HP seat for MK5

[Diverspoint]

Hi there.

Today I opened up a MK5, and I saw a HP seat I had never seen before.

It was totally flat on both sides, and white. The reg did not leak, IP was about 135 PSI and stable, si I guess it fitted perfectly. I changed to a Trident seat, and then IP was stable at 125 PSI

Would anyone recognize this? Just curious

 

[runsongas]

the old style seats were that design like a hockey puck. the cone seats are a later iteration.

 

[melloyello]

What's the functional reason transitioning from puck to cone?

 

[Couv]

the old style seats were that design like a hockey puck. the cone seats are a later iteration.

Yes, just as ROG mentioned, the white, flat on both sides, seats were good in that they had a solid IP lockup. They lasted a long time, and could be flipped over. I think they were made of Teflon. However, SP went with a series of different colors and materials-some successful, some not. I think the cave cone shape came about in an attempt to improve airflow, and deal with an issue that may not necessarily have anything to do with a flat seat. That issue was a noise (more like a groan) some SP piston first stages were making. Unfortunately, this noise was not totally resolved with the cave cone seats and was/is probably more related to the friction between the piston stem and stem o-ring. There are other theories as to the source of the groan. One is simple harmonics of the stem as air passes through it causing it to vibrate like a didgeridoo.

Long story short-the white seats worked well and lasted a long time.

 

[Diverspoint]

Ok,now Ii know.

Any idea when the cone style came in?

 

[Couv]

The MK5/6/7/8/9/10 all used the same hp seat p/n 10-101-105. My first MK10 was purchased new in 1986 and had the white puck seat. The oldest diagram I have that shows the "cave cone seat" p/n 10-101-151 has a date 1988. Unfortunately, my collection of schematics is not complete, but from the above it would seem the seat change took place somewhere between 1986 and 1988.

BTW the seat in my original MK10 stayed in use until 2006 and was replaced just as a matter of service, not because I had any IP issues.

 

[Diverspoint]

Ok, thank you all.

This does mean that the MK5 probably has not had a service in a long time

But I got it fixed. I am now waiting for a retainer ring to get the MK5 DIN fixed

 

[axxel57]

I quite sure the MK10 came 1984 on the market and the new HP seats had also the little advantage that, depending which seat was used (+/-I/-II), one could raise or lower the IP.......