pistons hitting
03-16-2011, 04:59 PM
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pistons hitting
ok, I'm going to try to explain this the best I can......(this is not my truck but is in my shop)
Bought a 1992 3.0 Truck with a blown motor, took a 3.0 out of a 4runner that had 140K miles on it and had been flipped. Put new outside parts on it and tune it up and put it in the truck. Ran strong, REAL strong. 35K miles later the water pump locked up and it ran hot. Had it towed home. Crank up at home and motor was knocking, decided to tear into it put all new gaskets. Did not tear into the block. There was a noticeable scar where the #3 and #5 pistons were hitting a valve in each cyclinder. Cleaned everything up and started working the way back out. Pistons are still hitting heads, bad. Haven't went very far yet because can get the motor to turn through that stroke. Had an extra head to put on and see if it was in the head but got the same result. Everything looked fine on the bottom end when we removed the pan.
ANY IDEAS??
Bought a 1992 3.0 Truck with a blown motor, took a 3.0 out of a 4runner that had 140K miles on it and had been flipped. Put new outside parts on it and tune it up and put it in the truck. Ran strong, REAL strong. 35K miles later the water pump locked up and it ran hot. Had it towed home. Crank up at home and motor was knocking, decided to tear into it put all new gaskets. Did not tear into the block. There was a noticeable scar where the #3 and #5 pistons were hitting a valve in each cyclinder. Cleaned everything up and started working the way back out. Pistons are still hitting heads, bad. Haven't went very far yet because can get the motor to turn through that stroke. Had an extra head to put on and see if it was in the head but got the same result. Everything looked fine on the bottom end when we removed the pan.
ANY IDEAS??
03-17-2011, 03:59 AM
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1. Replacing gaskets WILL NOT fix a "knock"
2. Could be broken valve springs letting thevalves hit the piston--the 3.0 IS a non-interference engine
3. MOST LIKELY it is piston rods that are loose & allowing the piston to go higher up the cylinder than normal. That would account for the "knock"
4. You need to tear into the block next time you have a "knock"
2. Could be broken valve springs letting thevalves hit the piston--the 3.0 IS a non-interference engine
3. MOST LIKELY it is piston rods that are loose & allowing the piston to go higher up the cylinder than normal. That would account for the "knock"
4. You need to tear into the block next time you have a "knock"
Last edited by TNRabbit; 03-17-2011 at 04:00 AM.
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