As fun as it is to try to describe and diagnose engine sounds via the computer, Ive got to ask

The kick wouldnt pass smog here in CA....the timing was out of spec.  I had the TB changed last year, and I guess the guy just put the belt on and turned the distributor cap all the way to tune it....

So it does not pass, and I take it in and the shop retimed it to spec (8 BTDC).  Now, when I am in 4th and 5th gears going over 55 mph at partial throttle it sounds like something is grinding.  It gets worse with speed.  I hear nothing in gears 1-3, and even 4th is not very noticeable.  I have never heard it before, and I am not entirely sure that it happened as a result of the timing change....not sure how that would happen anyway....

On the other hand, I did a little wheeling with the new lift from digger.....I was able to do 90% or more of the trails that a friend of mine in a lifted wrangler with 35 inch tires can do.....And my drive home was much more enjoyable.....

So anyway, if anyone has any ideas about what is making this noise, please let me know....it sounds bad.

Thanks!

are yo sure its coming from the engine? sounds more like a tranny noise if it does not do it in 1 - 3. if you're crusing in 5th and push the clutch in does the sound go away or get quieter?

derek

I would be checking into that tranny too. It doesn't sound like an engine issue. It would do it in all of the gears.

I would recheck the timing...severe detonation from too much advance, or poor fuel can sound sorta strange on  a high strung 4 cylinder.. I have had customers call it "grinding" before..

Are you aware of what pinging, or detonation sounds like in your engine?    Your description of WHEN it is happening would sound like detonation to me...

The sound goes away if you clutch in when it happens...

Now that it is retimed to spec, it does seem to ping a bit more..Is 8 BTDC the best spot for timing on this engine? 

OK, if you know what ping sounds like on this engine, then that isn't it.. just making sure...


I can't imagine what that could be, but I, like the others, lean towards tranny, and cooincidence

Ya....I have a hard time considering the tranny especially since the noise appeared just after a timing readjust....

Maybe it would be a good time to do a tranny and t case flush though.

Thanks for the help

Matt

Pilot bearing or Throwout bearing,
they can make grinding noises.

Wouldnt it do that in all of the gears?

The other thing is that I added a Calmini cat back exhaust at about the same time.

Do you have any vibration when it starts "grinding"?

Yes, I can feel it in the car a bit, subtle, but it is there.

Well....after logging some more miles in the zuki.....

It really seems to run rough in 4th and 5th gears.  Not sure if it is engine or trans, but the engine runs smooth in gears 1-3......

Any idea why 4th and 5th would be rougher? 

crawl under it and check the rear slip yoke on your rear drive line, any play in it? any fluid loss?