1QwkSport2.5r

I have a Norvel AME .049 that I intend to put on a currently-electric ugly stick. It originally came with a standard glow plug head and 3 or 4 head shims. I've run it a couple times, but it didnt run real consistent (the RC throttle was locked wide open). I'd like to see if I can get my hands on a new piston and cylinder, and a drop-in type glow head. I know there are Nelson plug heads available, but are they equal in performance to the drop-in glow heads? Does anyone have an AME .049 piston and cylinder that's in good shape or new they'd let go of? I've found NOS parts on eBay, but they wanted exuberant prices for those parts and I'm on a tight budget. Just wondering if there's anyone that might have some wisdom and/or parts to share?

skaliwag

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Sprinkle a little C-4 in the suck hole.

1QwkSport2.5r

Not enough room for the blasting cap.

SGC

Cylider/Piston assembly 04 Aero, AMD, Big Mig for new piston/cylinder and merlin plugs here :- Welcome to Merlin Glow Plugs!

1QwkSport2.5r

I don't want a Big Mig replacement set - I want the AME specific set as the two engines are different. I question whether the set sold for the "AMD and Big Mig" is just the regular BM set. I'll send them an email to find out.

1QwkSport2.5r

I got an email back from NV Engines. My suspicion was correct - The piston/cylinder sets for the .049 are for the Big Mig only.

So, if anyone has an AME piston/Liner they will part with, please PM me.

aspeed

The Big Migs just have holes for the bypasses. Maybe you could just mill them into slots. IDK, just shooting ideas. Some had chrome, some had some other coating. I checked rpms on a Big Mig .15 and the BB one, and it was only 1,000 rpm difference, so maybe the porting is not such a big deal. (or the bearings) I have not played much with the .049 ones. I did have trouble more with the AME ones, some would not run at all because of the huge control line carb, plus they liked little props. I necked down the carbs to 1/8" dia? for my purposes. (little combats on suction)

1QwkSport2.5r

The AME has larger ports and higher timing intended for higher rpm. As I understand, there's no difference between the RC or CL versions other than the RC throttle. I've been told that the CL engines ran best on a bladder or if you could manage to get the exhaust to seal well enough to pressurize the fuel tank. I'll try running mine both ways, but will likely end up using a bladder.

aspeed

The two examples I had were very large 3/16" bore, and would hardly fire off the prime. They came without a muffler The rc carbs are a more realistic size. I just pressed in an insert, and they are fine. I really don't like bladders although I use them occasionally on the F2D stuff. Only because that is the only option though. It would be quite easy to machine the ports on the Norvel liners if you can only find Big Migs. I have not found the need, but to go higher like for a pipe might even work. I would have to look, but think so. You need a Fora or Profi!!

Mr Cox

I only have the RC version and I haven't seen that much difference between the AME and the BigMig, but I haven't been very systematic either I guess.

Fuel draw has not been a problem on the RC versions, I'm also using the stock muffler with no extra care taken to seal them. (They seal better than the AP wasp anyway.)

Here are some numbers for a .049 pre-revlite RC engine on 10% nitro:
APC 5.7x3 prop: 18500 rpm
APC 4.75x4 prop: 20500 rpm

There might be some more power to have by fine tuning the compression ratio etc. But for a throttled .049 it runs pretty well I think. The only other throttled .049 engine I have that will beat it is the VA .049 MkII, it spins the 5.7x3 prop at 19500rpm on the same fuel.

As the weight is the same for the Norvel .061, and I'm not doing any competition, it is an easy upgrade to use the .061 engine, so those are mainly the ones I've been hoarding.

I bought a spare liner from NV, and got an AME version. Unfortunately it turned out to be pretty useless. I don't know if they have tried to make a new run of liners, but the tapering was all wrong. It was too steep, the piston would leak before the exhaust opened and still be too tight at TDC. I never got that one to run properly and others at the cox forum have had similar experiences. So the best bet for a new piston and liner would be look for the original Norvel engines.

1QwkSport2.5r

Mr Cox - that's what I kinda figured in regard to using old parts. I haven't had the engine apart, so I'm not even sure what the cylinder construction is in my engine. If it's a plated bore, I may enlist a friend to make a new piston for it if I cannot find some old stock parts.

Many chance the .061 cylinder and piston fit the .049 case or are the cases different? I wouldn't be opposed to trying that if the .061 parts fit.

aspeed

Just by reading the OP. Four washers is kind of a lot. Maybe the piston cyl. is just fine. Could just need a new plug, or less shims or something simple.

1QwkSport2.5r

I was told that 3-4 shims in these engines is common for using typical 1/2a fuel with 20-25% nitro. From the reading I've done, these engines with 0-1 shims is suitable for 5-10% nitro.

The piston seal is not the best and compression is not very good. I will pull all but one shim out and check it again.

Mr Cox

The .061 parts should drop right in, I don't know of any differences appart from the cylinder bore. The construction is visible from the outside, they went from ABC (early Steels engines), to AAN (the most common pre-revlite) and then finally to the "revlite" ceramic coated Al. Below is a little timeline from left to right.

