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Sat Jul 26, 2014 6:24 am

How often is it that Bosch Silicone Plug Wires Fail?

Have maybe a miss from one going under load but not sure...

Never had an issue in the past and have been running them on VW's
ever since being into them..

This set is on a 1600DP and Rev's to 4,000 all the time, thing is this set
on this motor is only 1 year old...

So, what is ya'lls take? Thanks for your time... RB

Sat Jul 26, 2014 7:04 am

RailBoy wrote: How often is it that Bosch Silicone Plug Wires Fail?

Have maybe a miss from one going under load but not sure...

Never had an issue in the past and have been running them on VW's
ever since being into them..

This set is on a 1600DP and Rev's to 4,000 all the time, thing is this set
on this motor is only 1 year old...

So, what is ya'lls take? Thanks for your time... RB

Hi, I wouldn't suppose any wire set would fail after only a year. What conductor type does the Bosch use? Silicone is the insulator and pretty much standard these days on any good wire. I would think your problem likely lies elsewhere. Are you using stock points, Bosch dizzy and cap? Maybe swap rotors in case the rotor resistor is failing. Have a look at your spark plugs or swap them out. Check the gap isn't too wide. Resistor spark plugs can fail especially if Champion makes them. Could be a bad distributor cap too or a poorly grounded distributor. Check coil connections etc are good. It could also be a condenser that has partially failed, but I doubt that one year old wires would be at fault even if they are the carbon wick conductor type. Unless of course, you have yanked on them in which case the conductor can be damaged. That type of wire should be treated gently. Good luck, Fred

Sat Jul 26, 2014 11:20 am

The resistors in the spark plug connectors can fail. If they are carbon core wires then they do wear out eventually.

check the resistance. It's easy.

Sat Jul 26, 2014 7:04 pm

The Bosch silicone wires can have the outer cover cut open when trying to install them in the stock plastic wire clips on the fan housing.
This can cause them to short out against the fan housing.

Sun Jul 27, 2014 4:45 am

I have all knew stuff, Plugs gapped at .024 thousandths, New Bosch Cap plus Rotar. And all good contacts/connectors, it is a new engine as of last year.... Coil is new as well...

Thing is this, I do have a Donut leak on the driver's side... But I run a BugPack Header w/Quiet Pack, plus Kads, guess that the donut leak could be leading to carburation issues for the back pressure is being affected, causing a miss/popping......

Wonder if you can put in a donut with out removing the engine?

Yea, it clears up at over 2,500 RPMs......RB

Sun Jul 27, 2014 5:51 am

You talking about the seal from the heater box to the header? Yeah - you can replace that without dropping the engine. One thing with Kads or any duals, is its hard not having the plug wire against the intake and it will get pretty warm. Also, your plug end is screwed on well?

But If your symptom is a miss in a specific RPM range, - like it clears up above and below, then I would look at your carbs. There are a couple little things that you need to address if you bought "off the shelf" kads from pretty much anybody except someplace like Kaddieshack, who actually set them up.

Sun Jul 27, 2014 5:55 am

andk, so you think that the heat getting to the Silicone Shielding broke it down and I am getting conductivity through it now maybe?

On the Header Leak, yea, coming from the heater box to the header on the passenger side I have a leak, not 100% sure I can get a donut in there or not, thinking of taking the "pinch bolts" off and wrapping it with a Beer Can and Putting two clamps on it, one on the header send and one on the heater box end and seeing what happens,lol....

Thanks for your time... lol.. RB

Sun Jul 27, 2014 5:57 am

RailBoy wrote: andk, so you think that the heat getting to the Silicone Shielding broke it down and I am getting conductivity through it now maybe?

On the Header Leak, yea, coming from the heater box to the header on the passenger side I have a leak, not 100% sure I can get a donut in there or not, thinking of taking the "pinch bolts" off and wrapping it with a Beer Can and Putting two clamps on it, one on the header send and one on the heater box end and seeing what happens,lol....

Thanks for your time... lol.. RB

See added info on my last post

Sun Jul 27, 2014 6:02 am

andk, yea my Kads are Kaddie Shack Kads, and yea, they are nice, they were "set-up" and "spec'd out", all I had to do was mount and do some jet tweaking....

Did cover the idle jets, there good, plus everything else, just getting some popping at low rpms which I can be from the donut issue, but the thing is I would not think the donut could lead to the missing, but this is at a spacific rpm range, so, makes me think that this could be plug wires, unless the donut is causing that much of a "flutter" at those RPMs'...

Been a bit since I have messed with 4 cylinder engines, just got back into the VW scene a few years back and my Super ran sweet up till a few months back, but took a break from it till now, summer is to hot for it, no A/C,lol.. RB

Sun Jul 27, 2014 6:13 am

Check for vac leaks and did you set the idle mix? But your exhaust leak is probably the issue. Just get yourself a set of exhaust gaskets and a new muffler seal. What I do when the engine is in the car is install the gaskets and leave everything loose until I get the heater boxes well inside the header or muffler, then keep working it while tightening.