SR20 crankshaft will not spin freely by hand after assembly. Normal?

[KingSpence]

Alright, I'm getting a little frustrated at this point, I'm going to call the engine shop again tomorrow and see what they have to say.

I'm rebuilding my 1997 blacktop s13 sr20det. Crank was polished and measures out to standard spec. ARP main studs, and I'm using ACL Race bearing that were checked with plastigage.

The engine shop recommended Clevite Bearing Guard assembly lube. It's red and feels pretty thick. I applied it liberally to the bearings, followed proper torque sequence and reached the ARP recommended 80 ft-lbs. in 20 ft-lbs cycles. I was sure to rotate the crank after every cycle.

Here's my issue, once I exceed 65 ft-lbs I'm not able to spin the crank by hand without aid from a wrench; but spins smoothly and shows no signs of binding. Once everything is fully torqued if I let the motor sit for a few minutes then try to spin the crank I really need to reef on it to get it to budge, but upon budging it spins smoothly (I still need the leverage of a wrench on the crank bolt).

I pulled everything apart tonight under the assumption I had plastigage deposits on the bearings that were causing resistance. I disassemble everything, meticulously cleaned everything and reassembled. Unfortunately, there was no improvement.

I'm confused what can be causing this, it just doesn't seem right. I would think I should be able to spin a crank with no pistons by hand quite easily. FSM main bearing clearances at .0002 to .0009. A few of my friend who have built domestic v8's said those clearances are ridiculously tight and the thick assembly lube could be making it harder to spin.

Any suggestions? Has anyone else experience the same issue as this? I'm debating finding another assembly lube, maybe something thinner? I have an old school needle torque wrench (I used a Snap-On for the studs) and the needle came damn near 100ft-lbs before the crank spun, but once it budged it made smooth rotations with little effort using the wrench.

Thanks!

[ShadowMan]

I know you don't want to use too much of that assembly lube, especially the thick stuff. You only need it there long enough to let oil cycle throught the system. When I re-assembled my bottom end, i was able to spin the crank, freely by hand, with the pistons and rods attached, so you're definitely playing it smart. Try just using a light coat, you don't need much, but dry fire the engine before starting it when it's all back together. I just pulled my fuel pump fuse and disconnected the ingnitor, then gave it a few 20 second cycles before trying to actually start it. I used redline assembly lube.

[jr_ss]

Ridiculously tight is a relative term. Nissan and most Japanese engine manufactures run tight tolerances to ensure a long service life. Your V8 buddies don't think those newer V8's are still running huge tolerances like they use to do they?

One thing about ARP mains, they tend to distort the main caps once torqued down. It's a different clamping load than the factory bolts, so it is recommended to have those bores line honed before assembly. Did you check bore diameters with the caps torqued down without the crank installed?

[KingSpence]

One thing about ARP mains, they tend to distort the main caps once torqued down. It's a different clamping load than the factory bolts, so it is recommended to have those bores line honed before assembly. Did you check bore diameters with the caps torqued down without the crank installed?

No, I never though of checking such a thing. The last thing I expected was ARP's to distort my block.

I talked to the machine shop today and they told me I need to have the block and rods align bored. I'm hoping the rods will be okay seeing that the Nissan and ARP torque spec are very close to each other, but the mains will need to be dealt with. I've never heard of such a thing, sounds freaky knowing I'm shaping my mains into eggs when I'm loading up the crank..

Apparently align boring is crucial if anyone plans of running aftermarket hardware that has a different torque rating than what Nissan calls for. And no, you can't just torque ARP's to factory specs.

I'll be dropping the motor off tomorrow morning, for the third time now. The second time was due to the timing cover sitting .004 higher than the block (I'm running a MHG.) I just want this thing running already!

[jr_ss]

It's a known fact that SRs distort under torquing loads. That's why you need a torque/deck plate and bellhousing torqued down for boring and honing.

[KingSpence]

It's a known fact that SRs distort under torquing loads. That's why you need a torque/deck plate and bellhousing torqued down for boring and honing.

Even honing? Seems a little far fetched to me. I'd like to think my block didn't banana when the shop honed it..

[jr_ss]

Honing removes material... If you hone and don't have simulated loads on head studs and bellhousing areas you can have things out of round when it is torqued down. I'm not saying this is the case all the time, but this is how professional, high powered motors are done. There is distortion and regardless of large or small amounts, it still happens. If you want to be absolutely sure there are no chances of distortion, those procedures need to be done.

[ShadowMan]

I must have been super lucky, because aside from dealing with trimming the arp's after they cracked my upper pan, everything went together super smooth and I had no problems with the reassembly. Granted I'm not running my SR at it's limits, but I consider myself lucky it hasn't fallen apart yet. I never thought about any of this either, I have habit of considering problems as they become problems, not before. So much more to consider the next time I attempt an engine build. You should definitely update this with how it all turns out though. Also, what about your thrust washers and those tolerances? Are they good? Not sure if this would even be a problem due to my inexperience but they seem like they would/could be a potential source of this problem. It was only after I disassembled the motor that I learned I was supposed to measure the clearance/tolerance of everything before hand to compare with the numbers upon reassembly. I guess it's already at a shop so it's out of your hands but food for thought maybe.