.67 OPS Engines ?

[Don Templeton]

Thinking obout going for a .67 rigger and would like some comments on OPS engines. I know MAC has a great reputation and CMB is also probably a great engine. I'd just like some input on OPS (Good OR Bad)!

Thanks,

Don :unsure:

 

[P THOMAS]

The ops is a real good engine many have run in riggers, some mods can be made to go faster like exhaust timing raised some.

The CMB and MAC engines i think more powerful and have more a robust case, crank, rod design, the ops has smaller crank and bearing assy.

 

[herbn]

I have been an OPS user for 25 years. The latest OPS 67 w/drum rotor is a magnificent piece of machinery. The rotor is bushed - there are extra ports in both sleeve & piston from older models, the rod is bushed on both ends with good oil holes & the power is awsome. Their case is the strongest in the industry. I have never had one break even when I threw a rod. (which sometimes happen in any engine) The only thing I do not like is their carb. While it is good, it is a slide valve carb & I do not like a slide valve linkage as it takes up too much room I prefer using an OS 8B carb which has a beautiful high & low end adjustment & it's 3rd channel is very precise.

Above all - Aeromarine Laminates is a joy to work with. They always have spare parts on hand & are very efficient in filling orders..

 

[Scott Schneider]

:unsure: Raced .67 OPS's for a few years @ 7 years ago. In stock form they are good engines, Not great ~ only good.

Put in an RPM or titan rod and better bearings to start with, A billet front housing is a BIG +.

The Aeromarine drum rotor is GREAT, add an @ .454 to .470 aeromarine or RPM carb and your getting real close to a Great engine.

Set Ex duration at @ 176 to 178, Set Intake on drum to open at @ 32 Degrees ABDC and close at @ 68 to 70 degrees ATDC , leave transfers alone and open up case to allow greater flow up transfer runners and a OPS .67 will haul ass !! Most of the time pipe was kept at @ 11 1/4" plug to weld using a international pipe or Mac marine stingered down a tad.

Fuel No hotter than 35% !!!

Keep head squish at @ .015 to .018 and open up bowl volume a little at a time if it's eating plugs. ~ plugs used ~ Mccoy Mc-9's

This was my set up for many years and set district fast times for 3 years in a row and a National record too.

Yes to keep an OPS together you need some trick parts or as the name implys ~~ OUPS ~ another PISTON & SLEEVE. :blink: AKA: OPS

Good luck. Scott

 

[Don Templeton]

Thanks for the input guys.

Yes, I ran them for about 10 years in the 70s and 80s with good success. My only problem was keeping the rotor lapped. Sounds like the drum rotor works a lot better. I'll probably go with the MAC but I just wanted to check out the options.

Thanks Again,

Don