mtntopgeo

My Feedback: (12)

Received a used MVVS .15 in the mail today ('bay item). First thing I noticed was it's weight. Is a tad on the heavy side; 'bout 7 OZs plus another 1 and 1/2 OZs for the muffler. Just looking at the rear crank bearing, con rod, & crank snot, the engine really appears to be built "stout". Next thing was the amt of compression & seal that the engine had. More than any other .15 that I own. First check on the seal at TDC was for 3 sec, then 10 sec, then 30 sec. The "pop" was just as strong when I released the prop after any amt of time. I think that it's about as close to "no leakage" as possible. Now to the test stand. .... Cold in the basement with the garage doors open, but I've already had this engine in my possession for at least 10 min., & still haven't run it yet! There was a fair amt. of discoloration on the piston top, so my thoughts were that the engine had a good amt of run time on it... That, & the fact that I had no 80/20 fuel, made the decision for me to use 5% nitro fuel with 20% oil (50% real oil, & 50% the make-believe stuff). about 4 drops of fuel in the carb, & flip, flip, flip, & not even a pop. Another couple of drops, & still nothing. Grab the electric starter, & same results. Put a couple of drops in the exhaust port, & it starts on the first flip. I was expecting old Enya workhorse-like performance from the MVVS, so was pleasantly surprised to get 16.6 K using a MAS 8x4 prop. A MAS 7x4, & an APC 6 & 1/2x5 gave almost identical numbers of about 20,850 RPMs. I didn't try to get the absolute last RPM outta her, just something that was clean, & near the top. Idle, as received, was about 4800, & I left the mechanical stop as was. I did play with the air bleed some, & it was easy to get a clean idle with good transition. The big surprise was the muffler. This thing really quiets the exhaust, A BUNCH. Not only that, but at nearly no cost to performance. Only lost 'bout one to two hundred RPMs with the small props. With the 8x4, results were a bit inconsistent. The speed would "wander" a bit, from a hundred lower to a couple of hundred higher, at times. Don't have the slightest idea of what's happening there, but getting too cold to look into it any deeper. All said, a pretty nice piece of equipment. Built "hell for stout", good performance, and can get that performance with little or no nitro. Think I'm gonna like this engine. ....... Now to find something a little lighter, cleaner, & faster than the Lil'Extras & Mini Ultra Sticks that I'm accustomed to having a .15 in. .................... George K.

combatpigg

My Feedback: (3)

That was very brave of you to buy one of those.....[:-]!! Actually, I've never heard much about MVVS except that they're not meant for much nitro. Morris Hobbies had a plane called the PENKNIFE that I got a video of, powered with a piped MVVS .21 and it put on as good a show as any larger 3D plane I've ever seen.

vicman

My Feedback: (10)

I have a couple larger engines from MVVS and like them quite a bit.

alcarafa

That's is correct CP MVVS are european engines designed for FAI fuel (no nitro) if you use do not go over 5% otherwise it will not run properly.

MJD

My Feedback: (1)

Hmm, I always say you should clean the snot from your crank on a regular basis..

I bought one at auction too, last year sometime,NIB with RE and a mini pipe. Here's what Pe Reivers had to say about the engine: (I always figured that anything set up for no nitro fuel is generally okay up to ~5%*, but he differs on that subject.)


Mike,
The little MVVS has an extremely flat torque curve from 12,000 rpm to 20,000 rpm. this means it does not perform all that well down low where other brands have higher torque, but propped for 17,000 or better the engine shines. 7x5 or 8x3 props are excellent.
Do use castor oil in the fuel. The engine does not like synthetic oil at all! 1% nitro is fine, 5% is too much.
All parts are available for some time to come. MVVS still has a good stock.
rgds
Pe

Actually the mid 16's on an 8-4 is quite respectable.

MJD


* except a Fox.. on the .74 for example you need -15% [sm=tongue_smile.gif]

Mr Cox

Yes, MVVS did make some serious engines in these sizes, and as said before just look at the inside;

fizzwater2

My Feedback: (61)

It's a shame that MVVS isn't making the small glow engines any more, but you can't blame them for continuing to produce something that isn't selling well any more. I know I'm sorry to see the small glow market going more and more electric.

I still have a NIB MVVS Q500 .40, complete with tuned muffler. Eclipsed by the Nelson/Jett engines, but still a fine engine all the same.

MJD

My Feedback: (1)

Let's see you break that rod! Well, anything is possible..

Here's the .15 I scored last year.

MJD

gkamysz

My Feedback: (19)

The first real engine I bought was an MVVS 2.5D from Carlson. It ran great. The rod did egg out in the little end eventually, probably from over-compressing it. I still have to make a new rod for it. The diesel turns very similar figures to the glow. I like them. I picked up another glow version a couple years ago.

BMatthews

Just a thought but if can find or make a slightly thicker head gasket to reduce the compression it should open up the tolerance for running with 5% nitro. It probably won't take much. Maybe 3 to 5 thou more than what is in there now.

And these were always engines that were intended for high performance and high RPM's. Going with a slightly smaller prop or less pitch would be the right thing to do.

combatpigg

My Feedback: (3)

Head shims can be made by tracing around the sleeve with a real sharp scribe until you cut through the shim stock....or if you have a good pair of cuticle scissors, just trace the sleeve dimensions onto the shim stock and snip away.

OTOH, some manufacturers sell shims seperately.

You can also chuck a head up on the flats of the glow plug and open the chamber up on a lathe or even a drill press to match a typical nitro head's proportions. This was considered standard practice to make FOX .36 engines run well with higher nitro.

mtntopgeo

My Feedback: (12)

[quote]ORIGINAL: MJD



Hmm, I always say you should clean the snot from your crank on a regular basis..



Hmmmmmm, Guess I need a Spell Check program, or at least put my cheaters on when I proof-read!!! ........George

I too thought that 5% nitro with 20% oil (50/50) was OK, but based on Pe's response to you, looks like I'll get some 80/20. ...
George K.