Datsun Roadster Forum-311s.org

Haven't had the timing cover off yet.

I am looking at the pushrods and rocker arms pretty closely.

https://vimeo.com/596867881

I don't really see much of anything that looks like it wasn't cut on purpose though. And it doesn't seem like something that would show up when the car was already idling nice and quiet to start.

OK, I misunderstood the source of the sound. So you're saying the snap sound is the cam springing forward, and not valves that are hanging up. OK. Going back to my U20 experience and observations while spinning it over by hand with an unshimmed tensioner (i.e. not really able to resist the chain without oil pressure) it would snap and sound exactly like that. The R16 cam tensioner is oil pressurized, so I can imagine the same thing could be happening. Has anyone ever observed what the chain and tensioner do when turning an otherwise assembled engine by hand without oil pressure? (Probably not, cause you would have to have the front cover off, right?). I was blown away by what I observed with the U20 on the engine stand (massive cam and crank timing misalignment, followed by snap!) using an unshimmed tensioner. With the clearances I am running and the history of the U20 upper chain cutting the guide it may be a bigger deal for the chain to always be tight, but I don't know Rs or how that tensioner reacts.

Well, good news first. Fixed my exhaust leak, def got oil in the top end. Oh and found an '07 ztherapy sig on my carbs, that was neat.

Bad news, still noisy. With the stethoscope thing I heard a decent amount of rattle on the timing cover, fuel pump (guessing just the arm...) but also somewhat throughout the engine. Guess the whole bottom end is acting like a drum.

Looking like a timing cover pull and/or full engine pull at this point.

https://vimeo.com/596975575

Honestly, if you didn't have the before and after videos where it was more quiet, I'd be saying it sounds ok to me. Again, I have never owned an R. It might be nice to have a few folks come by and compare. My U20 makes more noise than some.

I'll say again, pull the timing cover and look. I don't know R16's but I've caught timing chain problems on a couple of U20's. If your tensioner isn't working, you would have that type of delay.
On another note, if they are compatible, I'll trade you an oil filter base for your reverse light switch. Pat

U20 oil filter base Pat

If I have time today the timing cover will reveal its secrets. But at the rate this is going I'm starting to lose faith in anything short of a full teardown.

If your valve adjustments are correct, you've eliminated pushrods. You've got a 'clackey' problem, and you will find the source. The noise is not rod or main bearings, in my opinion, but timing chain, or rocker arms. Again, I know nothing about R16's. Pat

I know it seems a lot disheartening. I'm still struggling with persistent oil leaks which will mean an engine removal again. I don't like working on cars and should have just left this one alone as I never had to do anything to it before. It was a tired 1600 but never failed to start. At this point the new Z is looking very inviting. Sell these two and it will pay for it. But it still is not a roadster and unique. Time to pay someone else to do this.

Were it my engine given what you've found the thing would already be out of the car for a thorough examination. Much easier to deal with out of the car. Removal and install not fun but isn't terrible either.

That probably would have been the smart thing to do from the start, but I was always hopeful/delusional about that easy fix right around the corner with it in the car

The biggest engine I have pulled was 125cc and took about 8 bolts. I am dreading bashing up all the nice paint and powder coat in the engine bay getting it out.

That said, putting the head back on and getting the manifold together was actually fairly painless. Always easier the second time you do it.

Totally off the wall amateur question. What is this mark on the crank counter-weight? It has the blue coloring, from heat? The photo on page two is better.

RBMann wrote: Sat Sep 04, 2021 11:15 am Totally off the wall amateur question. What is this mark on the crank counter-weight? It has the blue coloring, from heat? The photo on page two is better.
Vo4auBj-1.jpg

Likely where they took some meat off to balance the crank.

Wellll, I took the day off yesterday.

I'm far from an r16 timing expert but I don't see anything wrong. Tensioner looks to be tensioning, the chain looks fresh and tight, the bolts are all snug and I don't see any wear marks.





https://vimeo.com/597926143

You can hear the noise twice here...around 1 second and 5 seconds.

gentlemen..I wish to humbly retract my previous statement. I probably should have realized there should not be an oil trail down the sprocket.

Video coming shortly..

shoutout to greydog who called it 8 posts in! My reluctance to pull the radiator and lack of a big enough socket probably cost me an extra 2 days of work...but I did find those damaged rod bearings, fix an exhaust leak, and fix my oil pan leak, so I guess it's not all for nothing.

Probably if I had reached up and wiggled the cam I would have noticed, or watched it from below while someone else turned it over.

https://vimeo.com/597941293

https://vimeo.com/597941750

Now the question is...is all right with the world after running like that.

That's an unusual one for sure..fortunately they don't typically come loose.

You might see if a 10x1.5mm bolt will thread into the cam--If so, it is a metric core.

If someone assembled it with a 3/8 bolt (3/8 is the correct bolt for a 3-main) , that would explain why it loosened up..

If the 10mm won't go in, it's likely the correct core and just poor assembly technique.

If you use the correct bolt, new lockwasher, clean everything really well and use some Loctite, that problem should be behind you. Glad you chased it down. Good job!