Frank, my shop copy Bently is worse than my Haynes. It's a real bitch, the
pages with the numbers I can never remember are the ones with all the oil. I
do have a house copy of the Bently but it's a bigger pain. I have to wash my
hands or get my wife to turn the pages.
Larry
-----Original Message-----
From: Frank Clarici <spritenut@exit109.com>
To: Larry and Sandi Miller <millerls@email.msn.com>
Cc: Hans Huber <hans@desmodromic.com>; spridgets@autox.team.net
<spridgets@autox.team.net>
Date: 29 July, 1998 3:47 PM
Subject: Re: Timing the '72
>Larry and Sandi Miller wrote:
>>
>> Hey Hans, you stole MY Haynes.
>>
>> Larry
>
>Larry, It's not yours, it's MINE!
>You should see my Bently manual, I think it needs an oil change!
>> -----Original Message-----
>> From: Hans Huber <hans@desmodromic.com>
>> To: spridgets@Autox.Team.Net <spridgets@Autox.Team.Net>
>> Date: 29 July, 1998 10:46 AM
>> Subject: Re: Timing the '72
>>
>> >
>> >Chuck,
>> >
>> >Advancing past a certain point won't actually do any good.
>> >That point is called MBT (Mean Best Torque (unless my
>> >notoriously porous brain dropped something)), and anything
>> >beyond that will just increase your problems (as Jeff Z said)..
>> >
>> >Having said that, the '72 is a hard puppy to get to ping,
>> >since they lowered the compression to 8.0:0 (for the US)
>> >for emissions-related reasons (meaning I really don't know).
>> >My guess is that they wanted to increase the advance for
>> >more complete combustion..
>> >
>> >My technique is to leave the vacuum advance connected,
>> >and advance the timing until it sounds like too much (starts
>> >to stumble a little), the back it off a bit past the
>> >ideal (fastest smooth idle) point, then a touch more for
>> >safety. and listen carefully for knocking. This is a crude
>> >and indefensible method of setting the timing, but it's
>> >always worked for me (with apologies to H.S. Thompson, and
>> >real mechanics, and my mother (sorry, mom)).
>> >
>> >Looking at my trusty (and usually trustworthy) Haynes manual,
>> >I see that they indeed made the advance curve steeper for
>> >the emission control models (although I think there's a
>> >misprint here, as 2 advance levels (19 and 23 degrees) are
>> >labeled "2,300 to 2,500 rpm".
>> >
>> >In any case, it's difficult to figure out what they're saying
>> >here, but it looks to me like it wants more than 10 degrees
>> >at idle. Big news, that. Looks to me like it might want
>> >as much as 26 degrees at idle, depending on what the hell
>> >that "19' at 2,300 to 2,500" line is supposed to be. You
>> >might try timing it statically, and see how much (centrifugal)
>> >advance you're actually getting at idle. The centrifugal
>> >advance comes in at 500 RPM on emissions distributors.
>> >
>> >I'd never heard of a timing light with an advance dial, as
>> >Jeff Z. just described. Woo hoo! Gotta get me one of those!
>> >
>> >As Jeff said, the best way to set the timing (from a
>> >performance standpoint) is to set the correct total (full
>> >advance) timing, and Jeff's light sounds like the easiest way
>> >to do that (you can also guess and/or mark off the total advance
>> >on the timing cover, but that's a crude hack (cough)).
>> >However you do it, you should rev up the engine after
>> >setting the timing, and see that the timing mark moves to
>> >somewhere in the vicinity ofthe total advance figure
>> >
>> >It looks to me like your engine ('72 emissions) wants
>> >37 degrees total advance (7' static + 30' advance at ?? RPM)
>> >
>> >Enough nattering on. Good luck with it.
>> >
>> >-Hans "advanced *way* beyond MBT" Huber
>> >
>> >P.S. Does anybody have a newer revision of the Haynes
>> >manual that has the correct info on centrifugal advance
>> >for emissions dizzys? My Haynes is old enough to be missing
>> >the title page (and at least pages 111-116), and is nicely
>> >rebound with black duct tape, so I don't even know when it
>> >was printed.
>> >
>> >On Wed, 29 Jul 1998 08:24:19 EDT Chuck Ciaffone wrote:
>> >> It happens every time I tune my '72. I set the timing,
>> >> using a timing lite, to about 10 degrees advance with
>> >> the vacuum advance disconnected and plugged. It runs OK.
>> >> Then I start turning the dizzy for more advance, and it
>> >> runs better. SoI would guess that I probably run normally
>> >> with about 15 or so degrees of advance, AND it still
>> >> never seems to ping. Can/should I just keep advancing
>> >> the timing till it pings? What's probably going
>> >> on here?
>> >>
>> >> chuck
>> >> --
>> >> =====================================================
>> >>
>> >> chuck ciaffone chuckc@ibm.net
>> >
>> >
>> >
>
>--
>Frank Clarici Toms River, NJ
>Too many LBCs
>3 Sprites, an Austin A40, and an Austin Mini all on the road.
>1 Jaguar XJ6 family car, 1 Racer Midget project , & 2 Parts Spridgets
>Check out my home page at http://www.exit109.com/~spritenut
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