Model T head, how can I tell if a T head has been milled?

[Catbird]

I have a '26 with a Canadian engine. I pulled the head. I would like to have it milled.

I would like that! However if it is already milled, I be making a problem.

I carefully cleaned and there are no markings, stamping, that would indicate. Any other way to find out?

[Henry K. Lee]

Take a depth check measurement at the edge to the inside of the machined surface, What is the measurement?

Hank

[Joe Bell]

The best way to tell is the stamped letters that will be on them, if no letters then it has been milled.

[Mark Gregush]

Are you asking about wanting to get it milled to increase compression or just surfaced to make flat?
Not exactly what you are looking for, but food for thought;
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Top of pagePrevious messageNext messageBottom of page Link to this message By Roger Karlsson, southern Sweden on Tuesday, April 24, 2018 - 05:34 pm:

The drawing for the high head said 2 11/16 or 2.6875" as the distance between the block surface and the top of a head bolt boss. I've measured my seemingly unmilled high heads and they're all between 2.680" and 2.700", most of them around 2.680". That's as a guide if you want to check if your head has been milled before.

I've milled my aluminum Prus head 0.100" but since a high compression head is very close above the pistons, I had to mill the top of the pistons some too. I'm very pleased with the resulting performance from 5.8:1 in compression and I don't think I'd like it much higher in a hand cranked car with splash oil system.

[BobShirleyAtlantaTx]

Most any competent machine shop will not cut a head too far. Take it to your machine shop and let them work their Magic. Be sure to chaise the threads in the block, use Copper Coat if your reusing an old gasket and don’t exceed 55 lbs with a clean dry thread. And that 55 is my upper most limit With new bolts, I feel a lot safer at 50.

[StevenS]

Just as a side note, this is what I do. When you figure out or know the amount that the head has been milled off the head, please stamp the amount that has been milled for future reference. Like -0.125 somewhere meaty on the milled side of the head. That way you will not have to remember it and the next person who owns your car will know too when he removes the head.

[Allan]

Bill, the volume of the combustion chamber is reduced by very little in milling the head. If you want a marked improvement in power, one of the replacement alumimium heads is the better way to go.

Allan from down under.

[Susanne]

I noticed the same thing Joe Bell did - every unmolested head I've seen has a number stamped on the mating surface, the ones that have the number missing also have telltale swirls or lines from where it was shaved. I will say this is not all inclusive, but so far it seems to hold true.

You can always get an ultrasound thickness gauge, that way you KNOW how much steel is remaining at any point of your head... but be warned, it is pricey.