Sometimes don't start

[VetteVet]

Here is the picture:

http://i827.photobucket.com/albums/z...et/Starter.jpg

The tapered rubber bumper seals very well in the radiused cavity in the cap. At this point, I have to apologize. I did not modify the bumper as previously stated (senility is apparently starting to set in). I debated modifying the bumper or the cover and chose to modify the cover. I cut a very shallow groove in the metal cover (visible at 12 o'clock in the picture). This prevents a vacuum from forming in the cavity and preventing the main contact (copper disk) from engaging and directing battery voltage to the starter motor windings. This only occurs after running to temp AND after a short cooldown period. Immediate restarts or waiting a substantial period of time do not cause any starting problems. When a no-start occured, I noticed a slight, but noticable drop on my volt gauge (due to solenoid energizing), but not a large drop (indicative of the starter windings being energized). If these are your symptoms, then this may work for you. I had numerous no-starts prior to this mod, but with several months of use after the mod, I never once experienced another no-start.

Jep

[max76]

Vettevet, but the modify is only a groove for prevent vacuum?
Which problem create the vacuum into the starter?
Is this the common problem of these starters?Also for zr1?
I thought that was a mechanical problem into the starter...
Thanks in advance

[VetteVet]

Originally Posted by max76

Vettevet, but the modify is only a groove for prevent vacuum?
Which problem create the vacuum into the starter?
Is this the common problem of these starters?Also for zr1?
I thought that was a mechanical problem into the starter...
Thanks in advance

max76,

When the solenoid is not energized, the tapered rubber "bumper" is seated in the radiused cavity of the solenoid cover by spring pressure. As the engine heats up, so does the air in that cover cavity. The heat causes the air in the cavity to expand and pressurize the cavity. That pressure works it's way out because the taper of the "bumper" and the radius of the cavity allow it. Once the engine is shut down and the air in the cavity starts to cool, it contracts and the pressure drops. This causes a vacuum to be drawn, which firmly seats the tapered "bumper" in the radiused cavity. In effect, the solenoid slug and main contact disk are held firmly in place. When the solenoid is energized at this point, the magnetic field created by the solenoid windings is not sufficient to overcome the force holding the slug and main contact disk in the deenergized position. The result is that the solenoid coil energizes, but battery voltage is not directed to the starter, because the main contact does not close. Result is a no-start. Hopefully, this will clarify things. Sorry for not explaining it better from the start.

Jep

[max76]

Vettevet,
am i that i don't know a better english, but i think to understand the problem...I hopr to repair soon my starter...
An other question, is so difficult remove the plenum and other parts for remove the starter?
There is a particular procedure?
Thanks a lot to everybody

[VetteVet]

Originally Posted by max76

Vettevet,
am i that i don't know a better english, but i think to understand the problem...I hopr to repair soon my starter...
An other question, is so difficult remove the plenum and other parts for remove the starter?
There is a particular procedure?
Thanks a lot to everybody

max76,

Here is a link: http://www.zr1netregistry.com/plenum.htm

Lots of good info on the ZR-1 Registry site!!

Jep

[max76]

Thanks vettevet