PO Chimped the Oil Drain Hole

[Targalid]

I went to change the oil for the first time yesterday so I could adjust the valves, install an auxiliary oil cooler and so on. Imagine my surprise when instead of a huge pull on the wrench, all it took was a small tug and the drain plug on the oil tank was finger loose! I cleaned the fine sludge from the drain plug and it looked fine. The drain plug was coated with a gray plastic which I assume is JB Weld. The drain looked OK until I installed the plug with new washer and it would not tighten. Apparently the drain threads are stripped enough that the drain plug will not tighten. What is the best fix? A forum search gave the following suggestions. Remove the tank, braze and retap the hole? Different drain plug that reaches farther into the hole? A different drain from Pelican? Part number: PEL-PP903144 Suggestions please for a drain repair that will not surprise dump 10 quarts of oil.

[dad911]

I'd remove the tank and bring it to a radiator/welding shop. They should have no problem welding on a new bung.

[John W.]

Would have been nice for the PO to mention this so you'd be prepared. I recall seeing some threads here about this problem so search a little. You're gonna have to remove the tank.

Good luck!

[Walt Fricke]

If you can braze - or even if, like me, you aren't very good at it - you can make a permanent repair using hardware store copper pipe fittings. All sorts of plugs fit these. I used an iron plug, and epoxyed a bar magnet into its interior cup.

Can't do it with the tank in the car, though. At least I certainly couldn't. I had to pressurize the tank some and apply soapy water around my brazing several times until I had filled in all the voids.

But 10 years later, it does the job.

[Targalid]

Well, so far, everyone agrees that I have to remove the tank. If that is the case then should I just braze the hole and retap it, do the Walt fix with copper fitting or use the Pelican drain valve since it involves removing the tank and heat, no matter which? Anyone ever used the turn the valve drain system from Pelican? Part number PEL-PP903144.

[JerryL]

I dont think you are going to be able to braze the existing fitting and retap it, I would buy a fitting either the replacement or as shown many brass fittings out there that would work.

On the drain valve, (not to piss anyone off) I think they are hokey, they do not flow like pulling the plug which is what I want when draining the oil. get it out of there quickly while hot and the dirt is in suspension.the fast flow will aid not getting "stuff" in the bottom of the tank.

Good luck

[Targalid]

Thanks Jerry. That's the kind of information I was looking for. I think Walt has the right idea. If a replacement fitting is placed lower than the tank, that gives the magnet a place to sequester any little bits that might come flowing through the oil lines, down and out of the way. Then, as you say, the debris can be flushed out at each oil change.

[Walt Fricke]

Well, I wasn't trying to make the magnet work better. Just to have about as good a setup as original.

While I like the idea of being able to open a valve without getting oil all over my hands, I've wondered if thos valves might not be more subject to accidental opening. Especially on a race car, so I have passed.

There is a fix which does not require removal of the tank. You can get a large self-tapping bolt, of some SAE size a bit larger than the stock metric plug, and screw that in there. It will hold a sealing washer tightly enough. At least for the first time. Someone gave me one of those, and I used it before biting the bullet. But eventually it will lose grip. Not a permanent solution.

[911pcars]

W/o confirming with the Pelican catalog, I believe it's a Fumoto Ball Valve they offer. I'm sure several thousand have been used in this application. It features a spring-loaded, over-center type release lever, and if so inclined, can be safety wired so it doesn't accidentally open of it's own accord. As for the flow volume, if the oil is at normal operating temperature, the tank will drain fine and carry contaminants out with it. However, if there are large chunks in the tank, you may have an issue.



Saves wear and tear on the threads too which you are now well aware of. And then there are cases where herculean strength and long extension pipes are no longer required to loosen the regular drain plug, or if the 10mm female hex is rounded and NG, then it's good luck along with more invasive procedures.

But there's no magnet in the Fumoto you say. In that case, cannibalize the neodymium magnet from a discarded, no-op hard drive now functioning as an elaborate paper weight. It's X times stronger and larger than the wimpy magnet embedded in the factory drain plug, then stick it onto the oil tank next to the drain hole. It's strong enough to capture and hold an errant connecting rod cap or cap pieces as is common in some cases. Got a second hard drive in similar condition? Attach the magnet to the oil filter canister.

Sherwood
(no affiliation)

[Jerome74911S]

Originally Posted by 911pcars

W/o confirming with the Pelican catalog, I believe it's a Fumoto Ball Valve they offer. I'm sure several thousand have been used in this application. It features a spring-loaded, over-center type release lever, and if so inclined, can be safety wired so it doesn't accidentally open of it's own accord. As for the flow volume, if the oil is at normal operating temperature, the tank will drain fine and carry contaminants out with it. However, if there are large chunks in the tank, you may have an issue.



