Hey Len: 2nd Gen OS LA CL engines

Len: You're the one to ask: What's the scoop on these newer OS LA CL engines? Is the timing the same as with the first gen RC engines? Has the sleeve plating changed or improved? Any other details worth noting?

I'm asking these questions because I'm seeing references to the CL LAs on other BBs.

The original LA is the same as the FP as to bore, stroke, timing, etc. They have a thinner sleeve so you cannot swap some of the parts from one to another, but they kept the same shaft and connecting rod. (Actually, they cheapened the shaft on the LA and used the same shaft on the last runs of the FP.) Since they have now for the fourth and final time (I am "pretty sure") decided to discontinue the FP engines, they have decided to come out with a CL version of the LA.

The second generation LA dropped the machining of the boost port. OS says they have gotten more rpm out of the engines doing this, but I have been running these things for years and have never seen an engine where we have blocked off the boost port and increased the rpm (this is a "boost" port, remember). To me, it is just another example of a cost savings measure on the part of OS. However, blocking off the boost port does bring the hp curve down to a lower rpm range and closer to the torque curve, enabling the engine to turn a larger prop at the slower rpms we like. That's the good part.

The first LA engines had VERY poor plating. They kind of washed the sleeve in the plating and moved on. It didn't matter if there wasn't anything that stuck. They tried the same thing with the FPs. It was horrible. They have since corrected this, so there is some improvement on them now. They, also, had problems with the back plate. You may need to check on this, but I think they are using the metal needle mount on this, too, now. You need to junk this, anyway, and move the needle up front. (Get one of the earlier FP needles, or use an ST needle and bore the venturi accordingly.) The venturi is the same as the one used on the FP.

So, put a front needle in. If they are still using the crummy back plate, get a back plate for the Tower 40 (It is cheaper than the FP back plate and Tower will ship it to you at no cost, which they do for their Tower 40 parts only.) If you want to be a real purist you could swap the Tower 40 shaft into the engine as well. Then you would have a fully machined bar stock shaft instead of the cast version on the LA.

Doing this, you may end up with a fairly decent engine. I would be curious to learn if it has the "burp" problem we experienced with the FP 40 conversions, however. If not, (If they have narrowed the slot in the sleeve) it should run OK with the above modifications. The case and shaft are still heavier than the earlier FP engines (or the Tower 40) so you still have a weight disadvantage, and the case is soft and subject to stripped screw threads. Bolt it together, run it, and don't take it apart again.

As noted, there are some improvements in quality, but it is still not my favorite engine and I don't plan to stock them.

Leonard Neumann