oil plug cross-threaded - best path forward?

[jtauxe]

Bad, bad news today.

For short version, scroll to the bottom of this post. Please advise if you have any insight.

I just removed the engine from a donor bus to use in the pickup. It has nice even compression, and seemed to be a good candidate.

After I removed it, I remembered to drain the oil. I set the 19-mm wrench on the plu, and it was typically snug. But -- the problem is, it was "snug" all the way out! OMG, I am thinking, did the PO actually cross-thread this thing?

The plug eventually came out, and the oil behind it. No copper washer... And the plug had shreds of aluminum on it. Damn.

I cleaned it up, and wanted to see if the plug would magically find the original threads again, but to no avail. It wants to use the horrible cross threads, and wants to be snug all the way in again. (I didn't run it in again, but got to the point where I could tell that is where it was going.)

short version:

So -- it looks like the oil drain tap is cross-threaded.

What do I do now? I see perhaps 3 options:

1. Try to force into its old thread, risking messing things up more.
2. Live with the cross threads, and hope the copper washer can take up the slack.
3. Refresh the original threads with a tap, risking getting shards into the case.

Thoughts?
_________________
John
"Travelling in a fried-out Kombi, on a hippie trail, head full of zombie..." - Colin Hay and Ron Strykert
http://vw.tauxe.net
1969 Transporter, 1971 Westfalia, 1976, 1977, 1976, 1977, 1971, 1973, 1977 Westfalias,
1979 Champagne Sunroof, 1974 Westfalia Automatic, 1979 Transporter, 1972 Sportsmobile, 1973 Transporter Wild Westerner, 1974 Westfalia parts bus, 1975 Mexican single cab *FOR SALE*, 1978 Irish 4-door double cab RHD

[SGKent]

Ouch. Any machine work you do carries risk of failure.

I would put heavy grease on a tap and try to retap it to the original threads. You can pull the inspection plate and feel if any shards are left in there I think. Then I would put the plug back in with the copper washer and some locktite teflon and see if it tightens correctly. If it does then I would find another way to drain my oil in the future because once damaged those threads are not going to withstand in and out continually. Most likely someone used an airwrench on it.

Edit: some folks suggest an oversize. I would not go that route until I first tried to rethread it. Old magnesium/aluminum can be brittle and you may find it hard to create clean threads if you drill it and oversize it.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[busdaddy]

It may be worth a trip to the FLAPS or the local Jiffy lube, there's a suprizingly large assortment of self tapping and even rubber plugs made for just your dilemma, seems those cavemen at JL strip plugs all the time
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[Amskeptic]

There are a couple of sizes before you are out of options. By all means try to tap the original size, you could luck out. Make sure the bolt has clean healthy threads. Do not fear torquing it to 15 ft/lbs. If it let's go, now is the time to find out about it. IIRC, the original is a 12, next size up is a 14?
Colin
_________________
www.itinerant-air-cooled.com

[Tvättbjörn]

Fast lube service station have self taping over-sized drain plugs. I would not go to 14mm before I´ve gone to the lube station and see what they have!

[toddgsanford]

you could install a helicoil fastenahl has a good selection of sizes or they can get them this is the forever fix and as your with gravity in your favor it is probably one of a few machining jobs you would want to tackle with an in the car engine. the self tapping ones are a band aid fix if your stuck in your mother in laws driveway and got to get the car moved. than can create bigger problems down the road like too big a hole or a large crack. I woudl use the wing nut rubber plug if you have to move it just my 2 cents worth of hard learned experience.

[encsdaddy]

A while a go in the featured ads I saw someone selling an oil plug with a buiit in valve for oil changes. once you installed it, you just had to flip a lever on it to drain your oil. This may be the way to go so you don't have to keep removing the oil plug. Just a suggestion, I haven't used it, so I have no idea how well they work.
_________________
77 Westy named Tiki - Daily Driver 80 miles a day!
(2.0L with hydro lifters)
78 Bus (8 seater w/ front bench) - Still trying to get it running! (fuel pump cuts out)
69 Sqauareback - RIP (Rear ended by a Volvo)
72 Bug - RIP (Rusted away!)

[MalibuLX3]

[jtauxe]

An update:

I finally got around to investigating this. I eased a tap in there, and it went in easily enough. Then I backed it out, and out came an insert with it! I had not noticed the insert in there. (Edited to add "not". D'oh!)

