Bringing the 914-4 back from mostly sitting for the past three years (under 1,000 miles in all that time), I forgot the oil drain plug was boogered up by a DAPO or oil change place...
Based on what came out, there were only a few shreds of thread somehow attached to the bottom of the drain plug hole, and a horribly mangled soft crush washer. Most of the "bore" is pretty smooth, with some original thread left at the top. Pic below.
My question is how to fix this. I see references to Heli-Coils, but somewhere I got the impression they need some thread left...? Whereas a Time-Sert or similar requires boring and fitting a thread insert.
How difficult is it to do this right with something like a Time-sert for a guy that reassembled some CV joints correctly on the *second* try? With the car up on jack stands in the back, so at an angle. And then what the heck do I use for a drain plug?
Thanks!
How about using an oversized drain plug from FLAPS? They are self tapping.
Really, self-tapping oil drain plugs? I honestly had no idea...
I did see a 2009 post ( http://www.914world.com/bbs2/index.php?showtopic=93648 ) that suggested using a pipe tap. Something like this: http://www.grainger.com/product/WIDIA-GTD-Sp-Flute-Pipe-Tap-2XTP3
If you can find a larger size drain plug from another model car, just retap the case to the bigger size. Might be better than a self tapping option.
Time-serts are dead simple to use and a very nice product. Either re-tapping or using a Time-sert seems like a fine idea. Use some grease on the tap to help capture the filings.
I used a time-sert on my 1.8 and never had an issue after that. Simple (but slightly nerve wracking) to do and they work excellent!
I notice that Time-Sert goes up to 24mm. So I reckon if normal tapping doesn't work, there's still a chance to try the other...
ADDED: Called EASY in Emeryville before I ran out to the store. Already forgotten the gent's name if he gave it, but he recommended the pipe thread tap approach. I asked about using a slightly larger drain plug from some other model, but he said it would be difficult to find a tap to match the thread pitch used, at least compared to hitting a decent hardware store for a pipe thread tap and matching plug.
FWIW my calipers tell me the diameter of the stripped hole is 13.65-13.75mm, and I've got ~8.8mm of depth before I hit the remaining original threads. An old 944 drain plug I have on hand is over 19mm - seems like a lot of material to remove, ignoring the question of a tap with the right thread pitch...
Clean it thoroughly, take it to a welder, weld it closed, drill it out, tap it.
As a cheap-ass, I would say tap it for pipe thread and buy a pipe plug to match. Both should be good and cheap at your local hardware or plumbing store, and effective as well.
I did the pipe plug on my dads vanagon, it worked just fine and was dirt cheap because I had the 3/8 NPT tap.
Timesert would cost over 100 bucks just for a tap kit that you would only ever use once. In this case I'd find a shop with the right tap and let them do it.
Both methods use grease on the tap to catch the shavings, go slow and clean the tap often.
I guess welding is an option, but only if the engine is apart.
BTW thanks to everybody for your replies, I really appreciate this.
I swear I have not been drinking tonight!
Crazy idea time....
Know any machinist?
Drill out threads will large Silver & DEming drill bit, use new plate that screws into the bottom of the motor. Sorry, not to scale, only had a few minutes to draw this up..time to go bed! I'll read all the negative comments in the AM, hahaha
I would think any regular bolt would work with a gasket washer. Just pick the right oversize, drill, and tap.
It was a bit of a pain finding a big enough tap wrench/handle for this tap but I finally got one today. Then I put on my big boy pants, gritted my teeth, prayed I wouldn't screw anything up, and tapped the oil drain. Used some old wheel bearing grease liberally applied to the tap to help collect the shavings. Test fit the plug, bored a little more, worried I might cross thread, but it all seemed good.
Plugged it, put in two quarts of some old generic Sunoco motor oil, and removed the plug - and some turnings that had collected on top of it. After that drained, refilled with some fresh oil and after a brisk ~10 mile drive tonight it seems okay. I'll check for a puddle in the morning. I'll replace oil & filter again in around a 1,000 miles just because.
I did apply blue thread locker to the last (outermost) threads of the plug for a little extra piece of mind.
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