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WBX flywheel pins and OBD plug - what / why?

Posted: 10 Aug 2012, 15:29
by silverbullet
OK one for the ex-works service dept. boys and the manual readers amongst us...

Just what are those rollpins in the back of the flywheel for, exactly?

Judging by the timing marks on the front pulley, they seem to line up with the sensor at about 11 deg. BTDC and then 18 deg. ATDC :?

I can guess that the first would have been for checking the original 10 degree ignition timing, but why have a trigger for so far after TDC?

(I'm investigating the potential for sequential fuel injection, which needs both crank and cam sensors. Lots still to work out)

Re: WBX flywheel pins and OBD plug - what / why?

Posted: 10 Aug 2012, 19:28
by Aidan
plugs into the vw machine (someone came on here offering one for a sale about 18 months ago for serious money), top dead centre detector, uses the info some set up operations and for revs afaics, but nothing that a digital timing gun can't do - some rebuilders just break them off/cut the cable - looks better with the cable and the plug nicely clipped to the alternator even if it is completely useless to us and the plug cover is missing on most so just three rusty pins on view

Re: WBX flywheel pins and OBD plug - what / why?

Posted: 11 Aug 2012, 19:40
by silverbullet
That's what I thought. I just find the apparent timing positions of those pins on the flywheel a bit odd...maybe the ATDC one is for checking injector timing? The inlet valve would be comfortably opening by then and on a split batch-fire system would do the job.

Anyway, looks like I'll be machining the backs of the flywheel for crank trigger duties like on most modern motors, then there's the thorny matter of where to put the cam sensor and trigger pins: #1 needs a double pip to identify, otherwise I'd use the rivets!

Re: WBX flywheel pins and OBD plug - what / why?

Posted: 12 Aug 2012, 01:57
by mrhutch
Arnt the parts from trigger-wheels easier to fit if you're going megasquirt route Ian?

Re: WBX flywheel pins and OBD plug - what / why?

Posted: 12 Aug 2012, 17:53
by silverbullet
Alright Hutch! Just weighing up the options, food for thought but you're probably right. Where does MS get the cam timing, Does it mean using a dizzy body with no guts and going fully mapped?

Re: WBX flywheel pins and OBD plug - what / why?

Posted: 12 Aug 2012, 18:22
by ELVIS
Was actually me who posted that on his log in.

You must know by now after the infamous melting loom 2e he has an injunction stopping him from touching any wiring for ever! :mrgreen: :ok

Re: WBX flywheel pins and OBD plug - what / why?

Posted: 13 Aug 2012, 08:16
by mrhutch
:rollin

@Elvis You may have posted that but I was definitely thinking the same thing!