Before I took 15 years off from the sport, I bought os engines. Who makes the best engine for the money now? I am thinking 40 to 60 size range.

You’ve asked a question that is sure to elicit many passionate answers. It’s kinda like, “what kind of car should I buy”. OS engines are still pretty good and some folk swear by them. I have also had good performance with MDS, Magnum, Norvel, PAW, Fox, and K&B (and even an old “Bluebird” that I got on e-bay). The prices are competitive and a difference of 10-20 dollars is not much when you will spend several hundred for the total project. The main decision is whether to go for a bushed engine or a ball bearing. The bushed will be cheaper, won’t require as much after run care, and will give adequate performance if you choose an appropriate size for your airplane. The bearing type engine is a little more expensive and will develop more power in the same displacement but some after run care is required to maintain bearings. The fact is that all the major manufacturers produce quality engines that will give good service.

First thing to do is determine what type of airplane you are going to build or buy. Then check what manufacturer
has the size you want. I personally always recommend one with a ball bearing supported crank and that covers almost all the manufacturers. As louw covered almost all the bases on the makers all you have to do is fix it in your budget. I have OS, ball & bushing types, as well as Magnum, K&B, Norvel and a few others I haven't had out of the box yet. Check with the pilots at your local field and you can find as many different answers as there are people. At least you can see which ones are hard to start, don't idle well and don't have top end RPM. There is also a variable to that as well. Some guys just don't know how to run their engines.

The new MDS are fine engines the 48 or 68 have lots of power and are not that costly
Ron