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Mac flatback O-Rings

Posted: Wed Nov 10, 2010 5:03 pm
by ted johnson
I need O-rings for the high and low speed needles on Mac flatback carbs. I could use as many as 20, but even four would help me rebuild my two flatbacks. Any other flatback parts out there? nosnhojkart@yahoo.com
Thanks! Ted J.

Re: Mac flatback O-Rings

Posted: Wed Nov 10, 2010 5:11 pm
by Rob Voska
Ted just get them at NAPA. Or call Ron & nake a trip into my favorite hardware store in Phx.

Re: Mac flatback O-Rings

Posted: Wed Nov 10, 2010 5:30 pm
by ted johnson
Thanks, Rob. I always thought those were a special. I thought they had a fatter cross-section than standard. Didn't realize I could just get Parker Hannifin pieces! Ratz, I was just at O'Reilley's in Casa Grande getting carb cleaner and naphtha! They probably have Chinese ones...on second thought-the Chinese ones are probably slanted! ;) Ted

Re: Mac flatback O-Rings

Posted: Wed Nov 10, 2010 5:59 pm
by Rob Voska
Soak in gas before buying a bunch of htem to make sure they don't swell. McMaster Carr will help also.

Re: Mac flatback O-Rings

Posted: Wed Nov 10, 2010 6:42 pm
by ted johnson
Rob, do you use Viton, Teflon or Buna N compound? Seems McMaster Carr has all of them. Running gas and synthetic (FHS) lube. I'd normally pick Viton, but don't know how it goes with the FHS 62R. Heck, I'm still trying to get that cotton-pickin' Mac paint off! I'd forgotten how tough it was, and the new "Tree-Hugger Brand" carb cleaners ain't what they used to be :shock: ! Thanks. Ted

Re: Mac flatback O-Rings

Posted: Thu Nov 11, 2010 6:32 pm
by Scott Kneisel
Lacquer thinner seems to work for most mac paint, all but the real old stuff. The carbs are the worst to get the paint off but when you do, there is usually a really bright diecast finish underneath. I usually soak in lacquer thinner for a few days and then use my pressure washer while holding the carb body with my feet, rubber boots on of course.

I got all my Mac small flatback o-rings from Vince Hughes. The round o-rings reform with flats after being in that bore for awhile. I really think BUNA N material should be OK for gas but I don't know about alky. I saw a chart online once specifying various o-ring materials and their resistance to different fluids. Oil, gas, alcohol and some others. I'll see if I can find it again.

How's that 5 coming Ted??

Scott

Re: Mac flatback O-Rings

Posted: Thu Nov 11, 2010 7:45 pm
by ted johnson
Thanks, Scott, I appreciate it. I'm using gas in the Mac carbs. I put them in a small can with Eastwood DeKote paint stripper. It'll even remove powdercoat. Left them in for about four hours, and even the old Mac paint came off. Carbs look good. I'll have Vince get the top plates rechromed. I like the DeKote, because you have plenty of time to wash it off your hands before it burns. The 5 block, piston and rod are still at Terry's for bore-to-fit and pressing in the pin. He's moving shops, and things take a little time! I'll call Vince tomorrow about the o-rings. I want a few on hand, but don't want to deplete Ron C's stock! Just got home from Ron's. Last Xterminator is riveted. I got in the way more than I helped, but I tried! ;) Later. TJ

Re: Mac flatback O-Rings

Posted: Fri Nov 12, 2010 4:19 am
by Mike Reller
Vintage Vixon appears to have some N.O.S. o-rings on Ebay.

Re: Mac flatback O-Rings

Posted: Fri Nov 12, 2010 8:43 am
by ted johnson
Thanks, Mike. Already have some comin' from Vince, along with a couple fresh HS needles from Zoe! TJ