EVOLUTION

Which part do you agree with?

I've had the same conrod in one of my old mt12s for almost 5 gallons and it's still in good condition although it hasn't been run as hard as some of my other engines.

What Corse R is saying,i think is that if you inspect and measure your conrod bushing and crank pin diameters every now and then you will not have a massive engine failure.There are several threads on the RB forum were Rody mentions the max diameter for the conrod(bushing)and min of the crank pin in terms of wear and if you exceed the tolerances then you should replace the necessary component(conrod or crank),therfor you wont have conrods exploding and damaging the whole engine,there are also other variables!

You shouldn't have to tear down the motor after every run,just periodically or if you have a run away or missed gear shift cause of a 2 speed problem which could stress the conrod etc.

EdwardN

iTrader: (1)

I wasn't talking about one which moment you got to chnage conrod, I was talking about how to make conrod and crancksahft life longer. Cors is right about inspection of engine periodically to prevent from major brack down, not after every run, but at list after 3-4 meetings.
What I was talking about there is ways to make engine life much longer. You just need perform abviose set up on it and it will last 2-3 times longer. All Novas and Rossi made after 1985 (if I am not wrong with date, but it start from Rossi F15) made the same way-too tight. It is due to the costs of setting P/S sets. So manufacturers are leaving it to racer. I try to recomend how to prevent from this damage by performing simple set up.

EVOLUTION

Top Gun 777,

I was making a general post and not one in reply to one of yours.Maybe you can grace us with some of your knowledge on how you prolong engine life!

Corse-R

Conrod wear is determined by many factors, but you're getting into a big error discarding the wear excercised by a engine running at 35000 rpms during, let's say 2 or 2.5 Seconds, let's see...

35000 movements going up and 35000 movements to down per minute is 70000 changes of direction per minute, this gives us 1166,6 movements per second, during 2 seconds gives us the final amount of 2322 movements of the conrod and 2322 moments of stress and wear of the crank (and I'm counting only when it goes to TDC and BDC, when stress is maximum.

This is a lot of stress and wear....


I got this practice of changing the conrod because is aproximately when it starts to have excessive wear and starts to develop slopiness (just check yourself with the piston at TDC or BDC, move slowly the cranshaft and see how it moves into the conrod bushing. This small wear is what put excessive stress on the conrod and makes it break.

Probably conrods last more, but I know that they don't break if isn't for anything wrong in the conrod construction, probably can use 2, 3 or 4 gallons, but spend too much hours modding mine own engines to risk it for a worn conrod. Prefeer to trash a conrod than a complete engine.

I'm playing with R/C engines for a long, long time, mine first engine was a Picco P5 (in those time, CMB and Cipolla engines were king, but Rossi engines were a POS - we're talking about 1989). From picco switched to Nova mills and I'm quite happy with them.

Regarding tear down the engines should be a common practice if you appreciate your engines I do it each weekend and I check everything when I reassemble it and lube it properly, ready for the next race/weekend (don't takes too long tear down and reassemble an engine, going very slow and carefully 20 minutes of maintenance to a such expensive piece of your equipment).

paulfitipauldi

Hi, Don José,, nice to see you here,,

well like these big guys says ,, you're lucky to have only a fallen bushing from your conrod,, My guess, but after seen your range of temperature you're running the engine now I'm sure, that the High temperature was the problem,, I run my engines at a maximun of 230 degrees and a minimun of 200 degrees,, remember that we live in a hot tropical Island ,, and when you put the shell ,, your engine must be reaching the 300 degrees or more ,,

And one last thing,, the maintenance is the key of an engine life,,

Well see yaa ,, next Sunday in Levittown,, OK!!

Ciao!!

modellor

I got to agree with Top Gun,

If you treat the engine right from the beginning it will last a lot longer. My RB 3-port engine got a lot of running for 2.5 solid years before I even considered changing the conrod. Only changed it then because it was starting to show slight signs of wear.

The P/L was changed once during this time and that was only 3 months before I changed the conrod. So, people will say I dont push my engines. Wrong. I like to have them squealing for mercy. The harder they go the better.

Its not a Turbo engine but it has hung with quite a few Salven 5-port Turbos in the Outlaw class. Using the right break-in method and making the fitting proper from the start will indeed increase the life span of the engine no matter how hard it is run.

EdwardN

iTrader: (1)

I don't discard wearing of conrod during the high rev time, I just saing, more stress on conrod and pin during the first 3-4 tanks run in time. Do us a favor, I am sure you can. When you got new engine, before you start it firts time-mesure the pin from six position and msure the bore on conrod in six position, after that start engine and run one tank and mesure it again. Give us please results of your mesurments. And for real experiment do it after each tank you run your engine-you will find a lot of answer on your questions so we will.
Well, I start work with engines in 1976 at age 14 years old. My first engine I worked on, was Russian copy of Rossi R15. I didn't do this stuff for last 10 years and at one moment was thinking a lot of was changed since that (actualy I was told by one racer on local track). But now,after 5 month back, I can tell you for sure, nothing got changed for last 10 years, at list tramendosly-no one manufacturer still use Berilium brass for sleeves, silicon content is still bellow 20%, just recently Sirio start using AAC sets. You wouldn't belive, we use this stuff 20 years ago. Berilum brass sleeve perfect for high temp application and haevy load engines, AAC are running cooler then ABC and Berilium sets.
I agree with you about cleaning and inspection of engine-this needs to be done periodically, but not realy very often, I would sugest to say ones a month take on parts and checked everything, but after every weekend take the head out and clean warnish, take backplate and inspect for abviose problem.
Have fun.

eddiethefish

That's IT!

I'm moving to Ireland. Everything seems to last forever there. First, the battery lasts 16 years, here comes the report of an RB engine lasts two and a half year. I'll take my wife with me, so she can stay forever young there, as well.

How difficult is it to move and live there?

Manticore

i told you, dont use WD40 on your engine !!

WD40 is too fast !!

Corse-R

Probably is the 'Adjusting tool' the one that kills and overheats engines (and not engines). And remember the ones that prefeer the rough

EdwardN

iTrader: (1)

Stop Eddie!!!!!!!!
Don't move we need fish here too!!! We will find you new wife every two years, just stay here!!!!!!!!

click, dublin

Hi,

You would be quite welcome to move to Ireland but consider the following:

MTX2 ProSpec approx. $800
MTX3 with MR12 $950
MRX3 $850

The RC scene in Ireland is quite small + our taxes are very high, its a small country so the suppliers tend to charge very high prices.

I'm refering to Southern Ireland regarding the prices.

So now you see why everything lasts so long . . except the Guinness!!!

All the best

EdwardN

iTrader: (1)

Eddie, don't go there, you can't afford it!!!!!!!!!!

paulfitipauldi

Manticore

well, it is no fun to make things last just because they are expensive. but i do think modeller has some secret magic to make things last !! i wonder if he would like to share his secret with us.