Help. I am stumped

[LeonardU]

I have a 427 SO 1966 with original medium riser heads. It is running a Demon Road Race 750 carb. The engine is stock with original bore, crank and rods. It runs great in warm weather; even in hot weather now that I installed the Taurus 2 speed fan. The problem is once it starts to get cold at 58 degrees it will start fine and run fine until it gets up to a good operating temp. It starts to miss a litttle and when you turn the engine off, it refuses to start. I can see gas fumes coming up thru the carb and it will momentarily refuse to crank over and may backfire. The only way I can start it is to spray starter fluid down the carb. I thought it was vapor lock, but it doesn't do it in warm or hot weather.

I have tried everything with no success. Help. And suggestions would be appreciated.

Len

[Woodz428]

With the little info you posted I would be looking at jetting. That is a typical example of lean jetting, the colder it gets the leaner it is and the harder to start as well as popping,etc. Now, some other info might point another direction...like what are the timing specs, cam specs other relevant details.
But, from the little posted, I would look at the jetting.

[undy]

keep a close eye on your fuel pressure. It may be creeping up on you. Also make sure your bowl levels are adjusted properly.

[mobilenuke]

Just for curiosity, look at your distributor cap contact areas for corrosion or missing pieces.
I had a similar problem and it turned out the cap was bad.

[RICK LAKE]

LeonardU Len give me a call now. 732-254-3536 need to do a couple of quick tests. Rick L.

[LeonardU]

I want to thank Rick Lake for taking his time to help me. I called him, he asked me a few questions and in a matter of minutes he solved my problem. I needed to replace my rotor and distributor cap. Well he was spot on. The car restarted perfectly after being brought up to temp and turned off.

This forum is so great with a bunch of guys like Rick Lake who take their time to help other cobra people. I want to thank Rick and the operators of this forum. You guys are the best.

Len

[elmariachi]

I like black so i run the GM big block caps and have found they don't last long on these cars....the center electrode turns to dust and the car starts missing. Glad you and Rick found your problem.

[Tugboat]

Only slow cars use black caps!!!!!

Larry

[elmariachi]

Originally Posted by Tugboat

Only slow cars use black caps!!!!!

Larry

Mine is real damn slow right now, sitting on that lift.

[Excaliber]

I've to replace my RED MSD cap a couple of times because that center electrode is so fragile, or possibly because I'm a caveman with rag when I clean the cap.

Whatever, gotta keep an eye on 'em.

[Rick Parker]

MSD makes Black Caps for the small diameter billet distributors. BTW there is no reason for the center carbon to be disintergrating unless it is overheating. Check to make sure it is being contacted by the center spring blade on the rotor. Put a small spot of dielectric graese on the button and see if it transfers to the rotor blade after assembly, if not bend the blade a little farther.

[elmariachi]

Originally Posted by Rick Parker

MSD makes Black Caps for the small diameter billet distributors. BTW there is no reason for the center carbon to be disintergrating unless it is overheating. Check to make sure it is being contacted by the center spring blade on the rotor. Put a small spot of dielectric graese on the button and see if it transfers to the rotor blade after assembly, if not bend the blade a little farther.

Well whatever it is, its happening to three different FE-powered Cobra replicas in Houston and the only thing we have in common is we park next to each other at the Saturday nite cruise-in. One is an ERA with a side oiler another is a Contemporary with a 428. We are all experiencing it.

[CJ428CJ]

That center button on the MSD cap always falls off within several thousand miles on my car. I bend the tab on the rotor up until it contacts the center button and that works fine until the next time I pull the cap off at which point the remaining portion of the button falls down into the distributor.

I switched from the MSD brand cap to the Summit brand and haven't had a problem since.

Chris

[priobe]

Originally Posted by CJ428CJ

I switched from the MSD brand cap to the Summit brand and haven't had a problem since.

Chris

Whats the part # of the new cap?

[bobcowan]

Originally Posted by elmariachi

Well whatever it is, its happening to three different FE-powered Cobra replicas in Houston and the only thing we have in common is we park next to each other at the Saturday nite cruise-in. One is an ERA with a side oiler another is a Contemporary with a 428. We are all experiencing it.

It's happened to my on a Mallory, and to a friend of mine on a differant Mallory. This seems to be a common problem with aftermarket caps. Nobody seems to know why.

I replace mine annually, and carry a spare in the trunk.

[CJ428CJ]

Whats the part # of the new cap?

Here's a link: http://www.summitracing.com/parts/SUM-G5234/

[Gunner]

High stress point in any engine; combine it with very hot MSD sparks, larger plug gaps and more high-rpm time than most engines and you'll get breakdown. I'd guess that having the center spring contact too tight is hard on wear, as well as having the spring too loose so that the spark has to jump the gap. There may be an optimum pressure setting but I'm darned if I can figure out a way to set it accurately.

[Anthony]

For the MSD cap, I think the best "cheap" cap is the Borg warner with brass terminals, part # Borg-Warner C158

Failure #2 of MSD distributor cap on FE ???

I was just thinking about this the other day.