7MGE Engine rebuild

oregonjoe · 08-31-2009, 05:00 PM

Assembled the crank and pistons into block. Laid the crank in on the new dry bearings and placed a piece of plasticgauge on the bearing face.

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Torque the main caps to crush the gauge and then removed the caps. Check tolerance was OK (0.022) then cleaned and reassembled again.

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Takes awhile to do it twice but felt better to know everything was in spec after 20 years. After the crank was bolted in the second time, it spun with very little effort – smooth as silk with all that assembly lube.

Next it was the pistons. Cleaned till new and disassembled and cleaned the writ pins. Reassembled the rods to pistons being sure all the little oil holes in the pistons were clean. Placed the rings on the pistons after checking ring end gap in cylinder bores. Amazed how much easier the rings go on then come off. After they are in the engine for awhile they get very brittle and just break. Performed same plasticgauge check on rod bearings as crank. Assembled pistons into ring compressor and pushed into cylinder from below (block was inverted on engine stand). Used some old fuel line tubing over the rod bolts which works really well because if you cut them about 3” long, they actually guide the rod onto the crank. All the pistons tapped in very easy.

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After pistons were installed with no problems, tried to give crank a spin and found it wasn’t easy. Using a torque wrench, I had to set it to 15 pounds to break the inertia and get the crank to move. Not nearly the same as when the engine was broken in. I know its going to take some time for the pistons to seat and for things to loosen up but wonder if 15 pounds is spec. I just think about all those new engines rolling off the production lines everyday with just a few hours of break in time. A lot of extra gas being wasted in the first 500 miles.

I cleaned the oil pump till it looked like new and gave it a test in a bucket of oil. Inserted the oil pump drive shaft and pressed in the pump.

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Still waiting for head and clutch to arrive so all I can do now is clean parts. The biggest cleaning job is the intake manifolds as they are clogged with residue from the smog stuff. PVC and EGT just destroy all the air passages. The throttle body took 2 days to soak off the layer of tar. Sure will be nice to get this engine to breathe again.

08-31-2009, 05:00 PM	#8
oregonjoe 3" Exhaust Join Date: Aug 2009 Location: Southern Oregon Coast Posts: 83	7Mge Rebuild - Installing pistons Assembled the crank and pistons into block. Laid the crank in on the new dry bearings and placed a piece of plasticgauge on the bearing face. Torque the main caps to crush the gauge and then removed the caps. Check tolerance was OK (0.022) then cleaned and reassembled again. Takes awhile to do it twice but felt better to know everything was in spec after 20 years. After the crank was bolted in the second time, it spun with very little effort – smooth as silk with all that assembly lube. Next it was the pistons. Cleaned till new and disassembled and cleaned the writ pins. Reassembled the rods to pistons being sure all the little oil holes in the pistons were clean. Placed the rings on the pistons after checking ring end gap in cylinder bores. Amazed how much easier the rings go on then come off. After they are in the engine for awhile they get very brittle and just break. Performed same plasticgauge check on rod bearings as crank. Assembled pistons into ring compressor and pushed into cylinder from below (block was inverted on engine stand). Used some old fuel line tubing over the rod bolts which works really well because if you cut them about 3” long, they actually guide the rod onto the crank. All the pistons tapped in very easy. After pistons were installed with no problems, tried to give crank a spin and found it wasn’t easy. Using a torque wrench, I had to set it to 15 pounds to break the inertia and get the crank to move. Not nearly the same as when the engine was broken in. I know its going to take some time for the pistons to seat and for things to loosen up but wonder if 15 pounds is spec. I just think about all those new engines rolling off the production lines everyday with just a few hours of break in time. A lot of extra gas being wasted in the first 500 miles. I cleaned the oil pump till it looked like new and gave it a test in a bucket of oil. Inserted the oil pump drive shaft and pressed in the pump. Still waiting for head and clutch to arrive so all I can do now is clean parts. The biggest cleaning job is the intake manifolds as they are clogged with residue from the smog stuff. PVC and EGT just destroy all the air passages. The throttle body took 2 days to soak off the layer of tar. Sure will be nice to get this engine to breathe again.