Weber Carbs and Fuel Pumps |
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Weber Carbs and Fuel Pumps |
mrbill |
Mar 19 2008, 10:53 PM
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#1
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Newbie Group: Members Posts: 14 Joined: 5-February 06 From: Palmdale, CA Member No.: 5,531 Region Association: Southern California |
I am struggling with my 914 right now.
The car was used when I got it a year ago with twin Webers and a cam installed. I had the motor rebuilt as well as the carbs. I really haven't put that many miles on the car and the engine sputtered while driving so much so that I had to take it back to the mechanic who did the rebuild. After fifteen weeks of sitting my mechanic has announced that the Webers are not able to be rebuilt and he wants to replace them with a new kit including linkage and manifolds. Meanwhile I came across this bit of information from another website: "Fuel Pumps and Fuel Pressure: Fuel delivery is critical to the proper performance of any Weber carb. From a basic 32/36 DGEV to a set of Triple Sidedraft DCOE's. Webers rely on a stable full float bowl in order to mix the fuel and air correctly. Mechanical pumps very rarely do this. They pulse fuel instead of giving a smooth even delivery and the amount of fuel varies with engine RPM. A Proper Electric Fuel pump will give the best performance and most stable tuning for any Weber carb application. We use only High Volme and Low Pressure pumps. Webers work best at approx 4 psi of fuel pressure (Not 2 psi like many of the older books stated.) and you need Volume not Pressure to keep the float bowl full. We ONLY use the Carter Rotary pumps. They are High Volume (60-70 GPH) but only 4 psi. This is PERFECT for all Weber applications from a Single 32/36 DGV on a Truck, Jeep or Car to a Triple Sidedraft setup on a Road Race car making 300 HP...This pump DOES NOT and SHOULD NOT use a Pressure Regulator for any reason. That is why we use it.... Problem Pump and Regulator setups: These are combinations that many of you are using and you could be experiencing problems because of it. Holly Fuel Pumps with Regulator: This is a very common combination and it has alot of problems. The pump puts out too much pressure so you have to buy a regulator for it. The Regulator is just a restrictor that inhibits flow. This causes a huge loss of Volume and overloads the pump causing alot of noise and premature failure. This results in the float bowl going low or empty under hard acceleration and causes cornering problems. Facet Fuel Pump: This is one of those little square pumps with the transistor mounted on top that make a ticking noise all the time. These pumps are TERRIBLE. No volume and High Pressure. These pumps have been sold for many years with Weber and Mikuni conversions and have cause many people alot of tuning problems. They are a pulse type pump that delivers almost no volume (usually less than the stock mechanical pump did) and usually at High Pressure. This cause flooding at idle and lean out conditions under high load. Do not use them.." Has anyone else ever had this problem related to fuel pumps? I have the Facet fuel pump installed in my car and will happily replace it if it fixes the carbs without having to replace the complete system. I appreciate any commentary regarding this. |
Jake Raby |
Mar 19 2008, 11:06 PM
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#2
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
I agree on the Carter rotary pump. This is the only carb pump we stock or use in our vehicles.
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Borderline |
Mar 19 2008, 11:15 PM
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#3
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Senior Member Group: Members Posts: 720 Joined: 8-February 05 From: San Juan Bautista, CA Member No.: 3,577 Region Association: Northern California |
I've been playing with an extremely used set of weber 40's for the last couple years and have found that most of my problems have been related to intake gasket leaks (engine backfire through carbs), and clogged idle jets. I've been running the facet pump and haven't had any problems that i can trace to it. I'm running 1.8L heads and have found that some of the intake gaskets don't seal very well. The thick ones are "universal" and have a very thin section that seems to leak. The standard 1.8 gasket is very thin and seems to leak. (IMG:style_emoticons/default/headbang.gif)
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bperry |
Mar 20 2008, 12:11 AM
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#4
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Lurker Group: Members Posts: 477 Joined: 16-February 04 From: Dallas, Tx Member No.: 1,661 |
I agree on the Carter rotary pump. This is the only carb pump we stock or use in our vehicles. Have you had a change of view? A few years back in response to this same information/webpage you said: Guess why they like the carter better??? I know the wholesale cost of both! The Facet works just fine !! --- bill |
McMark |
Mar 20 2008, 01:23 AM
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#5
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
Mr. Bill, if the fuel pump doesn't fix it, then send the carbs to a carb specialist. If THEY pronounce them 'dead' then it's time to shop.
