Head build-Modified
#1
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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/attachments/engine-performance-56/44295-head-build-modified-dscf6323.jpg?dateline=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/attachments/engine-performance-56/44296-head-build-modified-dscf6327.jpg?dateline=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/attachments/engine-performance-56/44297-head-build-modified-dscf6330.jpg?dateline=1337821131)
Did oil port Mod 1
![](https://www.miataturbo.net/attachments/engine-performance-56/44298-head-build-modified-dscf6331.jpg?dateline=1337821131)
The sharp edge of the combustion chamber was beveled down
![](https://www.miataturbo.net/attachments/engine-performance-56/44299-head-build-modified-dscf6332.jpg?dateline=1337821131)
A slight champher was done around the rest of the combustion chamber
![](https://www.miataturbo.net/attachments/engine-performance-56/44300-head-build-modified-dscf6335.jpg?dateline=1337821131)
The runners had some cast flashing removed
![](https://www.miataturbo.net/attachments/engine-performance-56/44301-head-build-modified-dscf6337.jpg?dateline=1337821131)
![](https://www.miataturbo.net/attachments/engine-performance-56/44302-head-build-modified-dscf6336.jpg?dateline=1337821131)
Now was time for the valve job, start with a basic 3 angle valve job
![](https://www.miataturbo.net/attachments/engine-performance-56/44303-head-build-modified-dscf6339.jpg?dateline=1337821131)
Checking seat placement on the valve.
![](https://www.miataturbo.net/attachments/engine-performance-56/44304-head-build-modified-dscf6344.jpg?dateline=1337821131)
Now I will do a throat cut.
![](https://www.miataturbo.net/attachments/engine-performance-56/44305-head-build-modified-dscf6345.jpg?dateline=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/attachments/engine-performance-56/44306-head-build-modified-dscf6348.jpg?dateline=1337821131)
This leaves a lip also
![](https://www.miataturbo.net/attachments/engine-performance-56/44307-head-build-modified-dscf6354.jpg?dateline=1337821131)
Now the lip needs remove and blended in.
![](https://www.miataturbo.net/attachments/engine-performance-56/44308-head-build-modified-dscf6357.jpg?dateline=1337821131)
The valves are ground.
![](https://www.miataturbo.net/attachments/engine-performance-56/44309-head-build-modified-dscf6371.jpg?dateline=1337821131)
Then lapped in and back cut
![](https://www.miataturbo.net/attachments/engine-performance-56/44310-head-build-modified-dscf6386.jpg?dateline=1337821131)
The head is CBN milled
![](https://www.miataturbo.net/attachments/engine-performance-56/44311-head-build-modified-dscf6358.jpg?dateline=1337821131)
First cut .003
![](https://www.miataturbo.net/attachments/engine-performance-56/44312-head-build-modified-dscf6362.jpg?dateline=1337821131)
Another .004
![](https://www.miataturbo.net/attachments/engine-performance-56/44313-head-build-modified-dscf6364.jpg?dateline=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/attachments/engine-performance-56/44314-head-build-modified-dscf6401.jpg?dateline=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/attachments/engine-performance-56/44315-head-build-modified-dscf6399.jpg?dateline=1337821131)
Then the stock spring pad and Vition blue stem seals.
![](https://www.miataturbo.net/attachments/engine-performance-56/44316-head-build-modified-dscf6400.jpg?dateline=1337821131)
Springs are then buckled up .
![](https://www.miataturbo.net/attachments/engine-performance-56/44317-head-build-modified-dscf6402.jpg?dateline=1337821131)
The head is now ready for HLAs, followers, and cams and cam caps.
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/attachments/engine-performance-56/44295-head-build-modified-dscf6323.jpg?dateline=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/attachments/engine-performance-56/44296-head-build-modified-dscf6327.jpg?dateline=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/attachments/engine-performance-56/44297-head-build-modified-dscf6330.jpg?dateline=1337821131)
Did oil port Mod 1
![](https://www.miataturbo.net/attachments/engine-performance-56/44298-head-build-modified-dscf6331.jpg?dateline=1337821131)
The sharp edge of the combustion chamber was beveled down
![](https://www.miataturbo.net/attachments/engine-performance-56/44299-head-build-modified-dscf6332.jpg?dateline=1337821131)
A slight champher was done around the rest of the combustion chamber
![](https://www.miataturbo.net/attachments/engine-performance-56/44300-head-build-modified-dscf6335.jpg?dateline=1337821131)
The runners had some cast flashing removed
![](https://www.miataturbo.net/attachments/engine-performance-56/44301-head-build-modified-dscf6337.jpg?dateline=1337821131)
![](https://www.miataturbo.net/attachments/engine-performance-56/44302-head-build-modified-dscf6336.jpg?dateline=1337821131)
Now was time for the valve job, start with a basic 3 angle valve job
![](https://www.miataturbo.net/attachments/engine-performance-56/44303-head-build-modified-dscf6339.jpg?dateline=1337821131)
Checking seat placement on the valve.
![](https://www.miataturbo.net/attachments/engine-performance-56/44304-head-build-modified-dscf6344.jpg?dateline=1337821131)
Now I will do a throat cut.
![](https://www.miataturbo.net/attachments/engine-performance-56/44305-head-build-modified-dscf6345.jpg?dateline=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/attachments/engine-performance-56/44306-head-build-modified-dscf6348.jpg?dateline=1337821131)
This leaves a lip also
![](https://www.miataturbo.net/attachments/engine-performance-56/44307-head-build-modified-dscf6354.jpg?dateline=1337821131)
Now the lip needs remove and blended in.
![](https://www.miataturbo.net/attachments/engine-performance-56/44308-head-build-modified-dscf6357.jpg?dateline=1337821131)
The valves are ground.
![](https://www.miataturbo.net/attachments/engine-performance-56/44309-head-build-modified-dscf6371.jpg?dateline=1337821131)
Then lapped in and back cut
![](https://www.miataturbo.net/attachments/engine-performance-56/44310-head-build-modified-dscf6386.jpg?dateline=1337821131)
The head is CBN milled
![](https://www.miataturbo.net/attachments/engine-performance-56/44311-head-build-modified-dscf6358.jpg?dateline=1337821131)
First cut .003
![](https://www.miataturbo.net/attachments/engine-performance-56/44312-head-build-modified-dscf6362.jpg?dateline=1337821131)
Another .004
![](https://www.miataturbo.net/attachments/engine-performance-56/44313-head-build-modified-dscf6364.jpg?dateline=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/attachments/engine-performance-56/44314-head-build-modified-dscf6401.jpg?dateline=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/attachments/engine-performance-56/44315-head-build-modified-dscf6399.jpg?dateline=1337821131)
Then the stock spring pad and Vition blue stem seals.
![](https://www.miataturbo.net/attachments/engine-performance-56/44316-head-build-modified-dscf6400.jpg?dateline=1337821131)
Springs are then buckled up .
![](https://www.miataturbo.net/attachments/engine-performance-56/44317-head-build-modified-dscf6402.jpg?dateline=1337821131)
The head is now ready for HLAs, followers, and cams and cam caps.
#2
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Thread Starter
iTrader: (1)
Join Date: Mar 2012
Location: Pensacola Fla.
Posts: 588
Total Cats: 203
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I will have to guess that if you are reading this thread, that you are looking to do something a little more than stock. ![wink](https://www.miataturbo.net/images/smilies/wink.gif)
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.
![wink](https://www.miataturbo.net/images/smilies/wink.gif)
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.
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