stop and pull the plugs.
cheers
Al.

cdminter59 10-22-2012 07:00 AM

Help reading spark plugs
 
Tell us some details about your small block. How much compression does it have? Aluminum or iron heads. What type intake and is a spacer used? Carburetor size. Cam specs. Type pistons, flattop, domed, dished. If you have detonation you don't want to increase heat. What is the timing curve, how much initial and how much mechanical?

hcompton 10-22-2012 01:50 PM

I tried to write something on how to read plugs. But it would be way to long.

I did a quick web search and didnt find anything that didnt have the same pictures as the Hayes/clymer manuals have in them. Those plugs are so bad might as well not even look at them.

I only look at the bottom of the porcelien deep inside the plug for a quick run. I use new plugs and shut if off with the throttle open and let it roll down on its own out of gear. If you let it fall back to idle the plug readings will change to reprsent the idle air mix.

I use a flashlight magnifier old ppl use to read. And look straight down in to the plug at the lower portion of the white insulator. Cant really explain without a picture.

An o2 sensor is easier to install than getting a good reading off a plug. Just fyi.

LJM97Z 10-22-2012 04:43 PM

Looks a bit rich in the idle curcuit but nothing serious, the spots could be detination, & the glaze over on the porcelin is an indication of too hot heat range, i'd run 1 step colder or better yet, go with a standard tip, not projected tip, in the same heat range the standard tip will run cooler. I've been running the Accel plugs in my 10.5.1 sb 406 & love them.

If all is good, you'll have/want a consistant light-med. chalk tan on the porcelin (all around) & 80% down with no speckling, the lower 20% "that you can't see with the naked eye" you want a light-med. brown, thats your WOT (jetting), your timing mark is on the strap, you want that in the middle, sometimes there hard too read, heat range is useally measured from the threads, you want around 3 threads from the top base down showing color, the base should have at least 50/60% (sometimes dark/fluffy with pump gas).

Caballerokid 10-23-2012 08:27 AM

Ok, here goes...

Its a 350 (1 piece rear main), crank turned .010"/.010", over sized bearings, stock rods, bored .060", hyperutectic pistons with .125" dome = -3.5cc, 882 cast iron heads, mild port work to the intake runners, 1.94" Int/1.60" Exh valves, 1.6:1 S/A roller rockers, Crane 100172 274-H06 cam and lifters set, hardened pushrods (shortened i believe), Edelbrock performer intake manifold, Holley 4777-1 650 DP (67 main jets, 76 secondary jets, 35 main nozzle, 25 secondary nozzle, 6.5 PV, pink cam on primary accel pump and I think black cam on secondary accel pump), carter rotary vane internally regulated fuel pump (6-7 psi), MSD e-curve dizzy, MSD 6T box and Blast SS coil. Initial timing is at 18, mechanical 15, vacuum advance 10 = 43 total timing. Its in a 1978 GMC Caballero (El Camino) 4 spd Saginaw 3.50 / 2.47 / 1.65 / 1.00 ratios, 2.73 rear gears w/ mini spool and 25" tires. (Still have alot of work to do...)

So I also had a set of R43T Delco plugs in when I was running leaded fuel and less timing. They looked to be too cold and carboned up. I can add pictures of those as well if that helps.

LJM97Z 10-23-2012 09:40 AM

Quote:

Originally Posted by Caballerokid (Post 1602221)
Ok, here goes...

Its a 350 (1 piece rear main), crank turned .010"/.010", over sized bearings, stock rods, bored .060", hyperutectic pistons with .125" dome = -3.5cc, 882 cast iron heads, mild port work to the intake runners, 1.94" Int/1.60" Exh valves, 1.6:1 S/A roller rockers, Crane 100172 274-H06 cam and lifters set, hardened pushrods (shortened i believe), Edelbrock performer intake manifold, Holley 4777-1 650 DP (67 main jets, 76 secondary jets, 35 main nozzle, 25 secondary nozzle, 6.5 PV, pink cam on primary accel pump and I think black cam on secondary accel pump), carter rotary vane internally regulated fuel pump (6-7 psi), MSD e-curve dizzy, MSD 6T box and Blast SS coil. Initial timing is at 18, mechanical 15, vacuum advance 10 = 43 total timing. Its in a 1978 GMC Caballero (El Camino) 4 spd Saginaw 3.50 / 2.47 / 1.65 / 1.00 ratios, 2.73 rear gears w/ mini spool and 25" tires. (Still have alot of work to do...)



So I also had a set of R43T Delco plugs in when I was running leaded fuel and less timing. They looked to be too cold and carboned up. I can add pictures of those as well if that helps.

The R43T will be too cold, look into the Accel plugs at O"Reillys, I've been having good luck with them.

Caballerokid 10-23-2012 09:45 AM

What kind of Accel plugs?... I'm not familiar with how those are rated, as far as heat ranges and such.

Caballerokid 10-23-2012 10:28 AM

As I read the plugs, the timing mark on the strap is nearly to the base which tells me I need to back off the timing as well as the spotting on the porcelain.

They are not hot enough as there is only one full turn of threads showing color.

The carb is fat due to the soot on the ring around the carb.

I also forgot to mention that the heads are 76cc chambers.

This is all with a 160 thermostat. I need to go to a 180 which will heat things up more. I need to take that into account when selecting another plug.

The thing that still bugs me is that the porcelain is only showing color on half of it. The other half is still white. No one and no information can still explain that to me...

techinspector1 10-23-2012 03:18 PM

Quote:

Originally Posted by Caballerokid (Post 1602264)
This is all with a 160 thermostat. I need to go to a 180 which will heat things up more. I need to take that into account when selecting another plug.

The motor will be more efficient with a 205 degree thermostat and a cooling system that will hold it there.

Caballerokid 10-23-2012 04:42 PM

How would that effect the heat range selection of a plug?

MouseFink 10-23-2012 06:44 PM

The clean side of the porcelain insulation is indexed towards intake valve. The incoming fuel/air mixture keeps the porcelain cleaned off which is normal in a wedge combustion chamber.

Get rid of the AC Delco spark plugs made in Mexico and install a set of Denso PTF-16TT spark plugs made in Japan. The Denso fine wire platinum spark plugs will run better, last longer and they are cheaper to boot. ($2.17 ea.)

Caballerokid 10-23-2012 06:51 PM

I thought the Platinum tip plugs ran hotter. I read that somewhere...

MouseFink 10-23-2012 07:21 PM

No,no..the depth of the porcelain insulation determines the heat range. The material of the electrodes has nothing to do with the heat range. The platinum center electrode and the titanium ground electrode of the Denso TT spark plugs run cleaner due to less resistance to current flow and erosion therefore they will last longer than conventional spark plugs.

The Corvette Z06 comes with Denso (platinum) or NGK (iridium) spark plugs because they wanted nothing but the best for their high-end car. GM has not owned AC Delco Parts Division since 1999. AC Delco was changed to Delphi with manufacturing sites in 38 countries and 21 of the 29 manufacturing plants in the U.S. were closed.


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