Fuel pump relocation front or rear? Type? |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
Fuel pump relocation front or rear? Type? |
jim_hoyland |
Sep 21 2021, 06:53 PM
Post
#21
|
Get that VIN ? Group: Members Posts: 9,225 Joined: 1-May 03 From: Sunset Beach, CA Member No.: 643 Region Association: Southern California |
Move the filter and pump to front trunk; added a shut valve and pressure gauge . A lexsn shield was added to protect the set-up
Attached thumbnail(s) |
nditiz1 |
Sep 21 2021, 07:11 PM
Post
#22
|
Senior Member Group: Members Posts: 1,164 Joined: 26-May 15 From: Mount Airy, Maryland Member No.: 18,763 Region Association: MidAtlantic Region |
Jim that looks great I may replicate when I move it from the engine bay.
On the topic of worm gear vs band, I recently had to use the worm gear to get a tighter clamp when the band produced leaks. Possibly the crimp style band would be better than the screw type band. I had a question regarding hose size. For pretty much everything I'm running 3/8 FI line. The 3/8 fits snug on the send line. The return line is thinner. While 3/8 fit I did need to use the work gear clamp. I'm using a 911 Fuel pump. The out end is very tiny, a worm clamp here allowed the 3/8 to fit, but a 5/16 probably could have worked. The fuel pump inlet is a struggle to make the 3/8 work. What is the normal setup for everything including the smaller fuel filter ports? |
jcd914 |
Sep 21 2021, 07:44 PM
Post
#23
|
Advanced Member Group: Members Posts: 2,081 Joined: 7-February 08 From: Sacramento, CA Member No.: 8,684 Region Association: Northern California |
All ready to order new stainless fuel lines for the tunnel and after talking to Auto Atlanta they suggest not replacing the lines in the tunnel as they are not prone to failure. Any thoughts? I had planned on replacing all of the fuel lines. Not advise I would take. The tunnel lines do fail and then you are sitting in a car with fuel inside with you. Not someplace I want to be. They are almost 50 year old plastic not designed to hold the pressure of the Fuel Injection system, just the weight of the fuel in the tank. If you move the pump up front you are now running high pressure fuel through the plastic line. Does AA even sell the SS lines? Jim Several older mechanics from Europe who have worked on 914s for many years have told me that the plastic fuel lines are bullet proof. Go figure. The added pressure may be an issue. BTW, it's advice, not advise. I am an older mechanic, although I only worked professionally for 20 years (3 Porsche dealers,1 independent), short by some standards. I have seen personally several 914s, where those bullet proof plastic lines failed and leaked without the pressure of the relocated pump and I would not trust them. And 914s weren't even that old when I was working on them full time. Jim |
windforfun |
Sep 22 2021, 11:14 AM
Post
#24
|
Senior Member Group: Members Posts: 1,766 Joined: 17-December 07 From: Blackhawk, CA Member No.: 8,476 Region Association: None |
All ready to order new stainless fuel lines for the tunnel and after talking to Auto Atlanta they suggest not replacing the lines in the tunnel as they are not prone to failure. Any thoughts? I had planned on replacing all of the fuel lines. Not advise I would take. The tunnel lines do fail and then you are sitting in a car with fuel inside with you. Not someplace I want to be. They are almost 50 year old plastic not designed to hold the pressure of the Fuel Injection system, just the weight of the fuel in the tank. If you move the pump up front you are now running high pressure fuel through the plastic line. Does AA even sell the SS lines? Jim Several older mechanics from Europe who have worked on 914s for many years have told me that the plastic fuel lines are bullet proof. Go figure. The added pressure may be an issue. BTW, it's advice, not advise. I am an older mechanic, although I only worked professionally for 20 years (3 Porsche dealers,1 independent), short by some standards. I have seen personally several 914s, where those bullet proof plastic lines failed and leaked without the pressure of the relocated pump and I would not trust them. And 914s weren't even that old when I was working on them full time. Jim I guess it's time to go stainless steel. Thanks for the feedback. |
914werke |
Sep 22 2021, 12:27 PM
Post
#25
|
"I got blisters on me fingers" Group: Members Posts: 9,889 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest |
