Can't tell if I have the valve keepers in right!

[KDMatt]

17 hours ago, Zed Head said:

Yes, solid valve trains are noisy.  If it's not ticking that means lash might be too tight and you're about to burn a valve.  On top of the valve lash noise is the injector ticking which can be surprisingly loud.  All you can do is take the measurements and trust the engineers and others who've been there.  I've had a noisy #1 lifter for thousands of miles but it's been fine.  

So, the assumption is that you got all of the seals replaced, all back together, and the engine's running now?

Correct. The seals are replaced, the engine is all back together, and it's running ... very smoothly too I might add. I gave it some fresh gas and a fresh filter this weekend so I could correctly tune the ignition timing and fuel pressure (because adjustable FPR), and I would venture to say this is the nicest I have ever had this motor running... save for the added noise.

The extra noise I've picked up is definitely from the valve/cam area -- I've had this car for 11 years and have never been able to hear valve or cam noise from inside the cabin of the car while driving. 

I suppose there's no harm in cracking it back open now that it's undergone a few cold/hot cycles to see if perhaps the clearances have gotten tighter or something. 

I didn't get any of the tappets/rockers mixed up when I put it all back together (because I did one at a time) ... only thing I can think of that even stood a chance of being put back together wrong would be the little circular lash-pads that live on top of the valve keepers. I tried to keep them all in the same orientation they came out in, but my magnetic puller might have flipped a couple. I've read in other threads that these little things can be a source of noise. Thoughts? 

Edited May 31, 2016 by KDMatt

[rossiz]

adjusting the lash hot has been important in my experience. others have differing opinions, but my reasoning is: when the engine is at operating temp, it is within a fairly narrow/specific temp (provided your cooling system is functioning properly). when it's "cold" you don't really know how "cold" it is - can be a relatively large swing depending on ambient temps. get the car good and warmed up, leave it idling while you get everything ready (blanket on the fender, 14mm and 17mm wrenches for valve adjust, 10mm socket w/extension for valve cover, large crescent wrench to turn the cam, feeler gauges set up (.010"/.25mm intake, .012"/.30mm exhaust), plug socket & extension, then when you're all set, shut her down, pull the plugs, valve cover, start at #1 and work your way down the line. you should be able to slide the correct feeler gauge in with a light resistance and the next size up should not go in. remember that the clearance gets tighter when you torque up the lock nut, so you need to back check every one as you go. once you get the hang of it, you can do all 12 in about 10-15 min.

set 'em right and she'll run nice and quiet.

[KDMatt]

Sorry about the delay. I had to finish installing all my new shocks and springs this week. 

I re-checked the valve lash and you guys were right. Some of them were WAY out of spec. Not sure how that happened, but after re-adjusting the ones that had gone wonky the whole thing quieted down considerably.

Now I just need to re-tune a bit more... adjust fuel mixture and what have you... getting a bit of backfire out of the intake, but I doubt that's related to this particular project. 

[Zed Head]

I adjust mine cold, then remeasure hot.  Lash gets looser when the engine heats up so if you make a mistake too tight when cold, the odds of burning a valve are lower.  Plus most of them will still be in spec. so you end up spending less time over a hot engine.  Actually, mine have always stayed in spec. on the hot measurement.  The principles of materials and thermal expansion suggest that they should all change to the same degree.  Nissan probably got rid of the cold spec. because it caused confusion in the shop (how cold is cold?) and tuneups are usually done within a few hours.  Otherwise a tune-up would be a leave-it-overnight job.

Just talking...  On why the lash isn't what you thought it was - when you tighten the locknut you actually change the lash, pulling the pivot up against the threads of its  hole.  Plus, it's easy to get a little bit off of the base circle of the cam lobe.

[siteunseen]

I'll tell you the mistake I made the first couple of tries.  The motors tilt to the passenger's side and I had the lobe pointing straight up when I set mine.  Now I have a Sharpie line drawn down the center of the cam towers.  I bought a 17mm wrench for the locknut now, I'd been using a 17mm crowfoot socket.  I still need the crowfoot on one or two but the 17mm wrench in my right hand and leave the 14mm on the adjusting nut with my left hand makes tightening them down alot easier.  For what that's worth. 

[KDMatt]

I think I was just in a hurry before and didn't have all of the lobes/cylinders at TDC, so as you might imagine some of the clearances were off.

Now that they're all correct to 'cold-spec' (after sitting for a few days) it's nice and quiet like it ought to be.

I just use a 14mm wrench, and 17mm wrench, along with the go/no-go method on the feeler gauges... and yeah, the locknut tends to move the adjustment out of spec -- I figured that out the hard way, but that wasn't why it was out of spec -- it was out of spec because I wasn't being fastidious about the rotation of the cam lobes.

Anyway, I think all is well in the kingdom now. Thanks guys!

[LeonV]

I've recently found that it's more accurate to measure lash with the mouse-trap springs removed from the rockers, FWIW.