dissapearing loud tapping on valve cover- gone for now

CBradio · Post by **CBradio** » Fri Nov 15, 2013 5:28 pm

I recently changed my head...
When I first started there was a loud tapping from what appeared to the 5th cylinder but after revving a little it went away.
Sounded almost like a quarter was in there or something.

Had no problem for a few days then the noise started up again as I was trying to adjust my idle mixture.

So this time I pulled the valve cover, readjusted the valves to .09 on the cam side, everything looked okay; I also made sure my exhaust manifold studs were on tight.

I put everything back together and there is a tapping; I revved for a minute, tapping was gone. Engine has never sounded better {I think cam side adjustment was way to go}. Injectors are louder than anything else I think.

Question is: what was this tapping noise? Did I drop a wave washer in my head? What else could explain this? Candidly, it is possible I did not install the chain tensioner correctly, but the noise is nowhere near that.

It seems like it is coming directly above the 5th cylinder. It went away however and I've been driving around the neighborhood all afternoon.
Engine is performing well, I think. Car seems A-Okay.

Also, I noticed that when I pull any of plug boots 1-4 the engine RPM drops and idle sound changes; when I pull boots from cylinders 5 or 6 the engine RPM at idle doesn't really drop and the sound doesn't change all that much. Just subtly.

Injectors are all ticking, and all getting the same voltage.
Spark plugs are also sparking. Wires tested okay too.
I'm just hoping I don't have a a potentially big problem with this tapping.

Any input always appreciated!!

CBradio · Post by **CBradio** » Fri Nov 22, 2013 1:36 pm

For anybody curious, as it turns out,
I did a compression test and I have ZERO compression on cylinder #5. I have about ~150 psi on the rest.

As I did compression test on cylinder #1, a bent washer {looks like a spark plug washer!} was spit out from #5.

Whats worse is that I found some compressed metal in #5 intake.

I am thinking I bent a valve, or worse. I will have to pull the head again.

I also pulled a smushed spark plug from cylinder #5.

but the car was running better than ever on 5 cylinders,
so I can't wait to have it running on all six.

Thanks everybody for your support!

CBradio · Post by **CBradio** » Mon Dec 02, 2013 12:37 pm

If anybody is curious, it seems I did in fact drop something in there, like a putz. This is what I found:

<a href="http://s1362.photobucket.com/user/CBrad ... f.jpg.html" target="_blank"><img src="http://i1362.photobucket.com/albums/r68 ... 9ea94f.jpg" border="0" alt=" photo photo_zps3c9ea94f.jpg"></a>

AND THIS IS THE DAMAGE DONE:

<a href="http://s1362.photobucket.com/user/CBrad ... a.jpg.html" target="_blank"><img src="http://i1362.photobucket.com/albums/r68 ... 66b77a.jpg" border="0" alt=" photo photo2_zps2e66b77a.jpg"></a>

{!_!}

LOOKS LIKE IT FOUND ITS WAY AROUND TO:
<a href="http://s1362.photobucket.com/user/CBrad ... d.jpg.html" target="_blank"><img src="http://i1362.photobucket.com/albums/r68 ... 4dcf5d.jpg" border="0" alt=" photo photo4_zpsc94dcf5d.jpg"></a>

<a href="http://s1362.photobucket.com/user/CBrad ... d.jpg.html" target="_blank"><img src="http://i1362.photobucket.com/albums/r68 ... 53d80d.jpg" border="0" alt=" photo photo1_zps0153d80d.jpg"></a>

<a href="http://s1362.photobucket.com/user/CBrad ... a.jpg.html" target="_blank"><img src="http://i1362.photobucket.com/albums/r68 ... 66b77a.jpg" border="0" alt=" photo photo2_zps2e66b77a.jpg"></a>

I was so close to having this car running normally!!

I obviously effed up here-
I found those two little pieces in my intake. I have no real idea what it is or how it happened; I thought I was careful.

Anyways, short of getting a new engine, does anybody have any suggestions on what to do with this?
Does the head look salvageable?
Does the piston look done?
Short of getting a new engine, what would anybody else do in my situation {on a budget!}

Any input appreciated.

GripGreg · Post by **GripGreg** » Mon Dec 02, 2013 1:35 pm

There's a guy, 'NSXguy7' on the Bigcoupe.com forum that's selling parts of his motor.

Do some research on the compatibility of what he has.

It's free to register for 'BigCoupe' with your same handle. The prices on the parts seem very low to me.
Good luck,,,,Greg

CBradio · Post by **CBradio** » Mon Dec 02, 2013 11:29 pm

Thanks Greg!

I was hoping perhaps somebody went through this before......
and maybe that I can have the head milled somehow to fix this mess...

But I'm thinking that would effect compression too much.

I think the car will have to sit for the winter here;

I hope next pics I post will be of 'finished' car.!

T.Hanson · Post by **T.Hanson** » Tue Dec 03, 2013 12:41 am

Only adding blabby for sympathy, as I suspect you've been going over your own list of options. Too bad you're sick like me, or the rest of us, to not choose the sane one: junk it and buy an e39.

From the photos, I'm thinking a winter search for a parts car. The sickness found my two, and a third years ago. Having a running car available to cheat off of for assembly visuals is fantastic. Of course it has to occupy space someplace.

Building an engine on a stand is another luxury. It's been amazing to see 150,000 mile engines with the cross hatching still in the cylinders. The pain with that comes in finding one with a good short block, no rust in the jugs, an '81 head, not cracked,...and the drat things are very heavy and clumsy to ship.

My opinion, a good short block lets you clean, replace components. Messing around with rods, cranks, pistons, rings, boring or honing,...is engine builder stuff. Money, for a good, trustworthy shop that actually knows what it's doing. Not easy to find one of those.

