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-   -   MVVS Q500 (http://www.rcuniverse.com/forum/glow-engines-114/2081971-mvvs-q500.html)

Dewey2 08-13-2004 01:08 PM

OK new engine, what fuel for break in and what after. i use cool power 15% will the nitro be OK or do i need to find 5%. how much extra oil do i need to add what type.will cool power work with added caster oil. i should asked what fuel we used i guise.:)

ChuckN 08-13-2004 09:28 PM

The MVVS Q500 engine was designed for AMA Quickie 500 pylon racing. It runs best on 10-15% nitro and needs a smaller prop like an 8x8 or 9x7. Break it in like you would any other ABC engine - that is, do not run it blubbering rich.

Dewey2 08-14-2004 09:53 AM

yea its on a gp viper with a apc 8.8/9/0 pylon prop. but what oil type and content dos the fuel need.

ChuckN 08-14-2004 10:08 AM

18% oil content is fine. Doesn't have to be anything special, just don't use R/C car fuel. It usually has less than 18% oil. At most pylon events the fuel is supplied by the club putting on the event and Morgan's 15% nitro Omega fuel is very popular. It has a synthetic/castor oil blend. This is the fuel I like to use for my sport flying.

DarZeelon 08-14-2004 11:42 AM

Dewey, Chuck,

The MVVS Quickie 500 engine was designed to run on 0% nitro and on pure Castor oil (note spelling; a caster is a self steering wheel, like on a shopping cart...).

Anyone telling you that adding head shims to decrease the compression, does not change the design of the engine, is BS-ing you big time!!!

Since it increases the squish clearance of the engine, it reduces its power and increases its sensitivity to detonation; both undesirable.


Don't let anything with more than 5% nitro get even close to the engine and don't allow anyone to convince you to add the head shims to allow 10-15% nitro.
It will run, but it will no longer be an MVVS Q500 engine, from any perspective.

Don't allow this engine to sniff the pure synthetic oil green CoolPower fuel, although Omega is a starting point.

It must have at least 8% Castor oil component in the fuel.
With the exception of Jett and YS, no manufacturer of ABC/ABN engines will recommend pure synthetic lubricant fuel to be run in his engines.

There is a reason for that, so just don't!

The total oil must be no less than 20% of the fuel, so if you buy any proprietary fuel, also buy some Baker's AA, Klotz BeNOL, Morgan CleanCastor, or another degummed Castor oil, to achieve this 20% oil goal.

MVVS, Rossi and other European engines will show higher power and RPM on 0% nitro, than most other engines will on 10-15.

jaka 08-14-2004 04:06 PM

I must agree with Dar.
The MVVS Q-500 engines I have competed with ran very good on just 0% nitro (20% castor oil and 80% methanol).
Props were 9x6, 9x7 and 9x6,5 APC. RPM around 18500 with the 9x6 and a Rossi 6 glowplug.
around 17500rpm with the other props also using Rossi 6 glowplugs.
I really doubt that the engine will work good on as much as 10% or 15% nitro with standard deck hight.
Jan K

ChuckN 08-15-2004 07:46 PM

In THIS country, the country the MVVS Q-500 was designed for, we all run it on 15% without any problems. You will not find 0% nitro fuel at an american pylon race. FWIW, this engine has been around for at least 10 years now. MVVS had the Nelson .40 in mind when they designed their Q-500 engine but it ended up being more or less equal to the Webra .40 Q-500 and the Jett .40 sport pylon engine. Great thing about the MVVS is it's a lot less expensive!

RaceCity 08-15-2004 10:10 PM


Chuck has a point, as I believe that the US importer (Morris Hobbies) does mention the use of 15% fuel
in this motor.

As a happy owner of several MVVS motors (no Q-500's though) I would have to wonder if this "15% compatibility"
isn't the result of an importer modification. ie: Head shims.

MVVS just isn't in the habit of designing motors for anything but low/no nitro fuels from what I've seen.



DarZeelon 08-15-2004 10:57 PM


Curt strengthens my point.

The ONLY good way to make an engine suitable for higher nitro, is to physically enlarge the combustion chamber, without changing the squish clearance.

Adding extra head shims does not comply with this prescription.

The new head is one-piece now. You must take the head, put it in a lathe and turn some alumimium out of the chamber itself, without altering its shape significantly.

But this is not allowed under some class rules.... Well, extra head shims are not allowed either, are they?

