NV BigMig 049 and 061 life expectancy

balogh Sun Nov 30, 2014 8:05 am

While I remain a stubborn COX worshipper, out of curiosity I took my 2 NV-s from their boxes for a closer look.

NV BigMig 049 and 061 life expectancy 061_an10

On the left if my Revlite 061 Big Mig R/C from 2013 on which I have sung a couple of bitter songs here (zero compression from the beginning, lousy power when starts up at all). I do not consider it an engine at all.

On the right is a brand new 049 Big Mig, its paper says it is from 1997. The text of its Manual proudly reads under the engine that its lifetime is not less than 6 hours. Its compression is sensibly better than that of the a/m Revlite dung.

Given that aluminum pistons like NV are far more vulnerable than the steel ones of COX, and castor varnish is said not to stick to aluminum like it does to the metal selection of COX, I really would not expect a lifetime from a NV anything near to that of a COX (100+hrs still with as-new compression in an old stock tapered 051), but I am wondering if any of you has had some lifetime measurement (i.e. when worn so much that the compression is not sufficient for a reasonable power) with this older design (pre-Revlite). I can only hope that it will last for at least 6.15 hours if the paper says no less than 6 hours. Very Happy

Though I accept that your experience with NV is far better than mine (that obviously makes me ballistic and biased when tallking about NV-s)

I am comtemplating to mount this 049 into my speedplane just to benchmark it with a TD049 or TD 051.

Ken Cook Sun Nov 30, 2014 9:44 am

I have a lot more than 6 hours on mine. Norvel engines like Cox are very inexpensive massively produced engines. They're a dime a dozen. If your looking for long duration and high performance than buy a Cylclon, Fora or Profi. I own one of each and I still use the Norvel due to the .061 making as much power as the above mentioned engines in a .049 format. The Norvel's work terrific for what they are. Cox TD's are gutless compared to a Norvel. In control line the newer rules state 42' line length which a TD can't fly on due to too much drag. Td rules were 35' lines and there's a reason for it. They don't make the power to fly competitively. They're old school technology that is very problematic to hot start and the ball socket is horrendous. If the ball socket isn't failing, the cranks are breaking. I run up to 60% nitro in my Norvel's while 40% is my standard fuel and never have I seen a crank failure as a result of doing so. I admire your Cox infatuation and I don't know what to tell you about your Norvel experiences other than you might need to look deeper into your engine to figure out what may be the problem.

Norvel heads leak notoriously, they must be flattened on a piece of glass using sandpaper. In addition, Norvel head gaskets quickly degrade and have a tendency to appear like a star washer. Sometimes too many gaskets are in place and they're so thin you don't even know they were in there. Once broken in a stock Norvel only requires 1-2. GET RID OF THE STOCK HEAD SCREWS. you can't tighten them properly and they're dead soft which not only strips but can shear the heads off when running (At least the way I run them). Deck heights of these engines can vary immensely. Lapping the top of the case carefully can lower the cylinder and raise the compression. Lapping the rear of the case and using RTV silicon on the case prior to installing the backplate is also highly recommended. If these engines are not heated up to temp properly, the stresses can not be fully relieved therefore a high nitro small prop run up can sometimes restore a problem like your experiencing. The Norvel has an extreme taper and it needs heat cycling in order for this to stabilize. The Norvel doesn't like large props like the Cox does. Keeping the diameter to 5" or smaller is highly recommended even on the .061. I run 3 1/2" props on my 1/2A combat Norvel. A 3 pitch is max for the Norvel. The APC 5.5x 2 makes a very good sport prop and keeps the rpm's up. APC does make a 5.7 x 3 which has good blade area which would essentially be the largest prop I would ever use on these engines. Ken

balogh Sun Nov 30, 2014 10:08 am

Ken Cook wrote:I have a lot more than 6 hours on mine. Norvel engines like Cox are very inexpensive massively produced engines. They're a dime a dozen. If your looking for long duration and high performance than buy a Cylclon, Fora or Profi. I own one of each and I still use the Norvel due to the .061 making as much power as the above mentioned engines in a .049 format. The Norvel's work terrific for what they are. ...............I admire your Cox infatuation and I don't know what to tell you about your Norvel experiences other than you might need to look deeper into your engine to figure out what may be the problem.

