Shaving a stock head

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Model T Ford Forum: Forum 2016: Shaving a stock head
Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Laughary on Thursday, July 28, 2016 - 12:28 pm:

How much can be safely "shaved" from a stock head? My Z head is a noticeable improvement but is only 5.x/1

Can 8/1 be safely achieved from shaving a stock head, or even from shaving a Z head?

Also, can the rest of the engine & driveline handle the extra compression and power?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Laughary on Thursday, July 28, 2016 - 01:05 pm:

http://www.mtfca.com/discus/messages/179374/197671.html?1300281780


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Thursday, July 28, 2016 - 01:06 pm:

Just about 1/8" can be shaved off a stock head, but beware, some castings don't have the thickness in the water jacket to do much shaving.



Have shaved a stock head .050" safely, and took off another .050 from the block too. But the 'Z' head gave better results.

Also, too much shaved off the head may compromise the pistons striking too. Pistons pop up over the block surface.




Top of pagePrevious messageNext messageBottom of page Link to this message  By Andre Valkenaers on Thursday, July 28, 2016 - 01:09 pm:

Chris,

In the past, when I was making engines for rally cars, I used paste that I put in the cylinder head and mounted it back to the cylinder . Turned the piston to it's TDC. Take off the head and I could see the thickness of the paste between the head and the piston. This give me an idea of how much I could shave off the head.

This said, I wonder if you could come to 8/1 in compression and I doubt the driveline can stand the more in stress. You will need to rebuild the engine with pressure oiling and all the stuff that go with it.

Do not forget to make good brakes on your car. Going fast everybody can do it but going fast safely that is an other story.

Just keep it safe and simple.

Andre
Belgium


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Thursday, July 28, 2016 - 01:11 pm:

The T deck is already only marginally thick enough to get good gasket sealing
The stock T bottom end is only good for a limited amount of HP gain


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Laughary on Thursday, July 28, 2016 - 01:29 pm:

Thank You

That looks like one of those 2-piece heads to use with a 2-piece crank on a Model T that split in half from braking with the Reverse pedal! Ha


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary Schreiber- Santa Isabel Ecuador on Thursday, July 28, 2016 - 01:30 pm:

You're new to T's and your T is new to you. I don't think I've read where you know for sure what your driveline is like so I'd start there before trying any HP gains aside from the bolt on head.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Laughary on Thursday, July 28, 2016 - 01:43 pm:

Thank You, Andre,

Lucky that we don't have to deal with interference valves on these flatheads.

I'm guessing someone here has the perfected formula for pump gas and splash oiling. Maybe the Z head already has the max squish ratio that the bottom end can handle reliably.

The 8/1 head offerred by vendors is rumored to be overrated and more like 6/1, but also prone to hot spots that cause preignition gremlins.

I hate chasing a wiring gremlin and I don't even know if a cylinder head hot spot leaves a mark. Maybe someone in this group knows.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Laughary on Thursday, July 28, 2016 - 01:49 pm:

Thanks, Gary! Yes, so far this is the only model T I've ever sat in. Hoping to find some other local enthusiasts soon. I agree that I must do the first things first.

This morning while looking up the stock head laying in my garage it occurred to me that I should go ahead and do whatever is best for it. I will media-blast and paint it myself, but I also want to visualize the future projects for it.

Our Saturday "Cars n Coffee" group has now grown to nearly a thousand members, but I'm the first T in the group.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Laughary on Thursday, July 28, 2016 - 01:51 pm:

Thank You, Les,

I have never milled block and won't do that to a rare T engine.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Friday, July 29, 2016 - 03:09 pm:

Chris - Not sure if this has been mentioned, but it should be noted that the increased performance from a "Z" head does not only come from the increased compression. Much of the increase in performance comes from the improved shape of the combustion chamber in the "Z" head. In other words, just milling a stock head to equal the compression to the compression in the "Z" head will not give you the same increase in performance as will a "Z" head,.....FWIW,.......harold


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Laughary on Friday, July 29, 2016 - 06:49 pm:

Thank You, Harold.
It sounds like I should just put my stock head on the shelf.


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