Crank slow to spin after installation
Thread Starter
Staging Lane
Joined: Oct 2009
Posts: 71
Likes: 1
Crank slow to spin after installation I’m assembling my engine the other night and after torqueing down the main caps, I noticed the engine was not as easy to turn over as I would have thought. I’ve read about 10 threads related to this topic everyone says it should turn over ‘by hand’, but there are varying degrees of ‘by hand’, so it’s hard to judge what is normal.
To give you an idea, I could turn it with my index finger on the side of a bob weight, but I struggled to turn it when using my pinky finger. Hanging some weight off the side, I’d estimate it at around 3-4 lb-ft of resistance. It’s nothing ridiculous at all, but it certainly doesn’t want to ‘coast’ as I saw one person put.
It’s been awhile since I disassembled the engine, but I thought I remember the crank spinning quite easily before. I was thinking/hoping it has to do with the fact that disassembly was on motor oil at 70*F whereas now it’s on assembly lube at 30*F.
Motor oil viscosity at 70*F would be about 0.08 Pa-s.
Assembly lube viscosity at 30*F appears to be around 14 Pa-s (similar to honey). This is about a 150x increase in viscosity and thus drag.
I would think this could be causing the difference, but I was hoping to hear from someone who has done this a few times to be sure. Will cold weather and assembly lube cause the crank to resist being spun? And yes, I checked the bearing clearances with a micrometer and dial bore gauge. I also ‘aligned’ the #3 bearing.
Appreciate any input.
To give you an idea, I could turn it with my index finger on the side of a bob weight, but I struggled to turn it when using my pinky finger. Hanging some weight off the side, I’d estimate it at around 3-4 lb-ft of resistance. It’s nothing ridiculous at all, but it certainly doesn’t want to ‘coast’ as I saw one person put.
It’s been awhile since I disassembled the engine, but I thought I remember the crank spinning quite easily before. I was thinking/hoping it has to do with the fact that disassembly was on motor oil at 70*F whereas now it’s on assembly lube at 30*F.
Motor oil viscosity at 70*F would be about 0.08 Pa-s.
Assembly lube viscosity at 30*F appears to be around 14 Pa-s (similar to honey). This is about a 150x increase in viscosity and thus drag.
I would think this could be causing the difference, but I was hoping to hear from someone who has done this a few times to be sure. Will cold weather and assembly lube cause the crank to resist being spun? And yes, I checked the bearing clearances with a micrometer and dial bore gauge. I also ‘aligned’ the #3 bearing.
Appreciate any input.
In my experience, assembly lube definitely puts more drag on the crank than oil. With oil, good clearances, and a good straight crank, you can turn the crank by hand and it will spin 1 or two more times before stopping. With assembly lube, it might turn 1/4-1/2 revolution.
Thread Starter
Staging Lane
Joined: Oct 2009
Posts: 71
Likes: 1
Taking the inner bolts to 80* and the outer bolts to 51* took about the limit of my strength on the breaker bar I had, so I think it's unlikely I went over the spec by and significant margin on any of the bolts.
I did find two other people on other websites who had similar issues with the same green Sealed Power assembly lube I used. That it was so sticky, it pulled the bearings out with the crank when they went to pull the crank and re-try assembly with motor oil. But without having personally experienced this, I'm probably to the point of needing to waste a few hours re-doing it just to convince myself.
This is what I was hoping to hear, though unfortunately your comment makes me think I could potentially have something wrong. There is no way that the crank would continue rotating even 5 degrees after I stop applying torque. I hate doing things twice, but there's enough doubt in my mind that I probably need to re attempt it with motor oil instead just to rule a possible issue out.
I did find two other people on other websites who had similar issues with the same green Sealed Power assembly lube I used. That it was so sticky, it pulled the bearings out with the crank when they went to pull the crank and re-try assembly with motor oil. But without having personally experienced this, I'm probably to the point of needing to waste a few hours re-doing it just to convince myself.
I did find two other people on other websites who had similar issues with the same green Sealed Power assembly lube I used. That it was so sticky, it pulled the bearings out with the crank when they went to pull the crank and re-try assembly with motor oil. But without having personally experienced this, I'm probably to the point of needing to waste a few hours re-doing it just to convince myself.
I really don't like to assemble with assembly lube for this reason though. If there is a problem, like some dirt or a nick in the bearing, it would cause a slight resistance that you couldn't really feel with assembly lube. I prefer to assembly with oil, preferably a "break in" oil. The only time I use assembly lube is if I knew the engine would be sitting for a long time before being used.
I really don't like to assemble with assembly lube for this reason though. If there is a problem, like some dirt or a nick in the bearing, it would cause a slight resistance that you couldn't really feel with assembly lube. I prefer to assembly with oil, preferably a "break in" oil. The only time I use assembly lube is if I knew the engine would be sitting for a long time before being used.
Trending Topics
if you went wth main arp studs clamping pressure is higher and crank will be much tighter or distorted. crank may not even turn. stock tty and proper new bearing proper clearance should feel smooth. did you line hone with new bearings? Also double cheak no 5 bearing you can install bearing tabs backwards. excessive leverage to turn crank is red flag.....
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Putting engines together here in WI where it's currently -5 to + 5 I can tell you that KCS is right on with the 1-2 turns (motor oil in warm summer) and that thick red Goo really creates drag and makes me think the same thing you are especially when it's this cold. I only use that stuff as KCS said when the engine won't be fired for quite a while. Trust your measuring instruments.
TECH Regular
Joined: Sep 2008
Posts: 425
Likes: 1
From: Scottsdale, Arizona
I'd take it apart, use some thin oil and reassemble. Use a dial torque wrench to see how much torque it takes to turn the crank. If it's free then you know that it's your assembly lube. If not then something is wrong.
