Author Topic: E/BGR Engine Build Thoughts  (Read 19941 times)

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Offline SPARKY

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Re: E/BGR Engine Build Thoughts
« Reply #45 on: February 04, 2015, 10:07:36 PM »
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Offline Saltfever

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Re: E/BGR Engine Build Thoughts
« Reply #46 on: February 10, 2015, 01:47:43 AM »
Thanks for the great post skip and the equally great thread that followed.

Adding mass to a piston crown above the pin pivot point is always a concern. By de-stroking the motor you are losing a lot of compression and you will want to get some of that back even if it is turboed. There is nothing you can do to the “B” head chambers. In fact there is very little you can do to any mod DOHC head CC because there is absolutely no room. Ford optimized valve size and position right from day 1. You can’t add weld material and you could never mill the surface to make up for the 0.25 de-stroke. So your only choice will be to add a very large mass to the piston crown. How much depends on the manufacturer and forging die. However, a nearly 50% increase in compression height along with increased mass, and maybe increased RPM, makes things seriously worse. I agree with others that cooling and strength are always priorities but you are introducing a new condition that only your piston manufacturer’s expertise will be able to answer.

It’s smart to take advantage of the inexpensive, widely available “B” head. 16 port head works fine with 8 injectors. It is a swirl flow design and the single injector is positioned over the predominant port. Even though both valves are the same diameter the ports flow differently and the short turn radii are different. Since the MMR manifold is fabricated, you could have an extra port welded at the same time in a more central position. You could go with a stock injector position first and then move it to a more central position. Or spend the money on flow bench work. Either way you are the test pilot and having fun!

Offline gasblender37

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Re: E/BGR Engine Build Thoughts
« Reply #47 on: February 11, 2015, 02:39:24 PM »
Thanks for the great post skip and the equally great thread that followed.

Adding mass to a piston crown above the pin pivot point is always a concern. By de-stroking the motor you are losing a lot of compression and you will want to get some of that back even if it is turboed. There is nothing you can do to the “B” head chambers. In fact there is very little you can do to any mod DOHC head CC because there is absolutely no room. Ford optimized valve size and position right from day 1. You can’t add weld material and you could never mill the surface to make up for the 0.25 de-stroke. So your only choice will be to add a very large mass to the piston crown. How much depends on the manufacturer and forging die. However, a nearly 50% increase in compression height along with increased mass, and maybe increased RPM, makes things seriously worse. I agree with others that cooling and strength are always priorities but you are introducing a new condition that only your piston manufacturer’s expertise will be able to answer.

It’s smart to take advantage of the inexpensive, widely available “B” head. 16 port head works fine with 8 injectors. It is a swirl flow design and the single injector is positioned over the predominant port. Even though both valves are the same diameter the ports flow differently and the short turn radii are different. Since the MMR manifold is fabricated, you could have an extra port welded at the same time in a more central position. You could go with a stock injector position first and then move it to a more central position. Or spend the money on flow bench work. Either way you are the test pilot and having fun!


Saltfever,

Thanks for the kind words. I never thought I would get all of these great comments from the members on this forum. It just shows what a great forum this is!!
Thanks again,

Skip
Skip

"Sometimes you get what you want and it is not what you expect."
"I reckon if this stuff was easy, everyone would be settin' records"