I found my biggest problem with this system is "heat" if you are sitting or
backing up alot or trying to get parked or what ever and not getting air
through the engine compartment you will generate alot of heat. It seems to
me that when I got this heat the ignition would quit. Now that I have the
Headers, ceramic coatings and the Jacobs wiring and added ignition system I
have licked the problem. For at least the pawst 7-8 years I have had no
problems and have not replaced anything accept the spark plugs at 6-7
thousand miles. Chuck. PS the plugs look great but I toss them anyway.
> FYI
> Many of us old time GMCers (10 years myself) have found that HEI Ignition
> failures are primarily cause by improper spark plug gaping. The OEM
> specified gap is 0.080" which is to great a gap & causes excessive Coil
> voltage, which can result in all kind of Ignition damage. The solution,
> w/o sacrifice of performance, is gap plugs at 0.060" ( AC R46SZ. Also
> use only Delco Ignition Modules & apply an abundance of the Thermal
> Conduction Grease on the base of the module during installation.
> Recommended spare Ignition parts are as follows:
> 1) Delco Ignition Module w/thermal grease
> 2) Ignition Coil (Delco only)
> 3) Rotor (Delco only)
> 4) Distributor Cap (Delco only)
> 5) Spare Ignition wires (2-3 wires)
>
> Also failures occur due to lose of the Coil ground which give erratic or
> non operation conditions (check for looseness on the Coil mounting screws
> & place both ground wires under one mounting screw).
> The GMC Motor Home Distributor is unique in its mechanical & vacuum
> advance curves & therefore a car dist. will not provide performance w/o
> modifications. Try Bob Lamey, 1-909-982-7747 Ontario, CA for an expert
> distributors Upgrade (new GMC Motorhome Distributors are not available).
> I too do not think a failure of the module is justification for
> replacement of the distributor (if not done properly, a step in the wrong
> direction).
> An HEI tester is available at many Auto Parts stores for about $10. A
> must for simple HEI trouble shooting. The HEI Tester is made by K-D
> Tools p/n 2756, "Calibrated Ignition Tester for HEI Systems".
>
> Duane Simmons
>
> ___________________________________________________________________
> You don't need to buy Internet access to use free Internet e-mail.
> Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
> or call Juno at (800) 654-JUNO [654-5866]
backing up alot or trying to get parked or what ever and not getting air
through the engine compartment you will generate alot of heat. It seems to
me that when I got this heat the ignition would quit. Now that I have the
Headers, ceramic coatings and the Jacobs wiring and added ignition system I
have licked the problem. For at least the pawst 7-8 years I have had no
problems and have not replaced anything accept the spark plugs at 6-7
thousand miles. Chuck. PS the plugs look great but I toss them anyway.
> FYI
> Many of us old time GMCers (10 years myself) have found that HEI Ignition
> failures are primarily cause by improper spark plug gaping. The OEM
> specified gap is 0.080" which is to great a gap & causes excessive Coil
> voltage, which can result in all kind of Ignition damage. The solution,
> w/o sacrifice of performance, is gap plugs at 0.060" ( AC R46SZ. Also
> use only Delco Ignition Modules & apply an abundance of the Thermal
> Conduction Grease on the base of the module during installation.
> Recommended spare Ignition parts are as follows:
> 1) Delco Ignition Module w/thermal grease
> 2) Ignition Coil (Delco only)
> 3) Rotor (Delco only)
> 4) Distributor Cap (Delco only)
> 5) Spare Ignition wires (2-3 wires)
>
> Also failures occur due to lose of the Coil ground which give erratic or
> non operation conditions (check for looseness on the Coil mounting screws
> & place both ground wires under one mounting screw).
> The GMC Motor Home Distributor is unique in its mechanical & vacuum
> advance curves & therefore a car dist. will not provide performance w/o
> modifications. Try Bob Lamey, 1-909-982-7747 Ontario, CA for an expert
> distributors Upgrade (new GMC Motorhome Distributors are not available).
> I too do not think a failure of the module is justification for
> replacement of the distributor (if not done properly, a step in the wrong
> direction).
> An HEI tester is available at many Auto Parts stores for about $10. A
> must for simple HEI trouble shooting. The HEI Tester is made by K-D
> Tools p/n 2756, "Calibrated Ignition Tester for HEI Systems".
>
> Duane Simmons
>
> ___________________________________________________________________
> You don't need to buy Internet access to use free Internet e-mail.
> Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
> or call Juno at (800) 654-JUNO [654-5866]
