Head build-Modified
 

It helps if you have read "What happens to a head in a machine shop"

https://www.miataturbo.net/engine-performance-56/what-happens-head-machine-shop-66082/

That will cover the basics


Head Build – Modified



I am going to skip the tear down and tech, and start, a basic clean casting.
https://www.miataturbo.net/attachmen...ine=1337821131
The guides are good, and I am going to use the customer-supplied parts.

>Manley single springs, Spec sheet 66 lbs @ 1.580
>EPN-Engnbldr Std size Stainless Steel valves


This head was also Belt surfaced, So I have to do a corrective mill to square the head.


I set it up on the grinding bench
https://www.miataturbo.net/attachmen...ine=1337821131

I know this head will see turbo use.
I inked parts around the combustion chamber and etched with a head gasket.
https://www.miataturbo.net/attachmen...ine=1337821131

Did oil port Mod 1
https://www.miataturbo.net/attachmen...ine=1337821131


The sharp edge of the combustion chamber was beveled down
https://www.miataturbo.net/attachmen...ine=1337821131

A slight champher was done around the rest of the combustion chamber
https://www.miataturbo.net/attachmen...ine=1337821131

The runners had some cast flashing removed
https://www.miataturbo.net/attachmen...ine=1337821131

https://www.miataturbo.net/attachmen...ine=1337821131

Now was time for the valve job, start with a basic 3 angle valve job

https://www.miataturbo.net/attachmen...ine=1337821131

Checking seat placement on the valve.
https://www.miataturbo.net/attachmen...ine=1337821131

Now I will do a throat cut.
https://www.miataturbo.net/attachmen...ine=1337821131

Notice the difference this makes, See the lip under the seat insert with the rough casting, (left bowl)

The bowl on the right had the throat cut.
https://www.miataturbo.net/attachmen...ine=1337821131

This leaves a lip also
https://www.miataturbo.net/attachmen...ine=1337821131

Now the lip needs remove and blended in.
https://www.miataturbo.net/attachmen...ine=1337821131

The valves are ground.
https://www.miataturbo.net/attachmen...ine=1337821131

Then lapped in and back cut
https://www.miataturbo.net/attachmen...ine=1337821131

The head is CBN milled
https://www.miataturbo.net/attachmen...ine=1337821131

First cut .003
https://www.miataturbo.net/attachmen...ine=1337821131

Another .004

https://www.miataturbo.net/attachmen...ine=1337821131

I milled another .002 to finish square the head.

Had a bad exhaust stud hole, so a heli-coil fixed that.
https://www.miataturbo.net/attachmen...ine=1337821131


Valve tip height is checked,
The springs are checked
Spring installed height is measured.
Springs will be installed at 1.530 @ 80lbs

Shims are placed on the head.
https://www.miataturbo.net/attachmen...ine=1337821131

Then the stock spring pad and Vition blue stem seals.
https://www.miataturbo.net/attachmen...ine=1337821131

Springs are then buckled up .
https://www.miataturbo.net/attachmen...ine=1337821131

The head is now ready for HLAs, followers, and cams and cam caps.

I will have to guess that if you are reading this thread, that you are looking to do something a little more than stock. ;)

This is another good thread with links to 1.8BP heads ported by the pros.

https://www.miataturbo.net/showthrea...104#post881104

Good info in there that may help with a DIY head port job.

You are awesome. Do you have a website with rates? Or how would one have a motor built by yourself?

I like what I see. I'm not in the market this year.. but next spring I might just be.

Sorry, I do not have a website up (yet)

Check with your supporting vendors, thats why they are here!