Speed Seal 'O' ring size

[meridian28]

The O ring is too small for me to get a measurement of the cross section. It's about as thin as heavy thread.


Has anyone had any luck?

[Jim Cate]

Originally Posted by meridian28

The O ring is too small for me to get a measurement of the cross section. It's about as thin as heavy thread.


Has anyone had any luck?

I've had the same problem, that is trying to source replacement o-rings since the demise of the company. I await a useful response!

Jim

[maine50]

Per another earlier post on another site--And hopefully others will appreciate too. I have a list of pump coverplate o-ring dimensions that I have gathered, not all Speedseal, many Johnson pumps had o-rings sealing the coverplate as standard. Any more, anyone?

Volvo Penta MD1 Speedseal Cover Plate = 1.5mm x 42mm ID nitrile

Vetus M3.10 Speedseal Cover Plate = 1.5mm X 51mm ID

Johnson pump F4B = 2.4mm X 49.6mm or 2.4mm X 54.6mm ID or 2.4mm X 59.6mm

Johnson pump F5B = 2.4mm X 57.6mm ID and 2.4mm X 59.6mm

Johnson pump F6B = 2.4mm X 57.6mm ID

Volvo Penta TAMD41P-a which is a Johnson pump F7B = 1.78mm X 63.22mm ID

Johnson pump F75B = 2.4mm X 64.6mm ID

Volvo Penta 2003B cover plate = 1mm x 40mm ID

Solo Coastal Sailing
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[Dsanduril]

Depends on which engine/pump. The original o-ring material was Nitrile-NBR 701RHD. The two I have referenced in the past (a Volvo and Vetus engine) both used 1.5mm cross-section o-rings, but I don't know about any others.

Easiest way is to measure the groove in the cover rather than trying to measure an o-ring. If you don't have the tools/calipers take the cover to a bearing shop and ask them to measure.

[dfelsent]

This ^^^^. Measure the groove width. Depth. And outside diameter. Outside because the inside is under pressure and the pump designer specified the groove by outside diameter and depth of groove. The depth gives you the squeeze that seals.
If you are inclined look up face seals in the Parker o-ring handbook. About page 4-19.
I used to design oring grooves and Parker is a great place to start. Their downfall is us vs metric in the handbook.
But for guessing the cross section, the groove width will be about or a bit bigger than the oring cross section diameter.
And the depth will be 70% to 80% of the cross section diameter. Diameter 1.25-1.4x groove depth.
This is really rough guidance. A place to start.
But static face seal oring grooves at room temperature for seawater are not difficult.
There are limited oring cross sections, metric and us standard. Should not be hard to guess the size.
And orings are inexpensive. A size up or down is not a lot of boat bucks.
If they are not cheap you are not shopping at an industrial supplier.

Oh yeah. Orings are often sold by cross section and id. But you can look up the od from the table that lists standard sizes. Try Marco Rubber for example.
You will see Inside and outside diameter and cross section listed and then a dash number. The dash number is sometimes how you order.
So a -134 oring is .103” cross section and 1.862” id per a chart. Add .206 to the id to get the od of 2.07”
I’d expect a groove depth of about .078” and an od of 2.07”.

[dfelsent]

Originally Posted by dfelsent

This ^^^^. Measure the groove width. Depth. And outside diameter. Outside because the inside is under pressure and the pump designer specified the groove by outside diameter and depth of groove. The depth gives you the squeeze that seals.
If you are inclined look up face seals in the Parker o-ring handbook. About page 4-19.
I used to design oring grooves and Parker is a great place to start. Their downfall is us vs metric in the handbook.
But for guessing the cross section, the groove width will be about or a bit bigger than the oring cross section diameter.
And the depth will be 70% to 80% of the cross section diameter. Diameter 1.25-1.4x groove depth.
This is really rough guidance. A place to start.
But static face seal oring grooves at room temperature for seawater are not difficult.
There are limited oring cross sections, metric and us standard. Should not be hard to guess the size.
And orings are inexpensive. A size up or down is not a lot of boat bucks.
If they are not cheap you are not shopping at an industrial supplier.

1 mm and 1.5 mm cross section. are metric orings.
1.78 and 2.62 and 3.53 mm are SAE or us sized orings. These correspond to .070”, .103, and .139”.

And pretty much every static seal is 70 durometer. That’s the squooshieness (highly technical term)of the rubber.
And nitrile (buna-n) is good for seawater and oils.