My car has had this intermittent tapping sound for quite some time now, maybe close to a year, I'm not really sure as far as when I first heard it. I recently got my exhaust redone and it quieted the engine bay drastically, giving me the ability to hear this tapping more and try to diagnose the issue because I am a bit ocd. Just to provide some history, this is a freshly built motor from about 2 years ago now and I haven't had any issues with the new motor. In effort to make this noise stop, I removed all the belts (no change), I have adjusted the valves, changed the oil (no metal), done a compression test (straight across the board), listened with a mechanics stethoscope (seems like pulley side but hard to tell), pulled each plug individually (no change pointing to one cylinder) and I can't seem to figure this out. It ONLY does this at idle. You also can't hear the sound from inside the car. I have been beating on the car for a while now and I really have no reason to believe that there is an issue with the motor except for this sound.

Notice that it's somewhat intermittent. Also, notice that I start the car @.0:14 and the tapping doesn't even start until 0:46.

 

Do you adjust valve lash ? Could also be bad LMA(s)also.

 

Yes, as mentioned I adjusted the valves. Also, maybe I should have clarified the motor. I figured people would recognize the valve cover, this is an LS motor (b18a1) so there are no LMA's.

 

could watch the vid on my phone, sorry in that case sticky a rocker(s) can also make that sound.

 

honestly, I think I could hear it but I think it might just be noisy rockers.

what do you set your lash to?

I used to think my car had a tick but it was just noisy fuel injectors


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This is a B18a1, I set the valve lash to In - .004 Ex -.007

 

your intakes are wayyyy too tight.

inset mine to .007 in .008 ex. its the loosest spec they say to run but its nice and quiet imo. one time I set my intakes too tight and they were loud as ****.

try running the lash at .007in and .008ex

lash becomes tighter over time btw, not looser.

 

Op- make sure, when adjusting lash, to put your feeler gauges between cam and rocker, not valve stem tip and rocker. Yes, that's way too tight on the intakes...

 

I used the service manual specs for a B18a1:

 

Those specs are for brand new cams/rocker arms/valves/seats/rocker arm pivot tubes, etc. Unless you have an all new cylinder head and entire valvetrain, the unhighlighted #'s are to be used. According to the chart both specs are way tight, not just intakes. I hope this makes more sense now.

 

Actually, the numbers on the left are mm and the numbers on the right are inches.

If you do the math .08 and .12 mm = .003 - .005 inch.

I tried to look up some other specs of what people are running for the b18a1 and everything I am finding matches the ones I listed.

 

Fair enough, I always assumed the #'s in parenthesis were (new) like the top of the chart says. I use the sticker under the hood for reference, but gsr has different #'s. Did you measure between cam/rocker when adjusting (per service manual)? The measurement will come out different than the valve stem/rocker arm point of measurement.

 

Yup, cam/rocker.

 

What service manual is that? Because my factory manual says a1 are .006-.007 intake and .007-.008 for the exhaust.

.003-.005 is for the b1 engines. They run different cams in them, but even still I wouldnt run them tighter than .007

I would try running.007in and .008ex and report back

Because the one time I ran them tight .005in
I though I spun a bearing...

Im not sure why but for some reason too tight makes them loud, and too loose makes them loud.

 

I am using the manual for the 1992 Integra. The only motors it included in the manual are the B18a1 and B17a1.

Which manual are you using? Which motor? I am open to trying looser specs, but I want to know that someone with the same motor is running 007in and .008ex with good results.

 

NO do not go looser! The more loose it is, the more noisy it will be.

.003-.005 is the correct spec for OBD-1 non-VTEC B-series engines, both B18A1 and B18B1. I usually adjust mine (B18C1 engine) to the middle, and check that the next size up won't fit, so .004 fits and .005 won't fit, for your engine.

The first time I ever adjusted the valves on my car, over 10 years ago, I botched one valve and left it way, WAY loose. The car sounded like a diesel it was so noisy. I ended up driving it from my parents house over 200 miles back to where I was living then, and fixed it in the underground parking garage under my office building.

*edit* just watched the vid, and most likely it's just the normal common Honda noisy valvetrain, or the injectors. Either way I wouldn't worry about it at all.

 

Lmao the b17a1 has the specs I listed, youre right for the b18a1
However, the b18a1 runs a lot nicer with the b17 specs. And no running them that loose does not make them noisier

The noise does sound pretty much like normal b series tappet noise though.

 

uhhh how would it not? Looser means more gap which means the rocker/cam lobes may never expand to fill the clearance, which would mean parts rattling around. As I said I left one loose one time and the engine was extremely noisy until I fixed it.

 

Loosening the clearances of the valves will make them noisier, however it is known to be a safer practice than going to the tighter side. The worst case being that it opens later and closes earlier affecting motor power/efficiently.

If they are too tight, the risk is that the valves do not close all of the way which could cause exhaust valve burn.

 

I didnt watch the video, my 0.02 cents is the fuel injectors cycling causing a small ticking sound. Again i didnt watch the video im at work.

 

Yeah I know looser is safer than too tight. I personally just prefer adjusting to the tighter end of the spec to try to reduce some of that noise.

 

Give it a watch later. It's not injectors. The intermittent tapping sound starts at :46

 

Very nice bay by the way, Does it see a nice amount of driving? Have you checked the alternator and tried lubeing up the pully and bolt? Other then that worse case is a lose rod bolt in the making.

 

Thanks Man, appreciate it. Yes, it's a weekend car but I beat the crap out of it (back roads, autox). Which is why I am so OCD about maintenance, weird sounds etc.

Build Thread here: http://forums.g2ic.com/showthread.ph...70#post2301470


I actually removed the alternator belt and started/ran the car and it had no effect on the sound. I'm not sure if that answers your question.

As far as a loose rod bolt in the making, I personally torqued the rod bolts on a freshly machined motor/crank and brand new rods/bolts/pistons myself. I've got less than 4k Mile on the motor, I would be surprised if it just loosen up without any signs of failure (mentioned in OP).

Still stumped.

 

The only update that I can add is that after much time probing with the mechanic's stethoscope it seems to be coming from the Flywheel, Shaft, Clutch, throwout bearing area of the motor/trans. As far as I can tell, it's not related to the actual engine.