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LS1 short block hard to spin

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Old Mar 25, 2021 | 07:13 PM
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Default LS1 short block hard to spin

Please school me on how much I don’t know here: putting together my first ls block for a little turbo t56 project I’m working on. It’s a 90k miles block bored to 3.905, wiseco pistons and eagle rods for a CR or 10:1. I have the short block together, cam and oil pump in and the motor seems much harder to turn than it should be. Takes approx 65 ft lb to “unstick” the motor and 45-50 to continuously turn it. Crank turns smoothly and without any noise. There’s a ton of assembly lube in there. Bearing clearances were all in spec.

any ideas?

am I overthinking it??

thanks for whatever you got


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Old Mar 25, 2021 | 07:29 PM
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Yeah, something is amiss with those numbers being just the shortblock. Try unbolting the cam sprocket and see if it gets better. Very common to have a camshaft bind. You said crank turned smoothly, so you can check off main bearings. Did you gap rings?
For a data point for you here, my last shortblock took 10.9 ft lbs. lbs to move and 12 ft lbs to spin, using my digital SnapOn torque wrench. Granted, it wasn’t your run of the mill build, with a lot of trick ingenuity.
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Old Mar 25, 2021 | 07:48 PM
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From: JunkYard
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What bearings did you use? Do you know what the clearances are?
Can you show us a picture of how the main caps are installed?
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Old Mar 25, 2021 | 08:49 PM
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Originally Posted by Che70velle
Yeah, something is amiss with those numbers being just the shortblock. Try unbolting the cam sprocket and see if it gets better. Very common to have a camshaft bind. You said crank turned smoothly, so you can check off main bearings. Did you gap rings?
For a data point for you here, my last shortblock took 10.9 ft lbs. lbs to move and 12 ft lbs to spin, using my digital SnapOn torque wrench. Granted, it wasn’t your run of the mill build, with a lot of trick ingenuity.

now that I think about it, seems like it did get a whole lot harder to turn once I had the timing set on. How to fi fix a bind in the cam? It didn’t seem to slide in super easy, but it was smooth
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Old Mar 25, 2021 | 08:53 PM
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Originally Posted by 1FastBrick
What bearings did you use? Do you know what the clearances are?
Can you show us a picture of how the main caps are installed?
sorry about the crappy pic, it’s a screenshot from a video I took. The clearances were all very close to .003 and the rings were gapped per wiseco spec, .026 and .028 if I remember right


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Old Mar 25, 2021 | 09:20 PM
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First picture show engine with heads installed - are you doing this with heads installed??


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Old Mar 25, 2021 | 09:25 PM
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Pull the rockers off first and get a reading.
Then try removing the timing gear.
I'd bet you spun the cam after install to make sure it was free?

Ron
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Old Mar 25, 2021 | 09:32 PM
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Originally Posted by Biebs
First picture show engine with heads installed - are you doing this with heads installed??
I am. Shouldn’t matter though I don’t think. No pushrods, no plugs etc. I put them on to measure for pushrod length.

Originally Posted by RonSSNova
Pull the rockers off first and get a reading.
Then try removing the timing gear.
I'd bet you spun the cam after install to make sure it was free?

Ron
Rockers are free. When I installed cam, I put all three screws in and could turn with a small screwdriver, but it didn’t spin very freely like I am now reading it should

ill Try all of this and report back
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Old Mar 25, 2021 | 10:09 PM
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so valves are closed and you are Turing the engine to push all the air out the spark plug holes - Hmm good compression!!!

I think you do not have a problem!!!
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Old Mar 25, 2021 | 10:42 PM
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Originally Posted by Biebs
so valves are closed and you are Turing the engine to push all the air out the spark plug holes - Hmm good compression!!!

I think you do not have a problem!!!
that wasn’t a factor that I thought about... even with plugs out you’ve still got some decent compression. Another aspect is I’m using screaming eagle assembly lube from my Harley days. It’s gotta be the thickest assy lube ever. Stuff is like honey.
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Old Mar 25, 2021 | 11:17 PM
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I'd replace the valley cover bolts with low profile button head bolts so you don't risk cracking your intake
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Old Mar 25, 2021 | 11:32 PM
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From: JunkYard
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Is the rear cap, #5 cap facing the opposite way?
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Old Mar 25, 2021 | 11:39 PM
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Originally Posted by 1FastBrick
Is the rear cap, #5 cap facing the opposite way?
yes. Points on caps all point towards the rear of the motor, except for #5, which is the opposite. Is this correct?
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Old Mar 25, 2021 | 11:41 PM
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From: JunkYard
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Originally Posted by J_kelly_22
yes. Points on caps all point towards the rear of the motor, except for #5, which is the opposite. Is this correct?
Yes. It's a common mistake for people to miss that on a first time build which is why I asked.
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