A few months ago I discovered a bad head gasket in my 73 Z.  Decided to pull the motor and rebuild instead of just fixing head gasket.    I've done a lot of small block Fords/Chevy's, but this is my first Z motor rebuild.  I want to make sure I do the rear seal correctly so it doesn't develop a leak later on (or immediately ).  The seals I'm using are from an IMT gasket kit.  The cap side seals are rubber with a wire inside to stiffen.   I assume I'll have good luck with these, right?

A few questions about assembly:

• Any thin sealant between cap and block surfaces adjacent to rear seal area?
• Can rear seal be placed on crank and then install rear cap?
• On the cap side seals, should the excess flash be trimmed from the ends?  Use sealant on entire seal?  Or just the ends?

Anyway, looking for tips from the pros so I don't have to do it twice!   Motor is a non-original L26 block and E88 head.  Had dished pistons but went with flat-tops with eyebrow reliefs.  Bores are +1 mm.  The crank is standard size and just needed polishing.  Mains are at .002 - .0025 clearance.  The head is stock.  I won't be pushing the engine hard very often, but it won't be babied either.  Machine seems to be fine, as the guy has worked on a lot of Z's.

I'm sure I'll have more questions in the near future.   Any suggestions or thoughts are welcome!

Thanks,

Ken

I'm pretty sure I put the seal on first then set the crank in. The best tip I got on the side seals from @Diseazd was leave the rear cap about an inch off the block then push the side seals down. When they bottom out tighten the cap down. Snip the excess off with side cutters. I put black rtv in the corners of the block before the cap too. When you get it torqued down put some where the cap's sides meet the block. I use Tom Monroes "how to rebuild your Datsun L motor", best instructions ever. $20 from amazon.com. It's the best money spent for me. I've built two that turned out perfect following his instructions. I'd never rebuilt a car motor either. That book and the kind folks on this forum made it easy. Good luck and ask anything, no smartasses on here. 8^)

IMO you can install the rear seal either way. Grease the lips of the seal before installing. When you install it on the crank journal , rotate the seal clockwise as you are installing on the crank journal.....position the seal where you want it to sit (slightly off any previous wear grove), then torque down bearing caps. I also install sometimes after the crank is in and torqued. Grease the seal lips and rotate clockwise on rear crank journal until snug and square. I then tap it in squarely with a flat edge (block of wood) evenly until seated flush. BTW, I see you are using Hastings piston rings....IMO, they are the worst (poor oil rings). I recommend Nissan OEM or Total Seal. Looks like a nice clean install....great pictures!  Note:  Looks like you've got the wrong (narrow bearing) bearing in the rear cap.

........therefore the cap to the left of the rear cap in picture 3 is too wide.   Always number your bearing caps so they go back from where they came off. 

9 hours ago, siteunseen said:

I use Tom Monroes "how to rebuild your Datsun L motor", best instructions ever. $20 from amazon.com. It's the best money spent for me.

Thanks, ordered that.  I'll wait a few days for the book before proceeding much further.

2 hours ago, Diseazd said:

........therefore the cap to the left of the rear cap in picture 3 is too wide.   Always number your bearing caps so they go back from where they came off. 

Yeah, they'll not laid out in order, and they are stamped.  I did notice the bearing in that cap you mentioned is wider, which needs to go on the rear.   Good catch.   Hopefully I can exchange those rings for Nissan or Total Seal.  Thanks.

I used Hastings on my 2.4, chrome faced moly.  My machinist got them for me after I searched and searched with no luck for 83mm rings.  You may have better luck with your 84mm size?  

I don't know anything about oil ring dynamics but I have great oil pressure, if that means anything? 

I'm pretty sure my machinist honed the block for those cast iron rings.  I think moly rings are usually finished off with a finer stone.   I need to talk with him if I decide on molys and if it's worth the effort.  Or just go cast iron.   I should have decided that before work began .  Ring size is .040 over.

Site.....All I'm saying is that the oil rings in the Hasting set aren't as easy to install as the other ring sets that I mentioned. It's important to install the lower oil rings correctly. I'm sure others install them with no problem, but I just find Nissan and Total Seal oil rings seem to "lay in" much nicer!

I was worried they were inferior oil rings. Thank you for letting me know it as an installation issue, I'll sleep better knowing that. 8^)

Cliff

 

1 hour ago, sfm6s524 said:

I'm pretty sure my machinist honed the block for those cast iron rings.  I think moly rings are usually finished off with a finer stone.   I need to talk with him if I decide on molys and if it's worth the effort.  Or just go cast iron.   I should have decided that before work began .  Ring size is .040 over.

I used Hasting cast iron on my 280 4 or 5 years ago. It still runs very well. I think the last compression check was 170.

My machinist honed mine for the chrome faced rings, you're right there is a difference. He told me the OE Nissan rings were chrome faced but cast iron was a fantastic replacement. It'll be explained by Tom Monroe. Pages 68 & 69.