The cheater car, engine on a stand took awhile. I pulled the bonnet off the receiver car, removed everything, and hauled it to a shop for the switch. I had all the clutch, shifter, guibo, bell housing junk in the truck for quick assembly on the hoist. Left the old iron at the shop for recycling. Once back in my garage I was working from the top.

Again, way easier when I could see where stuff went by looking at the other car.

Mike W. · Post by **Mike W.** » Wed Dec 04, 2013 12:14 am

CBradio wrote:If anybody is curious, it seems I did in fact drop something in there, like a putz. This is what I found:

<a href="http://s1362.photobucket.com/user/CBrad ... f.jpg.html" target="_blank"><img src="http://i1362.photobucket.com/albums/r68 ... 9ea94f.jpg" border="0" alt=" photo photo_zps3c9ea94f.jpg"></a>

AND THIS IS THE DAMAGE DONE:

<a href="http://s1362.photobucket.com/user/CBrad ... a.jpg.html" target="_blank"><img src="http://i1362.photobucket.com/albums/r68 ... 66b77a.jpg" border="0" alt=" photo photo2_zps2e66b77a.jpg"></a>

{!_!}

LOOKS LIKE IT FOUND ITS WAY AROUND TO:
<a href="http://s1362.photobucket.com/user/CBrad ... d.jpg.html" target="_blank"><img src="http://i1362.photobucket.com/albums/r68 ... 4dcf5d.jpg" border="0" alt=" photo photo4_zpsc94dcf5d.jpg"></a>

<a href="http://s1362.photobucket.com/user/CBrad ... d.jpg.html" target="_blank"><img src="http://i1362.photobucket.com/albums/r68 ... 53d80d.jpg" border="0" alt=" photo photo1_zps0153d80d.jpg"></a>

<a href="http://s1362.photobucket.com/user/CBrad ... a.jpg.html" target="_blank"><img src="http://i1362.photobucket.com/albums/r68 ... 66b77a.jpg" border="0" alt=" photo photo2_zps2e66b77a.jpg"></a>

I was so close to having this car running normally!!

I obviously effed up here-
I found those two little pieces in my intake. I have no real idea what it is or how it happened; I thought I was careful.

Anyways, short of getting a new engine, does anybody have any suggestions on what to do with this?
Does the head look salvageable?
Does the piston look done?
Short of getting a new engine, what would anybody else do in my situation {on a budget!}

Any input appreciated.

That one piston is kind of ugly, you really should think about replacing it. Odds actually are you'd be ok, but it looks rough, too rough. The other piston I might carve down high points, but it looks good from here. Sandpaper and a dremmel on the head and maybe a relap or even valve job on the one cylinder, maybe even new/used valves and the head should be ok. You're pics are good, but close up evaluation is essential.

CBradio · Post by **CBradio** » Wed Dec 04, 2013 11:30 pm

T. Hanson- I am weighing my options! I definitely have the sickness, if you can call it that. Maybe its a sort of love. Before my old head went bad, I did get almost a year maybe out of this car, and I did love it. I don't know,.

I don't know what it is. I like the greenhouse of the car. and the shape, the handling, the simplicity.... I have taken this car to the movies, dinner, and I have given this car lots of love and attention, I think soon I should propose to it, but she's bled me so dry I can only afford a crackerjack ring.

Thanks Mike also for your sage input. I was thinking I might be able to get away with just that. I will take a better look at the piston. I did read elsewhere I need to file down the pointy parts because they can get hot and cause pre-ignition. Also, the loss of compression seems to be the result of my exhaust valve not sealing.

I will keep everybody posted. And also, unrelated to this post, I did get fuel lines in from the dealer... about 50 dollars for both, they also seem to be coated with some paint or something, they are PRE BENT, and they came in two HUGE boxes. The dealer couldn't wait for me to pick them up- the boxes were mostly full of air.

Jelmer · Post by **Jelmer** » Thu Dec 05, 2013 2:01 am

I think I would do the next:

*Check the cilinder walls for any scars
*Sand/dremel both pistons so that it is a bit smooth again, clean the cilinders very good (compressed air)
*Sand/dremel the head and clean it
*take head to machine shop and have them check the valves (bend), do a valve job and have them check if the head is straight (I think it is, because it was before and it didn't run hot)
*Assamble the engine again and have fun!

GripGreg · Post by **GripGreg** » Thu Dec 05, 2013 2:05 am

Keep the faith, keep your chin up & stay in touch, please.

Falkenberg · Post by **Falkenberg** » Thu Dec 05, 2013 11:03 am

You might give the problem a low-budget approach as indicated above.
All depends on the money you have.
The cylinder seems in good shape, luckily enough.
It will probably run, look for deep holes, cracks, that could be a sign of future problems.
I'd say that any damage to piston rings would be a big problem as well.
Identify the cause of the compression loss and fix it.
After cleaning up, flow and compression characteristics would still be affected but who knows by how much. It will run though.

Some days ago I was looking at the picture of the head, trying to remember where I had seen such damage before. Only now I remember - my 2002 had these kind of marks on the head and on one cylinder. Not as many as yours. It ran fine.

If you are willing to spend more money, you know what needs to be done.

CBradio · Post by **CBradio** » Wed May 21, 2014 4:52 pm

SO:

After the car was sitting all winter, I started working on it again.

I took the head to the machine shop.

I bent two valves slightly, that's why I had no compression.

They replaced the valves, I put everything back together (took me 2 days),
and aside from adjusting the timing 100%, everything seems to be in order.

Thank you guys for all your help!!!!

Jeff Dennis · Post by **Jeff Dennis** » Mon May 26, 2014 2:22 pm

Thats really good news....