Norvel heads leak notoriously, they must be flattened on a piece of glass using sandpaper. In addition, Norvel head gaskets quickly degrade and have a tendency to appear like a star washer. Sometimes too many gaskets are in place and they're so thin you don't even know they were in there. Once broken in a stock Norvel only requires 1-2. GET RID OF THE STOCK HEAD SCREWS. you can't tighten them properly and they're dead soft which not only strips but can shear the heads off when running (At least the way I run them). Deck heights of these engines can vary immensely. Lapping the top of the case carefully can lower the cylinder and raise the compression. Lapping the rear of the case and using RTV silicon on the case prior to installing the backplate is also highly recommended. If these engines are not heated up to temp properly, the stresses can not be fully relieved therefore a high nitro small prop run up can sometimes restore a problem like your experiencing. The Norvel has an extreme taper and it needs heat cycling in order for this to stabilize. The Norvel doesn't like large props like the Cox does. Keeping the diameter to 5" or smaller is highly recommended even on the .061. I run 3 1/2" props on my 1/2A combat Norvel. A 3 pitch is max for the Norvel. The APC 5.5x 2 makes a very good sport prop and keeps the rpm's up. APC does make a 5.7 x 3 which has good blade area which would essentially be the largest prop I would ever use on these engines. Ken

Thanks Ken,

this is really comprehensive an explanation...do not get me wrong but what you say means to me that providing you have a mechanic's shop and tools and are also ready to re-build a new NV then chances are this will be an operating engine? I am not surprised as basically all Russian cars/engines I met in my life (especially prior to the Iron Curtain collapsing, when there was not too much of a alternative choice in this part of the world) required the same customer skills to make them run.

I would then stick to the 50 years COX that will run no matter what. Not wishing to reiterate the long songs I sang on my NV but one does not need to look too deep into what the problem of this one was. The poorest workmanship resulting in an inoperably lose piston/cylinder fit. And a defensive sales support that wanted me to send the engine back to Russia to an adress in St Petersburg that does not exist.

Anyways I will start and tach the NV 049 and am looking forward to some positive onservation.Maybe I am the one-time truck-driver who entered the highway from the wrong direction and complains that all other drivers are wrong.

Ken Cook Sun Nov 30, 2014 10:54 am

I've had a lot of success using the Big Mig series as well as many others have. I find my BiG Mig Revlite .061 swings a full 5x3 with a great deal of authority. My AME .061 Revlite has to swing a slightly smaller prop to get the speeds matched on identical planes. The AME can be fickle. It likes nitro while the Big Mig remains timid. I've experienced the wrist pin dropping out of the piston and getting jammed in the liner on my AME's. I'm not the first to experience this as many of my club members also have. The wrist pin staking is a single stake. I stake it again in a X fashion. to prevent this. Hard ground strikes and mid airs are largely responsible for this. I would also like to add that using a Merlin plug or better yet a Nelson plug is going to increase the compression on this engine. I generally take out a head shim until the plug blows and then I put one back in and try again. I use the Norvel plugs for break in only they're generally short lived. It appears to me that your .061 is using a standard plug. I find that any glow head conversion to accept standard plugs on 1/2A is highly responsible for the lack of compression and power. I don't use them period. A Nelson head combo works the best out of all of them. Your Big Mig .049 in the ABN format should be a great little runner. These can be most problematic if your running the muffler during break in. They like just a little prime through the exhaust 1-2 drops as this can readily flood the engine. Once the engine has some time on it, placing the muffler back on should be a non issue aside from robbing power. The venturi sizes for the .049's were all over the place. The top of that venturi comes off if need be for closer inspection. This engine should be very rewarding.

I hope you get this sorted out as I feel you will like the engine and you will really have the best of both world's. Ken

Surfer_kris Sun Nov 30, 2014 11:04 am

The Norvels are very reliable, and the older pre-revlite ones are a even a little easier to use (than the revlite) as they are more traditional in their construction.

They are very tight when new, you really do need to preheat the cylinder before starting them for the first few runs (even after that in colder weather it helps to pre-heat the cylinder a little). I prefer to use 25% all castor oil and around 10% nitro for the running-in. The APC 5x3 is good for running-in but you can go lighter than that and the APC 5.5x2 is also good, as mentioned above. A 6x2 can be a little easier to hand start, than a 5" props, just don't use a 6x3 prop.

I can't say anything about their lifetime, yet, as I have never managed to wear out a Norvel engine. They just seem to improve with time... Smile

andrew Sun Nov 30, 2014 11:08 am

EDIT: Looks like Surfer Kris posted while I was typing, but we are in agreement.

Ken's experience has been the same as mine. The earlier model engines shipped with an extreme taper near TDC. I have some .15's that are squeaky tight at TDC, much like the Formula 1 and Q40 engines. I think that a lot of NORVELs were damaged during break-in due to folks following the procedures they used on other engine designs, i.e., running sloppy rich and cool. My personal approach is to get these engines up to operating temperature as quickly as possible as soon as it starts -- I've used a piece of cardboard to temporarily block airflow on new engines just to get it warmed up. I'm convinced that NORVEL has backed off on the taper due to folks having difficulty starting these engines out of the box. Even SIG modified the instructions to recommend cold flipping to free up the fit (advice that I do not support). Although NORVEL hyped their engines as having a ceramic coating, I suspect it is a Type III anodize -- it is significantly harder than the Type I used on COX engines, it builds an oxide layer both above and below the original aluminum (Type I is substrate only) and it is much more difficult to apply. Running these engines cool does not allow the necessary expansion to occur in the cylinder and piston which may lead to premature wear --- this is why I don't flip or spin these engines cold. I always start with a heat gun until it's broken in and starts easily on its own.

