Hi Gene;
     At this point in the game these days, just finding ANY glow plug will be difficult!! You could try any long reach or R/C long glow plug. I prefer Glow Devil R/C Longs but I don't think they are shipping plugs right now either. Try SIG and their R/C long or Standard Long. Turbo plugs will not work as they require a precision seat for them to seat against. I like the R/C Longs with Idle Bar on any plug because it give carbon and other junk a place to stick to instead of the element coil. But in general, just see what you can find first. Some one posted on here about taking people's old, cast off plugs and soaking them in acetone or something to get the crud off the coils and then they run like new if the coil isn't damaged. It's work a try on the old plugs if you see performance starting to drop off.
  Good luck!
    Dan McEntee

               Gene, the two engines you mentioned are very low performance engines. I'm not a fan of the Fireball plugs. I've had the posts blow out of them and the insulation around the post leak profusely. The red is the hot plug and the yellow is a medium. I've had some success using the Fireball hot ( Red) but I've also had them take a dump. Brodak currently lists them in stock at $4 a piece which by today's costs is reasonable. I would purchase a few to offset any that may blow or leak. These plugs would work in there. You could also use a Sig plug but the cost is going to be more like $8 a piece.

Omega is 17% total lubricant, and only 30% of that is castor.  4 ounces of castor in a fresh gallon of Omega is a hair less than 20% total oil, and you're still only half castor.

I'm pretty sure that using Omega with four ounces of castor per gallon led to the demise of my OS MAX 25.  (It may have been eight ounces/gallon -- it's been years).

I'd suggest you add another eight ounces of castor per fresh gallon of Omega (for a total of 12 ounces, 1 1/2 cups), then cross your fingers that it's enough.  Or, get some Sig 25% castor.

There are some good suggestions for glowplugs already. I would suggest being very wary of being sold Fox and Fireball glowplugs, and be absolutely certain to get LONG reach ones.

A young club member once showed up at our field with a well used Fox .35 and a new short idlebar glowplug sold to him by a LHS clerk. It would change from dying rich to dying lean in one click of the NV. Installing a new long idlebar glowplug made it run the way it should. A new Thunderbolt R/C long/idle bar plug fixed several other club member's engines.

Speaking of T-bolt glowplugs...they were and probably still are made by Ohlsson Corporation, who also made K&B and many other American brands. Top shelf stuff, IMO. Fox made their own, as did Fireball. IDK about OK Cub and Johnson glowplugs, but I recall liking OK Cub glowplugs pretty well, many decades ago. Did Veco sell glowplugs? I've seen a RO-Jett glowplug, and it appeared to be a Thunderbolt with a different finish...all black...so that would also be an Ohlsson Corp. product.   

Along these lines, I would tend to avoid OS glowplugs, because...while they are excellent...they now come in a metric length which is sort of midway between long and short Yankee produced glowplugs. Having the nose of the glowplug recessed into the threads makes them effectively a colder heat range.    Steve

Question - Is it a good idea to remove the idle bar from an RC plug for u-control?

I flew Fox 35 stunts with and without the idle bar cut off on Fox rc long plugs..could not tell the difference and did it with multiple plugs and flights.

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