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Old 12-10-2009, 08:08 AM   #31
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as said above the vspec is the MOST used engine out there not matter how you slice it....I am a RB fan and I will admit it there are far less RBs/novas then Vspecs at any track I have raced at...my crack was on the very bottom of the case cause by rod/crank pin slop...on my current EB mod 09 style case I have not had a issue yet...
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Old 12-10-2009, 08:10 AM   #32
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I would agree but his point was that of course you will see more OS motors break because there are more of them on the track.

Numbers vary from track to track but typically if there are 50 racers at a track, 30 of them are using OS motors. So, if we assume this is a really tough track and 10% of racers will have cases break, that's 3 OS motors broken to only 2 of all the other types combined despite the fact that all the motors had the same failure rate (in this hypothetical example).


very good point for sure.... The V-Spec is a belly button engine, so what you say is definitely plausible....

I did however read some information about the different case manufacturing techniques, and the author was saying the older method of sand casting produced a stronger case then the modern injection molding... However I guess I was wrong about the injection molding , but there is definitely a different process being used in different engines...You can see the newer style of manufacturing has much cleaner lines and a much better fit and finish....The older sand cast blocks are rougher and less precise looking......I wish I could find the article I was reading, but that would be like a needle in a haystack......
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Old 12-10-2009, 08:27 AM   #33
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I ran mostly RB's & never cracked one but at my local club track I've seen at least 3 or 4 OS Vspecs & 1 VG cracked in the last couple of years.
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Old 12-10-2009, 10:47 AM   #34
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I know what you mean Maximo. I am no expert on aluminum casting but I recall hearing something about the new process Nova and some others use. Something about applying a vacuum or pressurizing with inert gas or something like that. Supposedly reduces the presence of air bubbles and voids in the casting, reducing problems from manufacturing defects.
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Old 12-10-2009, 11:11 AM   #35
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Investment casting

Investment casting of aluminum most commonly employs plaster molds and expendable patterns of wax or other fusible materials. Plaster slurry is "invested" around patterns for several castings, and the patterns are melted out as the plaster is baked.
Investment casting produces precision parts; aluminum castings can have walls as thin as 0.40 to 0.75 mm. However, investment molding is often used to produce large quantities of intricately shaped parts requiring no further machining so internal porosity seldom is a problem. Because of porosity and slow solidification, mechanical properties are low.

Investment castings usually are small, and it is especially suited to production of jewelry and parts for precision instruments. Recent strong interest by the aerospace industry in the investment casting process has resulted in limited use of improved technology to produce premium quality castings. Combining this accurate dimensional control with the high and carefully controlled mechanical properties can, at times, justify casting costs and prices normally not considered practical.

Aluminum alloys commonly used for investment castings are 208.0, 295.0, 308.0, 355.0, 356.0, 443,0, 514.0, 535.0 and 712.0


Plaster Casting

In this method, either a permeable (aerated) or impermeable plaster is used for the mold. The plaster in slurry form is poured around a pattern, the pattern is removed and the plaster mold is baked before the casting is poured. The high insulating value of the plaster allows castings with thin wads to be poured.
Minimum wall thickness of aluminum plaster castings typically is 1.5 mm. Plaster molds have high reproducibility, permitting castings to be made with fine details and close tolerances. Mechanical properties and casting quality depend on alloy composition and foundry technique. Slow cooling due to the highly insulating nature of plaster molds tends to magnify solidification-related problems, and thus solidification must be controlled carefully to obtain good mechanical properties.

Cost of basic equipment for plaster casting is low; however, because plaster molding is slower than sand molding, cost of operation is high. Aluminum alloys commonly used for plaster casting are 295.0, 355.0, C355.0, 356.0 and A356.0


Permanent mold casting

Permanent mold (gravity die) casting, like die casting, is suited to high-volume production. Permanent mold castings typically are larger than die castings. Maximum weight of permanent mold castings usually is about 10 kg, but much larger castings sometimes are made when costs of tooling and casting equipment are justified by the quality required for the casting.
Permanent mold castings are gravity-fed and pouring rate is relatively low, but the metal mold produces rapid solidification. Permanent mold castings exhibit excellent mechanical properties. Castings are generally sound, provided that the alloys used exhibit good fluidity and resistance to hot tearing.