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Jake Raby |
Mar 20 2008, 01:37 AM
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#6
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
I agree on the Carter rotary pump. This is the only carb pump we stock or use in our vehicles. Have you had a change of view? A few years back in response to this same information/webpage you said: Guess why they like the carter better??? I know the wholesale cost of both! The Facet works just fine !! --- bill The Facet pumps have changed since then... The newer units have very unstable fuel delivery and some have pressure over 7 PSI from the factory. NONE of these parts stay the same. It takes constant exposure to them to keep up with the current state of "whats best". Recommendations can sometimes only last for a few months with todays Chinese manufacturing and total lack of QC. The only thing that stays the same is the guarantee that nothing will stay the same :-) |
pin31 |
Mar 20 2008, 06:56 AM
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#7
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Member Group: Members Posts: 398 Joined: 30-January 07 From: Newport, Rhode Island Member No.: 7,492 Region Association: North East States |
I have (PO) the standard Bosch fuel pump (relocated to the front) with a pressure regulator feed my dual weber 40's.
I like what I've read about the Carter rotary fuel pump and would like to change my setup. Which part number do I need??? Jake do you sell them?? Thanks !! |
0396 |
Mar 20 2008, 07:34 AM
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#8
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Advanced Member Group: Members Posts: 2,046 Joined: 13-October 03 From: L.A. Calif Member No.: 1,245 Region Association: Southern California |
I am struggling with my 914 right now. Holly Fuel Pumps with Regulator: This is a very common combination and it has alot of problems. The pump puts out too much pressure so you have to buy a regulator for it. The Regulator is just a restrictor that inhibits flow. This causes a huge loss of Volume and overloads the pump causing alot of noise and premature failure. This results in the float bowl going low or empty under hard acceleration and causes cornering problems. I currently have this setup and have not experienced any concerns.. I currently have mine set at 6 1/2 -7 lbs pressure. Other wise it runs out of fuel. |
rhodyguy |
Mar 20 2008, 07:51 AM
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#9
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Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,079 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
self regulated rotary, you won't miss the RATTLE the facet produces. good filter, not the paper cone shaped one for a beetle, mounted upstream of the pump. what prompts the "not able to be rebuilt" diagnosis? like, the REASON!! he wants to sell you a set of $800 carbs huh? + the cost of install and tunning. there's a quick 1k. buy the rotary from jake or one of the other various vendors, but support your member vendor when you can.
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Allan |
Mar 20 2008, 07:53 AM
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#10
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Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
I use the CB rotary pump on my carbed six. Internally regulated at 3 1/2 lbs. and wurks gud...
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Joe Ricard |
Mar 20 2008, 07:59 AM
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#11
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CUMONIWANNARACEU Group: Members Posts: 6,811 Joined: 5-January 03 From: Gautier, MS Member No.: 92 |
That's what I was going to say. Hell rebuild kits are like 60 bucks and nearly any Monkey can replace the o-rings and gaskets in the kit.
Clean the jets and change the intake gaskets. Probably fix a bunch of your problems. |
rhodyguy |
Mar 20 2008, 08:13 AM
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#12
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Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,079 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
if you've never done it, inspect the bottom (inside) of your fuel tank. constant fouling of idle jets is a bunch of crap in the bowls which has been deposited there, and not from the 'gas'. rather than guess at the rebuild i took the easy way and sent my 44s to Air Cooled Engineering (type that into the search). give them the parameters of your engine. they will build the carbs to your needs and run them in on a test engine. the service is not cheap by any means but they will come to you ready to bolt up. after you clean the rest of your fuel system that is.
k |
degreeoff |
Mar 20 2008, 09:38 AM
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#13
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I like big butts and I can not lie! Group: Members Posts: 1,622 Joined: 9-February 03 From: Booowieeee MD (near DC) Member No.: 275 Region Association: MidAtlantic Region |
I am having issues with my carter pump....Jake do these NEED to be mounted below the tank or will a few inches above the bottom of the tank work? BTW I have already lowered it once from level with the top of the tank.
