Porting the 99/00 BP head
01-01-2013, 04:23 PM
#26
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Sorry for the threadjack but,
Would something like this kit from Eastwood get it done for a DIYer?
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01-01-2013, 04:56 PM
#27
can you please flow a stock port on that head, i never got to do it on my head and would like to know gains over factory, i would also like to compare my flow number vs yours, nice write up and looks real nice. i know what you mean about flow bench bores and actuators. our superflow was set up for v8's i had to make a dohc actuator and a 85mm bore stand
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01-02-2013, 10:14 AM
#28
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MT.net head porting for dummies?
Sorry for the threadjack but,
Would something like this kit from Eastwood get it done for a DIYer?
Sorry for the threadjack but,
Would something like this kit from Eastwood get it done for a DIYer?
can you please flow a stock port on that head, i never got to do it on my head and would like to know gains over factory, i would also like to compare my flow number vs yours, nice write up and looks real nice. i know what you mean about flow bench bores and actuators. our superflow was set up for v8's i had to make a dohc actuator and a 85mm bore stand
I have started to gather some of the parts for the stand.
Superflow is just a bit expensive on the stands they sell.
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01-02-2013, 11:09 AM
#30
You may have figured out, I don't have much hate in me. But yeah, removing the area of the port roof that supports the valve guide then cutting a significant portion of the guide away results in rapid valve guide wear. Not worth the flow gain IMO. I have seen over 230cfm at around .370 (BP6D intake) @ 28 hg on a skillfully ported head. That's about a 12% gain with stock cams. One can have their cake and eat it too.
Miata heads always die from valve seat wear and the OEM springs allow float at modest RPM. Why speed that process up? It makes as much sense as razor thin zillion angle valve seats that flow like mad and are toast in 20 hours.
I might cut away the valve guides for a Nationals grenade motor but not on an HPDE or DD build.
Miata heads always die from valve seat wear and the OEM springs allow float at modest RPM. Why speed that process up? It makes as much sense as razor thin zillion angle valve seats that flow like mad and are toast in 20 hours.
I might cut away the valve guides for a Nationals grenade motor but not on an HPDE or DD build.
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01-03-2013, 10:44 AM
#34
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Braineack... The port work looks good, and the guides touched at the end will have little effect on anything.
Emilio... I will agree, cutting the guides down is not the best thing to do on most heads.It does kill the support of the valve stem and wear will occure faster.
Most all the time I have seen excessive seat wear on a sinter metal or powder metal seat insert is from a valve job that did not control seat run out, and the valve had to pound the run out from the seat.
Emilio... I will agree, cutting the guides down is not the best thing to do on most heads.It does kill the support of the valve stem and wear will occure faster.
Most all the time I have seen excessive seat wear on a sinter metal or powder metal seat insert is from a valve job that did not control seat run out, and the valve had to pound the run out from the seat.
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01-14-2013, 04:16 PM
#36
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18psi.. it really comes down to the head.
But thos is the most common method.
https://www.miataturbo.net/engine-pe...er-head-64857/
Some times a guide will not just press out, then heat is used.
If heat does not work, then the guide will be "shelled out" That is a PITA, the guide is reamed paper thin, then chipped out.
But thos is the most common method.
https://www.miataturbo.net/engine-pe...er-head-64857/
Some times a guide will not just press out, then heat is used.
If heat does not work, then the guide will be "shelled out" That is a PITA, the guide is reamed paper thin, then chipped out.
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01-25-2013, 08:47 PM
#38
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Cleaning the combustion chambers.
BP combustion chamber porting.
The stock chamber.
Blue lay out dye has been applied.
A used HG is the template.
The main reason to do this is to remove the factory casting imperfections, along with removing potential hot spots.
Bevel the sharp edges.
Now the head is ready to be cleaned, and have the guides installed, and the valve job done.
The stock chamber.
Blue lay out dye has been applied.
A used HG is the template.
The main reason to do this is to remove the factory casting imperfections, along with removing potential hot spots.
Bevel the sharp edges.
Now the head is ready to be cleaned, and have the guides installed, and the valve job done.
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01-25-2013, 11:49 PM
#40
Is there a better than stock option for valve guides?
It seems head porting on BP motors doesn't make much more power. Is it worth the effort to take the guides out, port it, new (better?) guides, and reassemble. Plus the head rebuild while you're there. How much is 12% more flow help in a turbo car? Not doubting it wouldn't, but how much.
It seems head porting on BP motors doesn't make much more power. Is it worth the effort to take the guides out, port it, new (better?) guides, and reassemble. Plus the head rebuild while you're there. How much is 12% more flow help in a turbo car? Not doubting it wouldn't, but how much.
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