New to os motor !

[shadey26 ntc3]

I am new to O.s. motors. and I have a question. Do they have low pinch and low compression after break in? Pinch as in taking out the plug and turning the fly wheel. And compression as turning the fly wheel with the plug in. It is a 15 cvx in my girlfriend car. I just put a new piston and sleeve in it. I keep the temp to about 240 to 260 being the max. She runs 20% odonnel fuel. She ran 30% last time and the motor only lasted about 2 gallons. To me it seems that after the mill is ran it is so easy to turn the motor fly wheel. When its cool its a little bit better . It stills passes the one fingure test. I guesss I am just use to the novarossi's. I was thinking of tossing that mill and puting a xtm .18. I don't seem to have this prob with my x-cellrator :shrug:

 

[alkyula]

how is the engine running? does it have low compression and low power? if the engine is still making power i do not think the lack of pinch should matter. the 30% not shimmed in a small block may have led to the rather quick death of 2 gallons last time. my O.S. RG has 5+ gallons thru it..has barely any compression but it still runs with great power (comparably to new). O.S. engines seem to run the best when all the cold pinch is gone.

 

[shadey26 ntc3]

Man her car ran like a bat out of h$ll with the 30%. I knew i should of shim the mill, but I thought I could get away because it a .15. I run 30% thru my mt.12 and xtm.18 no prob. Wonder why ? I have 3 gallon thru the xtm and approaching 11/2 on the nova. Her car still has mad low in power and good x-cell. So I guess its fine. I guess I just use to the nova. I guess every motor is diffrent. How many shims should I use for her motor. What do you recomend? It would make it easier on the fuel part so I don't have to lug two diffrent jugs around! thank for the replie

 

[alkyula]

novas are known for lasting forever. id say adding one .10 shim and going a range colder or maybe two with the plug should be good for that engine on 30%. I've never personally ran 305 in a small block, but that is all i run in my .21+ engines!

edit: personally ran 30%

 

[shadey26 ntc3]

Don't worry about the edit I got you! Thanks for the info!