Not advise I would take. They are almost 50 year old plastic not designed to hold the pressure of the Fuel Injection system, just the weight of the fuel in the tank. Again .. MISINFORMATION! (IMG:style_emoticons/default/dry.gif) Ill agree tunnel lines can leak in stock form, but the incidence is (very) low and usually the causal reason is more likely abrasion from PO tinkering than simple pressure. While its true early cars (70-74) were equipped with tunnel lines that were not designed /spec'ed for the hi-pressure use of the OE FI pump relocated to the front, I continue to see cars that had been converted like this & have been running & driving for decades. The late cars 75-76 have PLASTIC (Nylon?) lines that ARE rated for high pressure. My own experience from breaking many many cars is that the tunnel lines are usually quite pliable and are likley to continue to perform as designed, in most cases. But use common sense & don't succumb to Internet FUD! All these cars are nearly 50 years old & its doubtful that Hans & Wolfgang engineers spec'ed these components to last this long. Add into the mix they carry fuel formulations that are significantly different from the 1970's ... IMO its not a bad idea to replace those lines (in particular early) but to bang the gong that "your all gonna die" unless replaced is irresponsible. More importantly, if still equipped with OE lines check them at the exit of the firewall in the Eng. compartment. This where they are exposed to EXTREME HEAT and can degrade crack & cause fires. (IMG:style_emoticons/default/bye1.gif) Fire away (IMG:style_emoticons/default/happy11.gif) |
Joec |
Sep 22 2021, 02:20 PM
Post
#26
|
Newbie Group: Members Posts: 16 Joined: 26-April 21 From: Delta, BC Member No.: 25,484 Region Association: None |
I would say where these lines exit the tunnel and enter the engine compartment is where I have some concern, the plastic or wherever the material is looks old, and while not cracked it certainly has had some exposure to heat, but the car has been parked for over 25 years so really not that much exposure. At this point and time I am just trying to get the car running to assess the engine's fitness. So it seems I am most likely fine with the existing lines. thanks for the comments.
|
Steve |
Sep 22 2021, 02:55 PM
Post
#27
|
914 Guru Group: Members Posts: 5,548 Joined: 14-June 03 From: Orange County, CA Member No.: 822 Region Association: Southern California |
All ready to order new stainless fuel lines for the tunnel and after talking to Auto Atlanta they suggest not replacing the lines in the tunnel as they are not prone to failure. Any thoughts? I had planned on replacing all of the fuel lines. Not advise I would take. The tunnel lines do fail and then you are sitting in a car with fuel inside with you. Not someplace I want to be. They are almost 50 year old plastic not designed to hold the pressure of the Fuel Injection system, just the weight of the fuel in the tank. If you move the pump up front you are now running high pressure fuel through the plastic line. Does AA even sell the SS lines? Jim Several older mechanics from Europe who have worked on 914s for many years have told me that the plastic fuel lines are bullet proof. Go figure. The added pressure may be an issue. BTW, it's advice, not advise. I am an older mechanic, although I only worked professionally for 20 years (3 Porsche dealers,1 independent), short by some standards. I have seen personally several 914s, where those bullet proof plastic lines failed and leaked without the pressure of the relocated pump and I would not trust them. And 914s weren't even that old when I was working on them full time. Jim Back in the late 70's, i had a 71 that was victim of an engine fire. It was the lines in the engine compartment. Back then there was a campaign by Porsche to replace all of the engine compartment fuel lines on the stock injection. Those fabric covered lines are horrible. I also just pulled a tank on a 75 and the original fabric covered lines broke in half and made a mess. |
930cabman |
Sep 22 2021, 03:36 PM
Post
#28
|
Advanced Member Group: Members Posts: 2,977 Joined: 12-November 20 From: Buffalo Member No.: 24,877 Region Association: North East States |
Not advise I would take. They are almost 50 year old plastic not designed to hold the pressure of the Fuel Injection system, just the weight of the fuel in the tank. Again .. MISINFORMATION! (IMG:style_emoticons/default/dry.gif) Ill agree tunnel lines can leak in stock form, but the incidence is (very) low and usually the causal reason is more likely abrasion from PO tinkering than simple pressure. While its true early cars (70-74) were equipped with tunnel lines that were not designed /spec'ed for the hi-pressure use of the OE FI pump relocated to the front, I continue to see cars that had been converted like this & have been running & driving for decades. The late cars 75-76 have PLASTIC (Nylon?) lines that ARE rated for high pressure. My own experience from breaking many many cars is that the tunnel lines are usually quite pliable and are likley to continue to perform as designed, in most cases. But use common sense & don't succumb to Internet FUD! All these cars are nearly 50 years old & its doubtful that Hans & Wolfgang engineers spec'ed these components to last this long. Add into the mix they carry fuel formulations that are significantly different from the 1970's ... IMO its not a bad idea to replace those lines (in particular early) but to bang the gong that "your all gonna die" unless replaced is irresponsible. More importantly, if still equipped with OE lines check them at the exit of the firewall in the Eng. compartment. This where they are exposed to EXTREME HEAT and can degrade crack & cause fires. (IMG:style_emoticons/default/bye1.gif) Fire away (IMG:style_emoticons/default/happy11.gif) Replacing the original "plastic" fuel lines is probably not a bad idea. Does anyone know what the plastic is? I am new to the world of things 914 and have had exposure to a 1974 and (2) 1975 models. Yes, the original fabric covered fuel lines are very brittle and must be replaced, but the original plastic lines are pliable. Again, probably safe to replace with new St Stl tubing, but when? |
