Moving the oil tank (a la 1972)

[jazzbass]

I was changing my oil tonight and started thinking - I wonder if anyone has moved their oil tank in front of the right rear wheel, like 72s, CTRs and 964/993s. No argument that its a better location, and might not be too bad if an exisiting tank could be made to fit. Probably a 964 tank, as 72s are expensive as hell and require fitting that cool little door. Searched the archives but didn't find much.

I think a project like this goes on my list of things to do when I have more money and time than I know what to do with.

[Bill Verburg]

Yes, a 993/964 oil tank goes very neatly into a '73-89 911

The '72 tanks are also on the small side. For any performance app, they should be expanded.

[jazzbass]

Originally posted by Bill Verburg
Yes, a 993/964 oil tank goes very neatly into a '73-89 911

Speaking from personal experience?

[Randy Webb]

I've thought about it -- it's probably more time and money efficient to sell my '73 and buy a '72. And how important is it anyway? I've asked if people who have driven a '72 and a '73 back to back to post their subjective experiences and never got a reply.

Another way to estimate the effects is with modeling. The wt. shift is not large. Remember when running the engie, a lot of the oil is not in the tank. Add (x qts. oil * wt. of oil) to the wt. of the tank and that's what your're moving x inches along the line from the end of the car to the CG....

But you _are_ shifting some mass form outside the wheelbase to inside -- maybe that effect is bigger than just he above calculation.... Dunno.

[jazzbass]

Originally posted by Randy Webb
I've thought about it -- it's probably more time and money efficient to sell my '73 and buy a '72.

My thoughts exactly.

Originally posted by Randy Webb
But you _are_ shifting some mass form outside the wheelbase to inside -- maybe that effect is bigger than just he above calculation.... Dunno.

I think it does. Besides, what I really want in the extra filler door on the quarter panel :

[Jack Olsen]

The other advantage is cooling. Having the tank in the engine compartment allows it to pick up radiant heat off the engine block (and vice versa).

I was planning on adapting a 993 tank for my car, but went with the 72 tank instead. I don't remember the details, but there was something that came up as an expensive roadblock on the 993 tank plan. Hopefully Tyson Schmidt or TRE Cup (Dave) will chime in on this, since they had done the detective work on it.

[Tyson Schmidt]

Modifying the car for a remote filler tube and remote dipstick were the big roadblocks. Not that big of a deal, but pretty significant when you're trying to build an entire car from scratch in 12 weeks. Starting with a '72, and modifying the '72 tank for more capacity just made a lot more sense.

Also, all that crap that hangs down low on the 993 oil tank would need to be dealt with, or it would be both unsightly, and in harms way on a pre- '90 car with their higher rocker panels.

[JSDSKI]

Oh no! Not '72 clones!!!

[Bill Verburg]

Originally posted by jazzbass
Speaking from personal experience?

Not on my car, but a "trackie" aquaintance started w/ an '86 Carrera coupe, added a full cage and Moteced 964, complete 964 oil system including tank.

It made for a very sanitary installation.

[304065]

Why not put it up front?

[jazzbass]

Originally posted by john_cramer
Why not put it up front?

From the threads I've read, you have to run the oil lines through the passenger compartment. Not a good idea on a street car. That, and its realy, realy, realy expensive. I think I read that the hose to plumb the oil lines with is $50+ a foot. Plus the tank. Ouch.

[Randy Webb]

Jack, I'm going to requote and modify your racer oriented comment for street oriented cars:

"The other dis-advantage is heating. Having the tank near the passenger compartment would allow it to dump heat onto the driver (and his kids if they are in back)." Anyone noticed any extra heat in the '72s? Did PAG do any extra insulation there?

BTW, I'm not convinced about the importance of the radiant heat exchange you note. Maybe it adds significantly to the heat load fromoil circulation -- dunno w/o measuring. Or it could be calculated with the temp.s of both engine parts and tank, and the view factors....

[Tyson Schmidt]

Well then Randy, don't do it. I'd rather my car stay as unique as possible.

On Jack's car, withe the old '73 chassis, the suction hose ran dangerously close to the B&B headers. I had to build a heat shield to keep from cooking it. The headers were basically pre-heating the oil right before it went into the engine. The '72 chassis with it's forward tank eliminated this problem.

All you need to do to fully appreciate the benefits, is to stand near the back of a running 911 after a few laps on the track, and then just take a few steps forward to where the '72 oil tank is. It's a huge difference. I've actually burned the tops of my feet from standing right near where the '73 oil tank is while wearing sandals. Up ahead of the rear wheel, it's cool as a cucumber.

Sure it probably puts a little more heat into the cabin, but Porsche did it on their street cars in '72, and back then, very rich and persnickety people bought these cars. Porsche deemed it acceptable. I haven't noticed any difference between my car and other non-'72 cars. Besides, have you ever felt how much heat is coming up through the bottom of the rear seats from the engine/trans? If you remove the insulation, it can get mighty hot. I think that's a bigger contributor than the '72 oil tank.

[Randy Webb]

"huge difference" -- Tyson that's a pretty crude way to estimate handling changes. Have you drive a 72 and 73 back to back and have any subjective comparisons?

[Speedster94]

we put one a few years ago in a 88 Coupe , if i recall it right we had a 993 Tank ,but used a 964 Tank instead because of the different Bottom-
outlets ( Thermostat ) . The Wheel is rotating air to and from the Tank
helping to cool it . And every pound of weight not behind the Rearaxle helps .
harald

[Bill Verburg]

Here's a carbon 964 tank


A complete 993 system


and a plain 993 tank

[Tyson Schmidt]

Originally posted by Randy Webb
"huge difference" -- Tyson that's a pretty crude way to estimate handling changes. Have you drive a 72 and 73 back to back and have any subjective comparisons?

I'm talking heat Randy, not handling.

[304065]

Bill, those photos are droolworthy. I gotta get to a GT class. . . this "keep it like it left the factory" stuff is inhibiting my creativity. . . but then again, controlling costs pretty well!

Why would you want to relocate the oil tank on a street car? I ask the same question of the factory mechanics, calling out to them through the mists of time, "Warum?" Remember in those days, they had just gone to dual batteries, long wheelbase, cast-iron weights in the front bumper, and Ralph Nader was decrying the Corvair. Maybe when they went to the heavier 915 box they decided to move some weight forward? Anyway, I submit that it would be hard to notice the difference on the street.

No question of the value of a relocated tank though, witness the 911R. I like Tyson's point about the heat.

Couldn't you use factory hardlines along the rockers? FYI my 911E has two -16AN lines run inside firebraid along the passenger's footwell and I would rather have them there than outboard. The ultimate solution is to do what Gunnar Racing did to their RATT-RSR- run an aluminum tube fore and aft.

[Bill Verburg]

Why would you want to relocate the oil tank on a street car?

You wouldn't, the only car I have seen this done to was a dedicated track car.

[Guy Chiattello]

Bill Verburg and Jack Olsen

Here is a reason to consider moving the oil tank on an SC in front of passanger side rear wheel. If you were considering a twin turbo installation, you could use the rear wheel wells for intercooler installation, especially if you don't want the turbo tail. Does that idea have any merit?

Guy Chiattello
83SC Black Coupe