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angello1 Samba Member
Joined: June 07, 2011 Posts: 93 Location: Europe
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Posted: Sun May 17, 2015 5:05 pm Post subject: Porsche 912E dual Webers tuning |
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Hi guys ,
My other 912E has finally arrived to Europe. It has stock engine , 91k , no rebuilds switched to Webers idf 40 long time ago. The engine was running very rough so I have made some basic tuning.
I have rebuilt the Webers ( new gaskets , o-rings , needle valves , new diaphragms , cleaning , set float , etc...). No dripping . I have tried to tune them by the book ( mixture screws and idle screws procedure ) but not sure about the results .
I have found following jets on them : air 200 , main 135 , idle 50 , emulsion is F14 or 11 ( cant read it well ) . Venturis are 28.
I have also put new cables , new distributor cap , new rotor , clean spark plugs , fresh oil and filter , checked timing and have set valve clearance.
I have some problems :
- Unloaded it idles ok , no backfire , popping or miss . But when I open the throttle fully and rev the engine I get smoke , not black , whitish I would say . Or bluish ?
- When I drive the car modestly is ok but when I open the throttle it starts to popping . Or it is misfire I am not sure .
So I am running lean or reach ?
- that smoking at high revs concerns me more , do I need an top end rebuilding ? Also valve train noise is still present inspite of the fact I have checked the valve clearance .
The engine seams strong , no oil leaks , I havent made a compression test yet.
Please watch my video if it helps anyhow . The sound is not so realistic I know.
http://www.youtube.com/watch?v=qNSj4...ature=youtu.be
Thanks for your suggestions _________________ 1974 Super Beetle convertible
1976 Porsche 912 E |
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angello1 Samba Member
Joined: June 07, 2011 Posts: 93 Location: Europe
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Posted: Mon May 18, 2015 3:25 am Post subject: |
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I have played with the carbs again . It sounds and goes much better now. No popping and the smoke at high revs is 80% gone.
Valve train a bit noisy but I reckon all type 4 engines are built that way. _________________ 1974 Super Beetle convertible
1976 Porsche 912 E |
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malsteph Samba Member
Joined: August 05, 2008 Posts: 42 Location: Liège (Belgium)
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Posted: Mon May 18, 2015 4:35 am Post subject: |
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The venturies are on the small side and probably do not help the engine at higher revs.
try 30 or 32mm venturies.
28mm work well with a type 1 1600cc.
30 or 32mm will not seriously compromise the torque at lower revs, but the engine will breath happy at higher revs.
What distributor is set up on your engine? Best is a 050. But often a 009 is fitted. Timing varies between the two and of course this affects also the overall settings and performances. |
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angello1 Samba Member
Joined: June 07, 2011 Posts: 93 Location: Europe
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Posted: Mon May 18, 2015 3:16 pm Post subject: |
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Thanks ,
I know I need biger venturis and smaller main and air , it runs lets say ok for now till I get them.
I cant read the numbers on the distributor but it has no vacuum canister so I reckon is 009. _________________ 1974 Super Beetle convertible
1976 Porsche 912 E |
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jdbuilder Samba Member
Joined: May 23, 2015 Posts: 1 Location: Florida
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Posted: Sat May 23, 2015 3:00 am Post subject: |
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Following since I have a 356 that I am tuning at the moment with the webber set up. |
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angello1 Samba Member
Joined: June 07, 2011 Posts: 93 Location: Europe
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Posted: Sat May 23, 2015 3:25 pm Post subject: |
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The engine runs ok now after couple of miles driving around a block and some more adjustment but it cant be compared with the original L-jetronic since there is no cold start mechanism on these carbs so engine runs on very low rpm till it warms up a bit. _________________ 1974 Super Beetle convertible
1976 Porsche 912 E |
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Wolfgangdieter Samba Member
Joined: June 25, 2008 Posts: 1958 Location: FL Panhandle
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Posted: Sat May 23, 2015 8:11 pm Post subject: |
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Years ago I put a big bore kit on a Porsche T4 914 - added Webers at same time. Never did get it to run as smooth as the stock fuel injection. Suspect part was due to fact that I kept the old FI cam. _________________ CMC '57 Porsche Speedster Replica and Dolphin boat tailed full pan VW MOD-T Street Buggy |
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914werke Samba Member
Joined: August 25, 2012 Posts: 21 Location: PNW
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Posted: Fri Jul 10, 2015 11:50 am Post subject: |
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Is there a reason you went Webers rather than keep the L-Jet setup on it? |
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Wolfgangdieter Samba Member
Joined: June 25, 2008 Posts: 1958 Location: FL Panhandle
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Posted: Sun Aug 23, 2015 11:44 am Post subject: |
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Dual Webers just look cool and it cleans up all those hoses on top of the engine. Tuning them is a near full time hobby though. I finally discovered that you could solder the brass jets closed and redrill them for different mixtures rather than having to buy different sized jets. _________________ CMC '57 Porsche Speedster Replica and Dolphin boat tailed full pan VW MOD-T Street Buggy |
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