Steve |
Sep 22 2021, 04:33 PM
Post
#29
|
914 Guru Group: Members Posts: 5,548 Joined: 14-June 03 From: Orange County, CA Member No.: 822 Region Association: Southern California |
Not advise I would take. They are almost 50 year old plastic not designed to hold the pressure of the Fuel Injection system, just the weight of the fuel in the tank. Again .. MISINFORMATION! (IMG:style_emoticons/default/dry.gif) Ill agree tunnel lines can leak in stock form, but the incidence is (very) low and usually the causal reason is more likely abrasion from PO tinkering than simple pressure. While its true early cars (70-74) were equipped with tunnel lines that were not designed /spec'ed for the hi-pressure use of the OE FI pump relocated to the front, I continue to see cars that had been converted like this & have been running & driving for decades. The late cars 75-76 have PLASTIC (Nylon?) lines that ARE rated for high pressure. My own experience from breaking many many cars is that the tunnel lines are usually quite pliable and are likley to continue to perform as designed, in most cases. But use common sense & don't succumb to Internet FUD! All these cars are nearly 50 years old & its doubtful that Hans & Wolfgang engineers spec'ed these components to last this long. Add into the mix they carry fuel formulations that are significantly different from the 1970's ... IMO its not a bad idea to replace those lines (in particular early) but to bang the gong that "your all gonna die" unless replaced is irresponsible. More importantly, if still equipped with OE lines check them at the exit of the firewall in the Eng. compartment. This where they are exposed to EXTREME HEAT and can degrade crack & cause fires. (IMG:style_emoticons/default/bye1.gif) Fire away (IMG:style_emoticons/default/happy11.gif) Replacing the original "plastic" fuel lines is probably not a bad idea. Does anyone know what the plastic is? I am new to the world of things 914 and have had exposure to a 1974 and (2) 1975 models. Yes, the original fabric covered fuel lines are very brittle and must be replaced, but the original plastic lines are pliable. Again, probably safe to replace with new St Stl tubing, but when? Personally it's cheap insurance, why not replace the plastic lines with SS lines? Do you have to, probably not, but for the price why not? They are easy to install and cheap. I got mine from rotary914. On my car, I replaced everything that was functional rubber or plastic. i.e fuel lines, brake lines, suspension bushings and shift bushings. |
windforfun |
Sep 22 2021, 06:54 PM
Post
#30
|
Senior Member Group: Members Posts: 1,766 Joined: 17-December 07 From: Blackhawk, CA Member No.: 8,476 Region Association: None |
Not advise I would take. They are almost 50 year old plastic not designed to hold the pressure of the Fuel Injection system, just the weight of the fuel in the tank. Again .. MISINFORMATION! (IMG:style_emoticons/default/dry.gif) Ill agree tunnel lines can leak in stock form, but the incidence is (very) low and usually the causal reason is more likely abrasion from PO tinkering than simple pressure. While its true early cars (70-74) were equipped with tunnel lines that were not designed /spec'ed for the hi-pressure use of the OE FI pump relocated to the front, I continue to see cars that had been converted like this & have been running & driving for decades. The late cars 75-76 have PLASTIC (Nylon?) lines that ARE rated for high pressure. My own experience from breaking many many cars is that the tunnel lines are usually quite pliable and are likley to continue to perform as designed, in most cases. But use common sense & don't succumb to Internet FUD! All these cars are nearly 50 years old & its doubtful that Hans & Wolfgang engineers spec'ed these components to last this long. Add into the mix they carry fuel formulations that are significantly different from the 1970's ... IMO its not a bad idea to replace those lines (in particular early) but to bang the gong that "your all gonna die" unless replaced is irresponsible. More importantly, if still equipped with OE lines check them at the exit of the firewall in the Eng. compartment. This where they are exposed to EXTREME HEAT and can degrade crack & cause fires. (IMG:style_emoticons/default/bye1.gif) Fire away (IMG:style_emoticons/default/happy11.gif) Replacing the original "plastic" fuel lines is probably