Building a Mazda BP Head
If you have not read
99/00 1.8 BP Head inspection
Porting the 99/00 BP head
The porting work is done, the head has been cleaned again.
The bronze guides installed.
The guides have an unfinished ID, so the valves will not fit in the guide.
Time to get the guide hone out.
I use one of my pilots as a gauge to set the guide ID.
Hone until the pilot fully seats, I also check the top of the guide this way.
Now the head will be washed yet again.
Now the seats can be cut.
Now there is an issue…
Went to lap a valve in to check valve seat placement.
The valve did not seat. At all!
Here is the issue, the casting hump on the valve is hitting the guide.
The close tolerance of the bronze guide to valve stem was not figured to work with stock valves, Most all quality stainless steel valves will not have this casting hump.
So now to fix this issue, machine the valve, or machine the guide? Machining the guide seems simpler.
A slight taper in the bottom of the guide will do.
Now the valve fully seats, and I can check seat placement.
Now the seats are cut, each valve is hand lapped.
With the valve work done, the head can be surfaced.
A total of .007 was removed from the head.
Now the head is assembled, valve tip height is checked along with spring installed height.
Viton blue hi-temp valve stem seals were installed.
Along with the Brian Crower valve springs for testing on the BP head.
Stock valve spring retainers were used.
Buckets, shim pucks, and cams are installed to check valve lash.
It is a bit easier for me to set lash since I have extra pucks.
What is needed to check lash, feeler gauges and a sharpie
Lash is checked.
It is some simple math and measurements to get the lash set where needed.
Now the head is done!
Placed in a box and shipped back!