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I know of nowhere to buy new caps. You'll have to find a donor and then line bore the engine. Caps are machined for one location in one motor only

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If I were in the middle of the outback and needed to get to the hospital, I might try swapping the cap from one motor to another just to save a life. But I would never expect it to last.

And I certainly would never try that on cap #4 or the rear cap #7.

So unless the guy you bought the motor from turns up the missing cap, it sounds like you bought a paperweight.

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Why not just source a cap and line bore? Its way cheaper than those caps

Can I get any L28 main caps, and have them line bored to fit?


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That depends. I believe there are 3 unique caps in the L28. The middle cap, the rear cap and the other common caps. You need to know which one is missing and then have it line bored with all the caps installed

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Well I'm not sure what everyone here is talking about when they suggest line-boring, but where I come from, it would mean putting all the caps into place at spec torque, and then running a cutter through to remove material thereby making sure all the journals all perfectly in-line and the same size.

But my question is... What then? You'll need larger bearings with more meat on the outside to make up for the material you took off. You got a source for that?

You can get "oversized bearings" with more meat on them on the INSIDE for when the crank is ground, but to find bearings with more meat on the OUTSIDE that were designed to fit into a larger block bore? I mean... I've never looked. Is that a thing?

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I suppose you might get lucky and only have to take material off the new cap. maybe you could weld the new cap in prep. 

But I'd think just buying a complete l28 block would be easier and cheaper. 

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Here, when they line bore, they shave all of the caps. Torque them down and rebore all the way through for a concentric std bore

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10 hours ago, jonbill said:

But I'd think just buying a complete l28 block would be easier and cheaper. 

I think that the caps are considered part of the engine block.  Not shown as available as separate pieces.  A guy could probably go to a wrecking yard and find one then have a machinist make it work.  But, it's still going to come from a used engine.  

I'd have the guy search his garage for that cap.

http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-280z/cylinder-block

 

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For the record though, you can buy main caps for a Chevy small block from numerous places.

You might call somebody like Datsun Spirit or Arizona Z Car, if you decide to try to save the block.  They build engines.  Might even have some used ones.

https://www.jegs.com/i/Speedmaster/746/PCE289.1002/10002/-1?gclid=Cj0KCQjw9_mDBhCGARIsAN3PaFNMd6jy7Ofu06P4cJsdCpPw58lu4UozC605W25FcJdrOXT8lkmMhT4aAjA4EALw_wcB

https://datsunspirit.com/

http://arizonazcar.com/

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For the record though, you can buy main caps for a Chevy small block from numerous places.
You might call somebody like Datsun Spirit or Arizona Z Car, if you decide to try to save the block.  They build engines.  Might even have some used ones.
https://www.jegs.com/i/Speedmaster/746/PCE289.1002/10002/-1?gclid=Cj0KCQjw9_mDBhCGARIsAN3PaFNMd6jy7Ofu06P4cJsdCpPw58lu4UozC605W25FcJdrOXT8lkmMhT4aAjA4EALw_wcB
https://datsunspirit.com/
http://arizonazcar.com/

Much appreciated, I’ll give them a call!


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For the record though, you can buy main caps for a Chevy small block from numerous places.
You might call somebody like Datsun Spirit or Arizona Z Car, if you decide to try to save the block.  They build engines.  Might even have some used ones.
https://www.jegs.com/i/Speedmaster/746/PCE289.1002/10002/-1?gclid=Cj0KCQjw9_mDBhCGARIsAN3PaFNMd6jy7Ofu06P4cJsdCpPw58lu4UozC605W25FcJdrOXT8lkmMhT4aAjA4EALw_wcB
https://datsunspirit.com/
http://arizonazcar.com/

Much appreciated, I’ll give them a call!


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15 hours ago, Patcon said:

Here, when they line bore, they shave all of the caps. Torque them down and rebore all the way through for a concentric std bore

Right. But unless they remove material from the block side of the journal, you aren't guaranteeing concentricity. And if you DO remove material from the block side of the journal, you'll raise the piston's stroke location in the cylinder.

Bottom line for me... I'm not in the outback.  LOL

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Nissan sells oversized bearings.  Not sure if they're meant for crankshaft or block.  Maybe they're bendy enough for either.

Probably want to see if they're available.  

http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-280z/piston-crankshaft/17

http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-280z/piston-crankshaft

I'm seeing that it's probably doable but might not not worth it since another complete block should be easy to find and cheaper overall.

https://rigiboreinc.com/articles/38/a-new-dimension-of-control-in-crank-boring-with-rigibores-auto-compensating-line-bar

https://www.enginebuildermag.com/2006/06/line-boring-equipment-a-boring-subject/

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[mention=34647]Remixaflip[/mention] What cap are you missing? 
I've got an F54 block here that I'm not going to use. 

I need one of the common caps. I have the middle cap and rear cap.


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Are you struggling with and just trying to get your Z on the road so you can enjoy it for years to come, or are you flipping this vehicle? Just need to get the engine running long enough for someone else to test drive it and buy it?

In other words... Are you planning to put this engine together and drive it yourself, or are you planning to make it someone else's problem?

Haha! Honestly, I'm not really keen throwing caps in there from a different motor and then dumping it in someone else's lap without telling them about it.    LOL

Does that make sense?

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Are you struggling with and just trying to get your Z on the road so you can enjoy it for years to come, or are you flipping this vehicle? Just need to get the engine running long enough for someone else to test drive it and buy it?
In other words... Are you planning to put this engine together and drive it yourself, or are you planning to make it someone else's problem?
Haha! Honestly, I'm not really keen throwing caps in there from a different motor and then dumping it in someone else's lap without telling them about it.    LOL
Does that make sense?

I plan on keeping this car for a long time. Maybe I misunderstood your statement. When you said you have an f54 block, we’re you referring to the complete block or just the mains?


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How much did you pay for this engine? Hopefully not too much. You said you want to keep it for a long time then the only answer is to do it right. If I were in your position I’d find another long block. You can get one for pretty cheap. I see them all the time in junkyards for $400+. That’s what I paid for mine. A cheap rebuild will cost you about $800 depending on what you do. Could be more or less. You have use this other engine that’s missing caps for parts. Was it a full engine or just a block? If a full engine there are parts you can sell to help cover your losses like the head etc. just an idea. Gotta know when to cut your loses vs putting good money toward a previous mistake.


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How much did you pay for this engine? Hopefully not too much. You said you want to keep it for a long time then the only answer is to do it right. If I were in your position I’d find another long block. You can get one for pretty cheap. I see them all the time in junkyards for $400+. That’s what I paid for mine. A cheap rebuild will cost you about $800 depending on what you do. Could be more or less. You have use this other engine that’s missing caps for parts. Was it a full engine or just a block? If a full engine there are parts you can sell to help cover your losses like the head etc. just an idea. Gotta know when to cut your loses vs putting good money toward a previous mistake.


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It’s a complete engine with all the pars except for the one missing main cap. I plan on doing a full rebuild any so doing having a machinist line bore the cap to fit isn’t a problem, I’m just having a hard time finding the one cap. I managed to get to engine for $500 dollars.


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Okay, so you just need to find a junked motor and steal the caps off it. Might be a hard find. See if you can find a cheap F54 block on CL or a salvage yard. Where do you live?


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2 hours ago, Remixaflip said:


It’s a complete engine with all the pars except for the one missing main cap. I plan on doing a full rebuild any so doing having a machinist line bore the cap to fit isn’t a problem, I’m just having a hard time finding the one cap. I managed to get to engine for $500 dollars.


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Is it also missing the bolts for the missing bearing cap?

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