Crank gear runout

[303epps]

Hey guys,

I have a DPR 78.4mm crank with a new OEM crank gear and a Bugpack aluminum standard type adjustable cam gear. Not sure if I'm being OCD here but there is about .002" backlash except at one point next to the key then it becomes zero. Cleaned the crank before installing with 400 grit and a fine file around the keyway. measurement was done with a dial indicator. Cam is a web 163.

There is no discernible tight spot and the cam gear doesn't walk out when turned in reverse.

Am I asking for trouble running like this or should I pull the gear and start over again?

Eric

[Danwvw]

There should not be any runout on the cam gear. It must not be seated properly on the cam. You may have to loosen it again and check that. I use blue threadlocker on the cam bolts so they will come loose just incase this happens. If you used red threadlocker then you will need some formable carb cleaner to get the cam bolts loose again.

_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[SBD]

If I'm understanding your problem correctly maybe you have a tight key in the slot in the crank?
http://www.thesamba.com/vw/forum/viewtopic.php?t=588951
_________________
"Just $99 down and $64 a month for 36 months buys you a brand new Volkswagen Beetle!"

[jason]

I agree on key. May also be a burr. I'd leave it if theres no burr.

[cbeck]

I just saw a thread on here the other day about a chewed up gear and a incorrectly sized keystock is the suspect.

[modok]

Sounds fine except the part about "right at the the keyway. Makes you worry the gear is too tight on the crank.

[303epps]

Hey Glen,

Does the crank gear take a shape that when it's pulled and put back on will it settle on round if the underlying crank is okay?

FYI- oem key, gear, spacer. Sanded burrs off key, lightly tapped in to key way.

Eric

[modok]

If the press fit is less than .002" per inch of shaft diameter, I think it will spring back for sure, but above that, it may not depending on heat treat.
This is a good rule of thumbs for press fits of any sold steel parts.
I've done a LOT of cam gears. Some too big to lift

With German parts, there was rarely any need to check any of it, but these days, ect, ect you've heard it before.
The crank gear often gets a little beat up from using a puller, and the mag cam gears get beat up easy too or get ugly with age, so sometimes there are tight spots, but I never saw any problem result from it that. Actually never had any problem myself, but we invent new ones all the time. While on the subject please remember don't use star type lockwashers on aluminum or mag gears. Cam companies are putting those in the box, and they should not.