SW 240A Fuel Pumps

[FatBoy]

Every "original" installation I've seen has a single feed from the tank to both pumps, which rules out the reserve suggestion.

Paul

[computerworks]

Originally Posted by FatBoy

Every "original" installation I've seen has a single feed from the tank to both pumps, which rules out the reserve suggestion.

Paul

Sorry Paul. Would you like to see pictures of original Comp fuel tanks?

If you feel strongly about it, you may plumb it as you see fit...no one will see it anyhow, once the sheet metal is in place.

Plus, it's just a fake anyhow, right?

[FatBoy]

Originally Posted by computerworks

Sorry Paul. Would you like to see pictures of original Comp fuel tanks?

If you feel strongly about it, you may plumb it as you see fit...no one will see it anyhow, once the sheet metal is in place.

Plus, it's just a fake anyhow, right?

Sure is.

It's much less about replicating what was original and more about plain curiosity to be honest.
I don't doubt what you say about the tanks, but having two pipes into the tank, isn't, in itself proof absolute of the two level pickup arguement unless we know for sure what they were used for.
Do you have any "original" pictures of the pumps with dual feeds from the tanks? To fulfil the dual level pickup arguement, each pump would needs its own seperate feed pipe and I haven't seen any pictures with that arrangement.

Paul

[computerworks]

Originally Posted by FatBoy

Do you have any "original" pictures of the pumps with dual feeds from the tanks? To fulfil the dual level pickup arguement, each pump would needs its own seperate feed pipe and I haven't seen any pictures with that arrangement.

Yes, i do...but i think I misunderstood you.

There are dual fittings on the tank...one goes forward to the mechanical; the other goes up to the twin electricals in parallel

[mickmate]

It's hard to tell from the angle of the picture I posted but that is a new Shelby tank with two different height pickup tubes. They are the same as they were back in the day except new ones have a bladder and flanges. They are all clearly stamped main and reserve on the front of the tanks by the pickups.

[FatBoy]

Originally Posted by computerworks

Yes, i do...but i think I misunderstood you.

There are dual fittings on the tank...one goes forward to the mechanical; the other goes up to the twin electricals in parallel

Ah, okay, hence only the single feed into the dual pumps. Was that normal practice in the period to have a reserve fuel capacity? Does that then mean that the second electric pump was a backup for the backup? That would seem a little extravagant and arguably, an unnecessary weight burden for a race car.

Does anyone know how the GT40s were configured because they used the same pumps, albeit they had three of them?

Paul

[computerworks]

Originally Posted by FatBoy

Was that normal practice in the period to have a reserve fuel capacity? Does that then mean that the second electric pump was a backup for the backup?

It was helpful when you did not have a fuel gauge and your crew underestimated your fuel load.

The 2nd pump was not a backup... it was in parallel such that the outputs were additive...perhaps for more adequate pressure.

[my427cobra]

I took two rotten old non rebuildable SW pumps, gutted them, bored them out, and installed modern electric fuel pumps inside the SW's.

Refinished and replumbed them and they look like this:



Cheers
Greg

[FatBoy]

They look good.

Couldn't you get the fuel to come out the original outlet?

Well done,
Paul

[Bernica]

Originally Posted by FatBoy

Is that an original S/C tank Nick?

That looks like my tank that Mickmate just re-did for my CSX 4000. It was clearly marked with "M" and "R" (main and reserve) on the tank when I took it out. Both my pumps run at the same time and I only use them for a few seconds during my start-up routine just to "prime" things. Then I rely on the mechanical, which seems to handle things fine.

[Bernica]

"Before" and "After" pics. Just follow the plumbing in any of the ones I have looked at, and it is as Mickmate and Computerworks state above.

[my427cobra]

Hi Paul. Thanks. It's fun coming up with wacky solutions. Couldn't find a short enough modern electric pump to fit inside the SW. So the inlet comes into the stock filter bowl inlet and out the top to a 90 deg head. Just plugged the stock outlet as it's on the back side and dosen't show.

Greg

[FatBoy]

Very clever.

I currently have a mechanical pump inline with a Holley Red Top. However, if I try to run on just the mechanical pump, the pressure drops off pretty much straightaway. I assume this is because the fuel can't be drawn through a non-running Holley.

As a side question, if the mechanical pumps work well enough, why does almost everyone use an electric pump?

Paul

[ERA Chas]

Originally Posted by FatBoy

Very clever.

I currently have a mechanical pump inline with a Holley Red Top. However, if I try to run on just the mechanical pump, the pressure drops off pretty much straightaway. I assume this is because the fuel can't be drawn through a non-running Holley.

As a side question, if the mechanical pumps work well enough, why does almost everyone use an electric pump?

Paul

That is correct-a mechanical will not draw through a non-running red-top. I have the exact set-up.
I run the red all the time feeding the mechanical-it's perfect. Priming with the red top on cold starts is a major help. Goes off on the key.

[FatBoy]

Can anyone confirm which pumps were originally installed on the S/C Cobras?

I'm trying to make sense of the differing information being offered.

Having a reserve on a full race car doesn't make much sense to me and I'm wondering if the 427 S/C fuelling arrangements were cobbled together when they were converted from race cars and that included a reserve fuel facility.

What is also intriguing is the location of the pumps. There is a plate behind the aluminium trunk panel that has two pairs of holes for mounting the SW pumps, but none of the period pictures I've seen appear to use those mounting locations due to the spacing between the pumps. Why?

Paul

[bkozlow]

Duel pumps worked in parallel, one switch. Third pump was on a separate switch for the lower pickup that acted as a reserve. This is the way the cars were setup for International racing. At least that is the way the Daytonas and GT-40 Mk. II's were setup, as I remember.

Bill K

[computerworks]

Originally Posted by FatBoy

Can anyone confirm which pumps were originally installed on the S/C Cobras?

I'm trying to make sense of the differing information being offered.

Having a reserve on a full race car doesn't make much sense to me and I'm wondering if the 427 S/C fuelling arrangements were cobbled together when they were converted from race cars and that included a reserve fuel facility.

What is also intriguing is the location of the pumps. There is a plate behind the aluminium trunk panel that has two pairs of holes for mounting the SW pumps, but none of the period pictures I've seen appear to use those mounting locations due to the spacing between the pumps. Why?

Paul

I think the correct info has already been given to you....

"...Having a reserve on a full race car doesn't make much sense to me"

It does, when you have no fuel level gauge.

The location and mounting for the pumps was not designed into the chassis by AC. They were mounted where they would be convenient and appropriate.

If accuracy is what you seek, I (and others) have given you the correct info.
I believe you need to not look at restored or converted originals...or replicas thereof... and just see a vintage era picture.

( and +/- an inch or so is acceptable. )

[FatBoy]

Fuel pumps all installed and looking pretty good.

The fittings were black anodised, which whilst very smart, didn't look very period, so a quick douse in oven cleaner took them back to bare aluminium, which looks much better.



Paul

[my427cobra]

Looks great Paul.

Greg

[FatBoy]

Thanks Greg.

In an attempt to get a definitive answer on this pump configuration question, I have been in touch with the guys who would know, namely, the guys who raced them in the 60's.
To that end, I have been in touch with both Jack Sears and Sir John Whitmore. Whilst Sir John, couldn't recall how or when the pumps were operated (it was a long time ago and he stopped racing in '66), Jack has said that the electric pumps ran for the duration and that there wasn't a reserve fuel capacity.

QED

Having spoken to other people, the general consensus is that the race cars didn't have mechanical fuel pumps fitted, which would make sense and fit it with the general practice of the time.

Paul