Does anyone know where I can find specs and info [tuning] on a OPS 60 Super SPA RCA ABC FIRE engine???

Thanks, Tony

I believe this is the five port? If it is the five port or the three port, here are some practical starting points:

1. From the center of the head, measure 14" to the widest part of the tuned pipe. Sometimes the pipe has a lathe line denoting this, but I'm sure you know what I'm talking about. This is a very conservative pipe setting.

2. Tach readings at this length on an 11 X 7 will be in the 13,500 range on 10% nitro.

3. Start trimming 1/2" pieces off of the header and keep taching the engine. 1/2" pieces could account for as much as 500 rpm gain or little as zero. Expect to see noticeable power increase by 1 1/2" of trimming.

4. My experience with my OPS many years ago was the length ended up being right at 12 1/2" to 12 3/4", center of head to wide part of the pipe. Ground tach readings @ 15,500 on 10% nitro with a wood 11 X 7. I loved to hear it unload in the air! Any shorter on the pipe and plugs popped after one flight. Not knowing what size prop or the amount of nitro could affect these parameters, so consider these figures ballpark.

I hope this helps.
Regards,
Mike

Here's OPS engines old spec sheet for tuning.

Thanks to you both for the info. A great help.

I am considering changing the head to accept the Nelson plug. They are tougher and less $$$ than a standard plug.

Why would you want to use Nelson racing plugs on a classic pattern engine? I tend to think they will turn out to be way too cold for reliable operation on a throttled "low revving" engine... They are tougher because they are very cold plugs.

Here's a Nelson HD and a Rossi 4... see the difference?

Rudeboy,

I think you are correct. After much searching I found this is indeed a lower rpm dedicated pattern engine, not the screamer I had hoped for. [] A Nelson plug would not be a wise choice. I should find a Bridi XLT or Curare to build. That would be perfect for the OPS.

Tony

I agree. It would be hard to get this engine over 17,000, and if you could, that would be the absolute top end output and risk blowing it up. See if you can find an OS .77 DF. Now that will get the rpms you want and will be the same size....
Regards,
GPB

Low and behold, there is a NIB OS Max .77 DF on Ebay as we speak. Very reputable dealer selling it, too. Just type in OS Max .77DF in the search and you will have it....

The OPS .60 pattern engine is a sweetheart, and it is no slouch in the power department, but no it isn't the one you were thinking of. Mine hauled an old Cass Pulsar bipe around right smartly, and it weighed in around 8 pounds (oink). Looking forward to putting it in a new home, whatever that home may be, dunno yet. Likely just what you're talking about.

Ugh I just nicked my index finger with an Xacto blade and now there are little red spots on all the keys I just used.. doh!

MJD