Plug Cuts

[stuartgb100]

I would be pleased to learn of the Group's opinion on this subject, and for those who would advocate this procedure, exactly how they would carry it out ..... and most importantly, how to evaluate the results.

There seems to be two basic streams of thought:

One seems the passionate advocate, the other would say a total irrevolance.

Regards.

[1964 S1]

huh?

[types26/36]

huh?

I didn't want to be the first to say that but can you explain what plug cuts you are refering to
Brian.

[stuartgb100]

As I seem to remember:

Find a suitable stretch of road (quiet and straight) on a dry day. With the engine at normal temperature, take it up to say 6000 rpm in third and hold it there for 10 seconds. Then in one continuous operation (and very carefully) depress the clutch and turn off ignition (mind any steering lock!), engage neutral and coast to a stop.

The plug can now be removed for analysis.

[type26owner]

Yup, that's the old way. Unfortunately that's the way John Passini did it back in his day. Kinda makes his insights less relevant and not very useful or reliable. When the only measuring sticks are fuel consumption, types of smoke emitted, seat-of-the-pants-feel and plug cuts chances are you're going to suck at doing it until you've got thousands of hours of practice until the trial and error experience finally kicks in. Good luck!

I failed miserably at it and with hindsight I realized I was doomed from the start. The fuel supply I was using was changing in it's vaporization behavoir from tankful to tankful.

Thank gawd the digital air fuel meter that is reasonably priced is now available. Anyone with some technical savvy and with proper coaching can do it with one of these units. Of course the plug cut is still necessary but only as the last step in the tuning procedure. To get the plug heat range selection into the self-cleaning temperature range.

[stuartgb100]

Keith,

Thanks for that.

So air/fuel meters are the way to go. A couple of (three) questions then please:

Which would you recommend that might be available this side of the pond?

How are they connected (manifold tappings) ?

What of such things as changes from day to day .... eg ambient temperature, humidity etc. Does the old adage (for Webers) still hold true, that a cool/cold but moist air supply is best?

Am new to Elans, but not the twin-cam engine

Regards.

[type26owner]

If you'd fill in the personal info a little more I'd know which side of the pond you mean.

The http://www.innovatemotorsports.com/ units are available world round now. There are also competing brands with similiar pricing available too. However, when you buy the Innovate stuff along with it you get access to Klaus Klatinn's advice on the forum. He's about the most knowledgeable guy on technical aspects of combustion I've ever heard before. He's also a Weber guy! Suggest you go and read up on the technology at their website.

Got experience with the twinkcam on the racetrack do we?

[stuartgb100]

There's only one pond, and I like to think I live on the best side (vbg).

Used to envy your weather .... but I'm not so sure anymore !

Thanks for the link. Will investigate.

Racetrack experience, sadly no ....... just a bit of the normal silly stuff on the open road, in my younger days (Cortinas). Now I'm having fun with an Elan ......... that I never could afford back then!

Regards.

[1964 S1]

Guys, I'm sorry but I still gotta say, huh? Are you discussing looking at the spark plugs to see how the individual cylinders are functioning? How far does an Elan coast when you turn it off at full chat in third gear? Can't you just put on the brakes and pull over (on the side of the road?) and then, take the plugs out?

[type26owner]

Since the head is a cast from relatively soft, gummy but abrasive aluminum the other downside to doing spark plug cuts is the threads eventually pull out. Helicoil to the rescue! It's easy to get them cross-threaded too. BTDT

[twincamman]

I still use that system -----turn the ignition off and dump the clutch as close as possible----at the top of the Andrettii not so straight away at Mosport coast to the pits read the plug ---do it on the vee and the sprite and both t. c. motors ---works for me ---tells what plug is rich or lean--all I want to know ed--

[pereirac]

It's interesting, but a completely different language to me
For the less technical ones amongst us... What is a plug cut?

Thanks

[stuartgb100]

I don't wish to be rude, but maybe reading the full thread thoroughly might begin to answer your question!

Regards.

[pereirac]

Without being rude back, all I can make out by 'reading thoroughly' is that it's something to do with sparkplugs !! A simple answer would have been more helpful.
If you read through the list you will see that I am not the only person who does not understand...

[twincamman]

sg booth --you asked a question----- please answer one without the attiude and with the courtesy you would expect ----ed