weiand head

[burl]

So im looking at purchasing an old weiand head.Two of the spark plug holes have been repaired and changed to 14mm.The other two are either 16mm x 1.5 or 5/8 18.Anybody know what size there are supposed to be ?I would like to make all of the plug holes the same.Just checking to see if anybody has had to make this repair and what they did.weiand 1.jpg

[Jim Brierley]

Probably 18mm, a common size for aftermarket heads back in the day.

[Kurt in NJ]

I have a near new one, never been cut the compression ratio is stamped in 2 places, on the gasket surface by the water pump --- if it's gone the head has been cut, mine is originally 8.5, if you look close it is stamped on the top between #2 plug and center stud hole, the plugs are 14 mm

[burl]

Originally Posted by Kurt in NJ

I have a near new one, never been cut the compression ratio is stamped in 2 places, on the gasket surface by the water pump --- if it's gone the head has been cut, mine is originally 8.5

I don't think this one was cut as we checked it to another one just like it.The depth to the combustion chambers is exactly the same.For some reason the previous owner removed the weiand lettering,must not wanted anybody to know what they were running.Just trying to find out what the plug size should have been.The orginals are either 16mm or 5/8 fine,not sure what plugs would fit that.

[burl]

Originally Posted by Jim Brierley

Probably 18mm, a common size for aftermarket heads back in the day.

Jim,
already checked it with tap,seems like its 16mm or 5/8-18

[d.j. moordigian]

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I agree with what was written. Don't weld the plug holes,..do a "mechanical repair" and
please use anti-seize on the threads..

My head has 14mm plug holes. Does anyone know if the head is thick enough too put a
"quench area" above the piston so I can use stock pistons?

[Kurt in NJ]

If it wasn't cut the compression ratio is stamped on the underside of the water pump boss, I will probably go where the head is and take measurements

It does look thick inside to be able to add a piston relief

It was common back in the day to enlarge plug holes to the next larger plug, snap on sold a spark plug tap set with a enlargeing reamer along with tap,

[closedcab30]

want to purchase either a thomas head or other finned head suit model a motor , anything out there thanks ...310 340 5715

[d.j. moordigian]

Thanks Kurt..

[burl]

has anybody ever repaired the spark plug threads in a head ?Just wondering what was used and how it was done.I have been looking at the thread sert inserts instead of helicoils

[Y-Blockhead]

Originally Posted by burl

I don't think this one was cut as we checked it to another one just like it. Just trying to find out what the plug size should have been.

What is the plug size of the other head you are checking with?

Originally Posted by burl

Has anybody ever repaired the spark plug threads in a head ?Just wondering what was used and how it was done.I have been looking at the thread sert inserts instead of helicoils

Did a lot of Corvair heads in the past using heli-coils. No problems.

[burl]

Originally Posted by Y-Blockhead

What is the plug size of the other head you are checking with?



Did a lot of Corvair heads in the past using heli-coils. No problems.

The original plug looks like it was 16mm or 5/8 fine.Both threads are very close to the same.I couldn't find and plugs that fit that size so I was thinking about changing all of them to 14mm which is a pretty standard plug.

[Jim Brierley]

Burl, I have never heard of a 16mm plug, better check to see if they are available.

[Tom Wesenberg]

Originally Posted by Jim Brierley

Burl, I have never heard of a 16mm plug, better check to see if they are available.

X2

I wonder if it should be 18 MM, which used to be a common size.

[Chris Haynes]

Thread serts are far superior to heli coils.

[PC/SR]

Mine has 14mm plugs, two cylinders of which have heli coils. There is no relief in the head for pop-up stock pistons. You can shave 030 off the pistons. DO check block height, from the pan rail to the deck. It may have been shaved in the past and the pop up may be more than stock.

[Tod]

Funny, I had a plan to make a top like this for the Weiand crow's foot chamber I use with my Winfields.

Tod

[katy]

Here's some modern 16mm plugs, my son's F-150 uses them

https://www.summitracing.com/int/par...view/make/ford

[Kurt in NJ]

I was thinking, perhaps it is 16 mm because it was helicoiled, I have used helicoil taps for 2mm larger threads of the same pitch

[40 Deluxe]

Originally Posted by katy

Here's some modern 16mm plugs, my son's F-150 uses them

https://www.summitracing.com/int/par...view/make/ford

Those plugs will NEVER work in an A head, nor any head except that particular model Ford pickup 5.4 engine!!