[Healeys] Healey 100-4 timing
Kees Oudesluijs
coudesluijs at chello.nl
Sat Nov 3 04:07:19 MDT 2018
Sorry should read max advance with a/vacuum retard system/
Kees Oudesluijs
Op 3-11-2018 om 09:48 schreef Kees Oudesluijs:
>
> The maximum advantage should be limited to prevent damage to the big
> end bearings. In general, depending on the engine, this is around 32°
> to 35° /*total*/ advance. The distributor advance system with the
> weights and springs is limited to about 17°, the vacuüm advance or
> retard (depending on engine) may produce another 5° or so advance or
> retardation. This means that when the ignition of an engine with a
> vacuum advance system is set at say 10° static, the maximum advance is
> a safe 32° at anything over about 2500rpm.
>
> Kees Oudesluijs
>
>
>
> Op 3-11-2018 om 03:05 schreef Michael Salter:
>> Thanks for your input on ignition timing Michael.
>> I have always found the factory specs to be a little confusing.
>> They state 6 degrees BTDC as the timing (which I presume to be
>> "static") and then state that the distributor produces 16 - 18
>> degrees at 2000 RPM (distributor speed) which I figure to be 32 -36
>> degrees at 4000 engine RPM.
>> I interpret that to produce 6 + 34 (2 x 17) degrees BTDC at 4000
>> engine RPM for a total of 40 degrees which sounds like an awful lot.
>> My engine does not sound at all happy with 40 degrees even with 110
>> octane!!
>> I'm wondering if I have been over thinking this process and the
>> stated advance is meant to be "at idle" with the vacuum connected
>> (not normal practice as far as I was taught) which would add 6
>> degrees of vacuum advance which would vanish at full throttle
>> producing a net of 34 degrees over 4000 at full throttle.
>> I have been setting the timing to 32 degrees BTDC with the vacuum
>> disconnected at 4000 RPM and the engine runs fey well and very cool,
>> in fact too cool without a 180 degree thermostat.
>> I am running 8.3:1 compressions with an M cam.
>>
>> M
>>
>>
>> On Fri, Nov 2, 2018 at 9:16 PM Michael Oritt <michael.oritt at gmail.com
>> <mailto:michael.oritt at gmail.com>> wrote:
>>
>> Wayne--
>>
>> Exactly right--it is total advance that matters and I arrived at
>> that number by gradually increasing advance and seeing the effect
>> upon water temperature at speed and under full load. Anything
>> more and the car would begin to overheat. A bit too much less
>> advance and performance fell off.
>>
>> BTW I am running a DW "fast street" cam and tubular header and a
>> Mallory non-vacuum advance distributor fired with their Unilite
>> module. I too have a Smitty's five-speed and the Toyota box, 180
>> XAS's and 3.54 diff set give me about 72-73 mph at 3K rpm's indicated
>>
>> Best--Michael Oritt
>>
>> On Fri, Nov 2, 2018 at 6:03 PM Wayne Schultz <waschu2 at gmail.com
>> <mailto:waschu2 at gmail.com>> wrote:
>>
>> Thanks to Michael and others I am going to stick with 34 - 35
>> degrees total advance for now. What, I think this means, is
>> that the advance at idle is secondary and not as important as
>> total advance. Cruising with the the Toyota five speed or the
>> original overdrive on the highway is right in the 3K RPM
>> range so I think this the perfect RPM to limit total advance.
>> I might make a run to my local airport and buy some 100LL
>> fuel. I have worked in aviation since 1967 so I have a few
>> friends😃
>>
>> _______________________________________________
>> Support Team.Net http://www.team.net/donate.html
>> Suggested annual donation $12.75
>>
>> Archive: http://www.team.net/pipermail/healeys
>> http://autox.team.net/archive
>>
>> Healeys at autox.team.net <mailto:Healeys at autox.team.net>
>> http://autox.team.net/mailman/listinfo/healeys
>>
>> Unsubscribe/Manage:
>> http://autox.team.net/mailman/options/healeys/michael.oritt@gmail.com
>>
>> _______________________________________________
>> Support Team.Net http://www.team.net/donate.html
>> Suggested annual donation $12.75
>>
>> Archive: http://www.team.net/pipermail/healeys
>> http://autox.team.net/archive
>>
>> Healeys at autox.team.net <mailto:Healeys at autox.team.net>
>> http://autox.team.net/mailman/listinfo/healeys
>>
>> Unsubscribe/Manage:
>> http://autox.team.net/mailman/options/healeys/michaelsalter@gmail.com
>>
>>
>> _______________________________________________
>> Support Team.Nethttp://www.team.net/donate.html
>> Suggested annual donation $12.75
>>
>> Archive:http://www.team.net/pipermail/healeys http://autox.team.net/archive
>>
>> Healeys at autox.team.net
>> http://autox.team.net/mailman/listinfo/healeys
>>
>> Unsubscribe/Manage:http://autox.team.net/mailman/options/healeys/coudesluijs@chello.nl
>>
>
> _______________________________________________
> Support Team.Net http://www.team.net/donate.html
> Suggested annual donation $12.75
>
> Archive: http://www.team.net/pipermail/healeys http://autox.team.net/archive
>
> Healeys at autox.team.net
> http://autox.team.net/mailman/listinfo/healeys
>
> Unsubscribe/Manage: http://autox.team.net/mailman/options/healeys/coudesluijs@chello.nl
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/healeys/attachments/20181103/dfaf2ff5/attachment.html>
More information about the Healeys
mailing list