SpeedTalk Store - Opinion Columns

What should a well tuned methanol plug look like?

General engine tech -- Drag Racing to Circle Track

Moderator: Team

What should a well tuned methanol plug look like?

Postby CSH » Sun Apr 22, 2007 1:30 am

Hello,
I was wondering if anyone has any pictures of what a methanol plug looks like on a well tuned race engine. What does it look like when it is too lean and what does it look like when your too rich. Trying to tune without any egt. or AFR gear so I need to rely on plug reading. I am no expert at this and would like to know as much possible. Any input would be appreciated.
Thank you for all your considerations and leads.. Craig
CSH
Member
Member
 
Posts: 51
Joined: Sun Jan 14, 2007 7:10 am
Location: Australia

Postby Stevespeed » Sun Apr 22, 2007 2:56 am

No picture but you need to monitor chamber temps by looking at the color change / cad burn on the plug threads. You should not see anything but clean white porcelin. Depending on spark plug cooling characteristics of your head, a thread down of burn should be safe, two threads getting close to the edge of too hot. You can have sky high egt's and still have cad on the face of the plug. All the egt's show in that instance is the fuel is burning in the pipe instead of in the chamber. Never rely on only one source of info when tuning. Always look at a second source to back up what you THINK you are seeing. Keep in mind different plug makes have different temp thresholds for the cad burn. That is where experiance comes into play.
Stevespeed
Pro
Pro
 
Posts: 489
Joined: Sun Oct 30, 2005 1:25 am
Location: Phoenix AZ area

Postby CSH » Sun Apr 22, 2007 6:36 am

Stevespeed,
Thanks for your reply. Any info you can think off feel free to throw it at me even if you think is very basic. What does detonation look like on a methanol plug, does it still give you a black peppered look. Is there a color that is visable down inside at the bottom of the porcelin if you go to rich or will it just stay looking like a new plug with no heating color change on the threads. What brand and part no plug would you use on a Yates headed sbf making around 650hp. It might help me use your method as you say different manufactures cad may burn differently. (which brand burns the cad the easiest). On a single dominator manifold feeding 650-675hp with your expirience what fuel presures do you recommend(BLP belt drive)at idle and top end?Engine turns to about 8200rpm.
On another point of interest for me is at what comp do you think you start to see a gain using methanol against petrol.

Once again I appreciate and thank you for any advice. :) Craig
CSH
Member
Member
 
Posts: 51
Joined: Sun Jan 14, 2007 7:10 am
Location: Australia

Postby Ken0069 » Sun Apr 22, 2007 7:13 am

I don't know how to read an alky plug but I have been running it for about 10 years now with no meltdowns. I usually tune by the time slip (MPH) and EGTs. I've been told by George Rupert that if it get's too lean, you will know it before it hurts parts although I'll admit that I've never had one that lean.

Fuel pressure: My BoLaws pump is setup with internal bypass and a built in regulator. Idles about 4psig and runs between 9 and 11psig down track. That setup will work with either gas or alky as I have run it with both. On gas it will idle at 3psig and down track it's about 7 to 9psig. BoLaws makes damn good stuff! You'll never wear that pump out!

CSH is right about EGTs. I've been chasing my tail now for a while on a 2 circuit 1150 Bill Mitchell Dominator.

There is a thread I started here dealing with a 3 circuit Dominator that has some interesting info and some REAL good links to more info on another site. It's worth the read for sure. There are also some guys posting there from Oz so one of those may be near enough to you that you could visit or phone them for more into. I spent an hour and a half on the phone with a guy across the other side of the US talking about carbs yesterday. Was well worth the time invested!
"Necessity is the plea for every infringement of human freedom. It is the argument of tyrants; it is the creed of slaves."
William Pitt, British Prime-Minister (1759-1806)


Big Boyz Toyz!

Global Warming Is a FRAUD!
User avatar
Ken0069
Guru
Guru
 
Posts: 2513
Joined: Sun Jun 05, 2005 9:25 am
Location: Historic Appomattox County, Va

Postby Cammer » Sun Apr 22, 2007 7:23 am

You can thank member Larry Meaux for this:

http://www.maxracesoftware.com/spark_plugs.htm

Check out Larry's software- some of the best at great prices!

__________________________
___________________

A Lion In Winter
Cammer
Pro
Pro
 
Posts: 387
Joined: Sat Mar 03, 2007 11:27 am

Postby Stevespeed » Mon Apr 23, 2007 12:51 am

CSH, for .750 reach gasketed plugs I use NGK R5671A-9 in most cases or go to -10 if the application has a ton of cylinder pressure or extended temperature. Same with Autolite. 3933's are about same as 5671A-9's, 3932's same as 5671A-10. You won't find a dark "fuel ring" at the base of the porcelin like you would with gasoline. Alky consistantly shows performance increases of 5% even with compression down to 11:1. Look for pepper on the porcelin just as in gasoline when looking for detonation. Missing ground electrodes and missing chunks of porcelin are a sure sign of detonation :lol: Sorry, couldn't resist. Happy hunting :D
Stevespeed
Pro
Pro
 
