Porting the 99/00 BP head
12-28-2012, 01:00 PM
#1
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Porting the 99/00 BP head
This is the same head casting from this thread.
https://www.miataturbo.net/engine-pe...pection-70069/
The customer is building for boost, and wanted some porting done.
What the stock head looks like down the runners.
The tools used.
No! Fae... You can not use a sawzall for this!!
Setting the head to start on the roof of the runner.
A 50/50
Getting the roof and divider rough into shape.
The burrs were loading up with aluminum.
This happens with some heads, but not all.
I added some cutting fluid to the burr, I get a cleaner cut now.
Roughing the bowls into shape.
Smothing the bowls some
https://www.miataturbo.net/engine-pe...pection-70069/
The customer is building for boost, and wanted some porting done.
What the stock head looks like down the runners.
The tools used.
No! Fae... You can not use a sawzall for this!!
Setting the head to start on the roof of the runner.
A 50/50
Getting the roof and divider rough into shape.
The burrs were loading up with aluminum.
This happens with some heads, but not all.
I added some cutting fluid to the burr, I get a cleaner cut now.
Roughing the bowls into shape.
Smothing the bowls some
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12-28-2012, 02:03 PM
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Glad you are enjoying them!
I am a little better set up than the avarage home DIY'er for porting. 
You can Thank Aaron for handing me a better camera, and givin me a lesson on how to use it.!
<<<<---- Like the one in my avatar pic??? lol
Ill have to get a new base, and make an actuator.
The base I have is 4" one side and 4.250 on the other, doubfull I would get an accurate reading with it.
Ill look into Getting a proper sized base so I will be able to flow decently.
The cheap and easy would be mill the head to get the compression up.
Some bowl work would help, but the casting is so rough in the runners, they need smoothed too,
Welcome to the rabbit hole... care to fall in????
On a NA engine, I would not work the bowls as heavy, there is no need for it, but getting the velocity up would help.
You can Thank Aaron for handing me a better camera, and givin me a lesson on how to use it.!
<<<<---- Like the one in my avatar pic??? lol
Ill have to get a new base, and make an actuator.
The base I have is 4" one side and 4.250 on the other, doubfull I would get an accurate reading with it.
Ill look into Getting a proper sized base so I will be able to flow decently.
Some bowl work would help, but the casting is so rough in the runners, they need smoothed too,
Welcome to the rabbit hole... care to fall in????
On a NA engine, I would not work the bowls as heavy, there is no need for it, but getting the velocity up would help.
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12-28-2012, 02:21 PM
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<<<<---- Like the one in my avatar pic??? lol
Ill have to get a new base, and make an actuator.
The base I have is 4" one side and 4.250 on the other, doubfull I would get an accurate reading with it.
Ill look into Getting a proper sized base so I will be able to flow decently.
Ill have to get a new base, and make an actuator.
The base I have is 4" one side and 4.250 on the other, doubfull I would get an accurate reading with it.
Ill look into Getting a proper sized base so I will be able to flow decently.
I'm not sure I've ever seen anyone post back-to-back numbers for hand porting on a BP. Hopefully you can get your base together before you rip through all the ports.
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12-28-2012, 02:29 PM
#10
The tool used to create valve seat has a big guide that creates the big step in the bowl. Ever seen a K20 port. That is how a company that obsesses over specific engine output more that how it handles, does their heads. FWD + Superbike ports or race car suspension design + head design that needs to wear a helmet.
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12-28-2012, 02:32 PM
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The tool used to create valve seat has a big guide that creates the big step in the bowl. Ever seen a K20 port. That is how a company that obsesses over specific engine output more that how it handles, does their heads. FWD + Superbike ports or race car suspension design + head design that needs to wear a helmet.
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12-28-2012, 02:52 PM
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I doubt when the engineers that designed the head for the BP, even considered bolting a turbo to it, it was all about MPG.
Thats understandable, at a min, have the basic checks done on the head before you bolt it into place.
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12-28-2012, 02:57 PM
#13
the tool used to create valve seat has a big guide that creates the big step in the bowl. Ever seen a k20 port. That is how a company that obsesses over specific engine output more that how it handles, does their heads. Fwd + superbike ports or race car suspension design + head design that needs to wear a helmet.