I use more than one head shim in a new engine, and once they are run-in then one head shim seems fine for 10% nitro.
I have one or two engines that feel a bit worn and doesn't feel very good when turned over, but like many cox engines they run just fine that way. It just means that you'll need spring starter to get them started and that the idle will not be quite as low and reliable.

1QwkSport2.5r

Thanks for that info. I will take the head off the engine today and get a look inside and post a few pictures. The one thing I don't have that I need is a head spanner wrench. I'm not a big 1/2a guy, but having had two .049s now, I should invest in a spanner wrench for the head. If I can get this engine running good, I'll be keeping it in my collection. My foam ugly stik should fly good with it.

aspeed

The Cox wrench works good. The heads too. Everyone has those around. I don't think I have ever worn a Cox P/C out yet. Had a rod wear through the top. They just get faster and harder to start. The cases wear, and give uneven runs. I have an old Stels with a rear exhaust that splits into two, and a Norvel where the muffler just goes straight back too. They might have been earlier models. The Stels is quick after I replaced the main bushings with home brew ones, which were way too loose from the factory. It would not give an even run at all. Up, down, up down. I tried to get mostly .049 Norvels, as that was the limit for the speed events. Since then, I have got a few .06 and .074s whenever I find them reasonable.

1QwkSport2.5r

I'll either make a spanner or find a Cox one. 1/2a is pretty much nonexistent around me, so finding stuff locally is out. I'll do some digging when I have more time to see if I can get one online. I'm sure they're around.

As for engine itself - it does have an AME cylinder - which version I do not know. It's not brass nor aluminum best I can tell. It had two shims under the head, which is all I have for it. I will try to get my hands on a standard glow head for it and try running it again and see what I get from it.

Mr Cox

Those are AAN I believe (the pre-revlite model). I haven't grounded any on the outside to see what is underneath the nickel layer though.

It looks like you have the adapter for a regular glow plug. They run better with the stock "glow heads", you can either try to find the original Norvel ones, or you can get the corresponding Merlin one. The Merlin ones will need a few more head shims than the stock Norvel head though. I guess the head you have now will run best with one head shim only, the conversion heads usually tend to be too low in terms of compression ratio.

1QwkSport2.5r

From the reading I'd done when I got this engine, it seems some of the earlier (IIRC) models came with a standard plug head and not the typical glow heads. I do intend to get my hands on some glow heads for it as I believe they run best that way - OR use a Galbreath head for using Nelson plugs. As I understand, performance is about equal between the 1/2a glow head and a Nelson plug.

Will the Norvel glow heads work with the head clamp I already have or will I need a different head clamp too?

Mr Cox

Yes, the very early ones came with a regular plug and a head that was a bit special (see below), but that was before the one you have, as far as I can tell.

The early clamp rings had a slightly smaller internal diameter and the later heads will not fit inside the those clamps without modification. From Merlin you can get a clamp and three heads in package which would fit your engine.

There is also the Nelson head which perhaps is the most performant one, if every bit of extra rpm is important. There are/were also turbo-plug heads from John Valentine that work well.

1QwkSport2.5r

The Galbreath Nelson conversion head is $12US and the Nelson plugs are $5US each; perhaps that's a more cost effective option that will perform well also. I'll look into the Merlin stuff and compare pricing. I'm strictly looking at the dollar value so much as what the best performing option is for the dollars spent. I don't think I'm going to get heavy into 1/2a, but if I did, I'd have a head and plugs that will work on several engines rather than just one.

Mr Cox

If you already have Nelson plugs, the Galbreath head will suit you well. It is perhaps the most performant one too, in terms of max power.
I feel that even the Hot Nelson ones don't throttle quite as well as a hot turbo plug will do, but it is not that important.

1QwkSport2.5r

I don't have any Nelson plugs yet - if I went that route, I'd just get some with the Nelson conversion head.

Who sells the Turbo plug heads for 1/2a engines? I do have some of those - Picco and Novarossi only though. I think the tapers are different between the Novarossi and Picco plugs if I'm not mistaken.

aspeed

The tapers on the turbo plugs should be the same at 60 degrees. Maybe it is just the tolerances adding up. Nelsons are much different. Mr. Cox likely went to bed, so I will give you Ron Valentine's website. Home Page I don't see anything listed. I guess he is custom. The Merlin plugs are available now, so the conversion ones are not really needed as they were in the past. The Cox ones are available again too, although they are pricey. Merlin sells his own turbo, turbo Glowbee, and Nelson plugs as well as the Cox/Norvel replacements. I believe the 3 head set includes the clamp ring which only fits his inserts.

1QwkSport2.5r

Its well known in the RC car world that different brands of Turbo plugs have different tapers. Or rather it may be the threaded length is different. Its said if you use, say, an OS Turbo plug in a Novarossi engine that the head deforms to match the plug and a Novarossi plug will then leak. The same has been said about Novarossi plugs in Picco engines. So the common practice is to use plugs of the same manufacturer of engine and glow plug. Its pretty much one of those things where you use one brand of glow plug and stick with it.