Posts: 489
Joined: Sun Oct 30, 2005 1:25 am
Location: Phoenix AZ area

Postby Shrinker » Mon Apr 23, 2007 7:42 am

Hello CSH; Methanol does build up brown on the porcelain. It varies depending on the engine. At least if the porcelain is slightly browning you know the mixture is safe. With a lack of any measuring equipment that is a safe way to start. Whereas petrol will brown the strap electrode methanol wont. Methanol will form a slight brown ring just below the radius on the top of the porcelain if its a safe burn in a correctly energized mixture. It takes a while to form deposits as it doesn't have the carbon in free form like petrol does. Look for excessive wear on the corner edges of the center electrode. If the plug is rounding these edges off its just on the side of too lean at sparktime.
The best strategy is to ignition time it safe. Without data you will have to sneak down from the rich side and go by engine feel and time slips.
On some engines a rich mixture will wash the plug clean and no coloration at all will get onto the center porcelain. When reading methanol plugs it gets a little more difficult if there is any Acetone in it. Some sellers add acetone to methanol and that builds up carbon like petrol does. So first you have to know your fuel. It doesn't hurt to ask. regards Shrinker
Shrinker
Pro
Pro
 
Posts: 221
Joined: Mon Feb 12, 2007 9:12 pm
Location: Adelaide South Australia;Australia

Postby mbmotorspt » Mon Apr 23, 2007 9:51 am

I think the easiest way to check the tune up on a methanol engine is to look at the exhaust valve on #6 cylinder (SBC).

A very light tan color is usually pretty safe. If the valve is white, that is too lean. If the valve is brown that is too rich. If the valve is blue you are probably in deep trouble.

Sometimes the port is hard to read due to idle circuits, racing conditions, etc. But if you look in your header there should be a slight trace of carbon in the entry to the header pipes and no soot at the exit. If you have black carbon soot at the exit of the collector you are too rich.

Anymore, at least in circle track applications, it seems like detonation caused by a lean condition will crack pistons under valve reliefs before they will burn the edge off. (Voice of experience speaking)

MB
Several pistons were harmed during the testing of our products!
mbmotorspt
New Member
New Member
 
Posts: 43
Joined: Tue Nov 01, 2005 9:25 am
Location: Lincoln, NE

Postby trikesrule » Sat Apr 28, 2007 7:22 am

Thats how I do it to MB. Never lost an engine (or piston). 2-Strokes on Methanol can be an absolute pain to get right. The team I'm with now run an inline six on Meth in circle track. Pull the headers. The only way to be sure. And get yourself a density meter. Zammit Bros here in Aus had/have a good one that we always could count on........trikes
trikesrule
 

Re: What should a well tuned methanol plug look like?

Postby MELWAY » Thu May 19, 2016 8:25 pm

I know this is bring up from the dead

If seeing a lot of black pepper spotting/splinters on porcelain after 2-3 dyno pulls. Is this a definite sign of detonation?

Or could bad ring seal or excessive carbon build up cause this?
3370lb Sedan 9.89@136MPH 358chevN/A
MELWAY
Expert
Expert
 
Posts: 678
Joined: Mon Dec 04, 2006 7:37 pm
Location: melbourne australia

Re: What should a well tuned methanol plug look like?

Postby pamotorman » Thu May 19, 2016 8:42 pm

I would compare the plug color against a brand new never used plug and if I could see any difference in color I figured I was OK. never burned one down so maybe I was lucky. :D
pamotorman
Guru
Guru
 
Posts: 1460
Joined: Thu Mar 06, 2014 11:55 pm

Re: What should a well tuned methanol plug look like?

Postby tuffxf » Thu May 19, 2016 10:43 pm

G,day James,
If I see pepper, ie that has a size or shape and is raised above the porcelain, than its detonating.
If you think you have excessive carbon on the pistons or chamber than its still detonating and rattling it loose.
Plug may look ok fuel wise but simply have too much timing, only has to be at one point, ie at peak torque.
Cheers
Paul
tuffxf
Member
Member
 
Posts: 95
Joined: Wed Dec 20, 2006 7:34 am
Location: Central Qld Australia

Re: What should a well tuned methanol plug look like?

Postby nitrokid60 » Fri May 20, 2016 7:03 am

I have seen new plugs that had little particles on them when inspected, now I always blow them out with air regardless. A scope looking thru the spark plug hole could be useful.
nitrokid60
New Member
New Member
 
Posts: 9
Joined: Sun Nov 09, 2014 6:29 pm

Re: What should a well tuned methanol plug look like?

Postby John Wallace » Fri May 20, 2016 8:13 am

This is from Larry Meaux on Spark Plug Reading.
(looks like his page is down?)

Spark Plug Reading

:)
John Wallace
Pontiac Power RULES !
www.wallaceracing.com
User avatar
John Wallace
Guru
Guru
 
Posts: 1081
Joined: Tue Jan 04, 2005 10:20 am
Location: was Central Illinois - Now in Sunny Florida!


Return to Engine Tech

Who is online

Users browsing this forum: 4sfed, 555RAT, bmcdaniel, Carnut1, fdicrasto, mxzman, Rick Finsta, turdwilly and 28 guests