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[GMCnet] Dumb Timing Confusion [message #75471]

Tue, 02 March 2010 22:41

Ken Henderson

Messages: 8726
Registered: March 2004
Location: Americus, GA

Karma:

Senior Member

I know this will sound like the dumbest question to come down the pike in a
long time, but I've go to ask it:

I've always thought I understood the 4-stroke cycle, timing, TDC, BTDC,
ATDC, and all the rest of that weird stuff pretty well. So, my current
state must undoubtedly be CRS, or some other old man slipped cog.

Today we located #1 cylinder TDC, using a probe into #1 cylinder as it came
up on compression stroke. A dial indicator on the probe indicated 0.000"
until the crank was turned in either direction.

I fabricated and installed a new pointer to reach the '89 Mercury Marquis
double serpentine crankshaft pulley, then filed a notch in the pulley to
mark TDC. Carefully measuring the diameter of the pulley, I calculated the
circumference and divided that by 60 to tell me the distance from the TDC
mark to the 6* BTDC mark I wanted to make for initial timing of my computer
controlled distributor and EFI.

That's when the confusion set it: Which way should I measure to 6* BTDC
from TDC? Let me explain how I've reasoned the answer and why I'm confused:
The engine rotates clockwise (CW) when viewed from the rear (driver's seat)
(Right???). So BTDC marks should be located CW from TDC, meaning the BTDC
mark will reach the timing pointer before the TDC mark -- right? Well, that
pretty well satisfied me until I looked at the timing pointer on the Olds,
and that which formerly fit the Cad, and THOSE BTDC marks are CW -- the TDC
mark does not reach them until AFTER TDC. OMYGOSH! I KNOW the OEM timing
indicators are correct, but I'll be darned if I can, today, reconcile what I
see with what I think I know.

Y'All please help me see the error of my ways. I'll gladly join TSUA
(Timing Screw Ups Anonymous) if necessary!

Ken H.
Americus, GA
'76 X-Birchaven
www.gmcwipersetc.com
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach

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[Message index]

		[GMCnet] Dumb Timing Confusion By: Ken Henderson on Tue, 02 March 2010 22:41
		Re: [GMCnet] Dumb Timing Confusion By: Craig Lechowicz on Tue, 02 March 2010 23:27
		Re: [GMCnet] Dumb Timing Confusion By: USAussie on Tue, 02 March 2010 23:36
		Re: [GMCnet] Dumb Timing Confusion By: USAussie on Wed, 03 March 2010 00:11
		Re: [GMCnet] Dumb Timing Confusion By: idrob on Wed, 03 March 2010 00:33
		Re: [GMCnet] Dumb Timing Confusion By: jimk on Wed, 03 March 2010 21:48
		Re: [GMCnet] Dumb Timing Confusion By: GMCWiperMan on Thu, 04 March 2010 05:53
		Re: [GMCnet] Dumb Timing Confusion By: Mr ERFisher on Thu, 04 March 2010 08:33
		Re: [GMCnet] Dumb Timing Confusion By: GMCWiperMan on Thu, 04 March 2010 23:09
		Re: [GMCnet] Dumb Timing Confusion By: George Beckman on Wed, 03 March 2010 00:41
		Re: [GMCnet] Dumb Timing Confusion By: Ken Burton on Wed, 03 March 2010 02:08
		Re: [GMCnet] Dumb Timing Confusion By: Surbo on Wed, 03 March 2010 04:35
		Re: [GMCnet] Dumb Timing Confusion By: g.winger on Wed, 03 March 2010 05:55
		Re: [GMCnet] Dumb Timing Confusion By: GMCWiperMan on Wed, 03 March 2010 06:32
		Re: [GMCnet] Dumb Timing Confusion By: USAussie on Wed, 03 March 2010 08:06
		Re: [GMCnet] Dumb Timing Confusion By: C Boyd on Wed, 03 March 2010 09:38
		Re: [GMCnet] Dumb Timing Confusion By: Steven Ferguson on Wed, 03 March 2010 06:58
		Re: [GMCnet] Dumb Timing Confusion By: USAussie on Wed, 03 March 2010 08:06
		Re: [GMCnet] Dumb Timing Confusion By: Gary Casey on Wed, 03 March 2010 07:10
		Re: [GMCnet] Dumb Timing Confusion By: Ken Burton on Wed, 03 March 2010 10:02
		Re: [GMCnet] Dumb Timing Confusion By: Matt Colie on Wed, 03 March 2010 08:16
		Re: [GMCnet] Dumb Timing Confusion By: g.winger on Wed, 03 March 2010 10:15
		Re: [GMCnet] Dumb Timing Confusion By: GMCWiperMan on Wed, 03 March 2010 16:14
		Re: [GMCnet] Dumb Timing Confusion By: USAussie on Wed, 03 March 2010 17:08
		Re: [GMCnet] Dumb Timing Confusion By: Ken Burton on Wed, 03 March 2010 22:23
		Re: [GMCnet] Dumb Timing Confusion By: k2gkk on Wed, 03 March 2010 17:17
		Re: [GMCnet] Dumb Timing Confusion By: Steven Ferguson on Wed, 03 March 2010 18:51
		Re: [GMCnet] Dumb Timing Confusion By: Rick Denney on Thu, 04 March 2010 07:12
		Re: [GMCnet] Dumb Timing Confusion By: GMCWiperMan on Wed, 03 March 2010 16:43
		Re: [GMCnet] Dumb Timing Confusion By: Marsh Wilkes on Wed, 03 March 2010 23:23

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