oil gallery

[djburton]

I'm prepping a mirror 105 block that has all screw in plugs except the one in the distributor hole. I knocked the cup plug out for cleaning and would like to put a screw in plug in that location. The factory drilled the hole,stopping about 1/16 inch from the lifter bore,leaving a ridge with the ID of the gallery bore. If I run a tap in there it will surely mess up that ridge. Should I go ahead and tap it as is,drill the hole all the way through with a 7/16 drill and tap...or leave it as is and stick another plug back in. It's a nice standard block and I don't want to screw it up.
Thanks!

[Rory428]

Personally, I usually leave that plug behind the distributor, a press in cup plug. Considering the challenge of tapping that hole correctly, without going in too deep and having the pipe plug protrude into the front lifter bore, or not deep enough , and it interferes with the distributor body, not to mention it is at the end of the lifter feed passage, so the oil pressure is likely lower there, I feel any potential benefit is outweighed by the potential problems. I can say that I have never had a properly installed cup plug in that location ever leak or fall out, in close to 50 years of playing with FEs.

[blykins]

I'm prepping a mirror 105 block that has all screw in plugs except the one in the distributor hole. I knocked the cup plug out for cleaning and would like to put a screw in plug in that location. The factory drilled the hole,stopping about 1/16 inch from the lifter bore,leaving a ridge with the ID of the gallery bore. If I run a tap in there it will surely mess up that ridge. Should I go ahead and tap it as is,drill the hole all the way through with a 7/16 drill and tap...or leave it as is and stick another plug back in. It's a nice standard block and I don't want to screw it up.
Thanks!

Don't worry about the ridge, just run a 7/16" drill through to the lifter bore, tap it 1/4 NPT, then come back with a lifter bore hone and clean up where the drill came through. 

[63ragtop]

What Brent said, I went to change out my distributor in my 428 ,pulled the old one out and looked down and saw the plug sitting there, they all get tapped after that.

[Tunnelwedge]

I find you have to thin the dist hole side of the plug as well as dress the lifter bore.
Some plugs are longer than others so that makes a difference also in the depth of threads.
It requires a deep cut thread, be patient.

[blykins]

A short Pioneer plug will do the trick without having to cut it/shorten it.  Tap until it will sit below flush and roll on.

[frnkeore]

The type of pipe plug that you will need, is called a "Dry Seal". Edit: The dry seal plugs, had a little different taper and that's why they don't go in as far.

In a critical area, you need to use a pipe plug thread gauge to be sure that the thread is deep enough but, as shallow as possible. The gauge has a flat on it, across 3 threads. When you reach those threads, the first is min, next is nominal and the last is max thread depth.

You may not need to drill all the way threw if, you use a pipe reamer. It tapers the hole the proper length for the thread.

[blykins]

The type of pipe plug that you will need, is called a "Dry Seal". Edit: The dry seal plugs, had a little different taper and that's why they don't go in as far.

In a critical area, you need to use a pipe plug thread gauge to be sure that the thread is deep enough but, as shallow as possible. The gauge has a flat on it, across 3 threads. When you reach those threads, the first is min, next is nominal and the last is max thread depth.

You may not need to drill all the way threw if, you use a pipe reamer. It tapers the hole the proper length for the thread.

You don't want a "Dry Seal" plug.  You want the plug to go in deeper in this area, not shallower.

Pioneer makes all kinds of different pipe plugs for engine scenarios.  Tall, short, drilled, etc.  The short Pioneer plug is the best choice here, don't have to cut them down, just tap the hole and screw them in.

[frnkeore]

Brent, you apparently don't know what a dry seal plug is.

Your short Pioneer plug, is most likely a a dry seal.

A pipe plug thread gauge will keep a lot of people out of trouble in tapping for pipe plugs.

[blykins]

Brent, you apparently don't know what a dry seal plug is.

Your short Pioneer plug, is most likely a a dry seal.

A pipe plug thread gauge will keep a lot of people out of trouble in tapping for pipe plugs.

They have different names, but I was going off of this description, that you typed in:

"The dry seal plugs, had a little different taper and that's why they don't go in as far."

You want them to go in further, not go in as deep.

Could be that we're talking around each other.  Or maybe we're not.  I really don't care either way.

[pbf777]

The type of pipe plug that you will need, is called a "Dry Seal". Edit: The dry seal plugs, had a little different taper and that's why they don't go in as far.

     I may be wrong but as I recall the major difference between NPT vs. NPTF thread was at the root of the thread of the NPTF was of greater diameter (at any equivalent point in the length of thread) and flatter than that of the NPT thread, this to cause a crowding and displacement of material in crest/point the adjoining thread profile in the tightening this which provided a more effective "dry-sealing" characteristic.   

     Of coarse, one is "suppose" to use the proper corresponding tap for the intention, NPT  vs. NPTF.   

     Scott.

[galaxiex]

I can testify to going slow and careful when you tap that hole behind the dist.

I forgot to drill thru first, so the tap bound up and I snapped the tap off in the hole when I did my 428. 

I can tell you I was sweating getting the broken tap out!
Near impossible to drill a broken tap!
Very limited room to work!

I did get it out but I buggered up the hole so that I had to go up to the next size.

I got it done but it was not a fun time.    Lots of cussin' involved....


(read my sig)

[Tunnelwedge]

Some 1/4" pipe taps.
I like to use sharp ones.

[frnkeore]

By "The dry seal plugs, had a little different taper and that's why they don't go in as far." I was referring to the depth, not going so far.

Anyway you should use "Dry Seal" plugs for all gallery applications.

[Urgefor]

You may not need to drill all the way threw if, you use a pipe reamer. It tapers the hole the proper length for the thread.

I'll second that on using a reamer.  While not necessary in most instances with the stock FE blocks, it does make the job easier when tapping the holes.  Just goes "smoother".  I also found (with the holes by the lifter bores that get plugged or piped) that a reamer lets you know immediately if you are dealing with an overly large hole to begin with.