O rings for an MRD head

Mouthfulloflake

Mouthfulloflake

ISJWTA member #2
Location
NW Arkansas
Where do I get them?

its a 701 MRD head with non-removeable domes.

who and where do I start my search?

I guess mabe I should just call Lehr power dude huh?
 
Phill

Phill

v Check out Little Matt_E
Location
Kennewick, WA
Hmmmm.......you could ask me.......


I cant remember if paul had the or not....

I got them from a local place.....


The size on the bag says... 3.500 x 3.687 x 0.103" <<<just like that....it seems like too many numbers......but I'm no expert....

You might try McMaster Carr?
 
Mouthfulloflake

Mouthfulloflake

ISJWTA member #2
Location
NW Arkansas
thanks guys, I will look into it.

I guess I could measure the O ring grooves and do that huh?
I dont recall any old ones in the box, but Ill look again,

so what about the LONG BIG O ring that goes around the perimeter of the head in that funky blocky shape?

just stretch it out, and get one that long?

so I match the diamter of the O ring, and the length, and get Viton.

OK, simple enough.
 
'Crockett

'Crockett

Freelance Smartass
Prem1x is correct the perimeter o-ring can be cut to length from Buna.

Remember that the grooves in the head around the chamber are over sized to allow the o-ring to expand when compressed so you will want a cross section that is smaller than the actual groove width.

I will check my notes and look at an MRD head when I get to the shop and see if I can come up with the correct size. Then it's up to you whether you want to find a local source or have them shipped in.

Dave Harryman is back in business again as MRD Racing, but not with heads and Injection units. I have heard though, that he is open to answering questions about his former product line.
 
Mouthfulloflake

Mouthfulloflake

ISJWTA member #2
Location
NW Arkansas
I have cut and glued O rings before, wasnt sure if that was acceptable for this application.

Cool, thanks alot for the info guys!

if you can get some infor or measuremtns Crockett that would help even more!

Thanks!
 
'Crockett

'Crockett

Freelance Smartass
I measured three 701 heads:
ProTec
MRD
Riva

Appears they all use the same size o-rings to seal the chambers . . . .

3.500 i.d x 3.687 o.d. x .094 cross section

That's : 3 1/2" i.d. x 3 11/16"o.d. with a 3/32" cross section

Groove width is .125 to allow for "crush" when torqued.

I'll post this in the other thread as well . . . . . . .
 
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Mouthfulloflake

Mouthfulloflake

ISJWTA member #2
Location
NW Arkansas
ok, Mcmaster Carr lists 4 typs of VITON seals.

from the website:

Standard: Has excellent ozone, weather, synthetic lubricant, animal/vegetable oil, aniline, chemical, and hydraulic fluid resistance.

FEP-Encapsulated: Perfect for sealing corrosive fluids, and FEP encapsulation makes these O-rings virtually impervious to most solvents and chemicals. Excellent resistance to friction and compression makes them ideal for static sealing applications. The FEP encapsulation meets ASTM D2116 and LP389A and is FDA compliant. Offers greater chemical resistance than silicone. Durometer hardness is A85 and temperature range is -15° to 400°F. O-rings are clear with a black inner ring.

Double-Seal: These Viton O-rings resist oil and some chemicals and can be used in place of standard O-rings. They have four sealing surfaces for twice the sealing protection. Also known as Quattro Seals, double-seal O-rings are symmetrically designed for sealing on the ID, OD, top, and bottom. This design reduces the amount of force needed to create a positive seal, increasing seal life and reducing maintenance.

Military Specification: These Viton O-rings have excellent chemical and oil resistance and meet MIL-R-83248C, Type 1, Class 1.


the standard comes in the correct sice and are 2 for $2.95, is that the ones I need?
 
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