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kinda worried about the rebuild


rchrd989

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I have been spending the past few months slowly rebuilding my L28 that im putting in my 240, (pictures soon) and im kinda worried. when i rebuilt the bottom end the crank spun freely. As i put in each piston and new rings it got harder and harder to turn over with my hands on the front pully, with the last piston in it took 2 guys to turn it over. each cylinder we lubed before instalation. With each piston in and the complete bottom end rebuild i put puddles of oil on the tops of each pistons to make sure all of the cylinders were lubed. I purchased a rebuild cylinder head from a guy that does a bunch of them (also stiff) which i expected due to the fact of pushing down valves, but i could turn it with a rag on an old timing gear with my hands. now i have the motor completly bolted together and ready to go. I was torqing the front pully bolt (105 lb ft) and the motor wouldnt turn! same with torqing the clyinder head timing gear bolt and washer. I guess im worried wheather or not my starter will have enough ummpphh to break it all free. I smothered engine lube on the cam lobes and made sure to fill the oil pump with fresh oil before i installed it, and i will definitly dump oil all over the cam and rocker arms before i install the cover. is there anyway I can oil the cam before it runs? and what about the crank? I made sure to use oil and assembly lube on all the new bearings. What do you guys think?

 

thanks for the long read!

 

Richard

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You don't gap the rings yourself, the gap is dependent on the piston bore in comparison the to ring size. I think what sweetleaf is looking for is, did you get oversized rings that weren't the right size for your bore?

Something definetely isn't right. It should turn over fairly easily.

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Im not sure on those clearences. The motor is complete now. As for the ring gap it was within spec i jsut dont remeber it off the top of my head. I didnt use assembly lube on the cylinders ( i didnt know of that) but I did use lots and lots of oil. I just hope it all works out.

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If you are skeptical on a couple things a stock head gasket isn't that much.

 

I would pop the head back off. I rebuilt a 22re last month and was a little wary of my rings. One didn't seem like it went in just right and it didn't slide as smooth as the other pistons, it smoked for a month before it finally sealed. Hopefully it was just because I used moly rings.

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what do you think of pulling the plugs and and spraying loads of fogging oil in the cylinders and cranking it over to cycle oil? that way my starter will be relieved of compression and the fogging oil will help protect the cylinders? the rest of the components wont be ready for start up for about a week or so. So i could even put some oil in the cylinders to help also?

 

thanks alot guys i really appriciate it

Richard

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Guest TeamNissan

Ya, I made the mistake of forgeting to use assembly lube on a vg once and it was the same thing. Take the head off and make sure you didnt damage the rings or the cylinder walls.

 

Either take a little time now or ALOT of time later, your choice lol.

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when i assembled the motor i had to turn the crank to TDC before bolting up the head and setting the timing. from moving it then there wasnt any scorn marks. When i assembled the bottom end the pistons with the new rings went in without any trouble. My service manager thinks i should do what i stated before. To remove the plugs, spray lots of fogging oil and crank it over to cycle oil. Both my service manager and this old guy at my work whos been a service manager say that if i use enough fog oil that it should protect the cylinders. remeber that its jsut tough to get it to move, but as soon as it does move its not to hard to turn it, its just that initial umphh

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The reason it's tough to get going is the ring pressure is able to push the oil out from between the cylinder wall and ring thus causing it to have no lubrication once it's settled. That's why assembly lube is so important, it's thicker and bonds to the metal during assembly.If fogging oil is a little thicker and you can get it in between the rings and the wall then go for it. I'd still be concerned with cylinder scoring and ring breakage.

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