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piston locked up in cylinder

kaiju

Well-known member
Joined
Jul 2, 2007
Messages
70
Location
barbados
I don't have any pictures unfortunately but my no.1 piston got hung up at a slight angle in the lower part of the bore,i can see the ring on the right side couldn't even pull it out by hand and its still in there right now and the ring looks like the moon during its first quarter and also a rod bearing to failed but i forgot which one ,prior to that happening the car dropped oil pressure twice even though the main and con rod journals were plastigauged within spec also the balance shafts were removed.

So my friend who built the block for me and i are wonder if it could have been a bad machining job that was done and another guy so far thinks so as well ,i had the block bored .20 and the rods machined to accept 2g pistons,they cracked one of my brand new pistons while pressing it onto one of the rods and they replaced them with 4 je pistons,i then asked them to bore over the block to 0.003 for the new pistons(they were telling me some crap about how forged pistons don't expand much)but i told them that's what i wanted because it was recommended to me by a fellow i know that built a couple rally and street car engines, he also said that with the weather we get here we could run the ring gaps a bit wider than usual cause we don't have any cold weather to worry about.

When we finally got everything to my friends garage to start the build we washed it down and checked over everything and it was up in a couple hours everything was going smoothly,we then dropped it into his mirage,primed the engine and started it up,it sat there for a while turned off checked for leaks changed the oil and took it out for its first road trip we also did a compression test 4 days into it and it was at 220 psi each cylinder,oil pressure was also looking good as i mentioned before until around the 5th day when it suddenly dropped to zero,turned off the car checked the oil and it was fine restarted and it went back up to normal, we decided to change the oil again and 2 days later it happened again 0 oil pressure that's when we decided to it it apart but while the car was on the jackstands we decided to start it one last time and that's when it puffed its last breath and seized the car also had a slight hard start when warm.

ANYONE HAVE A CLUE WHAT COULD HAVE HAPPENED ? i'm just looking for any idea so i can carry a decent argument to the machine shop (they did all the work,polished the crank,overbored the block,machined the rods,fit the pistons), it's a long wait and not cheap getting parts here (shipping is a bitch)so i really need to stick it to them when the time comes,i can either pull the piston and, inspect it then take it to them or take the whole assembly to them complete and pull it there.
My setup should have been block bored .20 over,8.5:1 compression,standard 1g big rods rod machined for the 22mm pin fully floating (je spiral locks),balanced rods and pistons,freshly polished crank, acl race main and con bearings,balance shafts deleted.Now i'm broke and the galant still needs an engine,great luck i have /ubbthreads/images/graemlins/bawling.gif
 

Terry Posten

Well-known member
Joined
Dec 16, 2003
Messages
9,009
Location
Davenport, Iowa USA
If the motor lost oil pressure twice, still had full oil, I would look at an oil pump failure.

Did you replace the front cover/oil pump when you rebuilt the motor?
 

toybreaker

iconoclast
Joined
Apr 30, 2006
Messages
3,581
Did you port the oil pressure relief valve?

The lack of oil pressure could very well be a problem with the relief valve hanging in the bore.
 

kaiju

Well-known member
Joined
Jul 2, 2007
Messages
70
Location
barbados
no to both,no one here sells new oil pumps for the engines we just made sure to clean everything and the stub shaft spun freely,so could that have been the main problem even though there were no obvious signs of rod knock besides the oil pressure drop and shouldn't that have happened before the piston locked up ?
 

BadVr4

Well-known member
Joined
Dec 30, 2004
Messages
678
Location
manchester, ct
you always want to replace the front case when rebuilding an engine. theres no point to cheap out on that. theres tons of places that sell them. get a new oem mitsu next time
 
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