I took a look at the FSM to refresh my memory, and the ring gap should be measured at the bottom of the bore where the wear is the least (77 manual EM-15 bottom left). Makes sense since what you really don't want to have happen is for that gap to close up to zero when things heat up.

You're a couple thousandths smaller gap at the bottom of the bores, right?  I'm no engine rebuild expert, but I think you're fine.

FYI:

https://www.classiczcars.com/forums/topic/59756-q-second-ring-gap/

 

Whose rings are you running? What is their recommendation for the ring gaps? The FSM and rebuild book are based on older materials. Some of the newer ring alloys might require a different standard?

These are OEM Nissan rings.


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Did you hone the block or bore it? I don't remember. CO's recommendation on measuring at the bottom of the bore might help. Are the bores with in spec? You really need a bore mic to check this. If the bores are with in spec then I would probably move forward.

My perfect circle rings came out with bigger gaps also - maybe because the cylinders were honed . I think your gaps would be okay . No where near wear limits . I would think ANY markings would identify top. Usually packages also identify rings by any type bevel or taper cut into the ring .

Finally got all my pistons in. Been busy lately but finally got the last one in today.
I wanted to post a pic of the rod bearing clearance. I used plastigage. The FSM says the clearance should be 0.025 to 0.055 mm.
Here’s how mine came out. Looks to be to be slightly more than the .051 indicator on the plastigage wrapper. So it meets spec in my opinion.
What do you all think?



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Rotation looks good. I work for an automotive company and our engines spin more than that freely, but we also have very high tolerances, select fit bearings and low viscosity oil for assembly. The rotating sound, sounds just like when we have a misassembled thrust bearing. I would pull it, measure and make sure it’s properly installed. 

Finally got all my pistons in. Been busy lately but finally got the last one in today.
I wanted to post a pic of the rod bearing clearance. I used plastigage. The FSM says the clearance should be 0.025 to 0.055 mm.
Here’s how mine came out. Looks to be to be slightly more than the .051 indicator on the plastigage wrapper. So it meets spec in my opinion.
What do you all think?



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Looks spot-on to me.

Okay, planning to get the head possibly installed today. Just wanted to confirm the process I’ve used to determine TDC for cylinder #1. I’ve used a dial indicator and the video is in
the link below. What do you all think?

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For marking or confirming the damper pulley I Ike the method of marking a certain distance down on both sides of ~TDC then splitting the difference to mark zero.  The crankshaft can move a few degrees at TDC with almost zero indicator movement because the rod end is moving almost sideways.

Don't you trust your damper pulley marks?  You don't need to be super accurate for installing the head or timing chain.

Edited January 21, 20205 yr by Zed Head

For marking or confirming the damper pulley I Ike the method of marking a certain distance down on both sides of ~TDC then splitting the difference to mark zero.  The crankshaft can move a few degrees at TDC with almost zero indicator movement because the rod end is moving almost sideways.
Don't you trust your damper pulley marks?  You don't need to be super accurate for installing the head or timing chain.

It’s not that I don’t trust the damper pulley marks but just following the rebuild book which talks about using a dial indicator to set TDC before putting the head on and avoid potentially damaging a valve. The timing cover goes on after and now I can verify the position. I set TDC using the dial
Indicator then temporarily placed the timing cover and damper on to validate the markings. With the crankshaft set as the video shows my damper indicates between 0 and 1 deg. Now I know exactly what the pulley should show.


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