Sorry to HIJACK!! Josh |
Cap'n Krusty |
Mar 20 2008, 09:45 AM
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#14
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Cap'n Krusty Group: Members Posts: 10,794 Joined: 24-June 04 From: Santa Maria, CA Member No.: 2,246 Region Association: Central California |
We have a name for people running stock 914 pumps regulkated down to work with carbs ................... Fire victims. I use the Pierberg rotary pumps. Yes, pretty much all fuel pumps should be mounted lower than the fuel tank.
BTW, Webers can wear out in ways no kit will ever fix. Stock 911 carbs are a good example. The Cap'n |
bperry |
Mar 20 2008, 03:46 PM
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#15
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Lurker Group: Members Posts: 477 Joined: 16-February 04 From: Dallas, Tx Member No.: 1,661 |
QUOTE The Facet pumps have changed since then... The newer units have very unstable fuel delivery and some have pressure over 7 PSI from the factory. NONE of these parts stay the same. It takes constant exposure to them to keep up with the current state of "whats best". Recommendations can sometimes only last for a few months with todays Chinese manufacturing and total lack of QC. The only thing that stays the same is the guarantee that nothing will stay the same :-) I''ve got a CB rotary but was interested in your current thoughts & knowledge. Good to know. Thanks --- bill |
SirAndy |
Mar 20 2008, 04:03 PM
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#16
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Resident German Group: Admin Posts: 41,634 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
i second the rotary pumps. i used a CB rotary with very good results ...
(IMG:style_emoticons/default/bye1.gif) Andy |
bobhasissues |
Mar 20 2008, 04:50 PM
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#17
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seemingly endless issues with my 914 Group: Members Posts: 218 Joined: 13-February 07 From: Chicagoland Member No.: 7,532 Region Association: None |
I had the CB rotary (which is a Carter as well) and have the $90 Carter pump. If you still have your heating system in place, there is really no room to mount the big Carter. Also, It makes a ton of noise, sounds like a vacuum cleaner running all of the time. If you make the mistake of mounting one of these things on your firewall the vibration will drive you crazy. I have tested the pressure on the CB rotary and they are fine. I have had tons of problems tuning my Webers as well. The advise you have received so far is all valid. I would ask your mechanic specifically why he can't rebuild the carbs and make your decisions from there. I was fooled into believing I had a fuel pump problem and that is why I spent the $90 in the big Carter. In my case the fuel pump was not the problem. I ran my big Carter for about two days and then switched back. If you really want to try one, I'll sell you (or anyone) mine for $50. Does the car run well at any rpm? If your idle circuits are wrong or plugged low end will run horribly, yet over 3000 rpm things usually get better. Someone here may have a jetting / vent configuration that works for their similar engine.
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J P Stein |
Mar 20 2008, 05:34 PM
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#18
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Irrelevant old fart Group: Members Posts: 8,797 Joined: 30-December 02 From: Vancouver, WA Member No.: 45 Region Association: None |
I have run the same unregulated Facet pump in my car for about 10 years. I have had no carb problems other that 3-4 plugged idle jets in that time. My carbs are in good repair, the float levels are set.....damn close to correct, but where I want them.
Most carb issues are (other than those worn out....which can be fixed) owner/tuner induced......that's my opinion, of course. Carbs are not plug in & play. They require tuning and if you don't want to take the time to learn this, take the car to someone that knows how.....or get FI & a laptop and learn to do that. Either way a skill set is necessary. Many problems are ignition issues....carbs just don't like modern gas. One has to tune them to run on it regardless and that requires (IMO) some compromises. The biggest one is to run em' rich.....they will not maintain an ideal A/F ratio throughout the rev range (and never have). If you have to run rich at idle/mid range to keep them from leaning out thru transition or at top end on the mains you had better do it. This requires an ignition system that can burn thru the rich condition. |
rhodyguy |
Mar 21 2008, 07:21 AM
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#19
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Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,079 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
you can easily mount the cb pump on the lower rear firewall, near the stock location/elevation. then use the STOCK pump harness with a plug end mod, andy's jumper trick and you're ready to roll. the rotary seems to be happier if you keep it at or below the fuel tank outlet level. let gravity do it's thing.
k |
Kansas 914 |
Mar 22 2008, 06:51 AM
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#20
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Advanced Member Group: Members Posts: 2,999 Joined: 1-March 03 From: Durango, Colorado Member No.: 373 Region Association: Rocky Mountains |
Has anyone had any experience with a BG pump and a regulator on dual 40IDFs?
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