And FYI, where is the FAI? In the USA, ofcourse.

FAI fuel was 'invented' in the USA for FAI racing and is 20/80 fuel, with no nitro at all.

The only reason 15% is allowed anywhere, is its popularity among sport flyers.

Racing has always been FAI, or 50-70% nitro, in specific classes. No 15% sport fuel.

MAJSteve 08-16-2004 12:09 AM

Dar - the FIA is in France.

William Robison 08-16-2004 01:21 AM


Dar - the FIA is in France.
Could that be what's wrong with it?



DarZeelon 08-16-2004 06:13 AM

Of course.

It is the Federation Aeronautiqe Internationale.

In my previous post I was not refering to its geographical location, but to its popularity, as far as events are concerned.

Most FAI classes, like F3D (Pylon Racing), F3A (Pattern) and F3C (choppers) are heavily represented by AMERICANS.
Much more so than French.

FAI Pylon is popular in the USA.

The fuel for FAI racing events has always been nitro-free.

We are talking about the MVVS Q-500 engine here.
To run well on 15% nitro, it needs to have its combustion chamber altered. Shimming the head will allow it to run, but not very well.

Ed Smith 08-16-2004 11:09 AM

A little clarification here.

FAI F3D pylon racing is not popular nor is it not flown in North America as a regular event. It is flown once every two years at the team trials for World Championship qualifying. There have been some attempts to promote the event by offering it at the Nats. At this years Nats it was offered at the end of the week only if the time slot was not needed by Q40. There were no awards or National Champion declared. There were only ten entries, compared to 70 for AMA428 and 60 For Q40.

The F.A.I. Head Office is in Lausanne, Switzerland.

The MVVS Q500 engine that I have seen promoted at the Toledo show By Morris Hobbies is, I was told by the importer, designed for the North American market to run on 15% nitro fuel. It is not a popular engine in racing circles as it does not compare in performance to the Nelson or Jett Q500 engines.

Ed S

DarZeelon 08-16-2004 11:52 AM


The US importer just wants to sell more and that is what he does.

Getting the best your engine can give, is your own goal; not his.

You would not expect to hear Josef *vajda, the MVVS head engineer, telling you to add head gaskets, would you?

Ed Smith 08-16-2004 12:15 PM


The US importer just wants to sell more and that is what he does.
I see nothing wrong with that. He is in business after all. His success will be determined by his integrity and the quality of the product. Who am I to call him a liar?

Getting the best your engine can give, is your own goal; not his.
That is a marketing strategy that is doomed to fail. "I will sell you an engine but it is up to you to make it work"! Probably why MVVS is no longer a serious racing engine in the US. Buy a nelson or Jett and they work. There is not much that can be done to them within the rules framework.

You would not expect to hear Josef *vajda, the MVVS head engineer, telling you to add head gaskets, would you
I have no idea what he would tell me. But why would I trust him any more or less than the distributor. I would rather listen to Henry Nelson or Dubb Jett, they obviously have more knowledge about racing engines as evidenced by the superiority of their product.

Ed S

DarZeelon 08-16-2004 01:21 PM


Jett and Nelson engines come from the factory set-up to use 15% nitro fuel.
You will not hear Henry, or Dub tell you to add a head shim, so your engine can achieve their projected RPM target.

Rather, you will see Dub tell you to return the engine, if it had not achieved this target RPM, on the stated fuel and prop.

If Clarence Lee of RCM is correct, Morris buys most of the Czech MVVS production.
As such, he can have the engines built with larger combustion chambers, to use more nitro without compromising the squish clearance.

...Or, he can sell this engine with two heads; one for 15% and the other for 0% nitro.
But he prefers to include the two bit head gaskets...

I would say MVVS don't want anyone to use more nitro, even if the big US dealer does.

If you want to see REAL competition power, MVVS have the #3070 GRRT and GFRT, with a full needle bearing con-rod and 30K capabilities, for pylon racing. The GRRT can even have an R/C carburettor.

Ed Smith 08-16-2004 01:37 PM


Jett and Nelson engines come from the factory set-up to use 15% nitro fuel.
You will not hear Henry, or Dub tell you to add a head shim, so your engine can achieve their projected RPM target.
They do not have to. Their engines always perform as advertised. I have spoken to both of these people many times and they have offered exactly that advice for changing conditions.

