EdwardN

iTrader: (1)

I am changing conrods only when it is playing on the pins, usualy when I do PM service on engine I am checking for unusual things as for instance-changed color on bushing, mesure for eleptic on the wholes, but other then that, I preferd to don't touch it. Normaly conrods should last as P/S set, if you need to change it earlier-something was wrong ( can't tell you because every single instance is unique-need to see).

stefan

The reason I'm asking is that I have an engine that has been running REALLY strong for over 4 Gallons now and it just keeps going, without any signs of getting tired.

I was thinking about changing the rod, because I don't want to ruin the entire engine bacause a $25 conrod failed.

But then again, the rod still looks great and doesn't have any play...

Sp Racer

iTrader: (12)

Top Gun 777 asked

Yeah, I can tell you how it was performing...

Tommy's car was like a missile!! I was using a NS3 Novarossi and he blew past me like he was running a .21....very impressive


......I want one Tommy!!

EdwardN

iTrader: (1)

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Ah10

hey Stefan, you might want to check the ID measurement on both bushing, the crank pin and the wrist pin, sometimes it doesnt wear on the crank pin side but it does on the wrist pin, also check the wrist pin see if it is still perfect round as well as the crank pin! Just a thought! I normally do that!

$25 or even $40 is cheap compare with $250 on a new engine!

EVOLUTION

Does anyone know the measurements for the conrod on the wrist pin side and what would be the max ID for the rod bush?

EdwardN

iTrader: (1)

thanx a lot for info.
Talk to Tommy he will arrange everything.
BTW, that engine doesn't have turbo scoop, it has huge chamfer on cranck. (see the picture from Tl211 post posted before).

Ah10

I dont have the measurement right now but let me get a brand new conrod and I'll measure it!

Manti, Corse R, you guys have the measurment??

Surge

iTrader: (2)

I've heard that as piston/sleeve compression starts reducing through use, that the head clearance should be reduced to regain some of the lost compression. Comments?

EdwardN

iTrader: (1)

I won't do it. I am setting up head clearance and try to keep it as long as possible ( unless ambient parameters have been chnged). If compression goes down it will lose perfomance, by changing compression ratio you can create a lot of mess inside combustion chamber, also on my engines head shim is already .125-.15 mm-no way I will go down.
There is only one way to change head gasket-to compencate wheter conditions.

Corse-R

Asked some time ago to Rody about this matter and gave me some measures for the crank pin. A brand new crank pin measures 4.27mm, he said 4.23mm is time time to replace the crank, specially when the crank pin doesn't wears round (it ovalizes). I measure it with an outside micrometer (see pages 2056, 2057 & 2058 from McMaster catalog - http://www.mcmaster.com). If any interested on buying one of those, check to have a precision of at least 0.0005" or better, Mitutoyo and/or Starrett are the best ones.

About the conrod never measured it (haven't found anything better than mine dial caliper to do it), but every time I disassemble mine engines I check the conrod/crank pin fitment, trying to find any excessive slope on several points. If found excessive slope I change the conrod prefeer to trash a 20US$ part rather than grenading a P/S.

On .12 the conrod isn't much fatigued, piston and conrod is subjected to less stress due to lighter weight, but this is much evident on .21 where the weight of the reciprocating parts is higher and the wear on the bushing of the conrods is more evident (just check too the other conrod hole for wear and inspect the piston pin too) replace if appears scratched or with signs of wear - Novamega has spare parts for everything, from e-clips to piston pins too.

loosenut

I'm confused...

Novamax

Novamega

Novarossi

All have a .12 engine. Are they the same just different labels or different engines? Also there's Rs12 and Ns12? Which one is better???????

Gary

EdwardN

iTrader: (1)

loosenut

Sorry, I know it's a weird question but I'm trying to decide on an engine for my mtx-3 lately and have been confused by all the brands.

Has anyone tried the v12 RB here? Were could you buy the rody version? Can't find them anywhere!

Gary

Ah10

Gary, Novarossi is a maker, Novamega is one of the engine line from Novarossi engines. and Novamax is a Novarossi base engine but it is a hand modified engine by Massimo Fantini. I think the correct name for Novamax is Max Power. some ppl call it novamax is because it is a nova base engine kind of like merge 2 words together.

Now RS12 and NS12, they are both Novarossi engines but the NS is a newer version and the RS is the older version.

I dont know much about the V12 engine but I have seen a few Rody X12 5 port died a few times, crank pin was wearing out to fast, less then 3~4 gallons. But the Rody X12 is very powerful on the bottom end and top end kind of like an on/off switch and it is very hard to control the power.

If $$ is not an object then I would suggest Max power, and if you are ok on $$ then I would suggest NSR series, NSR12 S3 or NSR12 S5 (depends on your club rules). And if you are on a tight budget then get the STS D5.

Hope that would help!