So, now I have a bolt (12mm x 1.50mm) and an insert, and a messed up hole. Darn.

I am scared to touch it. What do I do now?
_________________
John
"Travelling in a fried-out Kombi, on a hippie trail, head full of zombie..." - Colin Hay and Ron Strykert
http://vw.tauxe.net
1969 Transporter, 1971 Westfalia, 1976, 1977, 1976, 1977, 1971, 1973, 1977 Westfalias,
1979 Champagne Sunroof, 1974 Westfalia Automatic, 1979 Transporter, 1972 Sportsmobile, 1973 Transporter Wild Westerner, 1974 Westfalia parts bus, 1975 Mexican single cab *FOR SALE*, 1978 Irish 4-door double cab RHD

[SGKent]

is this the motor you are rebuilding or the daily driver?
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[jtauxe]

This motor is one I nabbed from another bus (a '77 Westy) because it had nice even compression, and aside from a noisy exhaust, it ran well.

It is going into my daily driver '78 double cab. The inferior engine from the pickup is going into the Westy. Both engines are GD.

After committing to this plan, I discovered the oil drain plug mess. At the moment, I am quite discouraged.

Should I attempt to reinstall the insert, or another one like it?
Should I tap the hole to 14 mm?
Should I cram it all together and just glom a bunch of JB Weld around it so that it will never be used again? (Just kidding.)
_________________
John
"Travelling in a fried-out Kombi, on a hippie trail, head full of zombie..." - Colin Hay and Ron Strykert
http://vw.tauxe.net
1969 Transporter, 1971 Westfalia, 1976, 1977, 1976, 1977, 1971, 1973, 1977 Westfalias,
1979 Champagne Sunroof, 1974 Westfalia Automatic, 1979 Transporter, 1972 Sportsmobile, 1973 Transporter Wild Westerner, 1974 Westfalia parts bus, 1975 Mexican single cab *FOR SALE*, 1978 Irish 4-door double cab RHD

[TGOT]

If the threads in the case where the insert came out of are good and only the internal threads of the insert are crossed I would find a matching insert and a new drain plug. That is kind of like the consolation prize you just found there, someone already did the scary part of fitting an insert for you.

[SGKent]

I would look at this two ways - temporary and permanent. You really can't do the best job of welding it up until the case is apart and cleaned first. That oil will taint the weld and if you turn it upside down you risk getting berries on the cam etc. But welding and an end mill is your permanent solution next time the case is split.

For now I would do like TGOT suggested and look for a similar size insert, use lots of locktite teflon sealant on it and get a bolt that the head can be drilled and safety wired. That way at least it can't back out. Or you can just look for a fine thread bolt or drain plug that is slightly larger than the hole, retap and use that until someday when you split the case.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[jtauxe]

[SGKent]

John - take a look at this website and see if you get any ideas. It looks to me for example that a stock Honda drain plug is 14mm. You might be able to figure what would fit and then find one at the local wrecking yard or dealer.

http://www.sherco-auto.com/drainlpluggasket.htm
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[jtauxe]

Wow - quite a variety of oil drain plug options, there.

It is interesting that of the 12-mm plugs, most have 1.75-mm threads, whereas the current one is 12 x 1.50. But, then going to 14-mm, most are 1.50, where the inserts I've seen are mostly 14 mm x 1.25. But, those are intended for spark plugs.

I have sourced some helicoil-type threads at 12 mm x 1.50 mm, and am going to attempt to make this work without sizing up, first. Wish me luck. My main worry now is making sure that the tang at the far end of the insert does not break off into the crankcase.

Edit: Mission accomplished. The previous threads for the insert cleaned out nicely, and match the new one. The tang came off after a good bit of abuse with some needlenose pliers (whew!) A new insert is now cemented in with JB Weld.
_________________
John
"Travelling in a fried-out Kombi, on a hippie trail, head full of zombie..." - Colin Hay and Ron Strykert
http://vw.tauxe.net
1969 Transporter, 1971 Westfalia, 1976, 1977, 1976, 1977, 1971, 1973, 1977 Westfalias,
1979 Champagne Sunroof, 1974 Westfalia Automatic, 1979 Transporter, 1972 Sportsmobile, 1973 Transporter Wild Westerner, 1974 Westfalia parts bus, 1975 Mexican single cab *FOR SALE*, 1978 Irish 4-door double cab RHD

[Westfabulous]