As Ken noted, folks tend to over-prop these engines -- they make their best power well up in the RPM range and running too large a prop doesn't let it wind up. The original designs can be traced back to the Zeus and NORVELs (Northern Velocity) were produced to support the C/L competitors. R/C engines came along much later and were slated for the mass market --- but, a lot of buyers did not have the experience to manage a high performance engine, so the detuned or Big Mig model came out. Yet, old school techniques continue to be used on new technology metallurgy.

You may have gotten a P/C match where the piston is at the lower end of tolerances and the cylinder is at the upper. If that's the case, you've gotten an engine that may not perform (that's not the norm). I run the COX engines when I'm just putzing around and like to tinker; I run the NORVELs when I like to fly.

balogh Sun Nov 30, 2014 1:03 pm

andrew wrote:.............. I run the COX engines when I'm just putzing around and like to tinker; I run the NORVELs when I like to fly.

Ken Cook wrote:Cox TD's are gutless compared to a Norvel. In control line the newer rules state 42' line length which a TD can't fly on due to too much drag. Td rules were 35' lines and there's a reason for it. They don't make the power to fly competitively. They're old school technology that is very problematic to hot start and the ball socket is horrendous. If the ball socket isn't failing, the cranks are breaking. I run up to 60% nitro in my Norvel's while 40% is my standard fuel and never have I seen a crank failure as a result of doing so. I admire your Cox infatuation and I don't know what to tell you about your Norvel experiences other than you might need to look deeper into your engine to figure out what may be the problem.

Poor COX engines, thanks to my topic they were given as many negative notes here as if it were a NEF (Norvel Engine Forum) Very Happy

Anyway I respect and rely on your opinion. Maybe I will order another spare set of NV061 piston/cylinder set (the set I ordered with the engine is equally rubbish) that hopefully has improved in its quality since the 2013 series came out that I had the bad luck with.

Surfer_kris Sun Nov 30, 2014 1:38 pm

I don't think that they will be very quick in changing things in the new production items, usually a run is made in a large series...

I think you would be better off getting some of the old-stock engines from ebay or similar.

andrew Sun Nov 30, 2014 3:15 pm

balogh wrote:
andrew wrote:.............. I run the COX engines when I'm just putzing around and like to tinker; I run the NORVELs when I like to fly.

Poor COX engines, thanks to my topic they were given as many negative notes here as if it were a NEF (Norvel Engine Forum)

balogh --

I was poking at you a little with the tinker/fly comment. Very Happy

I have a lot of COX and NORVEL motors -- almost every one needs a little care to run well. I don't have any NORVELs from the NV production runs (they may or may not be producing anything, simply building from old stock parts), but it sounds as if you may have a poorly fitting engine.

Having 25% more displacement in the .061 is advantageous, but I can get the NORVEL to spin up more easily. Once broken in, it takes less work to keep it running well and the R/C versions are more user friendly with a throttle than the COX motors.

However, if it helps, the last three engines I've cranked were COX. Surprised

andrew

balogh Sun Nov 30, 2014 3:33 pm

Andrew (I am also Andrew), no offense taken, we are all happy with what we find the best...the point is that we should all have pleasure in running these little critters with as many fingers left intact as possible...

Ken Cook Sun Nov 30, 2014 5:55 pm

I certainly didn't want to sound like I'm bashing Cox engines. I love my Cox engines and still use them. I love them for what they are. I own many of them, they were also a big part of my childhood. The memories alone I have with them are truly unforgettable. NV hasn't had any .061's in stock for almost 2 years. I inquired some time ago to only receive a unfavorable response. They feel that producing more pistons sleeves is somewhat a waste. They went in the direction of gasoline engine research and development. The new .40 is the bread and butter and the smaller stuff doesn't seem to be receiving enough attention to warrant production. Ken

**RknRusty** Sun Nov 30, 2014 9:43 pm

Andras, I won't add or subtract anything from the above guys whom I consider my teachers and authorities on such matters. But I did notice your engine on the right looks like one of the old ones built before the NV company came into existence. It does not have the black cylinder which I associate with Revlite engines, and I would assume if it it was built in 1997, that was before what is now called NV(rather than Norvel or AMD) came along and sold you the crap that isn't working. If you did get that one from NV, I hope it's old stock maybe made back when they were built the way we Norvel lovers have come to adore. Even my three Revlite engines predate the NV company by several years, and I have only had one problem. That one needs the crankshaft polished because it got aluminum fused to it and gets too tight at full running temperature and sags and quits. Sometimes that happens, but it was well after two years of regular flying... and my neighbor repeatedly crashing.