If you want to see REAL competition power, MVVS have the #3070 GRRT and GFRT, with a full needle bearing con-rod and 30K capabilities, for pylon racing. The GRRT can even have an R/C carburettor.
I would love to see this engine perform. Where is it, who is using it and what has it won? We are still refering to Q500 engines,right?

Ed S

DarZeelon 08-16-2004 01:59 PM


Once, Q-500 had only one meaning.

Today there is 428, 424, sport, whatchamacallit....

There are limits to each.

MVVS Q500 is not designed to compete in 428, but is accordingly much less expensive.

Yet it is too expensive to compete in sport class.

I also heard the tuned silencers are out for some classes...

How much of a compression ratio change do you need to make, for changing weather conditions?
About 0.1-0.3, like from 8:1 to 7.8:1.

For 15% nitro (for an engine set-up to run none), you need to change the compression ratio by 1-1.5, like from 9:1 to 7.8:1.
You need a much greater change, necessitating a much thicker shim.

Jett and Nelson don't tell you to run more nitro. They just tell you to use the accepted 15% and to adjust only for weather. Even the prop size is given and no other prop RPM is quoted (for Jett).

Ed Smith 08-16-2004 02:22 PM

The tone of this discussion is moving in a direction that would seem I have something against MVVs engines. I certainly do not.

A question was asked about the use of Nitro in an engine. I responded with the limited knowledge that I had on the subject and information I was given, no more, no less.

I will not be drawn into arguments as to the relative merits of head shimming, what constitutes Q500 or anything else that rambles on for ever and goes nowhere.

Ed S

jaka 08-16-2004 02:24 PM

Lots of talk here.[>:]....but It would be interesting to hear from someone who has actually raced one of the MVVS Q-500 engines on 15% nitro....
I have not ...only run on FAI fuel. But I'm damn curious....
Jan K

David_Moen 08-16-2004 07:29 PM

I'm the Canadian MVVS distributor. I run all of my glow engines on 5% fuel. In thier stock configurations, my glow are really unhappy on any more than 5% nitro.

Many of our customers have asked about "shims" for running higher nitro percentages, often they want to use up existing fuel stocks. In order to satisfy these customers, on my last factory order, I asked that they include a supply of "shims" for all the glow engines. To my suprise, I received new cumbustion chamber "buttons" instead. These buttons form the top of the combustion chamber and, I assume offer a little more CC volume, lowering the overall compression ratio. It could be that the US distributor is ordering his glow engines with the "high nitro" button installed right at the factory.

To me the ability to change the size of the combustion chamber to suit the fuel is a very nifty solution, much neater than guessing about the size and thickness of a shim!

downunder 08-16-2004 08:10 PM


FAI fuel was 'invented' in the USA for FAI racing and is 20/80 fuel, with no nitro at all.
Get your facts straight Dar before you make statements like that.

As others have pointed out, FAI is the WORLD controlling body for ALL types of aeronautical sporting competitions (models, balloons, parachutes, you name it). As such, they develop the rules which must be complied with for World Championships. Local events such as AMA or your club can make up whatever rules they like. "FAI" fuel was originally legislated for 2.5cc CL speed (and possibly free flight) to ensure that no competitor had an unfair advantage by using exotic fuels in events where absolute maximum HP is a necessity. In other words, they levelled the playing field. RC pylon would, I assume, be a late comer compared to CL and FF so FAI fuel would have been adopted to give the level playing field in international competitions.

ChuckN 08-16-2004 08:42 PM

This has come full cirlce, hasn't it? :D
MVVS designed their Q-500 engine for club sanctioned pylon racing here in the US. I had no idea this engine was even available in Europe (or the mideast for that matter). The 40 GRRT, on the other hand, was designed for international FAI racing. This racing is very different. Not only do the rules mandate FAI fuel (80%methanol/20%oil), the rules require competitors to race against the clock. They don't even race against each other heads up!

OK now, for those already familiar with north american pylon racing you probably don't need to read on. But for our friends over in Europe here's a short rundown of US pylon racing:

AMA Event 422: Q-40 (Quarter 40); wing area 400 sq inch min; 56 inch max span; 4 lbs - 5 lbs total weight no fuel; tuned mufflers allowed
AMA Event 428: Quickie 500; wing area 500 sq inch min; 52 inch max span constant chord wing; 3.5 - 4.5 lbs total weight no fuel; tuned mufflers allowed
AMA Event 424: Sport Quickie; airplane specs same as Quickie 500 except no tuned mufflers allowed

All three classes specify a 2-stroke engine that displaces .40 cubic inches max (.403 to be exact). The rules also state the fuel should be "not more than 15% nitromethane, and shall be supplied and dispensed by the hosting organization".


