Original Mk. II oiling system

RJB · 09-23-08, 01:53 PM

Were the original Le Mans Mk. II's wet or dry sump configuration?

Will Parker · 09-23-08, 03:10 PM

From what I can find doing a search, it appears they were dry sumped. I'm not sure why though. Seems like a lot of extra weight and plumbing, but there was probably a reason for using it. Race cars don't usually use stuff unless they feel a need.

Dutton · 09-23-08, 04:03 PM

Dry sump.

The oil tank in the first generation Mk 2 (later know as the 2A) was mounted at the base of the windshield. Along with the spare tire, it was pretty crowded up there.

The Mk 2B moved the oil tank to the engine compartment. The 2B oil tank was considerably smaller than the 2A; a larger coolant radiator at the nose was installed to offset the loss of cooling ability due to the reduction of oil onboard.

RJB · 09-23-08, 05:16 PM

Thanks for the info. I was under the impression the originals were wet sumped, but can imagine the greater capacity made sense for long distance racing. Also likely allowed the engine to sit lower & reduce the center of gravity, which might have made a difference since I believe the entire engine (block, heads and possibly manifold) were gen-u-wine cast iron.

Now I have another bit of expensive complexity to consider, assuming I finally get off the fence on this...

Jac Mac · 09-23-08, 05:59 PM

Heads were iron in first MkII's, intakes were alloy- were two different dry sump systems at one point- one by SAI & the other by E & F. Source- GT40-Ronnie Spain.

Cliff Beer · 09-23-08, 11:40 PM

According to Ronnie Spain's book, the originals produced and run by John Weir were dry sumped. When Shelby took over the program they changed the configuration to wet sump. Why? Apparently, for reliability reasons.

Jac Mac · 09-24-08, 12:12 AM

( John Wyer ) You must be on the Small Blocks Cliff, Shelby already had a very good track record with wet sumps in the Cobras & there was a 50lb weight saving in going back to the wet sump style on the GT40 ( Mk1 ) ( quote-John Ohlsen- Freidmans book)
Sump was not the only part that got chucked out, the whole engine went as well, along with the wire wheels, radiator, transaxle gears!

Mike Trusty · 09-24-08, 08:49 AM

The FE powered cars(MARK IIA & IIB) were dry sump motors. Scavage pumps were part of the cast aluminum two piece oil pans. They used the standard distributor driven pump as the pressure pump. The oil tanks were located as mentioned above. The Shelby's had the tanks in the front and the H&M's had them in the rear to the left of the motor. I believe that the MARK IIB's had them all in the rear. They actually moved the tank from the left to right side depending on what track they were at. Here is a picture at my attempt to replicate the oil tank.

Jac Mac · 09-24-08, 05:09 PM

This pic which was posted many moons ago, you can see the two piece sump/pan, alloy ?heads & intake. This pic would suggest the heads were alloy as well, but remember its obviously a display/mockup assy.
Some of you guys need to spend a bit more time on the search button, all of this stuff is on this site, sometimes you have to think outside the square when looking and follow the odd link or two, but its all here.
Also interesting is that I saw an old 352/390 on ebay yesterday with those rocker covers on it , $$$ at the time was not much either.

Cushmancompetition · 09-25-08, 11:38 AM

Here are some pics of my original MK11b dry sump stuff and a friends original Mk11a tank. All Mk11s were drysump.

Mike Trusty · 09-25-08, 01:07 PM

Jay:

Thanks for those pictures. Those are only the second time that I have seen pictures of the very rare right side mounted Mark IIb oil tank. Most of them were left side mounted tanks for better weight distribution. They used this tank on tracks that had more right turns than left. I learned that from the guy that probably built the tank that you have.

John W · 09-29-08, 09:52 PM

All ofthe above answers pretty much all the points.
One further thing - the very early 427 FE (side oiler) engined cars ran an external dry sump pump, driven off the nose of the crank with a toothed belt. This specific design is covered in the SAE papers for the mkII. The internal pump was still used as the pressure pump though.

Points to note from Jay's pictures that most miss when making tanks:
- the front mounted tank also has a lump that sticks down into the foot well area, and is not often seen in pictures of the mkIIs as not many take pictures of this area.
- the rear mounted tank has a lump that hangs down below the top of the rear sponson. Does this protrude into the cill area ?
- the routing of the pipes through the chassis was different between the Shelby and H&M cars, not least because H&M removed the centre tunnel on their later cars.
- all shelby engined cars as far as I've discovered were changed to use alloy heads.

Cushmancompetition · 09-30-08, 01:10 PM

The external scavenge pumps were stole from the comp cobras. These were only used in the very first prototype Mk11s. All production cars used the system in my pics. The Mk11b had tanks made for either side depending on the track.

Many Mk11a's as well as small block cars were updated to the rear tanks later on.

Heres a pic of both right and left side tanks as well as a few pics of 1043 with a Mk11a tank