As for the 6 hours, I don't know, but maybe that's under high stress competition conditions. I know I have way more time than that on all of mine. And they all still have finger bone breaking compression. I only sport fly so far with them. I usually use 35% fuel with 50/50 castor/synthetic. I'll soon be trying my 4th, a pre revlite AMD and have high hopes for it. I probably will try my hand at combat with it.

I also use starter springs on all of them. I don't try to use the little hole for the spring, I just bend the spring's tang out of the way and zip-tie the spring to the wood beams. They even work on Brodaks and other engines that way too. It's especially helpful if you have a flooded engine which i sometimes get from over priming with a bladder.

Good luck. I hate that you've had such a disappointing experience with them. I hope it turns out better with your pre- revlite engine.
Rusty

**RknRusty** Sun Nov 30, 2014 9:50 pm

balogh wrote:Maybe I will order another spare set of NV061 piston/cylinder set (the set I ordered with the engine is equally rubbish) that hopefully has improved in its quality since the 2013 series came out that I had the bad luck with.

Maybe you can find some new old ones, even pre-revlite on e-Bay rather than going through the NV company.
Rusty

balogh Wed Dec 03, 2014 12:02 am

I wrote a mail to the US sales guy but he does not even bother answering.Either trying to escape the unresolved warranty case or may have read my emotional albeit factual postings about my experience with the Revlite 061 R/C ...I will check eBay though and if I find nothing the world of NV fans remains shorter with 1 member. So what...

Ken Cook Wed Dec 03, 2014 4:43 am

I suppose we could just bash the engines back and forth. I would just like to say my experience with NV to date is 100% different. Alex is the US rep for NV engines klondike17@juno.com. He's returned my e-mails within 30 min at any given time. I've also had him ship items before I paid for them. Again, I don't know what is or isn't happening there currently but a few years ago, those of us had NO resource for ANY parts. I commend them for even offering what could be the remaining stock of parts. In addition to having no currently available .061 Rev lite cylinders, he found me one and sent it. I had a contest to compete in and he came through. I can't thank him enough for doing so. While I've had terrific success, unfortunately yours isn't the same. The mystery remains. Ken

balogh Wed Dec 03, 2014 4:51 am

Thanks Ken,

my contact with NV in the US is Dmitry, the NV rep at info@nvengines.com" I will try your contact as well.

Surfer_kris Wed Dec 03, 2014 9:05 am

I've only noticed now that you seem to have a regular glowplug on it?
That's not going to help in any way, have you tried it with the stock Norvel head?

balogh Wed Dec 03, 2014 9:57 am

Sure, that was just one of my last efforts last year to squeeze some power out of the engine...BTW the conversion head is also sold by NV so it was not my improvisation. They sell it to facilitate glowplug replacement from commercially available regular plugs.

Anyways it also does not help to mend the fatal problem of lacking compression...was just a try.

balogh Wed Dec 03, 2014 10:44 am

[quote="balogh"]"...BTW the conversion head is also sold by NV so it was not my improvisation. They sell it to facilitate glowplug replacement from commercially available regular plugs.
........quote]

http://www.nvengines.com/index.php?page=shop.product_details&flypage=flypage-ask.tpl&product_id=71&category_id=5&option=com_virtuemart&Itemid=65

andrew Wed Dec 03, 2014 10:56 am

balogh wrote:

Anyways it also does not help to mend the fatal problem of lacking compression...was just a try.

Andrew

I'm inclined to think you, unfortunately, have an engine where the production tolerances have yielded a P/C fit that may not be repairable. Yours is just too loose for good performance.

Your .049 is an early manufacture, i.e., glued in venturi and a turned screen retainer. This engine should fall into the group with a very tight top end and with a good breakin, should be a runner for you.

andrew

balogh Wed Dec 03, 2014 11:12 am

Thanks Andrew,

incited, or rather, intrigued by my own topic, I primed and flipped then succesfully started for a short Brrrrrrppp..the 049 BigMig hand-held in the kitchen the other day (with a hair-dryer first heating the cylinder until the TDC pinch became light), and this really seems way more precisely fit than the 061 so my confidence is slowly returning.

So I will convert one of my engine mounts to accommodate the engine (about 1,5mm larger in cranckase diameter than my TD-s) and mount it on one of my birds to break it in then maiden it maybe this weekend.

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