Generator Idler Gear Stud to Cam Cover 'Hole' Clearance

[Ripley/Fla]

Does anyone have an idea on how 'tight' the generator idler and circuit breaker studs should be in the cam cover. Upon closer inspection of my recently rebuilt motor it seems that they have been opened up a bit. Now the cover was chrome plated and perhaps it was cleaned up to remove plating - but there is a lot of chatter and a stud will drop right in. Thanks for any opinions.

[FlatHeadSix]

Ripley
Good question. I've never actually checked the fit of the cam cover end, I've always left them anchored to the right case and installed the cover over the complete assembly. I don't think they were intended to "dowel" into the cover and I don't think there would be enough lateral thrust against the sides of those shaft ends to cause a problem if there was a little chatter or a slightly loose fit in the hole in the cam cover. I don't remember ever encountering an interference fit of those parts when disassembling or assembling one.

mike

[Ripley/Fla]

I'm not sure how much force is on them from the timer or generator - the studs are nice and tight in the crankcase, tho. The chatter is from machining not loose parts.

[steinauge]

I just measured a 49 in the shop after reading this post,it has what looks to be a pretty decent cover and the clearance is .005 for the circuit breaker drive gear shaft and .006 for the generator gear shaft.I will check a couple of more when I get home tonight and let you know tomorrow.

[Ripley/Fla]

Steinauge Thanks! My studs measure around .556 - the cam cover measures around .563/.565. From the machining it looks like it was drilled open with a 9/16" drill. Actually what you tell me is good news - if it has .005 clearance then the cover really doesn't support the stud, IF everything is perfect. I'm going to magic marker up the end of the studs and R&R the cover and see if something is scraping or not quite right.

[steinauge]

Measured 2 more another 8fin and a 4 fin-8 fin .5585 and .5587,4 fin .558 and .559.I measured a fresh set of (aftermarket) shafts and got .5556" on both using the same mike.HTH

[Ripley/Fla]

Ouch! Your cover shows .002/.003, where mine has .007/.009. That is a big difference. I tried the magic marker - but at my clearance it didn't even touch anywhere. Thanks for the measurements, I'll have to think about the risk here.