TR2/3/3A lower generator bolt

[Geo Hahn]

On the road and hoping someone can tell me the size of the lower front bolt for the generator.

This is the one that threads into the pedestal -- looks like it is 5/16 but am unsure of pitch and length.

I realize the real part has a shoulder but I'm not going to worry about that right now.

Thanks for any help.

 

[TR3driver]

Threads are 5/16-24 NF. The original was kind of short IMO, 1" IIRC. (I also found 1" listed on Rimmer Bros web site.) But I found that a 1-1/4" fit for me, even before I added a heavy flat washer against the aluminum housing. The longer bolt went deeper to grab the undamaged threads in the pedestal.

 

[trrdster2000]

Thanks for helping Geo out, he helps so many of us. I was going to PM him and give him my Phone number and take the one off the Roadster, as I think they are the same, if no one chimed in for the next few minutes.
Thanks again Randall, Wayne

 

[Geo Hahn]

Thanks, off to Ace Hardware for a get me home part.

... The longer bolt went deeper to grab the undamaged threads in the pedestal.

And that is quite possibly what we are dealing with.

BTW, it is actually for a 60 Italia.

 

[Geo Hahn]

Thanks again to both of you, bolt is on with blue loctite and all is secure.

 

[Lukens]

George, you're right about the shoulder bolt. The problem with NOT using a shoulder bolt is that every time you move the generator, the bolt will back out a smidge. I opened the hole on my alternator and slipped a pipe spacer over the bolt to achieve the same deal.
Russ

 

[Geo Hahn]

The car did make it home to Tucson from Santa Fe but went through 3 bolts in the process. Almost certainly the threads in the pedestal were badly knackered and having no shoulder on the replacement bolts did not help either.

The first generator had a failed front bearing, probably due to running w/o the lower bolt. The spare generator began to show signs of the same thing as the bolt would fall out along the way and it. too, would have to run w/o a lower bolt until a stop & check revealed it was ready for another one.

 

[TR3driver]

I think that technically, it is not a shoulder bolt, as that would imply a shank larger than the thread diameter (ie larger than 5/16"). Instead, I think it should just have a 5/16" unthreaded shank long enough to pass through the generator end plate.

And even with the shank, it is important to tighten the bolt after any generator adjustment. Probably best to loosen it beforehand as well, since the end plate may break rather than move with that much torque applied.

Anyway, glad the Italia made it home.