I been having a hard time tuning this N21 limited that I got used. Unsure of how many gallons put through it. So I decided to open it up and go through it and all looked pretty good. Watched some videos online and came across one to check for leaks. Tested and found a leake where the crank shaft goes through the front bearing. Now I would think new bearing but how to make sure the crank isn't worn either. Last time it ran it would start rev up and die. Couldn't get it to even idle.

needs front brng , pretty typical

Is a os 2060 pipe very good with a 21-4btt.

Get a new front bearing, Nova17011 and get a BUKU cap. It will outlast the engine :-)

Is the P5 really THAT good?

I mean, today was my second day with this newly broken in Beat B5 and it's every bit as powerful as my Plus 4 BTT if not more so. I planned on getting a Keep Off 7 as a "big" race engine but after running this P5, I don't see myself spending $400+ when this $200 engine seems to be doing everything right.

Your thoughts are similar to many who have raced the P5XLT based engines. I agree, the P5 does ALOT right with the correct pipe/header and proper tune. Although there are certain types of tracks where in a truggy application one could benefit from the higher performance of the Keep Off 2-17 and/or Virtus Off Road engines. I do not want to get into the ageless debate about speed vs. driving styles. For the majority of tracks, the P5XLT offers a fantastic value to performance ratio regardless if in a buggy or truggy.

Just picked up a P5xlt... Im having a really hard time starting it. When I rotate the flywheel, it locks up when the piston is at the top. Ive tried starting it on an AE box and burnt out the motor in the box. Tried again on my Ofna box and finally got it started and ran it for a tank and a half but chewed up the wheel on the box quite a bit. Is this normal for the engine? Its my first time with a new engine so... this is kinda new to me. Thanks!

You need to heat it with a heat gun. The sleeves are tapered at the top so when its cold its getting stuck at TDC. Make sure you dont leave it stuck in that position because the taper is what determines your compression therefore determines the lifespan of the motor also. Once you get it going always make sure you rotate the flywheel to the spot where the flywheel feels loose(BDC). Also if you have never broke in a engine make sure you watch a video or have someone that has done it help you. Pretty good video is http://www.youtube.com/watch?v=kZ5BsceGVbo

The engine may be in good shape, however, the piston and sleeve could be low on compression and this could cause issues. Get it resized by RayA and put a new front bearing in it. Make sure to clean it well.

ya know , I know Ryan personally and think he is a great ambassador for our awesome hobby buuuuutt wth mister?

I think he is forgetting a VERY IMPORTANT part of the break in process , you must preheat your engine guys at least to 170° , rule of thumb , if you gotta loosen the glow plug the engine isn't preheated enough , use a quality fuel with a castor bsed oil pkg such as byrons gen2 race blend pkg , do not "blip" the throttle during break in , keep temps around 210°-230° range and do not over rev . when cooling for heat cycling of parts leave piston out of the pinch zone and break in will go great

Agreed Houston, preheating is the most important part.

I did a break in vid if you want to watch.

http://www.youtube.com/watch?v=cQf-B2UqCTY

What size rear bearing is in the BTTS?

Preheating is good and all if you can swing it, but a must it isn't afaic.. Nitro engines are tougher than people make them out to be.

I preheat before every start...my engines last and last. Monty saw my plus 4 after almost 6 gallons of hard running (I run the low cooling heads at around 270 to 280 right after they drop there nuts) and compression was still great. Rod was over 8 gallons before I replaced it after a pinch. It releaves the stress of startups.

I've preheated engines more lately than I used to, and I notice zero difference. I've never had a rod go.. I had a Caster Grenade (Go 5-port) back in the day, which had extreme pinch, ran it in and for several gallons without ever preheating it. Sent it to the engine guy for a new rod after 4-5 gallons(of temps close to 300 pretty regularly..), and he sent it back saying it wasn't necessary(and not earning money in the process). Sold it off later and it still went fine for the next guy..

Lately I've been preheating less. I just don't believe in it that much. The fad of it took off a few years ago. If you listen to all the preaching about it you'd wonder how engines ever lasted more than a gallon before everybody started preheating.. Reminds me of all the sealing talk back in the day. "You MUST seal your backplate and carb throat etc, or you WILL get air leaks" etc etc... For the most part, overblown, baseless, and unnecessary. Same with preheating, I suspect..

It's a PIA too at a race.. Enough other stuff to worry about..

I'm not saying start it up and floor it from the first tank. Still do a decent heat cycling break-in on it, and go easy for the first half gallon or so. But it's a tremendous amount of effort and energy to preheat an engine (not to mention several..) before every start.., and I just don't think it's worth it, and suspect it's not even really necessary...

(Don't mean to sound argumentative.. Just my random 2c on the subject...)