Mechanical properties of permanent mold castings can be further improved by heat treatment. If maximum properties are required, the heat treatment consists of a solution treatment at high temperature followed by a quench and then natural or artificial aging. For small castings in which the cooling rate in the mold is very rapid or for less critical parts, the solution treatment and quench may be eliminated and the fast cooling in the mold relied on to retain in solution the compounds that will produce age hardening.

Some common aluminum permanent mold casting alloys, and typical products cast from them, are presented below.


Alloy 366.0 - Automotive pistons
Alloys 355.0, C355.0, A357.0 - Timing gears, impellers, compressors, and aircraft and missile components requiring high strength
Alloys 356.0, A356.0 - Machine tool parts, aircraft wheels, pump parts, marine hardware, valve bodies
Other aluminum alloys commonly used for permanent mold castings include 296.0, 319.0, and 333.0


pick one
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Old 12-10-2009, 11:19 AM   #36
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Damn you Google search ^^^^^^

I 100% agree with the fact that is in the numbers of OS motors at the track. They are so user friendly that any monkey with a screwdriver and a P3 plug can get it to run decent.

When 50 to 60% of the engines are all one brand of course they are going to break. I had one crack down the centerline and one crack at the mounting ears from truggy ABUSE. Huge triples and ugly landings on rock hard clay tracks do ugly things to engine cases

With the way noobs drive and the flavor of the month engines (it's currently the Nova Plus 4c in FL) we'll start seeing them broken soon enough.
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Old 12-10-2009, 11:27 AM   #37
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another interesting read taiwan vs. italy quality



After the boom, the Asiatic competition puts the Italian metal casting sector up against a wall. Only experience, flexibility, quality and competitive prices can contrast the Chinese giant.

FOR IMMEDIATE RELEASE

PR Log (Press Release) – Mar 06, 2007 – As anybody noticed, the European market was given a strong jerk by the pressing growth of new Asiatic economies (China and India above all), and in particular of the engineering and metal casting furnace.

In order to contrast the threatening advance of these emerging markets, it is necessary to focus on weak aspects of the provided services and products. In fact, it is true South-East Asia companies offer low-cost finished products but they feature second-rate quality compared to the European standards, Italian first of all.

In these conditions, the metal casting industry and mold-making industry have to turn to their experience, professionalism and ability to adapt to new market requests, all features that China and India can’t still provide for their new development.

On this regard, 7 important metal foundries and cast iron foundy have set up a Group: a truly effective Team aimed to solve problems and needs related to the mold production and metal casting.

These are the companies settled in Veneto:

• Procasting Srl: cast iron metal prototypes of any metal
• Program 2000: design, creation and production projects
• Modelleria Zuin: small and medium size models of metal, resin and wood for foundries
• Modelleria Griggio: production of metal casting models for medium and big foundries
• Modelleria 80: produces metal casting models and wooden moulds of big dimensions
• Tecnomodelleria: small, medium, big wooden and aluminium models for thermal-modelling
• Sand Form: cores: sampling and production for foundries

It is easy to understand that this partnership is the Team’s main strength as it gathers in one spot the know-hows of 7 companies. This union leads to some logical improvements as the cutting down on costs of prototypes and moulds production and on the replying time, whilst offering a wider range of technical solutions.

Today the KnowHow Team offers the most innovative solutions to problems related to moulds design and moulds production for the industry.

This article was written by Michele De Capitani with support from metal casting equipment. For any information on how travel insurance, please visit our web site.
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Old 12-10-2009, 11:29 AM   #38
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Quote:
Originally Posted by rdeppen View Post
Damn you Google search ^^^^^^

I 100% agree with the fact that is in the numbers of OS motors at the track. They are so user friendly that any monkey with a screwdriver and a P3 plug can get it to run decent.

When 50 to 60% of the engines are all one brand of course they are going to break. I had one crack down the centerline and one crack at the mounting ears from truggy ABUSE. Huge triples and ugly landings on rock hard clay tracks do ugly things to engine cases

With the way noobs drive and the flavor of the month engines (it's currently the Nova Plus 4c in FL) we'll start seeing them broken soon enough.


you are right with the os tuning rdeppen os engines will run even if you dont know how tune at all
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Last edited by houston; 12-10-2009 at 01:01 PM.
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Old 12-10-2009, 11:55 AM   #39
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you are so right with the os tuning rdeppen
Easy buddy. Some of us "monkeys" might take offense.
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Old 12-10-2009, 11:58 AM   #40
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just get a novarossi
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Old 12-10-2009, 12:06 PM   #41
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I have cracked a few cases.......

all in my MBX5T Prospec......

2-nova 528's and a OS 30.

I figured it was do to the GIANT moto style jumps that were popping up all over last year... since I have been more carefull and have not had anymore issues. But I have switched to a RC8T also, not sure if that really was a factor or not.
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Old 12-10-2009, 01:00 PM   #42
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Some of you get it - it's a simple matter of statistics and fact that, when you have conditions that are completely unrelated to the construction of the engine that contribute to failure, that engines that are in far greater concentration in the market will have the highest numbers of failure. It's probably safe to say that OS sells 10 or 20 engines to every engine sold by the next closest competitor. So, if all engines experience the same failure in the exact proportion to their sales, there will still be 10 to 20 times the number of reports of failure with the OS engines than any other brand even though it's completely unrelated to the actual construction or quality of the engine. Consider also the skill level of the people that own the various brands of engines and how they can influence the rate of failure. I would speculate that the average OS owner is less experienced than the owner of, say a Novarossi, Sirio, Picco, RB or other brand of engine. OS engines are the most visible and recommended engines, and newcomers may not even be aware that many of the other brands of engine are available. People that have been in the hobby longer are more likely to be exposed to these less-promoted brands, so they probably enjoy a customer base that is more experienced, and therefore less likely to cause damage to their engines.

Independent of the statistics, there MAY be some merit to one case being stronger than another, but some of the quotes posted here about what you've personally seen is ignorant of all the aforementioned. It's what's often called "science by a sample of one." Just because you see something happen once or even four or five times, it doesn't even begin to amount to evidence that there's a flaw. To actually find a legitimate flaw takes much more data and analysis, and none of us are in a position or are qualified to make that determination.

Merdith points to the OS carburetors as a problem, which ironically has been one of their most lauded accomplishments for decades. I've personally seen the extra steps taken in the manufacturing process to ensure their carbs adhere to very strict and repeatable tolerances, most of which are still not in use at any other engine manufacturer. The vast majority of experience engine people point to OS carbs as the standard by which all others are judged. But, perceptions being what they are, some people assume that, because they had a problem, it's universal and persistent.

Everyone is free to disagree because of their own personal experience, but facts and information collected over decades support the notion that OS is a top-quality brand that has the highest quality standards and has experienced fewer brand-wide problems than any other engine. I'm not suggesting they walk on water - of course they're capable of mistakes and have made some. but I've run through my share of engines (probably more than anyone on these forums) and these are my observations. I don't have any connection to OS, but I've been deeply immersed in the RC business since 1984 and have been running nitro engines even longer than that, so I think that lays the foundation for a much broader perspective. I give credit where credit is due, and they make an outstanding product. They may not be everything to everyone ALL the time, but on balance they're among the best, if not THE best in all matters of concern to the average nitro enthusiast.
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Old 12-10-2009, 01:04 PM   #43
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Easy buddy. Some of us "monkeys" might take offense.
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Old 12-10-2009, 01:10 PM   #44
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Chassis flex and Motor mounts are a big part of a broken case. If you mount the motor wrong it can crack the case. At tracks like the Nitro pit you just dont see V-spec motors any more because of the Big jumps, When the Chassis flexes you can break your case if you land upside down on the head you can crack the case. The new Worlds V-Spec and Ninja motors have a better case, but you are going to pay $$$$.
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Old 12-10-2009, 01:11 PM   #45
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so is it fair to say you really like os engines steve?

i will agree that os is a very popular engine but 10-20 to every other engine in sales , not too sure about that.


there are many good engines out there today and it is pretty much an opinion and what you choose to run ppersonally
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