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Henrik_K
Samba Member
Joined: November 17, 2013
Posts: 181
Location: Denmark
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 Posted: Sat Feb 03, 2018 1:08 pm Post subject: Type4 - 2.0 - Backfires. |
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Hi,
I've been all over my rebuilt 2.0 Type4 engine, to try to solve this puzzle. It backfires through the carbs.
It's a stock 2.0 engine, with 2 double Webers. Im running a 009 distributor with only centrifugal advancing. I have set the timing static.
The engine has hydraulic lifters, which I have adjusted to the best of my abilities.
Any pointers as to where to begin?
Rgds, Henrik |
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Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22712
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
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| Posted: Sat Feb 03, 2018 2:02 pm Post subject: Re: Type4 - 2.0 - Backfires. |
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Where did you set the timing? The 009 has a narrow acceleration curve as it's really meant for industrial applications. It should be set at about 30-32 BTDC at 3000 rpm, letting timing at idle fall where it may. However, around 15 degrees BTDC at static time should show improvement as a starting point.
If you drive it this way listen closely for pinking and adjust timing down accordingly till you can time it properly ASAP.
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SGKent 
Samba Member
Joined: October 30, 2007
Posts: 41031
Location: Citrus Heights CA (Near Sacramento)
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| Posted: Sat Feb 03, 2018 6:27 pm Post subject: Re: Type4 - 2.0 - Backfires. |
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what Tram said. Lean mixtures can cause this too. Start with Tram's advice and use a timing light. None of this static crap other than getting it to run and then immediately putting a timing light on it.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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timvw7476
Samba Member
Joined: June 03, 2013
Posts: 2202
Location: seattle
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| Posted: Sat Feb 03, 2018 8:38 pm Post subject: Re: Type4 - 2.0 - Backfires. |
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check the plug wire routing.
I've screwed the wire routing on rebuilt VW engines at least 1/2 dozen times.: \
always backfire through the carbs, sometimes the filters fly off & bonk me in the
head. |
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aeromech
Samba Member
Joined: January 24, 2006
Posts: 16961
Location: San Diego, California
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| Posted: Sat Feb 03, 2018 10:23 pm Post subject: Re: Type4 - 2.0 - Backfires. |
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Unless you dual carbs are correctly synchronized and the linkage is working correctly, you can expect some popping from the engine.
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Henrik_K
Samba Member
Joined: November 17, 2013
Posts: 181
Location: Denmark
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| Posted: Sun Feb 04, 2018 11:32 am Post subject: Re: Type4 - 2.0 - Backfires. |
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| Thx Guys.... |
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udidwht
Samba Member
Joined: March 06, 2005
Posts: 3779
Location: Seattle, WA./ HB, Ca./ Shizuoka, Japan
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| Posted: Sun Feb 18, 2018 3:07 pm Post subject: Re: Type4 - 2.0 - Backfires. |
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Webers will do this when cold and it's more pronounced/noticeable on colder days. Within 2-3 mins of start it subsides.
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