R16 noise, help me out

[unklpat]

It looks like the crank wasn't ground edge to edge, on the rod journals. The mains might show the same symptoms. Have you looked at your timing gear? I don't know R16's, but had a gent with a broken lower guide on a U20, similar noise. Pat

[JT68]

Well, wish I had better news. Rod caps were all good torque but found some surprises.

I would say, more a symptom of the metal in the oil than a cause. And also likely not my noise.. Going to check the mains next :/

Probably correct, I'd say the one deep score in the rod bearing was simply from a piece of trash that ran through it, it wasn't a bearing failure. Had to be inside the crank or galleys when assembled, that would not have made it through the filter.

The slight shiny traces on the edges of the bearings would probably never have caused a problem. The radius on the rod journals is well past the edge of the bearings, so also a non-issue.

The journals and bearing surfaces look ok other than the damage from the trash. So far you need rod bearings, but now you will need to check rod bearing clearances as well.

R16's don't have chain guides, just a lower tensioner.

[cbez]

Well couldn't budge the rear main bearing so here are the front 2. They all feel smooth, not noticable damage like the rod bearings:

[JT68]

Nothing I can see on the mains to worry about and 3-main bearing sets are expensive and hard to source. Does the thrust face look ok? can't see that.


Remember what I said about that rabbit hole? Unless you are going to pull it and tear the whole thing down, don't remove that rear main cap. Way too hard to re-do in the car.

[JT68]

are the rod bearings std? (they say on the back)

make sure you put the arrow on the main caps pointing forward. Clean carefully and coat with 20-50 or assembly lube.

You also need to square up the thrust surface when you replace the center main cap. You can call if you don't know how to do that.

[cbez]

C1-1002GP-UL-.25 NDC

Guessing .25mm oversize?

[JT68]

yep. .25 NDC's. To do this properly you will need a way to check the bearing clearances. However if you use NDC's again, there is probably minimal risk in swapping them.

[theunz]

Curtis has a point about high oil pressure at idle. I have very little knowledge of 1600’s, but since the upgrade oil pump is the U20 pump I would think oil pressures would be similar. That being said, usually if there is a comment concerning oil pressure at idle it’s that the gauge shows little to no pressure. As others have alluded to it seems as if there is blockage to the top end thus causing the valve train to not be sufficiently lubricated. I would yank the engine and completely disassemble and clean it thoroughly. It’s practically torn completely down now, so the cost of gaskets would be negligible. Good luck and keep the faith.

[JT68]

Curtis has a point about high oil pressure at idle. I have very little knowledge of 1600’s, but since the upgrade oil pump is the U20 pump I would think oil pressures would be similar. That being said, usually if there is a comment concerning oil pressure at idle it’s that the gauge shows little to no pressure. As others have alluded to it seems as if there is blockage to the top end thus causing the valve train to not be sufficiently lubricated. I would yank the engine and completely disassemble and clean it thoroughly. It’s practically torn completely down now, so the cost of gaskets would be negligible. Good luck and keep the faith.

No, That's really not correct. The U's always run lower oil pressures because there are so many other active oil feeds. The u20 head moves A LOT more oil and there are more feeds to the crank. That is why Nissan increased the flow volume of the U pump so much.

If the pump in the engine now is a u20 pump, that is why the pressure is higher. Also if "higher" is based on the factory gauge, I sure would not base any conclusions one way or another on that. +-20 psi accuracy? Maybe?

Yes , the conservative approach is to tear it all down. That is what I would do.., but unless that rear cam bearing is the culprit, he really has found nothing that would have caused any problem in the bottom end. I'm betting its the cam bearing or more likely the rocker assembly - Even the scored rod bearing would most likely have had no consequence.

(The rod bearing looks much worse than it is...all the trash did functionally was put a groove in the bearing. Some bearings are machined with a groove-the groove just fills with oil. Yes, I know it isn't pretty, but there was no serious wear on any of the bearings)

[cbez]

It's nos r16 pump. Previously had a u20 pump they couldn't get oil pressure from while trying to prime it, so it was swapped shortly before I took the car.

I will call on the thrust thing...the factory manual just says tighten center first.

I'm inclined to agree nothing of major consequence found..

[Curtis]

I have a U20 pump in my stroker and the gauge reads the same for the most part. Frankly I'm not that trusting about accuracy of the stock electric gauge. I've thought about hooking up a mechanical just to compare. As I noted before there is no lack of oil when I take the valve cover off or anything else. Have to keep a roll of paper towels handy.

[cbez]

[JT68]

Yep, that's not a u20 pump, looks like a nearly perfect 1600 pump. Based on your bearing condition, you didn't have a oiling problem from the main oiling circuit (pump/filter/main galley/crank). All looks fine except for the bit of trash in the bearing.

[DAC21]

I'm trying to follow this thread, but I'm not the brightest bulb when it comes to rebuilding old time cars, but wasn't this motor recently rebuilt by a Shop? If not stop reading. If so why aren't you asking them WTF? There is nothing so far to indicate why there was so much metal in that pan unless they left it in there? OP appears to be going to throw some more bearings in but has the original issue been resolved. Would hate for a rinse and repeat episode if something is grinding away in the motor.

[theunz]

JT I’m surprised to learn that the oil flow is so different. Good to learn new things from the knowledgeable members we have here. As I said, I have little knowledge of the R16, nonetheless with all the trash he has found and the lack of flow to the valve train I wouldn’t feel comfortable until the engine was thoroughly cleaned.