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12-28-2012, 05:00 PM
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Well, my machinist won't buy a tap to make sure the threads are good on my spark-plug hole so he expect me to pay money for the rebuild (if the valves are bent), then diagnose the spark plug hole problem. I can't dump $700+ into new valvetrain into a bad core, so I'm not really sure what to do at this point. Maybe time to give up.
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12-28-2012, 05:05 PM
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Exhaust side
Looking down the exhaust runner, stock
Working the roof and divider of the runner.
Keep in mind the head is upside down.
Getting it rough in, and thinning the divider a little bit.
I can only port for about an hour or so at a time, keeping controll of the grinder is key.
Working the roof and divider of the runner.
Keep in mind the head is upside down.
Getting it rough in, and thinning the divider a little bit.
I can only port for about an hour or so at a time, keeping controll of the grinder is key.
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12-28-2012, 06:04 PM
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Well, my machinist won't buy a tap to make sure the threads are good on my spark-plug hole so he expect me to pay money for the rebuild (if the valves are bent), then diagnose the spark plug hole problem. I can't dump $700+ into new valvetrain into a bad core, so I'm not really sure what to do at this point. Maybe time to give up.
But not wanting to spend $25-$30 on a spark plug thread chaser????
Last tool on right
$700? That must be a full ST valve and spring kit w/Ti Retainers.
The machinist you are using must be too busy, or not intrested in doing your head build.
Then a porting kit with mandral and cartarage rolls is another $30-$60
On porting this head I have used 3 diffrent burrs.
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12-28-2012, 08:17 PM
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Exhaust bowls roughed in
Now the intake and exhaust runners and bowls are all roughed in.
Looks a bit ugly at this point.
Time to pretty it up a bit.
Getting the roof and divider smoothed out.
Now the bowl blended into the runner.
Now the intake and exhaust runners and bowls are all roughed in.Looks a bit ugly at this point.
Time to pretty it up a bit.
Getting the roof and divider smoothed out.
Now the bowl blended into the runner.
Last edited by BogusSVO; 12-29-2012 at 04:37 PM.
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12-29-2012, 07:08 AM
#20
I have no pictures from my portwork, but some flow numbers
No real need to work the exhaust much for a NA build, but going to three angle grind removed a vortex on the exhaust side and increased flow somewhat (words from my builder, I'm just learning to appreciate the knowledge).
I have numbers from my VVT head stock and worked.
The flow values are at 10" water, CFM wet air followed by dry air.
You can "convert" the number to 28" H2O (e.g. Airflow Conversion Table, a factor 1.67)
The flow values are at 10" water, CFM wet air followed by dry air.
Code:
Intake Port Original Intake ported 34.0mm 1.0mm 16.2 16.4 19.7 20.0 2.0mm 35.7 36.3 41.0 41.7 3.0mm 51.4 52.2 59.3 60.2 4.0mm 69.8 71.0 75.3 76.6 5.0mm 84.8 86.2 91.1 92.6 6.0mm 99.6 101.3 105.6 107.3 7.0mm 108.8 110.6 117.1 119.1 8.0mm 114.9 116.8 126.2 128.2 9.0mm 118.1 120.1 133.2 135.4 10.0mm 120.7 122.7 138.0 140.3 11.0mm 122.3 124.3 141.7 144.0 12.0mm 121.4 123.4 145.0 147.4 13.0mm 121.5 123.5 145.6 148.0 Exhaust Port Original Exhaust ported 1.0mm 12.5 12.7 12.5 12.7 2.0mm 27.0 27.5 29.3 29.8 3.0mm 44.3 45.0 48.0 48.8 4.0mm 60.5 61.5 65.1 66.2 5.0mm 77.8 79.1 82.5 83.9 6.0mm 89.8 91.2 92.2 93.8 7.0mm 95.9 97.5 98.0 99.7 8.0mm 99.1 100.7 102.8 104.5 9.0mm 100.9 102. 105.7 107.5 10.0mm 102.7 104.4 109.9 111.8 11.0mm 104.1 105.8 113.3 115.2 12.0mm 105.2 107.0 115.9 117.8 13.0mm 118.2 120.2
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