L28 full rebuild assembly

[Av8ferg]

Gents,

So I thought I’d start a new thread on this since I’m now on the reassembly phase. I’ve had a few issues with the crank install albeit all self-induced.

I’ve posted a video on the crankshaft install and my concerns and questions.

Concerns:

-How much free spin force is normal?

-The shop has the caps in 180 out but in right location when I got the engine block back.

-Did I damage a bearing when we accidentally torqued caps to 58 ft lbs?

-Book says torque to 33-40 ft lbs, I set 36lbs.

-Thrust bearing clearance, could not determine.

 

Video capture all these concerns

 

 

Thanks

 

 

 

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[Dave WM]

just a guess but that ZERO clearance on the thrust bearing sounds wrong. Perhaps a few light passes on a flat plate on the bearing sides to take it down a bit. This coming from a guy that had NEVER done it, so just my thoughts based on reading. I suppose you could try removing the thrust bearing and see how it spins as a test. Did you check with plastigage? what kind of assy lube did you use?

Edited November 9, 2019 by Dave WM

[Av8ferg]

Dave, 

I did not use plastigage because the journals measured almost perfect (well inside tolerances).  i was there when he measured the journals and his comment was how surprised he was that there were exactly what the books specified and all nearly identical.  He said that he doesn't see that often on domestic motors he works.  This wasn't the first time he commented on the high quality of the motor vs what he normally sees.   Also, I bought standard size OEM Nissan bearings, not aftermarket.   I used Lucas Semi-synthetic high performance assembly lube.   This stuff is pretty tacky.  Its a bit messy, and leaves a long stringy mess, like snot but very slick. 

Edited November 9, 2019 by Av8ferg

[Dave WM]

hopefully someone with exp will chime in. I would think the center thrust bearing maybe an issue. I don't know if you are "suppose" to size them, Did the book say anything about what to do IF the clearance is too tight?

[Dave WM]

If It was mine, I would remove the bearing caps and see how it spins. if it seems tight, I would then remove the center thrust bearing from the block and see how it spins (again without the bearing caps installed). I would think inertia should allow it to continue spinning if you give it a good start. If all seems well then install bearing caps and compare. But again this is just me talking, still hoping someone with exp will chime in and help you out.

[Av8ferg]

Here’s what the books says, but I need someone who’s done this before to tell if I need to pull this apart and do it again. Says to sand the thrust bearing edges with 320 sandpaper to get the clearance. Should be .002 but not more than .007. The crank won’t move laterally (float) at all when pry it as instructed using a long flat screwdriver.




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[jonbill]

When I built mine it did have that lateral clearance. But I didn't have to do anything to the centre bearings to get it.

[Dave WM]

1 hour ago, jonbill said:

When I built mine it did have that lateral clearance. But I didn't have to do anything to the centre bearings to get it.

did you use OE bearings or aftermarket? Maybe the OE's are designed to allow for custom clearancing?

[jonbill]

Aftermarket, I forget which ones. Reasonably priced tri metal from rockauto.

 

I looked them up; Sealed Power.

 

 

[txvepr]

You look good as far as I can tell, I rebuilt mine 2 years ago and yours looks like mine. Its not going to free spin with your fingers or hand. 

You are using the L28 Engine rebuild book, right?   Its got everything you need for this. 

Keep it up!

 

[grannyknot]

I think you really need to find the clearance on the thrust bearing and measure properly so that it is repeatable, so you're getting consistent reading on both sides using the long screwdriver to pry. 

[Patcon]

The spinning looks proper for a crank with sticky prelube. they don't really "free spin". I think it would be good to have the clearance on the thrust bearing. How hard are you prying? You can pry pretty hard since both surfaces are steel. It's a little easier to check end play if you have a dial indicator and a magnetic base. Measure off the crank snout or flywheel boss.