Flathead V8 Welch Plugs

[Bob Moseley (RIP)]

Hi all
Whilst happily working on my flathead the other day I was talking to another restorer mate who expressed surprise when I mentioned the Welch plugs located under the sump cover in the block. He was not aware of these. Probably most of you readers would be but these plugs are a real trap for new players. When water is found in the sump and the owner can’t find any Welch plugs in the block, they often assume its one or both of the head gaskets or something more devastating. BIG TIP – if you have your motor out, remove the sump and check and replace with brass ones. Whilst you are there it is also a good opportunity to check the oil pump.
Bob

[Bob Moseley (RIP)]

I believe this is common to the Canadian flatheads but maybe not others. Educate me please.
Bob

[Keith Webb]

It's timely - I was thinking of making one myself, having heard from John Belfield about the engine in his LP4 and another restorer with the same problem. The symptom is water in the oil, which may of course be from other troubles, but Bob's is good advice.
Looks like after 60 or so years these plugs are finally reaching their use by date.
What wonderful motors these flatheads are!

[Tony Smith]

Some people can't afford the cost of welch plugs! I've pulled one motor apart to find the hole filled with RTV Silastic, no doubt relying on the sump pan gasket and the sump to complete the seal! Gad, some people Perhaps this might have been a field fix that should have been fixed at a later time, but the repair kept working, so it was left.
Bob, as far as international variations go I've got 3 Canadian blitz motors, 1 English Generator motor and 1 US 1939 truck motor and ALL have these plug holes on the sump face. Interestingly, the American '39 motor had these holes threaded at some time in it's life and allen key plugs now seal the holes instead of welch plugs.
Below is a pic of the silastic block. After the Silastic was removed, there remains a plie of rusty crud in the bottom of the water jacket. This leads me to think that the threaded plugs are perhaps a good way to go, clean 'em out evey time!

[Keith Webb]

Recently I took the sump off a Mercury V8. Hidden by the sump gasket are four small (about 11/16" or 18mm) welsh plugs. The two towards the front of the engine weren't fitted so this seems not to be a serious problem to the previous rebuilder. The holes were full of gunk and quite deep and they seem to go into the water jacket.

Has anyone had any experience of this?

A source of supply for these dished plugs in Melbourne? Once you could get this sort of thing at Repco but no longer.

[Alex Blair (RIP)]

Originally Posted by Keith Webb

Recently I took the sump off a Mercury V8. Hidden by the sump gasket are four small (about 11/16" or 18mm) welsh plugs. The two towards the front of the engine weren't fitted so this seems not to be a serious problem to the previous rebuilder. The holes were full of gunk and quite deep and they seem to go into the water jacket.

Has anyone had any experience of this?

A source of supply for these dished plugs in Melbourne? Once you could get this sort of thing at Repco but no longer.

Keith ..
I don't know what welsh plugs are but they look like frost plug holes to me///.If the block freezes ..they pop out instead of you block cracking..very common in Canada..Can pick them up at Canadian tire the next time you are by..
Merry Christmas..
Alex

[T Creighton]

The holes all go into the water jacket Keith. Try to get some brass replacement plugs Ford part no. 741135 B ($10 at our local V8 shop)
Cheers Terry

[Bob Moseley (RIP)]

Hi Keefy - if I knew how to link this to your current enquiry I would. However this is the information I posted on these plugs back in 2004.

Bob

[Bob Moseley (RIP)]

Hi all - just some more information on the Welch Plug.

"A Welch Plug is a round hammer-in device that is tapped into the side of an Engine Block to fill a Casting Hole that was left there to allow air to escape during the casting process".

Brief History of the Welch Plug

by Nevin Hubbard of www.hubbardspring.com

A brief bit of totally obscure history that I am one of the few living persons who knows.

My family business, established in Pontiac, Michigan in 1905, is the original manufacturer of the "Welch" plug. The Welch brothers had a motor car company at the turn of the century that was later bought by General Motors - the Welch Motor Car company. They would run the cars around Pontiac to "break them in."

At that time core holes in the engine blocks were fitted with pipe plugs. During one of these run-ins a pipe plug backed out. In order to get back on the road one of the brothers drove a quarter or half dollar into the hole. From this they developed the Welch plug, some with the help of my Great Grandfather Martin Hubbard. They then patented the plug and the M.D. Hubbard Spring Company become the sole manufacturer of the Welch plug for the life of the patent. To this day we have the largest range of sizes available anywhere.

So the Welch plug in origin is an American innovation and name.

Best Regards,

Nevin Hubbard
M.D. Hubbard Spring Company
www.hubbardspring.com

Bob

[Lynn Eades]

Welch plugs, Core plugs, Frost plugs (Mr Frost must have been Welsh)Get with it Alex!!!

[sth65pac]

Hi Keith,

Three options:

try http://www.flatattackracing.com/
They are an Australian Company. In Victor Harbour (South Aus). You might need to email him.

Autopro are always pretty good with the small stuff. As long as you have teh Outside diameter you are halfway there (You can use the MAC's website for a reference size from their parts.....)

Otherwise an engine re-conditioner should have the size you require.

If you have no joy with any of the above, PM me & I will look into it after mid January when everyone recommences work.

Ian

[Tony Smith]

Until a Moderator takes Bob's "Hint, hint" and links This thread to this current one, may I suggest using threaded Allen Plugs? 3/4"UNC ought to do the job fine (Or should that be Coarse?).

Also, I don't think these can be regarded as "Frost plugs" as once the sump pan is secured in place, these plugs would have nowhere to go IF the coolant in the waterjackets did freeze over.

[sth65pac]

Tony,

Questions/clarification :

Are you saying you need to tap a thread into the hole and then fit a threaded plug? I presume you would have to use some red silicone sealant to provide a gas/watertight seal.

How long is the 3/4 UNC allen plug? 1/4"? Is it a standard length.

I have this task ahead of me in the next few weeks. My engine is 'resting' on the garage floor now.....

Ian

[Keith Webb]

...for all the suggestions and help. I measured 18mm but I think 3/4" would make sense. There is only a small lip in which to nest them which is why the originals are dished rather than cupped. It's interesting just the sump gasket managed to seal this in the past - but there was a lot of gunk built up in there.

Tony, have you tried the allen plugs? I would have thought they were too deep to fit.

[Bob Moseley (RIP)]

Thanks for your comment Tony. I cannot believe the lack of knowledge of such a basic engine componant, although I must admit I haven't heard of or seen an Allen Plug. Welch plugs are readily available but if possible try to obtain the brass ones as most originals were steel. They are simple to fit, merely place them in the hole in the block with the concave surface to the outside and then expand the plug using a hammer and a drift. A touch of gasket cement around the edge of the hole wouldn't go ammis either. In the meantime read my thread on these or get that thread linked.

Bob

[Keith Webb]

OK... I found Automotive Surplus in Mitcham was open and they keep a range of welch in stock. Interestingly they said they had sold some to somebody else recently who had the same situation - two were missing when the sump was removed.

3/4" is the correct size, thanks Tony.

So the sump is now back on... the next job is to attack the water pumps with a press. Has anyone had experience in pressing water pumps apart? I'm thinking a bit of heat on the pulley and impeller might not go astray.

[Keith Webb]

So far managed to break the casting on one pump. Might wait for someone more expert to have a go at it.

Here's a shot of the new welch plug.

[John Stokes]

Originally Posted by Keith Webb

So far managed to break the casting on one pump. Might wait for someone more expert to have a go at it.

Here's a shot of the new welch plug.

Hi Keith your welch plug looks like it is up side down ? Thanks for the parts i have nearly finished the transfer case ,shift tower and linkages hope it rains tomorrow so i can stay in the shed catch up soon. John Stokes

[Tony Smith]

As in the post mentioned/linked above, I mentioned in 2004 that one of the engines I have has had the holes TAPPED for Allen Plugs. I'm only guessing (not sitting here in front of me ) that they were UNC thread, they could have been NPT, but find what plugs you can and tap that thread to suit. There is more than sufficient metal in the threads to tap into, and part of the plugs protrude into the water jacket, but they dont get in the way of anything.

Ian, you wouldn't need to seal the thread so much from leakage, as the sump gasket and some RTV Silicone would cover it, but more so as a corrosion inhibitor/antiseize to allow you to take the plugs out easily as often as you want to clean out the crud in the bottom of your water jackets. I'd guess you'd use the same thread sealer (Loctite, etc) that you would use on those head studs that thread into the water jacket from the top.

[Keith Webb]

Originally Posted by John Stokes

Hi Keith your welch plug looks like it is up side down ? Thanks for the parts i have nearly finished the transfer case ,shift tower and linkages hope it rains tomorrow so i can stay in the shed catch up soon. John Stokes

Hi John
No, it's the right way up - it's dished, not cupped, so it goes in with the convex side up which is then hit with a hammer and drift so it spreads to fill the hole.
Tony... there were no threads, just a shoulder for it to be fitted.

[Bob Moseley (RIP)]

Hi Keefy - snigger, snigger, sorry. At least you managed to get the water pumps out of the block. A lot of people are not aware of the holding bolt that is accessed through the bottom outlet. These can be a real bugger as often the bolt head is corroded. Now if you need new pumps, Mike Davidson here has them. Alternately in the part's suppliers section of this forum I have posted prices for the rebuild kits.

Didn't your welch plug supplier have any brass ones?

BTW, don't you want to link my 2004 thread to this one?

Bob

[Keith Webb]

Originally Posted by Bob Moseley

Hi Keefy - snigger, snigger, sorry. At least you managed to get the water pumps out of the block. A lot of people are not aware of the holding bolt that is accessed through the bottom outlet. These can be a real bugger as often the bolt head is corroded. Now if you need new pumps, Mike Davidson here has them. Alternately in the part's suppliers section of this forum I have posted prices for the rebuild kits.

Didn't your welch plug supplier have any brass ones?

BTW, don't you want to link my 2004 thread to this one?

Bob

That bolt in the hole is SUCH a bad idea, although having said that I haven't yet been defeated by one. This engine came close though with a corroded head. I had to hammer on a metric socket which did the trick.

The supplier didn't have any brass ones, so I thought this was a better option than no-more-gaps

Yes, I'd like to merge the threads but I can't seem to make it work.

[Tony Smith]

Originally Posted by Keith Webb

Tony... there were no threads, just a shoulder for it to be fitted.

I realise that the hole isn't factory threaded, but noted that on one of the engines that I have somebody had gone to the effort of doing this and I thought that the idea had some merit. If anyone wanted to do this, they would have to tap the thread into their block by machining away the shoulder to give a longer bore to thread.

[Keith Webb]

Originally Posted by Tony Smith

I realise that the hole isn't factory threaded, but noted that on one of the engines that I have somebody had gone to the effort of doing this and I thought that the idea had some merit. If anyone wanted to do this, they would have to tap the thread into their block by machining away the shoulder to give a longer bore to thread.

You'd have to be keen wouldn't you!

Incidentally I've just installed the engine. Milestone!

[Hanno Spoelstra]

Originally Posted by Keith Webb

Yes, I'd like to merge the threads but I can't seem to make it work.

Done.

H.

[sth65pac]

I read this today....

From http://www.vanpeltsales.com/FH_web/f...mp-removal.htm

The Trick to Removing Those Pump Bolts

The Ford flathead V8 engines produced from 1932 to 1954 were designed with twin water pumps. From 1932 to early 1937 Ford's water pumps were mounted to the front of the cylinder heads (left and right). In 1937 Ford changed the design to create pumps that doubled as the front motor mounts. They bolt up to the lower front sides of the engine (left and right). There are several variations of this design, depending on the year vehicle and whether it was a truck or passenger car. Thus, the pumps could have the wide groove pulleys or the later narrow groove. Likewise, they could have a short snout or long snout. However, they still mount the same way.

Often, when tearing down a flathead V8 engine, the novice is not aware of the "hidden" bolt of the four that hold each pump to the engine. You can easily see the hex heads of the three other bolts, but the 4th bolt is actually located inside the pump's hose fitting. In order to see this bolt, one must remove the lower radiator hose from the pump, and look inside the casting. It is a 9/16" hex head bolt just like the other three.

An important suggestion....use a six sided socket on this bolt! Ford used regular steel bolts on the pumps. The one inside the hose fitting can possibly be corroded badly and slip in the socket wrench as you try to turn it. Don't use a 12 point socket as you will likely round off the corners of the bolt before it loosens.

Should the bolt head be so badly corroded that a wrench won't turn it at all, you will have to resort to more aggressive means to remove it. First, try using one of those bolt remover sockets. They have a hardened spiral inside that grips what is left of the bolt head to help turn it out (available from Sears and other automotive tool suppliers). Should that fail to grab and remove the bolt, it may mean a cutting torch, reaching inside the pump to melt away the head of the bolt. Another final way is to destroy the pump's lower casting (either by cutting torch or by cold chisel and hammer) to expose the bolt to whatever means you have to cut it off. This will ruin the pump and destroy its value for rebuilding or using as a core exchange for a rebuilt pump. However, if it's the only way to get the pump off, so be it.

Finally, when it comes time to rebuild the engine, and you are mounting your new or rebuilt pumps, take this precaution. First, use a stainless steel bolt in place of the regular steel bolt. Second, put a bit of thread sealer on the new bolt. You may not ever have to remove it, but someone, someday may need to, and you can help the process become easier by taking this step now.

So there you have it.. I am not quite at this point myself, but it's only a few days away...

What about pan gaskets??? Anyone know of a good source in Australia????

Ian