Spark Plug Wire Issues With Headers

[c3po]

I am having an issue with spark plug wires on a small block chevy with headers that are Jet Hot coated. 1 of the wires is bad on the driver's side, does this mean the rest are ready to go.

I once had DUI Live Wires that had a wire sleeve on there but the boots melted on 2 wires near the back so they sent me my money back. No problems where the wire was sleeved.

1) MSD sells a Pro-Heat Guard sleeve for $90.00 that resists temps up to 1000 degrees.

2) Moroso and MSD sell a generic sleeve for $50.00 but it does not give a temp rating.

3) Thermo tec makes a header jacket for $91.00, they are like socks that snap on each header tube allowing it to breath.

No matter what wires I get I have to deal with this heat issue, let me know if I should do:

Only Number 1
Only Number2
Only Number3
Number 3 with a combination of Number 1 or 2

The header jackets are supposed to knock down heat by 70%, this is what I have read.the exhaust jacket is called Thermo tec high velocity exhaust jacket.

Any help would be appreciated.

 

[Buffman]

keep it off the header. I'd rather wrap the plug wires..

 

[bulwnkl]

I used to struggle with this on stationary big-block Chevys converted to run natural gas. Just ran a plain tubular-steel header (no coating) which dumped to atmosphere (yes, they were very loud). I was renting the place so I didn't feel like taking the headers off and wrapping them with header wrap, but I'd lose a set of ~$80 plug wires every month or three, even though they were supposedly designed/shielded to run next to headers like that.

Based on my experiences, and depending upon exact prices, I'd probably try #1 first, but go to #3 (or 3 + 1 or 2) if it didn't work.

 

[c3po]

I went ahead and got the MSD Pro Guard Sleeve which is good too 1000 degrees.

I did not get the header jackets because on each header there are 2 tubes that run so close to 1 another that they would not fit. I also read that these header jackets only cover 22 inches of each primary tube. This still is a problem for the portion of the header tube that is not covered.

If all goes well with this spark plug wire installation I may put a cowl induction hood that sticks up 2 1/2 inches, as this may let some more heat out of the engine.

 

[bulwnkl]

Hope it works well for you!

 

[c3po]

I hope it works well too, the other thing I am doing is getting universal wires so that I can have the correct length of wire from the spark plug to the distributor.

In the past I had wires that were already made and some were a little bit to long and kind of snaked up by the distributor.

The wires on there before were supposed to be good to 600 degrees and my header tubes as measured by the infrared gun were between 350 and 450 degrees, it seems wires do not like heat.

I do not know if I put a big mechanical fan back on the car if this would push more heat out of the engine.

 

[bulwnkl]

350-450 is certainly a whole lot cooler than mine ran, so the coating must be helping a bunch. Of course, I don't know whether there's an exhaust temp difference between gasoline and natural gas...

Mine used to run my IR gun off the scale, which max'd around 800 degrees?

 

[c3po]

Here is the problem with the way I take the temperature, after a long drive I shut the engine down and within a few seconds I pop the hood and take the temp, maybe I need to take the temp with the car running.

The Jet Hot Coating is coated on the inside of the header as well as the outside of the header.

bulwnkl, is this your car that ran on natural gas or some kind of dragster.

 

[bulwnkl]

Stationary engines (on stands) that powered well pumps and generators simultaneously. So, my measurements were with the engines running as I walked up to them. Actually, it was easy to tell which cylinders were starting to have wire issues (misfires). I would be able to get a temp reading with my IR gun on a misfiring cylinder, or alternatively when I'd go out at night those cylinders' header pipes weren't glowing orange.

 

[c3po]

I got the wires put on today, so far I have replaced:

1) Spark Plug Wires
2) Spark Plugs
3) Vacuum Advance Diaphragm
4) Distributor Cap
5) Rotor

Since I have done all of these things maybe I should replace my coil, it has been on there for 50,000 miles. I am wondering if a new 1 would make a difference.

I have not started the car yet because I need to get all of the wire looms in place, that will be tommorow.

 

[[RT] ProjUltraZ]

hey 3PO the easiest way to avoid it is to make sure no wire is within 1/2" of any pipe. zip ties, looms, anything to get em away. my LT1 opti has em running from the bottom front, also jet hot coated headers. i routed the pass side under the block and have em coming up vertically, loomed, creative zipties.

i also went to the Taylor full metal jackets (braided steel) but even those won't withstand touching or super close to the header, i burned 1 wire and replaced it w/ one of my old ones.
the taylor heatjackets can help, but they're bulky and if they touch it's over. the heat shrink MSD shields are prob better. I now have a set of 10.4mm thundervolts waiting to go on, better conductivity than the 7mm FMJs

also change the coil, they're cheap and easy to replace. don't forget to the disconn the battery, lethal shock possible

 

[c3po]

I will tell you that this MSD Pro Guard Shield that goes over the wires is fantastic stuff, tommorow is going to be nice so I will go out and start the car and see what happens.

I have no problems with the boots since I reused the boots that were on my old wires, they have some space age coating that is good to 1500 degrees.

Since I changed everything else I am going to go ahead and get another coil, might as well have everything new.

My buddy helped me loom the wires and they are at least 2 inches away from the headers. I may still do the exhaust jackets in the spring, I will have to see how things go.

 

[bulwnkl]

1/2" wasn't even close to sufficient on the Chevys I was running, but again they didn't have coated headers nor were the engines moving. Between 1 & 2 inches was the clearance I had. If half an inch will do it for you, then the coating and other shielding is working really well, I'd say!

 

[c3po]

Went too start the car and it would not start, sprayed some ETHER which is starting fluid and it started right up, maybe I needed too use the ether because the car was sitting for a week.

 

[OVERKILL]

Ether is VERY hard on an engine. Not a good idea.

 

[-Clayton-]

Originally Posted By: c3po
Went too start the car and it would not start, sprayed some ETHER which is starting fluid and it started right up, maybe I needed too use the ether because the car was sitting for a week.


I'd say your carb is either leaking from the casting plugs or the fuel filter in the carb is missing the little anti drain back valve. My quadrajet did the same thing when it sit for over a week without being started.

 

[c3po]

I will say this, before this week, this car has been driven almost everyday since 1985. This was the longest this car ever sat, it was in the garage for 10 days.

My buddy thought that since the wires were shot and not firing right there was some gas in the cylinder's.

This is his opinion and not mine, I am just happy that it is just running.