27 lbs torque to turn over new motor

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dustoff440

dustoff440

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Is 27 lbs of torque to turn over my completely assembled fresh 360 Magnum a good number. I have built dozens of "street" engines throughout the years but never checked the amount of torque to turn the motor over.
 
With a torque wrench on the harmonic balancer bolt, amount of torque needed to turn the engine over.
 
Are you talking to turn the crank and pistons? Or vavles as well? You shouldn't be using a breakaway torque wrench if you were..
 
The race engine we run is a R3 50mm needle bearing cam block with 1.5 mm rings and pistons with very little skirt. With the plugs out you can turn it over by hand easy by turning the balancer. That's with over 1400 Lbs. of valve spring pressure.
 
I'd think the thickness and type of assembly oil and lube you used will affect that significantly. The thicker and stickier oil/lube, the more torque to turn.
 
Yes, completely assembled engine crank pistons valvetrain. I have a buddy who built a super stock engine align bore the whole 9 yards and his was 14lbs.
 
A rule of thumb on a new engine is about 5lbs of resistance for every rotating piece. The crank is 5 and each piston/ rod assembly should be 5 as well. It may vary a little but a fresh motor should be around 45.

The key here is did you feel any binding or tight spots. This will reveal if something is sticking or out of round, it wont account for lose or tight rings.

It should be a pointer type torque wrench (hopefully without a bent needle)
 
I would think the most accurate tool to gauge would be a digital type wrench like the Snap-On Tech wrench or Tech Angle....JMO
 
Your just using a torque wrench? It's not the "right way" to measure it. You need a rotating torque wrench... That being said, if you have it all together and a normal lip type rear main I'd think it's a little tight. It would be closer to what I'd expect with a rope rear main seal tho. What were the oil clearances? What was the thrust measured at? What were the ring gaps measured at?
 
dustoff440 said:
Is 27 lbs of torque to turn over my completely assembled fresh 360 Magnum a good number. I have built dozens of engines throughout the years but never checked the amount of torque to turn the motor over.
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Oh boy knowing that & 1.00 will get you a cup of coffee. Yes i am a smart ***. LOL Hunky
 
moper said:
Your just using a torque wrench? It's not the "right way" to measure it. You need a rotating torque wrench... That being said, if you have it all together and a normal lip type rear main I'd think it's a little tight. It would be closer to what I'd expect with a rope rear main seal tho. What were the oil clearances? What was the thrust measured at? What were the ring gaps measured at?
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Youre really working me on this one, I put the short block together almost 2 years ago. I can't even remember what I had for dinner last night. I'm getting a lot of different answers on this question. Any professional long term engine builders/machinists care to comment with their opinion??
 
hunky said:
Oh boy knowing that & 1.00 will get you a cup of coffee. Yes i am a smart ***. LOL Hunky
Click to expand...


Hell i aint braggin, just curious. Even if it were out of specs id still run it and thrash the hell out of it. LOL
 
I just came in from measuring the one im workin on right now...25 lbs ...without valvetrain...j
 
just came in from measuring the one im working on now.. crank.slugs.chain gears and cam....25lbs..j
 
yes 27 lbs is a good number. As long as it is consistant and does not bind anywhere.
Bolt it up and break it in. race only motors are a different story altogether.
 
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