koster88 Posted November 14, 2012 Report Share Posted November 14, 2012 Hey guys... So this is my first build. My Motor MELTED both pistons last time, so I did a total rebuild. my Impeller was melted last time so i replaced that with a billet one. I have a 4mil crank, used Wisco piston, 30 over bore. Stock Carbs, adjustable timing set a 0 for now. 1 piston had 120 compression, the other had 15-20psi. I pulled the head, then jug off, and I can see that the bad piston was worn against the cylinder. the Rings are worn down, the piston, and the wall of the cylinder is scratched a bit. When I went to take it apart the wrist pin was STUCK... I had to use a CLAMP to push a socket through. was HARD as hell to get it out! What Do you think happened? What did I do wrong? Here are some pics.. Quote Link to comment Share on other sites More sharing options...
dave5.0 Posted November 14, 2012 Report Share Posted November 14, 2012 (edited) First guess would be an air leak. Depending which side it is that burnt. Nevermind, looks like clutch side. Lean? Carb jacked up? U do a leak down? Pipe seals? Low on coolant? Forget to put the pin in the w/p gear? Just guessing. Not from experience. Edited November 14, 2012 by dave5.0 Quote Link to comment Share on other sites More sharing options...
vulvafan537240 Posted November 14, 2012 Report Share Posted November 14, 2012 i agree with the leakdown. most important part of a rebuild imo. Quote Link to comment Share on other sites More sharing options...
dirtydownunder Posted November 14, 2012 Report Share Posted November 14, 2012 So only one piston fried ? What were your piston ring gaps ?, were the bores bored to the piston spec ? Quote Link to comment Share on other sites More sharing options...
Wheelman Chassis Posted November 14, 2012 Report Share Posted November 14, 2012 So only one piston fried ? What were your piston ring gaps ?, were the bores bored to the piston spec ? Thats what i was gunna ask. 360* of damage on both pistons...Kinda would have me looking into piston to bore clearance...if jetting and stuff is close. Quote Link to comment Share on other sites More sharing options...
special06shee Posted November 14, 2012 Report Share Posted November 14, 2012 Cold seizure?? Did you make sure to put adequate heat in the motor before beating on it?? If not that could of cause it! Ive been there done that:-( Quote Link to comment Share on other sites More sharing options...
AKheathen Posted November 14, 2012 Report Share Posted November 14, 2012 can you explain that 3rd pic? looks like burned leaking multiple gaskets with sealant on them.... Quote Link to comment Share on other sites More sharing options...
koster88 Posted November 14, 2012 Author Report Share Posted November 14, 2012 First guess would be an air leak. Depending which side it is that burnt. Nevermind, looks like clutch side. Lean? Carb jacked up? U do a leak down? Pipe seals? Low on coolant? Forget to put the pin in the w/p gear? Just guessing. Not from experience. I could have carb problems, I was just trying to tune them when this hapepned. I did a leak down when I built it, and it held air perfect. I did put the pin the WP gear. Quote Link to comment Share on other sites More sharing options...
koster88 Posted November 14, 2012 Author Report Share Posted November 14, 2012 Same thing happened with my meth motor. Turns out my fuel pump failed. I know how it feels, I had exactly 20 minutes on my motor. Fuel Pump!? Quote Link to comment Share on other sites More sharing options...
koster88 Posted November 14, 2012 Author Report Share Posted November 14, 2012 Thats what i was gunna ask. 360* of damage on both pistons...Kinda would have me looking into piston to bore clearance...if jetting and stuff is close. its not 360, is mostly on the intake side, the exhaust side isn't worn as bad. Rings /pistons should be correct. HJR did the port/cylinder work..and matched it witht he pistons /rings for me. Quote Link to comment Share on other sites More sharing options...
n2otoofast4u Posted November 14, 2012 Report Share Posted November 14, 2012 Is the part number on top of the piston the same on both sides? And in the last picture it looks that you have sealant on your base gasket? And its kinda hard to tell but kinda looks like there might be 2 gaskets on it? Quote Link to comment Share on other sites More sharing options...
koster88 Posted November 14, 2012 Author Report Share Posted November 14, 2012 Is the part number on top of the piston the same on both sides? And in the last picture it looks that you have sealant on your base gasket? And its kinda hard to tell but kinda looks like there might be 2 gaskets on it? Its just a bad pic. I did use 3Bond on the gasket. its just 1 gasket. Tore it up pulling it off. Was good before tho. I'm not sure about he part # on the piston, would have to go look. Quote Link to comment Share on other sites More sharing options...
BUILDER Posted November 14, 2012 Report Share Posted November 14, 2012 Looks like it was lean to me. Did you heart cycle the pistons a few times before you took off ripping on it? That is my only other thought. Quote Link to comment Share on other sites More sharing options...
possum Posted November 14, 2012 Report Share Posted November 14, 2012 breaking in a motor is better to be pig fat then anorexic lean. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted November 29, 2012 Report Share Posted November 29, 2012 Did you fix the problem that caused your last motor to fail? You mentioned water pump, but it may have been something else. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.