Saves wear and tear on the threads too which you are now well aware of. And then there are cases where herculean strength and long extension pipes are no longer required to loosen the regular drain plug, or if the 10mm female hex is rounded and NG, then it's good luck along with more invasive procedures.

But there's no magnet in the Fumoto you say. In that case, cannibalize the neodymium magnet from a discarded, no-op hard drive now functioning as an elaborate paper weight. It's X times stronger and larger than the wimpy magnet embedded in the factory drain plug, then stick it onto the oil tank next to the drain hole. It's strong enough to capture and hold an errant connecting rod cap or cap pieces as is common in some cases. Got a second hard drive in similar condition? Attach the magnet to the oil filter canister.

Sherwood
(no affiliation)

To use one of these he still has to address the bad threads in the bottom of his tank.

[911pcars]

Originally Posted by Jerome74911S

To use one of these he still has to address the bad threads in the bottom of his tank.

Of course.

Address = repair = weld in a new bung (see Walt's pic) or drill/thread to next oversize, possible, then install a new drain plug or valve.

Sherwood

[Targalid]

I am torn with indecision! If I disconnect all the lines from the oil tank will I create more leaks in an attempt to repair the drain? Should I just get a longer bolt and make a quick fix so I can test my current repairs. Just screw in the old drain plug and live with the drip? I adjusted the valves for the first time since 1993, according to receipts I found in the glove box. The engine had been rebuilt, I am guessing, based on a receipt for connecting rod and piston balancing. I checked the head studs and they were tight. So the engine probably has case savers. That was a relief. I was expecting to find studs I could turn with my fingers. I have a nifty little oil cooler I want to test in this July weather. I don't want to have to take out the tank right now. Am I being stupid? Shortsighted?

[Kidasters]

Fix it once, fix it right.

I'd pull the whole tank and look for a good used tank, and just do a swap.

But that's me.

[dad911]

You decide. But if the drain comes out and you dump 13 qts on the side of the road, you risk blowing the engine, an oil spill, and a tow. Worth it? I don't think so.

It really shouldn't take more than a few hours to remove the tank and re-install.

[Jeff Burger]

don't know what year your car is but if 73-89 there are quite a few good used oil tanks around and run $75- 175

[Targalid]

Yes, you guys are right. I'll fix it. It sucks but I'll fix it. One reason I read this forum is because of the assembled wisdom. Thanks for the wise counsel. I'll post pics when I finish.

[andyt11]

I'd go with replace. But before you do that, is it possible to try and drill and tap the next larger thread and use a bigger plug? Or is it no practical?

Lots of ideas, a good used tank could be the most straight forward though.

PO was a little tight with the information here I think. I wouldn't be able to sell a car like that. Kind of wrong.

[john walker's workshop]

find another tank.

[Walt Fricke]

Be careful with used tanks. The used tank I bought turned out to have roughly the same problem mine had: the lower threads were stripped, and only by removing the sealing washer was the plug going to stay in. So I'd inquire carefully, and inspect if possible.

I caused my own problem with the original tank. Thing was always wet, so naturally I really twisted hard on the plug after each oil change, and in between also, tryng to stop the leak.

Turned out that one of the ears brazed to the tank up top, which hold the bolts that hold the tank to the chassis, had torn the tank's skin. Being up high, it wasn't a gusher. But track/autocross maneuvers sloshed oil up there. Not that that is your issue, but I'd wager that most of the problems with stripped threads here are due to us owners being ham handed. Not you, of course. You didn't have the chance.

I am doubtful that one can drill and tap to use a larger bolt. I don't think either a drill nor a tap that large reside in many toolboxes. On top of which the wall of the stock drain extension is not all that thick. And it is relatively soft brass material, which is why the threads stripped in the first place.

I think the only practical band-aid would be a longer plug, so you can catch the couple of decent threads high up, and still have room for a sealing crush washer. Or maybe a Dowty seal, which incorporates an O ring into the crush washer. But I don't know where you would get pieces of that diameter. Perhaps, by the time you get done sourcing parts you could have had a replacement tank in. Or had the fix I applied done for you by a shop.

[Evans, Marv]

I'll also go with Jeff, Andy & of course JW. Another tank won't cost much difference, it's right, and you avoid all of the jerry rigging.