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M16-1.25 or M16.4-1.33


Stinky

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On my '86 720...the oil plug stripped out on my oil change.  AND, it just happened to be my oil change at 200K.  So, I run down to Napa and they look it up.  They come up with a plug that is nothing like my old one.

 

The old plug, has raised letters M16-1.25.

 

The new plug has the letters m16.4-1.33.   I ain't never heared a dat and neither had the Napa boys.  But that looked at it several times in the computer and they swore that was the correct plug.

 

So, the new plug is slightly larger, and the threads are finer.

 

I screwed in, sorta.  It seems like it is cross-thread.....duh.  I got it all the way in.

 

What size is the correct plug?

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7 hours ago, Stinky said:

On my '86 720...the oil plug stripped out on my oil change.  AND, it just happened to be my oil change at 200K.  So, I run down to Napa and they look it up.  They come up with a plug that is nothing like my old one.

 

The old plug, has raised letters M16-1.25.

 

The new plug has the letters m16.4-1.33.   I ain't never heared a dat and neither had the Napa boys.  But that looked at it several times in the computer and they swore that was the correct plug.

 

So, the new plug is slightly larger, and the threads are finer.

 

I screwed in, sorta.  It seems like it is cross-thread.....duh.  I got it all the way in.

 

What size is the correct plug?

I am pretty sure datsun used the m16.4-1.33, that's the thread size for my 521.. so it should be right if that's what they say for that year...

A little poking around makes it seem like nissan started using the m16-1.25 at some point... not sure when...

 

If the new one screwed in my guess is you corrected the threads.... 

If it was truly a m16x1.25 the m16.4 being larger diameter would not have screwed it.... the thread pitch is only .005 different... 

 

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Also a helicoil might not be the best fix for this.... 

You would have to retread the hole anyhow....

Probably be best to go up a size to m18x1.5.... this requires a 16.5 drill so it will remove the old threads and then rethread the hole to m18x1.5...

 

https://www.ebay.com/itm/311436820154?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=_9GOGMlUSya&sssrc=2349624&ssuid=2B08jY5FRkS&var=&widget_ver=artemis&media=COPY

 

 Screenshot_20221201-081827_eBay.thumb.jpg.9cca1d7fa114357abe29925200e55869.jpg

 

 

https://www.ebay.com/itm/225213778798?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=FZwfDofqThi&sssrc=2349624&ssuid=2B08jY5FRkS&var=&widget_ver=artemis&media=COPY

Screenshot_20221201-081912_eBay.thumb.jpg.07a1bbc4ca7c3e4b2a9075169fa93d19.jpg

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Skib, I think that is the technical term for the issue....at first, I only thought that it was messed up.

 

I looked at rockauto.....

 

It is NOT 16-1.25.

 

M16.4-1.33 was used, according to their cross-over, from 1971 to 1986 D21.  They list pretty much everything made, 1200, 210, 310, 510, 620, 720., and more.  AND, Peugot, Volvo, Mercedes, Jeep, and others.

 

Now, how long is this gonna last.  I sorta like the M18 route.  Next time I drain the oil, I'll get under there and take a good look at the threads on the hole.

 

Where can I get a bung?

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Do not know how this would work here, buttttttttt the last honda I got at auction had a stripped bung hole.  The pan is magnesium and its quite a job to do as the "pan" is not just the bottom and lots of bs gotta be moved.  I used a single oversize piggyback drain.  I have never used one before.  I drained my oil, ran the insert in, backed it out and dumped the old oil back in to hopefully flush any cuttings out.  I then had the luxury of letting it drain all the way out for a week.   I then  roughened up the pan around the drain and put the piggyback back in.  It then got a healthy coat of jb weld.  Let it set a week.  Has not leaked since.  But in full disclosure, I filled the sumbitch up after this "repair" and a couple others, only to be rewarded with a bad seam on the fuel tank.  So, I have only put 100 miles on it.  

 

https://autofastenersandclips.com/collections/drain-plug-bolts-and-gaskets/products/auveco-11782-1-2-20-single-oversize-piggy-back-drain-plug?variant=19613939207

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9 hours ago, Crashtd420 said:

Even with the timsert the oil pan would need to be drilled out and rethreaded... and a possibility of leaking past the outer threads of the timsert.....

 

 

 

Naw, these work. Lock tight keeps em’ sealed. I suppose it’s possible though. Used for this application many times. 

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1 hour ago, Stinky said:

Skib, I think that is the technical term for the issue....at first, I only thought that it was messed up.

 

I looked at rockauto.....

 

It is NOT 16-1.25.

 

M16.4-1.33 was used, according to their cross-over, from 1971 to 1986 D21.  They list pretty much everything made, 1200, 210, 310, 510, 620, 720., and more.  AND, Peugot, Volvo, Mercedes, Jeep, and others.

 

Now, how long is this gonna last.  I sorta like the M18 route.  Next time I drain the oil, I'll get under there and take a good look at the threads on the hole.

 

Where can I get a bung?

 

11128-69200 is the part number and it goes farther back than that to the '62 Patrol and also includes the 520/521, SP/SR 311 (Roadster) and all 510s.

 

In the 720 and the '86.5-'89 D21 Hardbody it was only used in the 2wd Z24 and Z24i. 4x4 got a different plug 11128-01M00 used in '82- FWD 310, Pulsar, Sentra, Stanza, KA and VG D21s, 300zx, S12s CA andd VG engines and pretty much everything up from here

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