Questions about flanged cranks ...........and VW addiction. Thursday, 06-Jul-2000 01:12:00 Message: 18.104.22.168 writes: I was putting my 88x103 moter together and ran into a few problems.First off after 3 days of pre assembles i ran into a problem that i cant figure out ,and that drives me nuts.Well what happend is the moter was locking up because the distributer drive gear was trying to push its way out the top and hitting the bottom of the mag .Well i dykemed the gears and found out that the steel gear was chewing up the brass gear so i changed it to a new one and started modifing the steel gear untill it rolled smooth so there go's that problem.But fixing a problem without knowing why bugs me.It is a early ARPM case non dropped cam 4 in bore.I was thinking that the Scat flanged crank might be the culprit as it needs more end play than a non flanged crank (i'm told).So does the excessive end play cause the gears to bind ? Or is the case machined wrong? So has anyone had trouble with the distributer drive gear trying to jump out of the case in a aftermarket case ? .Well guys ?????Lets hear from the forum and talk shop... :) Thanks ... Mark Reilly
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I noticed this happens when I shim the drive gear's end play to .006", AND turn the engine over backwards. Keep the rotation CW (or the distributor bolted in!) and you won't have the problem. (n/t) (John Connolly) (06-Jul-2000 01:44:39)
Re: Hey John, i was rotating clockwise. I tried different shimming and the mag was always in ..????I put 10 thou endplay for the flanged crank. (n/t) (Mark Reilly) (06-Jul-2000 04:32:02)
what I meant was this.... Not the crank endplay (flanged crank endplay is fixed, and dependent upon the bearings), but you can shim the distributor drive pinion to .006" (that's what I do anyways). (John Connolly) (06-Jul-2000 10:57:52)
Re: John,i also got to say that the mag does drag but the moter would seize up and not complete a full rotation because of the bind in those 2 gears..Bad Case machining ???also whatta bout the 12 thou end play ?I had 5 !!!! (n/t) (Mark Reilly) (06-Jul-2000 12:36:14)
for kicks try to put a 009 in there and see what happens. genuine VW gear? The cheap ones suck.... (n/t) (John Connolly) (06-Jul-2000 13:26:15)
Re: I ran into the same problem a few weeks ago with a stock case. No matter how I shimmed things up (dist.,crank etc.) it would push up???I ended up using a different case. I have questioned the same thing??? (n/t) (tw) (06-Jul-2000 10:15:59)
Re: John, i shimmed the dist. drive gear 4 ,6 and 8 thou with the spring and without.Also i chucked up the rear main bearing in a lathe for the extra end play,but i should of left it at 5 thou...it's 12 now :( (n/t) (Mark Reilly) (06-Jul-2000 12:31:44)
It might be the end play! If the crank is in a different spot now, the drive gear is ALSO in a different place, and might be causing the problem. I'd hate to think you have to buy new bearings! (if you do, e-mail me) (n/t) (John Connolly) (06-Jul-2000 13:28:18)
Mark, .010 to .012 thou. end play on a flanged crank is the norm for a full race motor. Try shimming the dist. shaft at .030 thou. (n/t) (Andy Costello) (06-Jul-2000 14:39:23)
One last thought: are the gears oiled up? If they aren't, they are gonna' grab and climb'.... (n/t) (John Connolly) (06-Jul-2000 14:55:55)
Thanks for the input guys.By the way both brass gears were genuine VW.It rolls sweet now and should dyno it soon !!! (n/t) (Mark Reilly) (06-Jul-2000 21:52:06)
what was it Mark?? (n/t) (John Connolly) (06-Jul-2000 22:27:54)
Re: He ground on the gears till they fit. Also..... ( Mark H) (08-Jul-2000 03:18:56)
the load on the drive gear is one reason I don't like a mag'... (n/t) (john Connolly) (08-Jul-2000 18:09:29)
what I meant was this.... Not the crank endplay (flanged crank endplay is fixed, and dependent upon the bearings), but you can shim the distributor drive pinion to .006" (that's what I do anyways).
Thursday, 06-Jul-2000 10:57:52
I don't have any experience running a mag (I'm a firm believer in computer ignition), but they DO increase the drive gear/pinion load a LOT. On my engines they are just turning the shaft, which has less load than stock (no points).
I shim to .006", and keep the anti-chatter spring in there, and things always look good upon teardown, even if the drive is "pushing up" like yours (mine does it too). I don't worry about it. Maybe someone else knows more!
Re: He ground on the gears till they fit. Also..... Saturday, 08-Jul-2000 03:18:56 22.214.171.124 writes: The brass gear had a wear mark that started low at the begining of the tooth and went to the top at the end of the tooth. Does this sound normal or is the wear mark supossed to be in the middle of the tooth for the length of the tooth.I have`nt had a chanch to look at an old gear yet. Also the other motors at the shop had "destroyed brass gears. These are fuul race 300 HP Autocraft case motors. Does the mag do this or are all of these after market cases made wrong?? do they have the distributor drive bore in the wrong spot or wrong angle?? By the way he had to grind alot! Mark H