Worn distributor gear (Page 2/2)
Greg872.8SE APR 04, 01:03 PM
Thanks Patrick I really appreciate you taking the time to find that spec. My gap was a little wide, .027 in. Here is a picture of the toothed washer just sitting on the end of the shaft so that you can see the diameter difference between the shaft and washer. When installed (teeth inside aluminum housing) it has a lot of slop. Is that normal? I know it shouldn’t be tight on the shaft, but it seems like it should be a snug fit, inside the aluminum body, but loose enough to rotate tooth to tooth inside the aluminum body of the distributor.
Patrick APR 04, 03:58 PM
That washer with the tabs is fine... but I see what you're saying about the chewed up gear. Strange.

It's difficult to tell in your photo, but if the top of the gear (on the left in photo) is chewed up as well, then we can probably rule out the distributor not being seated all the way down. Makes me wonder if the camshaft gear was machined properly.

[This message has been edited by Patrick (edited 04-04-2020).]

Greg872.8SE APR 04, 08:22 PM

quote
[B]Originally posted by Patrick:[/B

It's difficult to tell in your photo, but if the top of the gear (on the left in photo) is chewed up as well.....




The gear shows the same wear top to bottom, so I would agree the distributor was probably seated. My thought right now is to get the proper end play on the distributor (.005-.015), put the new gear on, apply some Prussian blue and install the distributor, then rotate the engine, with a wrench on the crank, pull the distributor and see if something jumps out and really gets my attention. If nothing catches my eye then I’ll lube the gear on the distributor and reinstall it and reassemble everything else I pulled off to fix the oil pan leak. I’ll buy a half dozen of Rodney’s high temp o-rings and start driving it. I’ll pull the distributor at 100 miles and check the gear, if no wear than 250 more miles I’ll check again, then 500 more miles, and so on till I’m comfortable that it’s ok. If it shows wear at any time than I’ll be on here asking opinions on performance cams and changing the cam.
My hope is the wear was caused by the high volume pump causing to much mechanical loading on the gear and/or a cheap gear on the new distributor. My fingers are crossed.

Gall757 APR 04, 09:24 PM
So you think the cam gear is not at fault? It sort of looks like the valleys in the cam gear are not deep enough.
cvxjet APR 04, 10:32 PM
I have a couple of suggestions; A) Bad (Incompatible) gear on cam, or B) No oil getting to the gear mesh area....How does that area get oil? Does it come from the lifters? Or drip down from the heads? Or does it have it's own supply?

One other possibility; Does that gear look the same as what normally is used in a Fiero engine? (Maybe the Distributor gear is the one that is not right)

Also, I hate to say this...but if your dist' gear looks like that, what does your cam gear look like? (Can you look down the dist' opening and see the cam gear?)
Patrick APR 04, 11:22 PM

quote
Originally posted by cvxjet:

How does that area get oil? Does it come from the lifters? Or drip down from the heads? Or does it have it's own supply?



I don't know exactly how it gets there, but that whole area has (or is supposed to have) high oil pressure... which is why it's a common location for bad oil leaks when the rubber O-ring on the distributor gets too hard and doesn't seal properly.