HELP! Read my plugs!

[petek]

Oh darn, we've got to drive our Cobras hard occasionally. What a bummer!

[chill]

...the technical advice is fantastic and I echo Keith's enthusiasm about this site, but I especially like the advice to drive it hard!! Keith, here's your chance, all you need to do is show Elizabeth this thread and tell her it's necessary maintenance, and you're in the clear!

[Chad Johnson]

I just scanned the responses, so forgive me if I repeat somebody elses thoughts. I would start with the following:
1. Check to make sure the intake manifold is tight
2. Install new plugs and run with leaded gas to determine if the carburetor is too rich.

If the intake is tight check valve seals and compression to determine where the oil is coming from.

It may not be as bad as it looks right now.

Good Luck

[LateApex]

Keith,

Bring it here. I'd be happy to give it an "Italian Tune-Up".

[excelguru]

I need to drive it harder??? Well, twist my arm!

Hell yea! I finally have a good excuse!

Keith

[xlr8or]

Do not POUR water in the carb to clean carbon deposits. Yes they will cause detonation by offering a hot spot to ignite the intake charge but should be cleaned by spraying a heavy mist.

Water does not compress and if you get a little gulp down the intake runner your can do major damage.
A friend of mine was holding the carb open so the RPM's were at about 2800 while trying to pour water out of a small container into the carb. He slipped and dumped about a half cup of water in there at once and grenaded two pistons and cylinders.
He had shattered pistons, bent rods and a unusable block when it quit spinning.


Scott

[Excaliber]

Uh,,,point well taken! Water in the carb should only be done by "trained proffesionals" such as myself. And ONLY after you set your beer bottle on the fender cover............."misting" is the ticket! "Pouring" takes place AFTER the carb work.

LOL

Ernie

[Steve R]

Keith,
Ship the car here to Houston. I specialize in "Big block carbon removal"
Steven
PS, did you have that engine dyno tuned for proper air/fuel mix?

[KobraKarl]

DRIVE IT HARDER !!!

Now THAT is preaching to the quior.

[petek]

I've got to print out this thread and keep it in the Cobra.

"Honest officer, the experts told me I HAVE to drive it hard! See. just read this."

[cscott67]

I'm with Mr Fixit. Lose the old ignition system/coil set-up. Running a little rich won't hurt the motor, but you'll keep changing plugs unless you upgrade. Scott

[niles]

keith;
You must get the mixture right. Especially with your 2x4. Their about as high maintenance an a 20 yr old super model.

dont leave it rich; washes down cyl's. fouls plugs, pollutes oil.

Two ways to get the F/A right; one expensive-one cheap.
go to good dyno guy and have him calibrate/rejet carb.
or weld in a oxygen sensor bung in one header pipe and install a $15 O2 sensor and put your digital multimeter on it and read directly the F/A mixture. This way you can calibrate idle, midrange, WTO percisely. Works like a charm. Hint: where does your FI computer gets it's dynamic F/A input.
If you need any additional info; or the O2 voltage output curve; give me a call.



gn

[Steve R]

GN,
Hey! Could you post the curve? Pinheads like us love curves
Steven

[niles]

OK guys; letting out my industrial secrets.

go to: http://www.bob2000.com/

Section on: Carb tuning the scientific way.

read everything in the world about Holley carbs; the o2 curve and keys to F/A bliss are on page 17.



gn

[Excaliber]

Now THAT is a great idea! If you guys haven't got a digital volt meter all ready, GET ONE! It is the most oftened used tool in my roll-a-way.

OH,,,,any particular model O2 sensor recommended? They vary a LOT in price! And, three wire or two wire model? Three wire uses battery voltage to "warm it up" faster for more accurate readings with a "cold" motor.

[LateApex]

Great site Niles, thanks for the contribution!!!

[niles]

I used the most simple universal 2 wire about $15.
I understand that with an unheated configuration you should mount in a header within 12 in of the head to keep the heat up to get the V output. Don't fall for the common mustake to put it in the collector area to get the average of 4 cyl's. it's too cold there to get the output. Notice where there mounted in your modern FI car; usually less than a foot from the exhaust port.
gn

[KobraKarl]

I find if you use a 2x4 on your supermodel her maintenance goes way down .

[Steve R]

Niles,
Just printed it and skimed it. looks like good info. I've got some reading to do at lunchtime. Thanks bro.
Steven

[ZZZZZZ]

Saw someone say something about bent pushrods if the motor is popping or backfiring. When I run up the rpms in say 3rd or 4th gear and just let off the gas and have the motor slow me down it popes and backfires. Does this mean I could have bent pushrods.