zero-cool

I have this fora 40.that I have run a few tanks through.It takes nelson glow plugs.ive gone through three plugs so far.and I havent even flown it.im not running it lean.ive only got it up to 17k on a 8.5x7.0 there were three extra head shims that came with the engine.no instructions came with it either.heres the dumb question.what are the head shims for?im still kindda new to tinkering with engines.and now im stuck for a while.because I have no more plugs.and have to order them.and they take forever to get here.

Mike Connor

My Feedback: (5)

Did you get your Jett sleeve straightened out? Was wondering if the performance is acceptable now. Nice to get feedback on advice.

combatpigg

My Feedback: (3)

Stick all 3 shims in there and see how it runs. This is a pretty expensive engine to be learning on, BTW [:-] You are better off working from the under-compressed angle, than visa-versa. If the engine is under-compressed too much, power will be way down.
I would also make sure to run at least 22% oil, with castor included, at least until the engine is broke in and you are completely sure about what you are doing.

MJD

My Feedback: (1)

No kidding, sorry to double up but CP hit it on the head. If you are unsure what head shims are for, then why do you have a Fora? No insult intended, but engines like that are meant for folks with some performance engine experience. Or was it just too enticing?.. that can happen. If you could hook up first hand with someone like that your experience may go a little better. It's not rocket science but you need a bit of hands-on to know what it's telling you. Once you get it singing it should be a riot.

MJD

zero-cool

well.MJD I got the fora because.I saw it on ebay and ended up getting it for 140.00 new .so i could not resist.but nobody at my field runs any performance.engines so im on my own

combatpigg

My Feedback: (3)

To play it safe you want to stay away from props that maximize power too much. This will make setting the needle less critical, you'll be able to set the engine richer than if you were running a max load prop. Don't be afraid to let it rev.....just always make sure that you set the mixture with the model pointed straight up. The engine should be set for a slightly rich scream with plenty of castor oil and smoke out the exhaust. Don't spend all day looking for peak rpm on the ground, find what seems "clean enough", then back off 500-1000 rpm and settle for that.
You might find that a 9x5 is a good choice to ease the engine into action with.
Check with the guys in the Pylon Racing forum for their thoughts....you got that engine for a really good price !

MJD

My Feedback: (1)

Good deal! I hope you get it purring, then go out and scare the pants off everyone..

MJD

daven

My Feedback: (1)

Blown plugs are caused by either too much compression or a lean run, a too large prop could contribute also, but it sounds like you have a small enough prop on so that is not an issue. Also, a peak of 17k on that prop/motor sounds low, like you may have another issue.

Did the motor come with any documentation, or instructions on operating? It is not a common motor in the U.S., since the few that were imported and tested by racers were not competitive with the Nelsons or Jetts so few (if any) were ever raced.

You can start by adding the head shims, but I suspect something else is wrong. Are you using a bladder type tank (ie tetra) to eliminate any fuel foaming or air in your fuel? Check the port to the exhaust and verify the sleeve hasn't twisted like jetts can possibly do. If you see carbon buildup on the piston and or head, you were too lean. Are you getting backpressure from the muffler? Verify that the hole in the exhaust nipple is clear.

In the latest issue of the NMPRA newsletter (June) there is an article that mentions a new Merlin Glow plug that fits the Nelson threads but has the smaller head of a standard glow plug. A friend here has tried them with good success. You can check it out at www.nmpra.org

combatpigg

My Feedback: (3)

Dave, how close to being competitive are they? If they can be found for $140 and are otherwise mechanically sound...what do you think about that?

Their .049 and .15 engines are world class, but they are direct copies of the Cyclons.

Ed Smith

Iwould suggest that you get the engine out of the airplane and on to a test stand. On a test stand it is much easier to play with.

How thick are the head shims? If you are destroying plugs then the engine is probably overcompressed. Make all changes in moderation. .002" shim can make a difference.

Another source of Nelson type plugs is a company called Merlin. It has a website.

Use fuel that would normaly be used for racing. Typically 15% nitro, 18% lubricant, Synthetic oil is suitable, or a Synthetic/castor blend such as Powermaster.

Ed S

zero-cool

hey daven,mjd,combattpig thanks for all the great info.this is a big help for me.I must go fast.so im trying to learn all that i can about proper use of performance engines.thanks for taking it easy on me.

zero-cool

when dave says there not compitive to the jetts or nelsons hes only talking about 800-900 rpm.but it will still turn a 8.5x7.0 at 20k.and for someone like me. who does not race.thats fine.its on my viper with a clipped wing.to 40in.so I hope it packs the mail

daven

My Feedback: (1)

Exactly, I am not saying it is a bad engine, just that the Nelsons and Jetts have the edge and a 5mph advantage is nearly half a lap lead at the finish line

I had actually mixed up the Fora vs Profi motors in this message so Iedited it.

The Fora was not competitive with the Nelson or Jetts (this goes back nearly 5 years) a couple friends of mine were sent motors to test and evaluate, and none of them were in the league of our top 428 motors. However, they were very nice running motors and would make great sport speed motors. I remember some complaints about the muffler and a thread on RCGroups that got a bit heated, but haven't ever seen one actually used in a race. Considering they were not competitive with the SS, they would be quite a bit off the mark of the current LSmotors.

20k out of a 8 1/2" x 7 is good for a sport motor, but the Nelsons/Jetts are turning a bitmore pitch at that rpm, and unloading more.

daven

My Feedback: (1)

Not sure if this is helpful, but another thread on the same motor from a couple years ago. I think there may have been a language barrier present

http://www.rcgroups.com/forums/showthread.php?t=638724

combatpigg

My Feedback: (3)

Dave, sounds like a typical exchange, their way of thinking does not allow for slang. You have to spell everything out as perfectly as possible. When you say, "off the top of my head", you might as well be speaking to a space alien. That guy must have been a sales rep. I'm kind of surprised that the .40 doesn't cut the mustard because the .36 FORA is competitive against the Nelson.36 in C/L combat. The difference is that the average pylon race lasts a minute and the average combat match lasts 15 seconds.