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Av8ferg

L28 full rebuild assembly

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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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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 by Dave WM

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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. 

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B537FC3A-EC8E-4E0E-B8A2-45F9255D4B60.jpeg

Edited by Av8ferg

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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?

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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.

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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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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.

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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?

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

 

I looked them up; Sealed Power.

 

 

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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!

 

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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. 

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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.

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I’m was prying pretty hard, it wasn’t going to move, the big screwdriver was bending. I guess I’ll pull it all apart and try and shave those flanges a tad. Book says to measure them prior and then lightly sand.
Thanks for the advice guys!


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Besides it gives you the opportunity to turn those caps around.


Well, I did that already. The block came back with the caps on. I reviewed my disassembly photos and noticed the arrows were the wrong way so fixed that when installed the bearings.


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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!
 

Thanks. I am using the L28 rebuild book. I guess it’s better to be safe than sorry. I’m going to double back, check my work, pull it back off and try and get some measurements off this thrust bearing.


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Did they line bore the block? If they did, I would ask which way the caps were installed when they did it. If the block wasn't line bored then install them with the arrows forward

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Did they line bore the block? If they did, I would ask which way the caps were installed when they did it. If the block wasn't line bored then install them with the arrows forward

The block was only tanked and bores honed.
I’m going to buy a dial indicator tomorrow and if its within tolerance then I won’t pull it apart.


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It is a great rebuild tool. It will help with measuring TDC and any piston protrusion from the block

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Head is finally in my garage and looks pretty good. $300 for all the work.
Cleaned, replaced valve seat, and complete valve job.
I just wish I had time to put this engine back together.
Side notes. This is double confirmation that the OSK timing chain kit doesn’t have the V-notch on the sprocket. Was $68 on EBay. Nice kit IMHO.

Rod bearings arrived too. I purchased tri-metal standard bearings made by Taiho $38. Tried to buy the Clevite 77 P- series but they are no longer available anywhere in STD sizes for Rods.


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you may want to make your own notch. I would put the two sprockets back to back, then using the old one as a guide, scratch in some marke where it should be. then use a v cut file and make your own. easy to do while its apart.

did you try spinning the camshaft with the valve gear not in it? looking for a nice low drag, no tight spots spin.

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you may want to make your own notch. I would put the two sprockets back to back, then using the old one as a guide, scratch in some marke where it should be. then use a v cut file and make your own. easy to do while its apart.
did you try spinning the camshaft with the valve gear not in it? looking for a nice low drag, no tight spots spin.

Dave, I put the old sprocket on and spun the cam about a 1/2 turn to try and stop any of valves from protruding past the deck.
Good idea with the sprocket but I could also check the timing position using the old sprocket and then once set put the new one on in the same hole.


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I am thinking mainly to make sure things line up, some times installing the sprocket can get dicy with what link its on. Plus you will want it to check for wear later on.

I would suggest you remove all the valve rockers and make sure you don't have any tight spots on the camshaft. If it does you maybe able to correct with careful tightening of the cam tower bolts.

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3 hours ago, Av8ferg said:



Rod bearings arrived too. I purchased tri-metal standard bearings made by Taiho $38. Tried to buy the Clevite 77 P- series but they are no longer available anywhere in STD sizes for Rods.



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Are the "P" series harder than the "A" series? 

https://whiteheadperformance.com/product/clevite-77-trimetal-rod-bearings-cb-966p-l24-l26-l28-l28et-datsun-240z-260z-280z-280zx/

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