Exhaust Manifold Stud Size

[Rod]

Can anyone please confirm the size of the manifold studs. Am I correct in that they are 3/8 UNC? I had a look in my parts book and I think this is what I have deciphered. What length are they?

I can't seem to find any reference on Rares.

Many thanks.

Cheers

Rod

[Errol62]

You should find they are readily available at decent parts retailer, but maybe not supacheap. Hence rares don’t stock them. I know the red motor ones are 3/8 unc and grey no doubt the same. The new ones are longer than originals.


Sent from my iPad using Tapatalk

[Harv]

Haven't got one here to measure, but according to the MasterParts catalogue, the studs are 3/8-16UNCx1 9/16" (the corresponding bolts are 3/8-16UNCx1 1/8").

Cheers,
Harv

[Maco]

Harv, do you mean 3/8UNC X 1.5/8 long.
Cheers
John

[Harv]

Apologies - typo on my part. Yes, the bolts (not studs) are 1.5/8" (one and five eighths of an inch).

Cheers,
Harv

[Rod]

Thanks Lads for the reply.

Harv, I found reference to 3/8 - 16 UNC 1 9/16" for the studs into the head (outer two fixing points) and 3/8 - 16 UNC 1 1/8 for the manifold bolts into the head, in the Master Parts Catalogue. Bugger if I could find the studs that go into the manifold. The listing in the catalogue was a little confusing (3.275 - off the lising).

Anway all I needed confirmed really was the thread size. Now I need to take the plunge and remove the old worn studs. I have been soaking them with every known penetrate know to man for a couple of weeks.

Once again many thanks as usual for your input.

Cheers

Rod

[my8thholden]

Rod ..they will need heat , oxy always works , if not ,a gas torch ,and vice grips ….Vern

[Rod]

Hi Vern,

While I haven't got an oxy I have MAPP Gas and I am going to have a go using it. I have also got a stud remover tool which grips the stud much more (contact surface)than the vice grips. I just need to take the plunge. I am sick of broken bolts and having to remedy them. In addition to the Main Bolt saga I had, I had two of the four holt box bolts break. I welded nuts to them, etc... but still didn't work. I was then faced wilth drilling and retapping. I am getting good at it!

Cheers

Rod

[my8thholden]

hey Rod ..yep , hot box bolts will teach you to swear , Mapp gas and stud remover good way to go ,heat it up then let cool down , believe it or not ,we have some times initially turned the stud/bolt in the tightening direction ever so slightly and then,in the undo direction , when it moves back and forth , back and forth , with some oil and WD40 together , then should turn out ok ..if you have a problem you've got someone to blame ...Vern

[Rod]

Cheers Vern. I will give that a try. Do you think I should let things cool down naturally or shock it with cold? I have a can of Loctile Freeze at hand.

Oh I forgot another broken bolt / "screw" I need to attend to, bugger. This is a broken screw in the water pump which hold to plate onto the body. It never ends.

Cheers

Rod

[my8thholden]

Rod ..We don't apply anything to cool ,by cool I mean down from very hot to warm ,( museum workshop where I volunteer )we removed some exhaust manifold studs recently from a 1918 International Engine block ,plenty of thick cast iron ,we have been amazed at the condition of some of the bolts and studs in this old engine ,it really helps if the parent steel in a stud was originally good quality ,our guru of stud removal The Right Honurable John Hills heated the area around the stud with oxy ,not stud it self ,until just glowed dull red,left it few minutes ,then with Record brand multigrips,rocked it back and forth till first sign of movement ,apply some oil and WD40 together,back and forth to get that brew to work its way down thread ,then out they came ..then clean up the thread with tap ,we have new studs UNC ,all good ..totally different circumstance with water manifold studs on same block ,he wouldn't touch them , too much corrosion ,engine spent some of its life in water , he said stud would not come out ,the area where it is will just break out piece of the cast block ,don't want that ..we have not formulated final solution,as you can imagine in a group you have 10 suggestions..
Your water pump ,its one of the countersunk slotted screws that holds the spacer plate on to the body of the pump ,if its not a slotted screw then it may be a replacement and wrong thread ,its unusual for a screw that installed/removed with a screwdriver to break ,how ever as its a thru screw,set it up accurately and drill out ,should remove with easy out ,give a good soak with penetrant ,wouldn't be a need for heat ...cheers Vern .