Distributor Gear Roll Pin
 

Can these be reused?

Thanks.

I always have reused them. I'm no expert but no troubles yet.

If you still have to drive them in then there good to go.

I always have. Never had an issue.

I reused mine. I figure as long as it's tight, its doing it's job.

Thanks guys.

I am very sure that the OP greatly appreciates the insight and help you have offered with the above reply.

I never reuse roll pins; old habits ( aircraft maintenance background) die hard…

After you use them they are smaller than a new one, and cheap.
I keep some spares in my tool box and use them once.
After all, they are inside your engine and spinning around.

Seems like by design they're really intended for one time use. They compress but never re-expand. Anyway, the one that I put back in the distributor was still very tight. Doesn't feel like it's going anywhere. OTOH, the one I put back in the previous distributor I would not have confidence in.

I think of a roll pin as a spring. It compresses going in, but springs back to provide the retaining force. By design, it should not "bend" or permanently deform when installed, so I don't think they are a "one-time" part.

All the comments about "if it feels tight, it's OK" make sense to me but I'd also make sure the bores in BOTH parts appear round and smooth with a quick visual inspection.

As to replacing, I'm not sure I'd trust the strength of a hardware-store pin in today's cost-driven world. I trust the quality of a 50-yr-old GM part more, even if it's just a roll pin. The shear strength of the pin is what matters and the spring force just keeps it in place.

Consistent with my habit of over-thinking, here's a blurb I found on roll-pin joint design that doesn't talk to re-use but spells out how they work:

https://www.spirol.com/assets/files/...urface%20area.

Mike

I have ONE somewhere thats almost solid, its not built like a C its just like you rolled up thick sheet metal as tight as you can, ... Iff theres no deformation obvious wear from slop and it fits tight then it basically has all the properties of a new one

I do replace mine because i have an assortment box of pins

Now does anybody sweat installation of a roll pin rotationally speaking?

Yes, coiled vs slotted as in the Spirol paper I linked

Agree

Good insurance

Are you asking if the roll pin is a reliable way to retain the gear and transmit rotational loads? If so, then you may be stepping into all the cam and oil pressure threads! I haven't seen postings of sheared off roll pins but I guess it could happen if the torque to drive the oil pump somehow went ballistic? Seems we have seen some oil pump shaft carnage on PY but has anyone ever experienced a roll pin failure?

Mike

Yes but in a Ford and no carnage, distributor quit spinning and shut the engine off.

seems like reusing a condom, yeah it'll probably work but replacing it is cheap and a LOT could go wrong if it fails!

Quote"
Are you asking if the roll pin is a reliable way to retain the gear and transmit rotational loads? If so, then you may be stepping into all the cam and oil pressure threads! I haven't seen postings of sheared off roll pins but I guess it could happen if the torque to drive the oil pump somehow went ballistic? Seems we have seen some oil pump shaft carnage on PY but has anyone ever experienced a roll pin failure?

No.. talking about the opening of the C in terms of how its installed... i didn't mention failures either

Why reuse any connecting device after it has been "driven out" to do other work ... my 1st thought, FWIW.

Seems like $4-$5 investment at Harbor Freight (<- I know, bad word) for 100-120 unused roll pins would be a good idea. Maybe the other sizes could be used elsewhere?

Ogre

Got it, thanks for clarifying. You were asking about the orientation of the slot or "C" relative to the distributor shaft axis.

Maybe some mechanical engineer on here knows the "optimum". Personally, if the pin has to be driven in, I think it's good, but my SWAG for "optimum" would be 45 degrees off-axis.

Mike

I’ve reused them.

A new spring pin isn’t a bad idea.

One might have to question the actual material used in a typical hardware store or Harbor Freight spring pin, if the factory pin still fits tight I’m sure it’s still fine to use.

Factory hardware is known to be of high quality.

If you’re worried about it working its way out you can always peen and flare the ends a bit into the chamfer in the gear using a pointed punch.

So maybe the answer is that it depends on the application (eg., aviation) and the technicians assessment. Like I mentioned, the one I put back in the car felt very tight. The one I put back in the donor distributor was not. I would not have put that one back in the motor. The pin that I used in the final install was a DUI factory installed pin that I obviously re-used. The loose pin was most likely a BOP pin (I say most likely because I didn't do it myself, but that's what I think is probably correct).