R16 Engine knock

[Greaser2]

Are those aftermarket valves?

Piston 1 and 2 have some side to side movement but not much. 3 and 4 seems snug. Not sure of the clearance between pistons and cylinder walls. Maybe wouldn’t know for sure till rings are removed.

[Bwk2000]

And the gear set was the Early/Late timing set from Datsun parts, you can see it’s set at early as this as a 3bolt SAE

Everything under there looks ok to me

[david premo]

You might as well remove some bearing caps both rods and mains and see if there is any damage. Also with an extremely bright light look at the backside of the pistons and rods. As I recall the shop manual calls for a very tight bore clearance about.001 to .0015 if I remember correctly.
Dave

[redroadster]

The way the valves are sitting looks wrong like the seats were not narrowed ,because it appears the bottom of the valve it flush with the end of the seat , & it seems the intake valve has been super hot , definitely over rich on fuel , I'd sure take to a very good machine shop to check out , and machine the head surface .
1 thousandths cyl to piston ?
Hell no, that's a recipe for pulling the piston apart .010 should be more like the min. You can try rocking the crank back and forth to hear a knock in a rod

[david premo]

You got me Redroadster my apologies I was off by .0002 to .0005.

That is out of the shop manual, I’m sorry I was not precise enough for you but it is a pretty tight clearance.
Dave

[redroadster]

Show me a one thousands feeler guage , luv to see the piston installed too the piston expanse quicker than the cyl ,way hotter , most workers on Datsuns back then didn't drive ,there were many typos in the service manuals we had ,occasionally they sent a page that stuck onto the page to correct

[Greaser2]

The way the valves are sitting looks wrong like the seats were not narrowed ,because it appears the bottom of the valve it flush with the end of the seat , & it seems the intake valve has been super hot , definitely over rich on fuel , I'd sure take to a very good machine shop to check out , and machine the head surface .
1 thousandths cyl to piston ?
Hell no, that's a recipe for pulling the piston apart .010 should be more like the min. You can try rocking the crank back and forth to hear a knock in a rod

Yes, definitely rich, I was adjusting that when I noticed the low knock. Will have the head redone since its all apart now.

[redroadster]

You got me Redroadster my apologies I was off by .0002 to .0005.

That is out of the shop manual, I’m sorry I was not precise enough for you but it is a pretty tight clearance.
Dave

Dave your experienced in automotive engines ...the book meant 10 to 15 thousandths its a common mistake to add a extra zero ,
what the 1st thing a tech does after pulling the head ? Checks , ...which wouldn't work for .001 clearance .
At Datsun we kept the service manuals in the alignment cabinets ( I did the alignments)so when a stack of these sticky back page corrections needed to be placed on the exact page of a manual, guess who got the task

[Gregs672000]

Well, you're damn near a complete teardown, may as well push the pistons out and check the wrist pins to be sure. Mine was fractured into 3 pieces, and only the strength of forged pistons saved me, lucky to have them. I had noticed a little binding when I built the engine and had worked them a bit with Emory cloth, and obviously had them feeling good or I wouldn't have installed them... wrong!
That's a broken drum stick I used to push the pin out of the piston. I actually drove it like that to (7000rpms!)

[NISSTECH]

That must be a U-20 Diesel that has .010-.015 piston to wall clearance
You might want to recheck those numbers

[Bwk2000]

IMG_4578.png

[redroadster]

He has his open ,feeler guage it to see what the gap it is

[Greaser2]

Will check the gap for sure, before i completely explode the engine, what other gaps should I check.

Also, the cylinder walls don't appear to have any scoring, good, but are very smooth, no cross hatching for example, guess this a sign of well used cylinders?

[redroadster]

You want to try to move the pistons side to side E to W & N to S to see if the rings are seized in the lands or from carbon build up , if you clean off the deck and have a straight edge check it for warpage with a feeler guage ,if you turn the crank throws
90 ° then rock it back and forth and mist paint thinner with food coloring you should be able to make out play in the rod bearing ....it way easier to pull the sp wire to see if the knock goes away

[Greaser2]

Is there a good rebuild manual?