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timing a 1600 twin port beetle
Posted: Sat Jun 29, 2013 10:45 am
by advinnie
Hi all I have a 1600 twin port beetle with dual 34 carburetors and a svda distributor what should I set the timing to? Cheers
Re: timing a 1600 twin port beetle
Posted: Sun Jun 30, 2013 6:36 pm
by Jim Ed
The SVDA is set to 7.5 btdc with the vac hose plugged.
http://vw-resource.com/tune-up.html#svda
Re: timing a 1600 twin port beetle
Posted: Tue Jul 02, 2013 5:24 am
by madmike
If it runs like 'it can do BETTER' after you do it by the book try this: plug hose to carbs,and rev it to 2500-3000rpms and set it @ 28-30*, reconnect hose take it for a spin
Re: timing a 1600 twin port beetle
Posted: Wed Jul 03, 2013 6:18 pm
by Jim Ed
madmike wrote:If it runs like 'it can do BETTER' after you do it by the book try this: plug hose to carbs,and rev it to 2500-3000rpms and set it @ 28-30*, reconnect hose take it for a spin
Isn't that how you set a 009 dizzy?
Re: timing a 1600 twin port beetle
Posted: Wed Jul 03, 2013 7:29 pm
by Marc
If it truly is an SVDA, like the 0 231 170 034, its centrifugal advance mechanism provides 20 to 25° of advance which is not unlike the centrifugal-only 0 231 178 009 - HOWEVER on the 009 it's "all in" by ~2500 RPM and on the SVDA it's not until ~3800 RPM, so following this procedure is virtually guaranteed to end up with too much total advance. If you're uncertain whether you're getting the correct ported-vacuum signal from the carb(s) it could be a valid troubleshooting technique, but only safe if the centrifugal-only max timing is limited to ~32° at 3800.
If it's not really an SVDA, but a vacuum-only distributor like a 0 231 137 036, it'd be a miracle to make it work with 34ICTs no matter what you did - an 009 would be a better choice.
Re: timing a 1600 twin port beetle
Posted: Wed Jul 03, 2013 11:26 pm
by advinnie
Marc wrote:If it truly is an SVDA,centrifugallike the 0 231 170 034, its centrifugal advance mechanism provides 20 to 25° of advance which is not unlike the centrifugal-only 0 231 178 009 - HOWEVER on the 009 it's "all in" by ~2500 RPM and on the SVDA it's not until ~3800 RPM, so following this procedure is virtually guaranteed to end up with too much total advance. If you're uncertain whether you're getting the correct ported-vacuum signal from the carb(s) it could be a valid troubleshooting technique, but only safe if the centrifugal-only max timing is limited to ~32° at 3800.
If it's not really an SVDA, but a vacuum-only distributor like a 0 231 137 036, it'd be a miracle to make it work with 34ICTs no matter what you did - an 009 would be a better choice.
Hi there it is a SVDA DISTRIBUTOR the centrifuge advance gives you 25 degrees max advance and the vaccum unit give an extra 10-12 degrees of advance. So what your saying is set it to 7.5 btdc then with the centrifuge advance that would give me exactly 32.5 degrees BTDC but with the vaccum line connected I get 42-44 degrees advance is this right?
Re: timing a 1600 twin port beetle
Posted: Thu Jul 04, 2013 5:02 am
by madmike
I stand corrected
Re: timing a 1600 twin port beetle
Posted: Thu Jul 04, 2013 8:11 pm
by Marc
Yep, centrifugal mechanism gives you 20-25° and you get another 8-12° from the vacuum (under light load) so with initial of 7.5° you should get a max between 35.5 and 44.5° - in my experience more often than not towards the high end of that range, 42-44° is quite typical.
I do not know how appropriate the vacuum signal from a 34ICT is, compared to that from a single 34PICT-3. I've heard stories of the need to tee off both carbs in order to get a strong enough signal.
madmike wrote: I stand corrected
still a good idea for troubleshooting/experimenting, just don't
leave it set that high unless you have a way of knowing that it's safe.