not a bad idea. Does anyone know what the plastic is? I am new to the world of things 914 and have had exposure to a 1974 and (2) 1975 models. Yes, the original fabric covered fuel lines are very brittle and must be replaced, but the original plastic lines are pliable. Again, probably safe to replace with new St Stl tubing, but when? Personally it's cheap insurance, why not replace the plastic lines with SS lines? Do you have to, probably not, but for the price why not? They are easy to install and cheap. I got mine from rotary914. On my car, I replaced everything that was functional rubber or plastic. i.e fuel lines, brake lines, suspension bushings and shift bushings. Good job. Right on!!! Do you want to sell your car? I hate gasoline. BTDT. (IMG:style_emoticons/default/smile.gif) (IMG:style_emoticons/default/smile.gif) (IMG:style_emoticons/default/smile.gif) |
jcd914 |
Sep 22 2021, 10:47 PM
Post
#31
|
Advanced Member Group: Members Posts: 2,081 Joined: 7-February 08 From: Sacramento, CA Member No.: 8,684 Region Association: Northern California |
Not advise I would take. They are almost 50 year old plastic not designed to hold the pressure of the Fuel Injection system, just the weight of the fuel in the tank. Again .. MISINFORMATION! (IMG:style_emoticons/default/dry.gif) Ill agree tunnel lines can leak in stock form, but the incidence is (very) low and usually the causal reason is more likely abrasion from PO tinkering than simple pressure. While its true early cars (70-74) were equipped with tunnel lines that were not designed /spec'ed for the hi-pressure use of the OE FI pump relocated to the front, I continue to see cars that had been converted like this & have been running & driving for decades. The late cars 75-76 have PLASTIC (Nylon?) lines that ARE rated for high pressure. My own experience from breaking many many cars is that the tunnel lines are usually quite pliable and are likley to continue to perform as designed, in most cases. But use common sense & don't succumb to Internet FUD! All these cars are nearly 50 years old & its doubtful that Hans & Wolfgang engineers spec'ed these components to last this long. Add into the mix they carry fuel formulations that are significantly different from the 1970's ... IMO its not a bad idea to replace those lines (in particular early) but to bang the gong that "your all gonna die" unless replaced is irresponsible. More importantly, if still equipped with OE lines check them at the exit of the firewall in the Eng. compartment. This where they are exposed to EXTREME HEAT and can degrade crack & cause fires. (IMG:style_emoticons/default/bye1.gif) Fire away (IMG:style_emoticons/default/happy11.gif) I'll disagree with your conclusion but no fire from me. The thread is about relocating the fuel pump on a 74. The 74 would have the early plastic lines not the high pressure nylon line the factory switched to for 75/76 when they move the pump up under the tank. I have seen and worked on 914s where a tunnel line leaked. So I can't recommend moving the fuel pump to the front and running pressurized fuel through the old plastic line. Thanks Jim |
wonkipop |
Sep 23 2021, 02:29 AM
Post
#32
|
Advanced Member Group: Members Posts: 4,159 Joined: 6-May 20 From: north antarctica Member No.: 24,231 Region Association: NineFourteenerVille |
Not advise I would take. They are almost 50 year old plastic not designed to hold the pressure of the Fuel Injection system, just the weight of the fuel in the tank. Again .. MISINFORMATION! (IMG:style_emoticons/default/dry.gif) Ill agree tunnel lines can leak in stock form, but the incidence is (very) low and usually the causal reason is more likely abrasion from PO tinkering than simple pressure. While its true early cars (70-74) were equipped with tunnel lines that were not designed /spec'ed for the hi-pressure use of the OE FI pump relocated to the front, I continue to see cars that had been converted like this & have been running & driving for decades. The late cars 75-76 have PLASTIC (Nylon?) lines that ARE rated for high pressure. My own experience from breaking many many cars is that the tunnel lines are usually quite pliable and are likley to continue to perform as designed, in most cases. But use common sense & don't succumb to Internet FUD! All these cars are nearly 50 years old & its doubtful that Hans & Wolfgang engineers spec'ed these components to last this long. Add into the mix they carry fuel formulations that are significantly different from the 1970's ... IMO its not a bad idea to replace those lines (in particular early) but to bang the gong that "your all gonna die" unless replaced is irresponsible. More importantly, if still equipped with OE lines check them at the exit of the firewall in the Eng. compartment. This where they are exposed to EXTREME HEAT and can degrade crack & cause fires. (IMG:style_emoticons/default/bye1.gif) Fire away (IMG:style_emoticons/default/happy11.gif) I would agree with 95% of what you say here. the lines in the tunnel i pulled out 2 years ago (74 