Thank god I'm not the only fool who bought that BMW cap. What a scam! Yes, it "locks", yes it "fits", just doesn't lock to the car.... Man.

However, I just pulled it out of it's hidey hole, and grapped a gas filler opening ring to understand how this looks and why it doesn't lock.. I may see a way to modify the ring so these caps actually lock.. Give me a day or two to fiddle....

At least you guys could get the cap onto the car. I bought a BMW 1600 gas cap, and it didn't fit.

The good thing is that it's easy to remove the ring and look at the fitment for locking purposes.

47 minutes ago, zKars said:

Thank god I'm not the only fool who bought that BMW cap. What a scam! Yes, it "locks", yes it "fits", just doesn't lock to the car.... Man.

However, I just pulled it out of it's hidey hole, and grapped a gas filler opening ring to understand how this looks and why it doesn't lock.. I may see a way to modify the ring so these caps actually lock.. Give me a day or two to fiddle....

 I was curious if anyone had modified the cap or ring. I don't have a locking cap to look at but I'm assuming the tab width on the cap is the problem. Looking forward to your mod.

 

Steve, yes the OD of the BMW cap as it fits in the ID of the filler ring is a very snug fit. Wouldn't take much of a tweak of the ring to make it too tight. 

As to the venting, I believe these caps are not vented. there is no obvious opening. Mind you, I can blow into the lock cylinder area, lips sealed around it (no comments....) and air comes out somewhere inside the cap. Can't tell if its through the locator or locking tab openings or between the inner and outer layer. Will have to do some testing.

 

18 minutes ago, zKars said:

Steve, yes the OD of the BMW cap as it fits in the ID of the filler ring is a very snug fit. Wouldn't take much of a tweak of the ring to make it too tight. 

As to the venting, I believe these caps are not vented. there is no obvious opening. Mind you, I can blow into the lock cylinder area, lips sealed around it (no comments....) and air comes out somewhere inside the cap. Can't tell if its through the locator or locking tab openings or between the inner and outer layer. Will have to do some testing.

 

Scene: Chevy Chase is on the phone as Don Pardo announces, "And now Weekend Update with Chevy Chase."

Chevy: "No...that's just what they call it...No, you don't actually blow on it." Looks up. "Uh, I've gotta go." Hangs up phone. "Our top story tonight..."

To Mark's post, here are pictures of the BMW cap and Z cap. About the only way for the BMW cap to latch would be to clamp down on the ring. You can see the possible range of motion on the BMW cap. Ideally for a locking cap would be for a block on the cap to slide to slot on the ring to keep the cap from turning.

 

 Thanks, I think I understand now. The ring needs a couple notches on the bottom side so the tabs can move up and down to lock and unlock the cap. Seems straightforward enough if you don't mind altering the orig ring.

 

OMG Steve, ROFL,  I'm just recovering now about the Chevy Chase scene... Oh my aching sides  I've learned my lesson with you guys for sure.

Ok, after staring at the ring and BMW cap for 10 minutes, the solution is really pretty simple.

You just need a stop block at the right spot. Pictures are worth 1176 words..

First weld in a scrap of metal, here. 

Put BMW cap in, twist to stop position, turn key to lock, lock tab now protruding and trapped behind welded in tab. 

A pic with the key in open position, free to turn CCW to unlock.

Had to use the rubber gasket from the stock cap, which is thicker. The tabs on the BMW cap are angled away from the body and will leave the cap loose if you don't have enough gasket thickness. Stock is about .012, BMW was only .08 ish

Another issue is the cap OD verses the ID of the mounting ring. Dang tight fit. I just did a little hammer tap tap around the inside to roll the lip just a smig and it slips in easy.

Ok who wants a modified mounting ring? Choice of powder coat, CAD plated, spray paint or sand blasted bare DIY.

Google leads you to all kinds of fun places

http://www.fillernecksupply.com/?gclid=CL-pvsGSt80CFQusaQodfioFiA

BTW, we have a 58 mm filler neck

Oh crap, never mind. That fillernecksupply thing is 58 OD.... Still, they have cool stuff.

I was trying to remember where I bought this thing, and it was MSA.

http://www.thezstore.com/page/TZS/PROD/50-2201

While its listed as no longer available (wonder why...), they do mention it is VENTING.

Just now, zKars said:

OMG Steve, ROFL,  I'm just recovering now about the Chevy Chase scene... Oh my aching sides  I've learned my lesson with you guys for sure.

Ok, after staring at the ring and BMW cap for 10 minutes, the solution is really pretty simple.

You just need a stop block at the right spot. Pictures are worth 1176 words..

First weld in a scrap of metal, here. 

Put BMW cap in, twist to stop position, turn key to lock, lock tab now protruding and trapped behind welded in tab. 

A pic with the key in open position, free to turn CCW to unlock.

Had to use the rubber gasket from the stock cap, which is thicker. The tabs on the BMW cap are angled away from the body and will leave the cap loose if you don't have enough gasket thickness. Stock is about .012, BMW was only .08 ish

Another issue is the cap OD verses the ID of the mounting ring. Dang tight fit. I just did a little hammer tap tap around the inside to roll the lip just a smig and it slips in easy.

Ok who wants a modified mounting ring? Choice of powder coat, CAD plated, spray paint or sand blasted bare DIY.

I do !!!   How much are you selling it for???   Whichever "coat" looks best with a Red Z.

Thanks for figuring it out!

Jai 

On June 4, 2016 at 0:54 PM, Powderkeg said:

Mark,

I had a locking gas cap from a 68-71 BMW 1600 that worked on the 76 280Z I use to have.

Partstrain.com has them for $28.00. The part number is: W0133-1621968.

Parts train shows a very different looking gas cap with that part number than the BMW cap are discussing?

4 minutes ago, Redwing said:

I do !!!   How much are you selling it for???   Whichever "coat" looks best with a Red Z.

Thanks for figuring it out!

Jai 

Oh yeah, the $$ thing. 

Maybe we should lock down a supplier of those locking BMW locking caps before we get too carried away.

I can paint and powder coat at home, have to take the ring in for plating. CAD plating looks best of course. Mind you the cap is chrome. Gas is likely to take off spray paint (except POR/Chassis Saver). Black or silver powder coat might be the best all round looker/performer.. Good thing I have nothing else to do today...