My son and I are just finishing up a rebuild of his SB350 - new pistons/rings/bearings. The motor is still on a stand, heads off. The rotating assembly seems a bit stiff to roll over.
Can anyone give me an idea of how many ft lbs it should take to turn over a fresh build like this by hand?
We like to do everything possible to get stuff right the first time as it's a Fiero V8 conversion and dropping the engine is quite a chore.
Specs:
ZZ3, Speedpro pistons and rings, bores scuffed to promote new ring sealing up but not a bore job.
Lusox
Unfortunately, I don't have any torque specs for you on that. And it is tough to come up with a truly meaningful torque number because the breakaway torque to start the rings moving in the bores, is higher than for steady rolling. And once its rolling, its a bit hard to keep a nice steady rotation on the wrench as you roll it over.
Then with a fully assembled engine, you run into also compressing valves springs at 16 different points. The whole point is, it is hard to get one smooth torque number to refer to. If you try to use a clicker torque wrench, you'll find that it will click at one point, but not the same at another. If you use a beam type torque wrench, you'll find the needle moves back and forth as you move around.
But when everything is right, during short block mock-up without rings, you can expect the engine to roll over very nice and free.
During final assembly with only the crank (with proper end play), cam and timing chain installed, you should find that it still rolls over nice and easy if everything is still right. Then as you final install each rod/piston assembly, it will turn over progressively harder because of ring drag. The increase in roll over torque should progress upward steadily and evenly until all the rod/piston assemblies are final installed. This is perfectly normal and expected, though if there is some sudden out of the ordinary jump in drag, then something is not right.
Later, as you install each rocker arm, the roll over torque will also go up because of comrpessing the valve springs. When you are completely done with the build, it will turn over WAY, WAY stiffer than during short block mock-up roll over with no rings. So, if you have been careful to install everything right, then stiffish roll over torque when you are done, is normal and expected. For those building their first engine, they might think something is terribly wrong, when it is perfectly fine. Assuming you've done things correctly, I doubt you have any problem at all. :thumbsup:
