• Welcome to RCTalk! 🚀

    Join the #1 RC community where hobbyists connect, share, and get expert advice on RC cars, trucks, boats, drones, and more!

    • ✓ Friendly & passionate RC enthusiasts
    • ✓ RC tips & troubleshooting
    • ✓ Buy, sell & trade RC gear
    • ✓ Share builds & upgrades

New Picco .28 Air leak???

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
A

atitagain

RCTalk Member
Messages
30
Reaction score
0
Points
76
Location
Wi
RC Driving Style
  1. Bashing
  2. Racing
I bought a new Picco .28 and it is leaking oil out of the front crank bearing! I have been having big time tuning issues with this engine, and I'm wondering if this leak has anything to do with it. It is set rich for break in, as I'm only on the 5th tank. At a higher RPM and very rich HSN setting, as soon as I let off throttle it goes very lean and then goes back to pig rich at idle. I have both HSN and LSN set rich for break in. Is the front bearing letting air in and causing it to go lean when I close the throttle? Should I replace it? Please help!!
 
i have a hyper mac . 28, just tore it down over the weekend. when i took off the flywheel there was some fuel/oil sitting around the bearing. dont know if you could put alittle silicone on crankshaft that goes through the bearing.
 
Replace the bearing and seal your engine, Silicone WILL NOT work, Proper repairs will save alot of headaches, and keep you from getting frustrated with Nitro, Never 1/2 ass anything you will end up doing it multiple times.
 
Try leaning the lsn and richening the hsn. It may need a new bearing, but I highly doubt it. Bearing leaks are normal to some extent, especially when an engine is rich. You're not going to get any significant air leakage through a front bearing.
 
Thanks for the info everyone! I have tried to both lean and richen the LSN and also the HSN. When I lean the LSN the case gets worse. When I fatten it up, it wont even idle. then I'll have to increase the idle gap to keep it running. (idle gap @ about 3mm manual says keep it at 1-2mm). HSN is rich enough where it wont clear out completely (again I'm still breaking it in, so its rich..) But as soon as I close the throttle after a mid -to-high speed run it goes lean for about 5-8 seconds and then back to the rich setting that I am trying to keep during the break in period. I feel the front bearing is leaking more than is should. It it defiantly more than a "seep" There is a full drop about to drip off the engine right now..
 
The front bearing does not create an air tight seal for the engine, the seal is made just behind the bearing between the crank and block and a thin film of oil between the two is what seals the engine. At only 5 tanks of fuel I would not be worried about it tuning in properly as these higher end engines take a lot longer to break in the the rtr engines. I would keep your rpm lower and just take it easy running it around for at least a gallon, once the engine starts to break in it will then become more easy to tune and less erratic.
 
Rich settings tend to cause that. The Picco 28 is somewhat known to have leaks around the area where teh HSN section connects to the carb body. This causes air leaks. It may not be pretty, but clean the carb off with DA and try putting a thin coat of high temp RTV on the surface around that area, yellow line:
2013-0101-picco28-front-carbMark.jpg


It could be the bearing, but this is something you can try first. They are known for front bearing issues as well though.

As ERCM said, most engines are pretty weird at break-in as the parts wear in, so giving it some time may also cure it. I've had pretty erratic tune with my LRP's for the first 1/2-1 gallon of fuel and they calmed down after a gallon as well.
 
Okay great! I will try your tips on sealing the carb and give it some more time for break in. Thanks for your help!!
 

RC Builds

Back
Top