Milwaukee-Eight™(M8) Loose Valve Seats - Part 2
25.7 هزار بار بازدید -
7 سال پیش
-
This is a follow-up regarding
This is a follow-up regarding the Milwaukee-Eight™ (M8) Valve Seat issue. We had a lot of good comments and we wanted to go through what we did before we decided to post this notice.
We noticed the problem on our big bore kits when we were putting the heads back on with new rings - we make it a standard practice to put the head on torque and leak the motor down. To make sure that we have no issues. That’s when we saw the 25-28% leak down. Please note - this was NOT going past the rings. It was past the valve and the valve seats.
GMS Racing helped us identify a means to pressurize the port from the outside so we can show you the leak down. It was a great idea.
You will note that the leak down is not going past the valve seat. It’s between the head and the seat itself.
The whole issue is not a machining issue - it’s when the seats are being installed. When the seats are pressed in or, knocked in - it cocks and takes the material and scores the bore to the bottom of the seat hole. Material is built up under the seat area.
When we measure our press fit using a micrometer, we’re seeing .0025”-.0030” of variation in the O.D. of the seat and that material ends up at the bottom. That’s what cocks the seat and allows for it to leak underneath. So the seat does not have a complete press all the way around it. That’s why we’re seeing this issue.
We just wanted to share the effort that we went through to prove the issue. This was not a single head issue, it was repetitive so we wanted to make you aware of it.
If you have any questions - contact us at 336-993-7068 or, visit us online at https://tmanperformance.com/
We noticed the problem on our big bore kits when we were putting the heads back on with new rings - we make it a standard practice to put the head on torque and leak the motor down. To make sure that we have no issues. That’s when we saw the 25-28% leak down. Please note - this was NOT going past the rings. It was past the valve and the valve seats.
GMS Racing helped us identify a means to pressurize the port from the outside so we can show you the leak down. It was a great idea.
You will note that the leak down is not going past the valve seat. It’s between the head and the seat itself.
The whole issue is not a machining issue - it’s when the seats are being installed. When the seats are pressed in or, knocked in - it cocks and takes the material and scores the bore to the bottom of the seat hole. Material is built up under the seat area.
When we measure our press fit using a micrometer, we’re seeing .0025”-.0030” of variation in the O.D. of the seat and that material ends up at the bottom. That’s what cocks the seat and allows for it to leak underneath. So the seat does not have a complete press all the way around it. That’s why we’re seeing this issue.
We just wanted to share the effort that we went through to prove the issue. This was not a single head issue, it was repetitive so we wanted to make you aware of it.
If you have any questions - contact us at 336-993-7068 or, visit us online at https://tmanperformance.com/
7 سال پیش
در تاریخ 1396/10/15 منتشر شده
است.
25,777
بـار بازدید شده