4.9l rebuild
06-10-2015, 09:56 PM
#1
4.9l rebuild
I would post this in the engine forum but this forum gets more traffic. I am trying to rebuild my 4.9l this is my first ever rebuild. I pulled the Pistons today and found out 5 and 6 had broken rings. When I compression tested the motor all cylinders had roughly 130. 
Would this cause it to run badly?
Would this cause it to run badly?
06-10-2015, 10:18 PM
#2
Senior Member
Were they broken for sure in the engine, or could they have broken pulling the pistons out? Did you ream the ridges before removing the pistons? Those compression numbers aren't too bad, why did you rebuild the engine in the first place?
06-10-2015, 10:23 PM
#3
4.9l rebuild
No I did not I had the motor upside down and pushed on the connecting rods and then slowly twisted and pulled them out. This is for a project truck and I had it sitting around but it was running odd spitting and sputtering. I put plugs fuel filter and tried everything. Check compression then checked for a bad head gasket and I wasn't going to use this engine but I've never gone threw an engine before so I wanted to do it. If I don't rebuild it and just scrap it at least I'll know how to dismantle a motor. But I'd rather put a rebuilt motor into a project truck than one with 165k.
06-10-2015, 11:03 PM
#4
Look for scoring (big scratches) on the cylinder walls. Broken rings would do that. But at 165k if I read that right, you'll have to have the engine bored and put in oversize pistons anyway, in which case the boring should clean up everything anyway.
06-11-2015, 07:34 AM
#6
4.9l rebuild
Originally Posted by Chris_1
Look for scoring (big scratches) on the cylinder walls. Broken rings would do that. But at 165k if I read that right, you'll have to have the engine bored and put in oversize pistons anyway, in which case the boring should clean up everything anyway.
