Anyone running the United Motors vented distributor cap?

[454cid]

The thread about wires, and my truck running a bit rough lately has gotten me looking at ignition components again.

United Motor Products is the only company I've seen specifically market a vented cap. Anyone use one? It has brass terminals too.

https://www.rockauto.com/en/moreinfo.php?pk=1991918&cc=1353451&jsn=103913

 

[L31MaxExpress]

The thread about wires, and my truck running a bit rough lately has gotten me looking at ignition components again.

United Motor Products is the only company I've seen specifically market a vented cap. Anyone use one? It has brass terminals too.

https://www.rockauto.com/en/moreinfo.php?pk=1991918&cc=1353451&jsn=103913

When I still had a distrubtor cap and rotor on my L31, I created a positive vented distributor base like the later opti sparks that was vented by vacuum.

 

[454cid]

When I still had a distrubtor cap and rotor on my L31, I created a positive vented distributor base like the later opti sparks that was vented by vacuum.

Do you have more details on that in another thread someplace? I know nothing about the Optispark except that it has issues from the factory.

 

[L31MaxExpress]

Do you have more details on that in another thread someplace? I know nothing about the Optispark except that it has issues from the factory.

The early ones had issues. The later ones were vented using hoses connected to the intake manifold.

I basically tapped the distributer base for 2 fittings that were elbows that had 1/8" nipples on them. I drilled a small hole through the throttle body above the throttle plate and inserted a piece of aluminum tubing that I epoxied into place. I connected a vacuum hose to one of the fittings on the distributer base to this fitting. The second fitting I connected to the air intake boot using a small hose barb. Above idle when I was on the throttle it would pull the ionized air out of the distributor and vent it with fresh air. I sealed the cap to the base with a small bead of RTV. It virtually eliminated the cold/wet weather moisture related misfires I was seeing and the cap and rotors lasted much longer.

I first tried using constant vacuum but the engine idled too high with the constant vacuum leak of the 1/8" hose. Fuel trims were did not change because the MAF was reading the vent air.

 

[HotWheelsBurban]

This is great idea to do if I pull the distributor. Knock on wood, I haven't had any trouble since I went to the Blue Streak rotor and Accel cap. Think some of my "hard starts" last year that I thought were ignition problems were really mr.passlock....

 

[454cid]

Hmm, I was thinking putting the distributor between the MAF and PCV hose.

I'm not crazy about the idea of rtv/silicone sealing it. This idea of venting this way may be overkill, for me. I didn't have a moisture issue until a couple of years ago. It may not even be the distributor. It started not wanting to start a second time after washing the engine compartment.... the icm has pooped out a time or two, as well.

 

[someotherguy]

That cap isn't any more expensive than the other brands (and actually cheaper than AC Delco and Delphi); I say give it a shot. Considering the crappy quality of so many Vortec distributor caps these days, it would be hard for it to be worse. And it may actually be great!

Richard

 

[kenh]

If a cap is dusty inside and they do get that way, moisture is attracted by the dust. Once enough moisture/dust has accumulated, the spark will start to follow a path to ground. Once that path has started it carbonizes that track and no amount of cleaning will help. Only new cap will cure the problem.

Ken

 

[HotWheelsBurban]

Here it is, came Friday. Hope to get it installed after lunch. The little round thing is the vent; in the upside down picture, you can see the hole for it. Hope it works as advertised!

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It looks well made,and has a "heft" to it that the cheap caps don't have.

 

[Schurkey]

the icm has pooped out a time or two, as well.

Have you tested the ignition coil? Failed ignition coils are a common cause of repeat module failures.