Fuel Tank - What were they thinking?

[Quickstep192]

You may have seen my other posts about my fuel line/tank replacement project.

I’m replacing the old tank with an SC Tank and moving the pump up forward. While trying to figure out how to protect the fuel pump from undercarriage impact, I noticed that the underside of the fuel tank is the lowest point in the front end of the car. At first I thought that it was because the SC tank was lower, but the old tank is the same way.

A ride over a parking lot barrier could take the tank out, or at least badly damage it.

What were these guys thinking?

[fanaudical]

Hmmm...I will have to look but I'm pretty sure that the front tow hooks on my 75 are lower than the bottom of the gas tank...

[RNajarian]

Originally Posted by fanaudical

Hmmm...I will have to look but I'm pretty sure that the front tow hooks on my 75 are lower than the bottom of the gas tank...

They are also the lowest on my ‘75, though years of bottoming out damaged them pretty badly, so I upgraded to the Rennline tow hooks our host sells.

https://www.pelicanparts.com/More_Info/RENE03R.htm?pn=REN-E03-R&SVSVSI=

[Quickstep192]

Here’s a picture of my tow hook relative to the underside of the tank. The tank is probably 30mm lower. I guess if the thing I hit his high enough, it will hit the tow hook first, but the tank is definitely the lowest part of the car.

[RNajarian]

Not sure if that welded loop in your photo is a tow hook, or even a tie down point. If it is I certainly wouldn’t use it as such.

We are talking about the covers for the front end control arm which hang down lower than the fuel tank. See the link and photo below. . .


https://forums.pelicanparts.com/porsche-911-technical-forum/935339-carrera-front-tow-hook-removal.html

[David Inc.]

The tow hooks won't stop a rock. My tank has a huge knock on the bottom of it from who knows how many years ago. I had it stripped and coated recently and the guy smoothed it out a bit, but it doesn't impact function so whatever. I imagine most tanks have some hits on them.

I guess they did it because lower is better, and the likelihood of impact is there but not the worst.

[rothaus]

A friend of mine switched to a plastic tank, and he added a skid plate for protection of the tank. That's maybe an option.

Something like this

https://www.rennline.com/911-skid-plate-sku-u07/

[Showdown]

Ask Duane [mention]75911 [/mention] about his saga of rock vs. tank en route to Luft… he now has a new tank and a rennline skid plate.

[porsche930dude]

My fuel pump nearly got ripped off from just the crown in the road. Iv since relocated it up higher. Also almost went in the ditch once and that put a big gouge in the tank but its ok. I had made a skid plate for it at one point but it was heavy steel so eventually took it off. I used to go on alot of dirt roads but they have mostly paved them all now. I figure it keeps me from doing anything too dumb.

[Cory M]

These cars didn't come from the factory slammed on low profile tires...

[3rd_gear_Ted]

The tanks internal fuel filtering screen doesn't help out the -044 type Bosch fuel pumps from small scale bits either.

[chrismorse]

I started cleaning up my tank and found rust perforation, so ordered a TMP, (Tasker Metal Products) from out host., Good fit.
However, looking at the abuse that the bottom of the old tank took, I decided to try a truck bed liner spray coating to add a little more protection, before painting.
I think the heavy metal pan under the pump and rack provide not only protection for those components but also add a bit of stiffness to the front of the car, so i wouldm't do without it for lightness sake.
I did a bit of beta testing for Len Cumings, (the fuel line guy :-) for his front pump mount and it helps kep the pump out of harm's way, nice piece.
Side note: The TMP replica tank also has a "stock like in tank filter", but it has a very coarse screen - so i cleaned and re-used the original in tank filter.

chris

[Quickstep192]

Originally Posted by rothaus

A friend of mine switched to a plastic tank, and he added a skid plate for protection of the tank. That's maybe an option.

Something like this

https://www.rennline.com/911-skid-plate-sku-u07/

That looks like just the ticket. I have an email in to Rennline, but while I’m waiting for a response, does anyone know if that will fit a ‘73 Targa?

[PeteKz]

Originally Posted by Cory M

These cars didn't come from the factory slammed on low profile tires...

Ditto that. I haven't had a problem with hitting the bottom of the gas tank, but I keep it at "Euro" ride hight with tires that are about 24.4' in diameter.

[75 911s]

Originally Posted by Showdown

Ask Duane [mention]75911 [/mention] about his saga of rock vs. tank en route to Luft… he now has a new tank and a rennline skid plate.

Yep.

Hit a good sized rock on Angeles Crest highway and it knocked a bunch of surface rust inside the tank loose, ultimately clogging my fuel pump. To be fair, my car is extremely low, the tank was original from 1974 and the car had sat at one point for over a decade. I tried to repair it. I flushed it at a shop but looking inside after the fact didn't inspire confidence as there was still a lot of suspect areas on the inside. I ended up buying a new Dansk tank. They sent me a previously returned tank that was damaged in several areas. I returned it and got a second tank that was still dented, but usable. The new Dansk tank has a swirl bowl and filter is included FYI.

I did pick up a skid plate here on the bird. I'll post some pics when it's all done. Seems like a good idea for low cars like mine.

Sorry not a great pic, but here's a wet wipe showing some of the rust that got sucked through the screen and clogged up my pump.

[Cory M]

The Rennline skid plate is a nice piece and an easy bolt on installation.

[Quickstep192]

Thanks for all the insight. I don’t think I would have found that skid plate on my own.

I called Rennline and they say it will fit, so I ordered one from our host.

The post about knocking the rust loose makes me feel better that I’m replacing everything. New tank, new pump, new lines. Moving the pump up front has been a bit of a magical mystery tour with routing hoses, but hopefully this will all pay off in the end.

[rothaus]

Originally Posted by Quickstep192

Thanks for all the insight. I don’t think I would have found that skid plate on my own.

I called Rennline and they say it will fit, so I ordered one from our host.

The post about knocking the rust loose makes me feel better that I’m replacing everything. New tank, new pump, new lines. Moving the pump up front has been a bit of a magical mystery tour with routing hoses, but hopefully this will all pay off in the end.

What year is your 911 ? If you got the aluminum cross bar, there should be enough space to mount the pump. On my 71 I had the steel cross bar and to mount a fuel pump was quit a pain.

Good luck.
Engelbert

[Quickstep192]

Originally Posted by rothaus

What year is your 911 ? If you got the aluminum cross bar, there should be enough space to mount the pump. On my 71 I had the steel cross bar and to mount a fuel pump was quit a pain.

Good luck.
Engelbert

Mine is a “73, so no aluminum crossbar. I thought of replacing the cross bar, but that job looks like it might require more skill than I possess.