model) were still pliable and in first class condition. external to the firewall were brittle and would break by just bending them. the brittle area extended maybe 6 inches or so back into the tunnel beyond the engine bay firewall. i doubt anyone in vw or porsche believed the cars would still be on the road in the numbers they still are at this point in time. i'd love to know what the material and who the manufacturer of those fuel lines was. the germans are/were incredible formulators of synthetic materials. i don't believe those fuel lines at that quality are available anymore, anywhere. i think they used plastic with a view towards collision protection. the only thing that concerns me about stainless steel is it is brittle. but i guess any accident where the fuel lines have to survive being bent in the tunnel is going to be one a human will find hard to survive? re vapor lock problem with cars with rear fuel pump. the problem is the magnesium fan shroud. on shutdown it is a heat sink for all engine heat. it gets very hot. radiates at the fuel lines as well as the fuel pump. the problem was a combination of the exposed fuel line which was only gravity fed as much as the fuel pump. with the pump in the front that exposed bit of fuel line along the rear firewall could be pressurised to overcome the vaporisation problem. i'm leaving my pump in original location and heat shielding the fuel lines. i never had a vaporisation problem with my original fuel pump. but i do have one now with a modern in line pump in the original location. i think the modern pumps are even more vulnerable to the vapor problem than the original roller cell pumps. |
windforfun |
Sep 23 2021, 10:57 AM
Post
#33
|
Senior Member Group: Members Posts: 1,766 Joined: 17-December 07 From: Blackhawk, CA Member No.: 8,476 Region Association: None |
My lines in the engine compartment are still soft & flexible. Only 48K miles. Just lucky I guess.
(IMG:style_emoticons/default/idea.gif) |
porschetub |
Sep 23 2021, 02:23 PM
Post
#34
|
Advanced Member Group: Members Posts: 4,695 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
Not advise I would take. They are almost 50 year old plastic not designed to hold the pressure of the Fuel Injection system, just the weight of the fuel in the tank. Again .. MISINFORMATION! (IMG:style_emoticons/default/dry.gif) Ill agree tunnel lines can leak in stock form, but the incidence is (very) low and usually the causal reason is more likely abrasion from PO tinkering than simple pressure. While its true early cars (70-74) were equipped with tunnel lines that were not designed /spec'ed for the hi-pressure use of the OE FI pump relocated to the front, I continue to see cars that had been converted like this & have been running & driving for decades. The late cars 75-76 have PLASTIC (Nylon?) lines that ARE rated for high pressure. My own experience from breaking many many cars is that the tunnel lines are usually quite pliable and are likley to continue to perform as designed, in most cases. But use common sense & don't succumb to Internet FUD! All these cars are nearly 50 years old & its doubtful that Hans & Wolfgang engineers spec'ed these components to last this long. Add into the mix they carry fuel formulations that are significantly different from the 1970's ... IMO its not a bad idea to replace those lines (in particular early) but to bang the gong that "your all gonna die" unless replaced is irresponsible. More importantly, if still equipped with OE lines check them at the exit of the firewall in the Eng. compartment. This where they are exposed to EXTREME HEAT and can degrade crack & cause fires. (IMG:style_emoticons/default/bye1.gif) Fire away (IMG:style_emoticons/default/happy11.gif) Replacing the original "plastic" fuel lines is probably not a bad idea. Does anyone know what the plastic is? I am new to the world of things 914 and have had exposure to a 1974 and (2) 1975 models. Yes, the original fabric covered fuel lines are very brittle and must be replaced, but the original plastic lines are pliable. Again, probably safe to replace with new St Stl tubing, but when? Personally it's cheap insurance, why not replace the plastic lines with SS lines? Do you have to, probably not, but for the price why not? They are easy to install and cheap. I got mine from rotary914. On my car, I replaced everything that was functional rubber or plastic. i.e fuel lines, brake lines, suspension bushings and shift bushings. My experience was this...all my fabric covered hoses were really bad,plastic lines soft and not in any way due for failure,not worth me importing a kit to due to cost I did the hard lines in larger diameter truck brake pipe as I already had the right bender for it,then did the tunnel (pressure) line in late model VW blue HP EFI line . Used FI hose and clamps and used the old return to run a wire to power my LP fuel pump up front on the steering rack. |
Lo-Fi Version | Time is now: 28th March 2024 - 10:25 AM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |