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Old 01-05-2008, 04:29 PM   #61
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If someone has a worn out engine, I could make a new piston for it.


It'll be 7075 aluminum, so I can't guarantee that the engine wont' blow up.

Just PM me.
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Old 01-05-2008, 09:12 PM   #62
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In general, the machined piston is more dense and will expand more when hot, but the cast can run a tighter fit, since it doesn't expand as much. Also, the microcast its lighter, but softer.
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Old 01-06-2008, 05:12 AM   #63
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Originally Posted by Rocket42 View Post
I don't know if its possible but it may be better to machine a aftermarket ringed piston and then sell the rings seperate.
reason they are not ringed now is the rpm and temps run would kill the ring. Also they have too many ports for the ring to snag.
I would think you could make the piston the same weight out of the harder material , but it may not work because the sleeve could be worn out of round, the breakin would be horrible too, I personally have a few tricks up my sleeve when it comes to pinching that helps keep things correct , I personally think that pinching is the most economical way to freshen up a worn mill.

I want to find an easy way to rebuild crankshafts personally , I think that is the most costly thing that wears out, resurface the barrel and crank pin with some sort of super hard coating (maybe nitride or carbide?) and then regrind it back to factory specs. And do this for say- $50-$60 dollars

Last edited by mremtr; 01-06-2008 at 05:13 AM. Reason: fogot to add something
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Old 01-07-2008, 03:31 AM   #64
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I have a few Novarossi engines my self and have see many. They have a bearing issue. They need find a supplier that will give then bearings to live up to their name. Novarossi's are very reliable engines and will last you a long time if you maintain and treat them correctly. Their price is getting higher and higher every new engine. a 500 dollar buggy engine is pretty rediculous. Take the new Plus 367 for example. Its 500 bucks, has bearing issues among a few other issues have been reported. They are sub par engines. They have been tested on the X-Dyno and there are many engines out there that are better and cost less. I understand some of their high price being that they are ISO certified but honestly for 500 i would just buy a JP Racing engine or something cheaper to have modded and it will outperform. I think they need to up the ante a little bit, their 2 major competitiors are pumping out better Race bred engines right now. Their budget N21 series is a excellent engine i have 3 of them one is the Original T21BF, R21 2000BF, and T21 2000R. All Excellent performers for a great price, i did haft to replace the bearings before the 1 gallon mark but other than that no complaints other than they pretty much deny the 2000 series engines. Basically my only problem is this. They need to fix the bearing problems, they need to make some more power and their powerbands are really rough instead of broad and smooth, and they need to come down on the price which could be a dist/dealer problem.
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Old 01-07-2008, 08:57 AM   #65
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Originally Posted by German Muscle View Post
I have a few Novarossi engines my self and have see many. They have a bearing issue. They need find a supplier that will give then bearings to live up to their name. Novarossi's are very reliable engines and will last you a long time if you maintain and treat them correctly. Their price is getting higher and higher every new engine. a 500 dollar buggy engine is pretty rediculous. Take the new Plus 367 for example. Its 500 bucks, has bearing issues among a few other issues have been reported. They are sub par engines. They have been tested on the X-Dyno and there are many engines out there that are better and cost less. I understand some of their high price being that they are ISO certified but honestly for 500 i would just buy a JP Racing engine or something cheaper to have modded and it will outperform. I think they need to up the ante a little bit, their 2 major competitiors are pumping out better Race bred engines right now. Their budget N21 series is a excellent engine i have 3 of them one is the Original T21BF, R21 2000BF, and T21 2000R. All Excellent performers for a great price, i did haft to replace the bearings before the 1 gallon mark but other than that no complaints other than they pretty much deny the 2000 series engines. Basically my only problem is this. They need to fix the bearing problems, they need to make some more power and their powerbands are really rough instead of broad and smooth, and they need to come down on the price which could be a dist/dealer problem.
The 2K series engines appear to get swept under the mat. The 2000, 2001, 2002, there's no info for these engines. Some I heard a 3 port, 6 port, 7 port, etc.,. JP racing seems to modding these, but I guess they one shot engines as you'll never find any parts or info on them.
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Old 01-07-2008, 02:27 PM   #66
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The 2K series engines appear to get swept under the mat. The 2000, 2001, 2002, there's no info for these engines. Some I heard a 3 port, 6 port, 7 port, etc.,. JP racing seems to modding these, but I guess they one shot engines as you'll never find any parts or info on them.
the 200 series was swept undert he mat. the 2001 series is here to stay and very quickly replaced the 2000 series. the 2002 series is JP Racings modded versions.

There is a 212000 buggy engine thats 6 port and the 212000 rallye/onroad engine thats 7 port. i have them both. Alot of ppl thing they made the 2000 series out of leftover new old inventory.
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Old 01-07-2008, 03:59 PM   #67
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The JP 2002 series 7 port engine is a wicked screamer !! That is the old RS7 configuration , I just hope they kept the porting the same on the 7 port versions . I have the old RS7 Crono and it is wicked fast . If you notice on all the specs available the cranks are all 14 mm I think the 14.5 mm cranks didn't work nearly as well , and made for a persnickety tuning beast.
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Old 01-07-2008, 06:47 PM   #68
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The JP 2002 series 7 port engine is a wicked screamer !! That is the old RS7 configuration , I just hope they kept the porting the same on the 7 port versions . I have the old RS7 Crono and it is wicked fast . If you notice on all the specs available the cranks are all 14 mm I think the 14.5 mm cranks didn't work nearly as well , and made for a persnickety tuning beast.
The JP 2002 are available and for a good price, too. Has the all the hardened black treatment to the case and crank.
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Old 01-08-2008, 04:05 AM   #69
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Who sells the JP's in the US now ?
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Old 01-08-2008, 09:00 AM   #70
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Who sells the JP's in the US now ?
US Distributor is Model Sports Racing Products. There are other sellers also.
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Old 01-08-2008, 09:29 AM   #71
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Yeah, I saw that on the JP sight as well , I want to know if there is any places on the web that may have them , couldn't fine a sight for Model Sports Racing Products?
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Old 01-08-2008, 12:14 PM   #72
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Yeah, I saw that on the JP sight as well , I want to know if there is any places on the web that may have them , couldn't fine a sight for Model Sports Racing Products?
YGPM!
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Old 01-08-2008, 01:53 PM   #73
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The JP 2002 series 7 port engine is a wicked screamer !! That is the old RS7 configuration , I just hope they kept the porting the same on the 7 port versions . I have the old RS7 Crono and it is wicked fast . If you notice on all the specs available the cranks are all 14 mm I think the 14.5 mm cranks didn't work nearly as well , and made for a persnickety tuning beast.
we have done all our testing conclusion.

The bigger the crankshaft the bigger the problem with break down and tuning
the bigger the bearing and the more bearing balls in the bearing the bigger the sooner the bearing will fail.
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Old 01-08-2008, 03:16 PM   #74
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Hey mremtr,
I've actually tried a few different ways of renewing cranks with pins that are out of round as well as experimenting with Titanium nitride coating the crank. What we found was that chrome dipping the crank pin was very labour intensive as far as regrinding once the pin had been dipped, especially with some of the OS engines which have an oil hole throught the crankpin as they needed to be redrilled. Also the longevity of the chrome dipped pin just wasn't there, it would only last maybe 4 litres at best not to mention that when chrome does break down it tends to flake off which obviously you don't want happening inside your engine. On to Titanium Nitride obviously TiNi can not be applied thick enough to fix an out of round crank pin, but we did use it on a new crank, the testing of it went fairly well as far as you could feel a little difference in the way the engine performed but it was very subtle, the only benefit was that it obviously reduced wear on the crankpin. But the testing showed that the TiNi would wear off from the crankpin at best case scenario about 5-6 litres this really wasn't enough to justify the extra expense of coating the crank as well as the very minor performance gain. We also produced a fair few prototype rods for various engines there rods were about 40% lighter than the novarossi R7 rods and did make a very big performance difference that you could really feel just by driving the engine in a vehicle but again the longevity wasn't there I think the most fuel one of the rods would see was about 5 litres and then it would have a full let go from the bottom end. We also experimented with different bushings such as sintered etc (self lubricating) but again this didn't seem to make a massive difference to the longevity of the rod or crank. Full titanium rods were the next thing on the agenda but this idea was shelved when we found out about the relationship between methanol and titanium. (Methanol causes cracking in titanium unless it is diluted but even then it is still not recommended). So basically this is all just to say that these engine manufacturers have probably tested most ideas that we have had or will have and we probably have now the best solutions as far as how our engines operate. In other words I think it would be very difficult for anyone to really reinvent the wheel. Also I would just like to say we also tested nikasil which is the coating inside the team orion CRF engines, and didn't find any major benefits in our testing.

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Old 01-08-2008, 04:08 PM   #75
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Well from what I have seen , the 14.5 cranks were the ones doing all the failing too. Now the front bearings have been leaking for years and I still see no end in sight it seems . This was the only issue I had with all my Novas and OS's . Front bearing would start to leak and then tuning issues, changed the bearings and the engines are still running like new! My Crono CLB4N has 12-14 gallons on it ,lost count after the 3rd case of fuel, still has the original rod/piston/sleeve/crank /bearing(large) and carb! I changed the head just for a color matching. My 421B/N is still ripping fast and powerful and it too is all original except the front bearing,and soon the rear because it is starting to make a bit of noise. This engine has been ripped on HARD!! And for 3 full seasons at 2 cases per season,thats a lot of fuel for one engine. This is why I love Novas!!
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