MIRROR FINISH ON PISTON WALLS

[280zdude]

Hey guys it’s been a minute. 
 

soo my 77 280z has a glossy finish in the cylinder walls. Is this normal on a stock car or should there be cross hatching. 
 

I don’t want to build the bottom end.

[Patcon]

Did you do a compression check before disassembling?

[dutchzcarguy]

Glossy finish...  normally a good thing ... on paintwork... Not so much on a cylinderwall!  The cross hatching is for lubrication of the piston and.. is very poor now i think..  You need to take the pistons out and restore the cylinders.. or buy another block that has them and has a good compression..

Normally a wall is still good after 200000 miles provided that there has been good maintenance i think.. your engine had a lot more miles or bad maintenance.. not sure..

Here i have a pic of a wall with 120000km on it or 74,500 Miles..  (From my 280zx, just a clean up and new seals needed.)

 

Maybe you can restore these with special tools and new rings?  somebody chime in with experience?  Some pics of your walls would be nice!

Edited November 18, 2021 by dutchzcarguy

[siteunseen]

Moly faced rings get the smooth hone. Iron gets the cross hatch from what I remember.

Agree with the compression test first though but it sounds like you've pulled the head already.

[280zdude]

Well it’s a little too late I already pulled it. What can I do now 

[280zdude]

[siteunseen]

They're not a shiny as I remember mine being. How long since the car has been run? Nissan used chrome moly from the factory so it should be slick and more shiny in my opinion.

Take your thumbnail and go up down all the holes and see if you find any scractes, gouges. Your fingernails shouldn't get caught on anything. You can get some rags and lacquer thinner and clean those holes of the carbon. Be sure and take the oil pan off or drain it for sure before cleaning.

This pic looks odd, the carbon build up on that one side. The scraper ring should keep them clean. I'm guessing that engine hasn't been run lately ?????

 

[dutchzcarguy]

14 hours ago, siteunseen said:

This pic looks odd, the carbon build up on that one side.

Can it be a reflection? some spots are a copy of the spots on the top of the piston.. 

Anyway.. i do see some hone stripes.. not so bad.. give it a good clean.

[EuroDat]

Im 100% with dutchzcarguy. It looks a lot like reflection and hone cross hatch and that is a good sign. If you can't see any vertical scores in the bores, it shouls be ok.

Nissan had a good reputation with the iron they used in the blocks.

[280zdude]

Okok I’ve never seen an inside of a engine this up close and personal. The reflection threw me off. In pictures and videos it look like a stain ish reflex due to the cross hatches. 
 

thanks guys! 

[280zdude]

The car only has 58k miles on it so I was really concerned haha 

[Patcon]

58k

That motors not even broken in good yet!