MK5 HP Seat

[boat sju]

It may not be as bad as you think. Really kind of hard to tell what's what from the quick video. I spent about 20 minutes looking at it from different angles and what looks like a ding turns out to be bad lighting/glare from a different angle.

Of course now I'm going to spend another hour looking at it. So thanks for that rsingler
.
ugh. I think you're right

 

[Gonad]

Lots of flat inexpensive aftermarket seats around. They match the original flat Mk5 seat, which was discontinued after the cone seats were introduced.
But your flat seat isn't "wrong". Another possible cause of your IP creep is an imperfection in the knife edge. The cone seats are more forgiving of that.

Flat seats were original with the mk5

 

[Gonad]

Oof! Those are two large dings on the wrong side of the knife edge. Especially #2. That's a big restoration project, @James79 ! I'm guessing IP will go up 10-15 psi after you get to the bottom of those. Still, fun to see it work, given enough time and effort.
View attachment 705737
View attachment 705738

Polish the knife edge with a pencil eraser

 

[boat sju]

I just got the service kit yesterday but probably won't be able to get to it for a few days. @James79 is interested in trying to repair it, but him and @rsingler also got me wanting to try my hand at repairing it myself. The nicks are on the outside of the knife edge but don't seem to have compromised the actual edge. Like the damage occurred from me scuffing the piston even though I was using the protective bullet, maybe???? We'll see.

 

[boat sju]

The micromesh showed up in the mail yesterday:

A little higher than I was hoping for but . . .

 

[halocline]

If you've fixed the creep (that piston does look bad to me) and the IP is solid at 142 or so, you can either live with it or get a taller seat. Find a NOS scubapro kit for the MK5/10, they're all over the place, and it should come with three seats. One has a +, one has -, one has =, on the bottom. Use the =. It will be the tallest seat and it will lower the IP the most.

BTW, you can't flip the conical seats, it absolutely will not work. And the conical seats are much better for airflow anyways, and they tend to help with the occasional humming piston problem you see on these regs. It's about the aerodynamics when the piston just barely separates from the seat under demand. The conical seats allow for air to flow more smoothly across the piston edge.

 

[boat sju]

Find a NOS scubapro kit for the MK5/10, they're all over the place, and it should come with three seats. One has a +, one has -, one has =, on the bottom. Use the =. It will be the tallest seat and it will lower the IP the most.

Yeah, my kit wasn't NOS and only came with one seat. I'm tempted to shim the seat as an experiment.

The otoscope/endoscope I used for that video really didn't work very well. It was hard to tell if I was looking at cotton swab lint, fingernail scraping, or a piston nick. The glare from the LED's was terrible. @rsingler had some great resolution in his pics so I'd like to get an inexpensive microscope if anyone has a specific recommendation.

 

[boat sju]

So I bought an inexpensive "Plugable" 250x, 2 mp microscope. Here are a few pics showing the quality, in case anyone is considering purchasing one. The dog hair was for scale.

 

[James79]

So I bought an inexpensive "Plugable" 250x, 2 mp microscope. Here are a few pics showing the quality, in case anyone is considering purchasing one. The dog hair was for scale.

Link?

 

[boat sju]