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-   -   compression?? (https://www.rctech.net/forum/offroad-nitro-engine-forum/442405-compression.html)

wLdNout 10-11-2010 11:00 AM

compression??
 
I think my motor is shot.

Cold motor- Can turn it over very easy with hand and has a small tight spot up top but not much. Does not make a good healthy thump.

It will still run when the motor is cold but once it gets up in temp (210-215 degrees) it just starts running like shit. example, wont stay runnin, suddenly acts like its not tuned, spitters and sputters.

Anybody got any education they can share.

location is louisiana, humidity is high, elevation is low (our highest elevation is called a hill) temp lately has been about 70-80ish.

Hopefully Ive included all the necessary information.

quixoticboi 10-11-2010 11:03 AM

Definitely sounds like the engine has lost compression. New piston and sleeve will fix that problem up for you. Or, you can just get your piston repinched/resized. There are a few that do them professionally on this board. I actually just sent two p/s to get repinched. Most say it runs like new or sometimes better and will get 3 gallons or so with the new pinch. Hope this helps!

wLdNout 10-11-2010 11:47 AM

I think imma just hold out till have enough funds for a quality .21. It has a .28 now and I was waiting till it gave out. thanks for the help

Sylvain 10-11-2010 12:59 PM


Originally Posted by wLdNout (Post 8056117)
I think my motor is shot.

Cold motor- Can turn it over very easy with hand and has a small tight spot up top but not much. Does not make a good healthy thump.

It will still run when the motor is cold but once it gets up in temp (210-215 degrees) it just starts running like shit. example, wont stay runnin, suddenly acts like its not tuned, spitters and sputters.

Anybody got any education they can share.

location is louisiana, humidity is high, elevation is low (our highest elevation is called a hill) temp lately has been about 70-80ish.

Hopefully Ive included all the necessary information.


It looks like you'll need a new engine :)

Storydude1 10-11-2010 01:07 PM

Yep. low compression.

arayracing will do a pinch for ~20 bucks. You can get a few more gallons out of a repinch, assuming it's not too far gone.

How many gallons on the motor now?

jwm2 10-11-2010 01:08 PM


Originally Posted by wLdNout (Post 8056275)
I think imma just hold out till have enough funds for a quality .21. It has a .28 now and I was waiting till it gave out. thanks for the help

No sense in replacing parts or repinching a cheap mill. I'd do like you plan and save up the funds for a better motor. In the meantime just run it until it dies. Run it lean if you have to and don't care about what happens to it. Maybe reseal the carb and backplate to be sure no air is leaking into it and then give it a go.

J.Whiting 10-11-2010 03:03 PM

please use the correct forum next time. i will move your thread to the motor section..

blktransam 10-11-2010 03:14 PM

on a engine that losses "all" compression with heat, it is better to run the engine "rich" NOT "lean" as lean will just get it hotter faster which will make LESS compression, rich will keep it cooler and the compression will stay tighter...I will run a pinched engine several times before buying a new p/s...one of my sponsors does pinching locally using rayaracings tooling and I just send him my motor when it starts acting up he snugs it I run it a couple gallons he snugs it again etc etc etc....and to be honest his engines run twice as good as any new engine I have ever owned....

wLdNout 10-11-2010 03:33 PM

Thanks for the input. I'm just gonna hold out till I can get a new motor. I'm thinking either the B5 or Team Losi CRF that includes the pipe for that engine.

quixoticboi 10-11-2010 03:33 PM

Getting a sleeve pinched is only $15-20. Which is way cheaper and can give you a good backup engine. New .21 will run upwards from x10 that much (~$150+). Just a thought.

RayA 10-11-2010 06:23 PM

typo
 

Originally Posted by Storydude1 (Post 8056548)
Yep. low compression.

arayracing will do a pinch for ~20 bucks. You can get a few more gallons out of a repinch, assuming it's not too far gone.

How many gallons on the motor now?

TYPO

RayAracing

Recondition-Reize ALL .12 thru .46 engine models ;)

NitroXray80809 10-11-2010 09:30 PM

If u dont want pinch sell it as parts engine and buy urself a new engine. Pinch is nice but new is better lol. nothin like a new fancy shinny head stickin out of a dirty car haha.

quixoticboi 10-11-2010 10:07 PM


Originally Posted by NitroXray80809 (Post 8058960)
If u dont want pinch sell it as parts engine and buy urself a new engine. Pinch is nice but new is better lol. nothin like a new fancy shinny head stickin out of a dirty car haha.

Polished pinched sleeve is just as good if not better imo... A little research and many, even racers, agree their engines run better than when they were new...

NitroXray80809 10-11-2010 10:09 PM


Originally Posted by quixoticboi (Post 8059073)
Polished pinched sleeve is just as good if not better imo... A little research and many, even racers, agree their engines run better than when they were new...

I know lol it was a joke but he posted before hes wanting a new engine because he dont like this one. I think he said it was a 28 and he wants a 21 but dont just wanna junk out an engine.

wLdNout 10-12-2010 04:43 AM

Yeah I don't wanna just junk it out and do away with it. I think I may look into getting it pinched for a back up motor. I'm not against the idea of a pinched motor but I want something quality, new, in a .21 size. I've read alot of debates between the .21 and the .28, and overall the .21 side wins my decision.

wLdNout 10-12-2010 04:45 AM


Originally Posted by RayA (Post 8057975)
TYPO

RayAracing

Recondition-Reize ALL .12 thru .46 engine models ;)

Advertise much? Lol.

Storydude1 10-12-2010 11:56 AM


Originally Posted by RayA (Post 8057975)
TYPO

RayAracing

Recondition-Reize ALL .12 thru .46 engine models ;)

I do apologize fine sir. :)

BTW, I'm the one that TXT you last night in regards to the VG engine.

RayA 10-12-2010 01:53 PM

reize
 

Originally Posted by Storydude1 (Post 8061318)
I do apologize fine sir. :)

BTW, I'm the one that TXT you last night in regards to the VG engine.

My typing is worse ...

Glade to have helped you so as not to ship non-salvegable P+S set for servicing.

RayAracing


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