Where does the MVVS Q-500 fit in? Well, it doesn't anymore, to be honest. The Jett and Nelson 40s with their highly tuned exhausts and 17mm crankshafts make the MVVS engine a non-contender. Awhile back, though, regional organizations like SEMPRA (South East Model Pylon Racing Association) ran a non AMA sanctioned event called Sport Pylon along with the AMA 422 and 428 events. Sport Pylon rules allowed competitors to run tuned pipes on front intake side exhaust "sport" engines and race separately from the superior Nelsons. This was the class the MVVS Q-500 engine was made for. I was at the first race the MVVS was brought to and I vividly remember the ensuing arguments. Those that were running the Webra Q-500 and Jett Sport .40s vehemently opposed allowing the MVVS engines to run, based only on the fact that MVVS touted their engine "will outperform all other unmodified engines, no further tinkering is required!" In reality the engine was actually about even in performance with the Webra but not quite on par with the Jett. It never found any real success in pylon racing here, but lives on as an affordable high performance sport engine.

RaceCity 08-17-2004 04:46 AM


I feel bad for the first poster (Prophanger) who merely wanted to know what fuel to use for break in
on his new motor.

'Prop....did you get your answer or do you still need one? PM me and I can offer you some suggestions.

Ed hung up the phone on us...

Chuck has some informative inputs on sport racing as well.

So it's clear, I DON'T race, but I do own MVVS engines. I couldn't be happier with them.

If anyone really cares, these posts illustrate to me what is wrong with competition flying these days.

Webra and Jett owners were "Vehemently opposed" to running alongside the MVVS for no other reason than
a marketing claim that wasn't even made by the manufacturer AFAIK. In most quarters...this means they were worried they were gonna get their *****es kicked.

No real data to support the claim...just the "say so" factor.

And so it is with much of competition flying IMO. It's a particular-name-brand, marketing, eye-candy-for-the-judges bunch of
hoo-hah. This is the reason Pattern is so dead these days, and I can promise you...SA, Pylon and Q500 aren't far from the deathbed either.

Fashionable equipment scores more points than creativity and good tuning, and friends it gets real tough to keep up
with the Jones' every year when the "trend" flip flops around like it does.

Frankly? If MVVS started charging $500.00 per copy for those engines...they'd have a much bigger following. They certainly have
a racing heritage that goes back more than 50 years.

When Nelson and Jett can assemble a motor of the same quality as an MVVS for $189.00? I'll buy those instead.

Until then...I'm sticking with MVVS.

Gentlemen...I LOVE r/c, but I am DONE spending my paychecks on the equipment everyone else thinks I need.


ChuckN 08-17-2004 06:38 AM

Very well put, RaceCity! I have no interest in R/C airplane competition anymore, either. I find pattern interesting, but at this point I just can't afford the big engines and planes that are "required" to be competitive. Perhaps this is why R/C car racing is rising in popularity here? I know a lot of sport flyers that also race cars on the weekend.

Sorry if I veered this thread off on a tagent, prophanger1. I do have something that may be of great interest to you, though. It's a copy of Clarence Lee's (of RCM) product review of the MVVS Quickie 500. I can scan it and email it to whoever is interested. It includes a short history of Q-500 engines and some useful MVVS Q-500 specs such as:
Bore: 21mm (.827 inches)
Stroke: 19mm (.748 inches)
Carb Throat Dia: 9.3mm (.365 inches)
Compression Ratio: 8.63:1
RPM with wooden Rev-Up props and 15% fuel:
9X6 - 17,800
9x7 - 17,500
10x6 - 16,400
10x7 - 13,100
11x6 - 12,300

Something that Clarence Lee pointed out is very interesting. Quoted word-for-word:
"...the Quickie 500 engines are test run prior to shipment with 15% nitro fuel which in this case was Jim Morgan's Omega and a 9.5 x 6.5 APC prop. A certificate of performance accompanies every engine which must turn between 17,400 to 17,700rpm."

Prophanger1, did your MVVS come with this certificate? This article was written back when MVVS Corp. of America in Woodlands Texas was the importer. It's possible that they test run the engine and provided a certificate of performance and not the MVVS factory back in the Czech Republic. Hope that this was helpful rather than simply long-winded :D

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