Forgotten.... What thread size are head studs into the block ?
 

As or title, I want to buy a cleaning tap for my block, what size threads are the studs again?

Cancel.... Got it it's 7/16 UNC

Richard, Try not to use a tap, unless you can get a well worn one.
Try grinding a groove in an old stud with your angle grinder, and use that. The least amount of "meat" you cut out, the better. It will be important to use a good thread seal anyhow, to prevent water running up the head studs.
As you know a slight relief will also help to transfer "load" out into the deck, as long as you are careful as the new studs will have a "bulge where they seat into the block deck.

Cheers for that Lynn. I have an old thread cleaning tap the correct size so I just used that to chase out the threads.... All appears good ! The studs will be given a dose of sealant when I dial them in for good !

Just on a tangent here, the water jackets on the flatheads, are they split per bank ? Reason I ask is there's only one water temp sender which would be a bit daft as the gauge would only be telling you half the story so to speak (if the jackets are seperated)

Rich

Yes the banks are independant, a sender in each head doesn't hurt. You'll see a spike that way. I'm geared up for two into one gauge.

Ben

That was my thoughts Ben, was not sure about two into one gauge but as you say the temp would spike and give you a heads up at least.

I like the spiral wire brushes as first step
 

Hi Richard

I like the 1/2 diameter spiral wire brushes in a drill at low speed to clean stud/bolt holes as a first step in cleaning threads. Soak the threads with the acetone and ATF over night or a couple of days then run the spiral wire brush in with the drill at slow speed when it bottoms reverse and run it out. I buy the cheap ones when I see them at flea markets.

Then as Lynn suggests use a worn tap of the correct size.

Which gets back to your original question what size? From time to time I have seen thread chaser sets which are intended for this purpose to clean but not really cut into the threads.

Cheers Phil

Here is a pic of how Henry set it up. One is variable and one is a switch.
(two terminal and one terminal, are wired in series)
I will also include a bit on the oil pressure sender. Be aware that there are two types of different resistance. you need the one to match your guage. The early one is harder to find. (I think the later one has "80" in a circle stamped on the face of the brass square.

That's great thanks Lynn, I have the oil sender which is getting tested this weekend (fingers crossed it works.... Bloody expensive they are !

I will try and trace down the second temp sender with the two posts on, I have the single post one in the head (again to be tested at the weekend)

50lb sender

80lb sender

Note that the 50lb sender MUST be used with a 50lb gauge, and the 80lb sender MUST be used with the 80lb gauge.

Is there anything on the back of the gauge to tell you ? I have not got mine to hand...

Thanks for the link Tony, the one I saw on eBay in the states was £80 mind zero bids were made on it.

Should probably re title the thread as "useful V8 info"

Oil Pressure 50lb versus 80lb
 

Correct me if I am wrong but the 50lb / 80lb pressure units go with their respective gauges , but also remember are there not two different types of oil pumps that can go in the sump , one high pressure and the lower pressure ones that the carriers use ( 50lb ). Macs auto in the States make repro sender units from ,I think Mexico , but these are for the 80lb units, so save your old low pressure units for reuse.