Oil pan tap size?

KJ 119 · **Posted:** Fri Feb 27, 2009 7:26 pm

I'll be installing the Fumoto F-102 to an oil pan that will need to be tapped.Last oil change I was lucky to get the plug back in.
Does anyone know the size and threadcount of the pan?
Also I remember some used a different gasket???Copper mabe?Why and where can I find one?

Bub

warp2diesel · **Posted:** Fri Feb 27, 2009 8:55 pm

There are many right ways to skin a cat and the CRD Tech section discusses several options, some that I contributed.

Good Luck

kdlewis1975 · **Posted:** Fri Feb 27, 2009 9:30 pm

I was in a Murray's auto parts (owned by Advance Auto) and they had a variety of oil pan plugs and washers. They had a variety of washers of varying sizes and materials of composition include copper. You can get like 3 of them for $2. It may be as simple as that if you're looking for the gasket.

KJ 119 · **Posted:** Fri Feb 27, 2009 9:32 pm

warp2diesel wrote:

There are many right ways to skin a cat and the CRD Tech section discusses several options, some that I contributed.

Good Luck

Thanks warp2diesel
Now I'm confused

Guess I should think this one out a lil more.

Bub

Joe Romas · **Posted:** Sat Feb 28, 2009 8:18 am

Definetly rethink about what your doing here :shock:

Now you indicate you had trouble getting the plug back in last time right? That means the gasket may have been left off the previous change and the tapered shoulder on the plug that normally centers the washer buggered the first thread or two. This is a very common mistake :oops:

The problem is there's only 4 or so threads total :cry:

It it were me I would clean what's left with brake cleaner or the like and examine the threads. If they're mostly there I would use red lock-tite and install the correct fomoto valve with a washer.

Asking about thread size is reopening up a can of worms as it's close to several but there's only one "real deal"

LanduytG · **Joined:** Sun Dec 11, 2005 6:59 am **Posts:** 188

Thread is PF-3/8

Greg

KJ 119 · **Posted:** Sun Mar 15, 2009 9:26 pm

Joe Romas wrote:

Definetly rethink about what your doing here :shock:

Now you indicate you had trouble getting the plug back in last time right? That means the gasket may have been left off the previous change and the tapered shoulder on the plug that normally centers the washer buggered the first thread or two. This is a very common mistake :oops:

The problem is there's only 4 or so threads total :cry:

It it were me I would clean what's left with brake cleaner or the like and examine the threads. If they're mostly there I would use red lock-tite and install the correct fomoto valve with a washer.

Asking about thread size is reopening up a can of worms as it's close to several but there's only one "real deal"

Joe,you were right there was no washer on drainplug. :oops:

Greg,trying to find a PF 3/8 tap locally was impossible.Was told that the PF was a Japanese thread similar to British.?Wierd

Anyway just went for it,and installation was a sucess.Also used a copper washer instead of blue one.And ended up cutting the tip off with a bandsaw.Turning the valve to drain oil is just too cool.Not so happy with how low it hangs.
Will definitelybe upgrading to skid row skids soon.

Thanks to everyone for the advice.

danoid · **Posted:** Mon Mar 16, 2009 12:12 pm

The original thread specification on the plug is BS21 :1985 Appendix C: Special parallel external threads for gas appliances where pressure tight seals are made on machined faces.

The size is 3/8.

Complete specifications are 19 threads / 25.4 mm, basic major diameter 16.662 mm, basic pitch diameter 15.806 mm, basic minor diameter 14.950 mm, with a 55° included angle on threads.

I don't know if the pan thread is tapered or straight.

In the states, it doesn't really matter though, since you won't be able to get either tap.

warp2diesel · **Posted:** Mon Mar 16, 2009 12:31 pm

Re-tap it to 1/2" NPT after you drill it out to the proper size. Buy a Steel or Brass 1/2" NPT reducing bushing, bore the hole to the desired drain plug size and tap it to that size. Apply Loctite to the outside threads to seal it up.
I would go with 5/8" X 18 and use a copper washer.
If you want you can use 3/8" NPT plug and not have to bore and tap out the reducing bushing.

I have done both on aluminum alloy pans before and it works.

WolverineFW · **Posted:** Tue Mar 13, 2012 6:38 pm

danoid wrote:

The original thread specification on the plug is BS21 :1985 Appendix C: Special parallel external threads for gas appliances where pressure tight seals are made on machined faces.

The size is 3/8.

Complete specifications are 19 threads / 25.4 mm, basic major diameter 16.662 mm, basic pitch diameter 15.806 mm, basic minor diameter 14.950 mm, with a 55° included angle on threads.

I don't know if the pan thread is tapered or straight.

In the states, it doesn't really matter though, since you won't be able to get either tap.

Your clue to the straight or tapered answer is in the standard you quoted from above. Parallel threads. and seals are made on machined faces indicate a parallel or straight thread. Tapered threads seal on the threads themselves and in most cases require a thread sealant.

Oil pan tap size?

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