"cutting back spark plug electrode"
Thread Starter
Racer
Joined: Aug 2005
Posts: 469
Likes: 1
"cutting back spark plug electrode"
hi there all,
hope all is well with you all!
i read in the tpis insider hints book that cutting back the centre electrode shield can help produce 10 horse power and 1 mph in top speed!
is this true?
does it really help do you think?
when i looked at the spark plug ,the electrode does shield part of the spark plug there fore could restrict some of the flame?
any way thanks for reading guys!
glen
sxyvet
Australia
hope all is well with you all!
i read in the tpis insider hints book that cutting back the centre electrode shield can help produce 10 horse power and 1 mph in top speed!
is this true?
does it really help do you think?
when i looked at the spark plug ,the electrode does shield part of the spark plug there fore could restrict some of the flame?
any way thanks for reading guys!
glen
sxyvet
Australia
Melting Slicks
Joined: May 2005
Posts: 3,134
Likes: 11
From: At the St. Louis Playboy club.
You only cut back to half way across the electrode. So you got half to set the gap with.
I noticed a small improvement in perf. But I was fouling plugs & it really helped not foul the plugs.
I noticed a small improvement in perf. But I was fouling plugs & it really helped not foul the plugs.
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
Likes: 71
From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
It shortens the effective life of your plugs and is way more trouble than it's worth. Unless you're a class racer going for every last fraction of HP, put your efforts elsewhere. You'll certainly never feel the difference. Standard indexing is more effective and I also consider it a waste of time with modern ignition systems.
Team Owner
Joined: Sep 2003
Posts: 88,393
Likes: 2
From: eville in
Originally Posted by Corvette Kid
It shortens the effective life of your plugs and is way more trouble than it's worth. Unless you're a class racer going for every last fraction of HP, put your efforts elsewhere. You'll certainly never feel the difference. Standard indexing is more effective and I also consider it a waste of time with modern ignition systems.
Le Mans Master
Joined: Jul 2002
Posts: 5,818
Likes: 2
From: Alive and well in Burlington NC
If you want to try it, go to 65Z01s site and scroll down to the "How to cut back spark plug electrode" link.
http://www.geocities.com/jgkov/index.html
I did it on a set of Autolite plugs a while back. Didn't notice any SOTP difference but didn't index them either. Can't speak to the life of the plugs since I changed them back to Rapid Fire # 5s the next summer.
http://www.geocities.com/jgkov/index.html
I did it on a set of Autolite plugs a while back. Didn't notice any SOTP difference but didn't index them either. Can't speak to the life of the plugs since I changed them back to Rapid Fire # 5s the next summer.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
not worth the effort. I thought AC Delco or some other plug manufacture was selling them now. From what I've read what little performance gain noticed is in RPM ranges we don't typically go to in DDs.
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Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
If it is hard enough to do and takes long enough, you'll swear you can feel the difference. S.O.T.P. However, I defy anyone to document a difference.
I put around 10k miles on the Vette each year with quite a few 1/4 mile at a time and find I need regap my cut-backs around twice a year. A set will last around 2-3 years before the inside edge of the center electrode becomes worn down to the point where I feel the need to install a new set.
This "old dragracer's trick" works because it unshourds the flame front for better access to the charge and so more a complete burn.
I cut my stock AC Delcos back till the outer electrode is just at the edge of the center electrode. I use a std gapping tool. Since I'm running a Hyper Tech set up with performance wires I gap to .045"-.047" range and regap when they burn open to >.050".
Pro
Joined: Mar 1999
Posts: 678
Likes: 0
From: Oslo, Norway
Hi. There is an other aspect with having larger gap that is that the voltage rises to a higher level before the spark comes. Thereby is the islation in the coil more stressed especially in the stock coils.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Thereby is the islation in the coil more stressed especially in the stock coils.
I went to the HyperTech setup since I modified my TPI to provide good power to nearly 6k RPM and so now need reliable firing up there.
thanks guys for your help and comments,,,
Last edited by 65Z01; Nov 19, 2006 at 07:23 PM.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by jan-erik
Hi. There is an other aspect with having larger gap that is that the voltage rises to a higher level before the spark comes. Thereby is the islation in the coil more stressed especially in the stock coils.
RACE ON!!!
