Name the odd sound! w115 gas

[Topher39]

1969, w115 gas, no ac. Mystery sound!

Hello all, calling the vintage experts! Start up, car purrs, run around town 2-3 miles, park and I can hear another layer of sound, seems to come from up towards the front of the engine, seems to be more from the drivers side, hard to say for sure. Sounds like an extra clatter that increases with rpm, then smooths out at higher rpm. Here is the kicker, turn the car off, restart the car and that layer of sound is gone - every time. If I take it for a 20 min drive on the highway, return home, I don't usually here it. Seems to come after the car is mid temp maybe. Seems to come from the valves maybe, towards the front . . . Just hard to say. Valve clearances are spot on, I can't find any valve train parts loose or out of the ordinary.

Some of you vintage guys must have run into this????
Maybe I can post two Lund files, one with and without th odd sound.

Timing chain guides?
Distributor gear?

This bugs the heck out of me, I need to know what the heck this sound is! This is my only real worry that I can see/hear mechanically. You know how it is, when you drive a 43 year old car every day, and it's your baby, you are tuned into every nuance and sound - this random sound/issue is making me crazy, LOL. I just want to fix it if I can, I don't want any surprises down the road (so to speak)

Good luck solving this one, looking forward to the help.

[Topher39]

46 views and no response! Tough crowd, tough crowd.

[Shortsguy1]

I think a few of us were expecting an audio or video file.

[Mike D]

Unplug the auxiliary fan and report.

[Topher39]

I don't have an aux. fan.

[Mike D]

Oh well. Just a guess.

[alabbasi]

how's your cam? Maybe the spray bar is not feeding enough oil

[meltedpanda]

How much chain stretch do you have. Heat expands so sounds associated with wear usually decrease with heat

[Topher39]

Good thought Meltedpanda, I did check for stretch, and found little if any, based on the cam position against the crank.

What seems to me to be key is that it does not do it while its cold, only after a med warm up of a few miles, I don't usually hear it happen when really hot either, say after a 15-20 min hwy drive. And why, when cycling the ignition on and off it goes instantly away. I see where you are going with the heat factor and I thought the same. I just can't seem to isolate the component. It's as if removing the tension of the unknown component, allows it to re-seat in some way, reset, or fall into proper position. As I said originally, this phantom sound smooths out when you bring it to a very high idle, than falls right back in when you reduce idle - like a loose bearing or similar issue, yet the sound I more of a clattering. I seem to feel the clattering sound coming through the valve cover, I checked the tension of the cover bolts, they are neither too tight or loose.

I originally thought it was one of the wire guides/clips that hold the tappet in position over the valve, as one side of one of the clips was not seating properly, I bent that clip back and I believe it has been ok since. Wonder how much noise that could make, though why the start stop change. (Just talking out loud)

Maybe this helps the pondering. I was hoping there would be an easy, "oh, yeah, that's a your "doggy dit bit" needing replacement"! No such luck yet. If I knew what it was I would feel better knowing if its a real issue or not, something to worry about or just let go.

Ugh!

[Topher39]

Wonder if something is up with the timing chain tensioner?

[meltedpanda]

Is this a sound that has developed all of a sudden or after some service you did under the hood. If the latter retrace your steps
Is your starter selenoid releasing all the way? Do you have a mechanics stethoscope. That might help as well

[Topher39]

I do all my own service, have noticed this over the last month or two, no change in anything to trigger. As to the starter, it does not sound like it comes from down low, or the rear of the car, and sound developers after running for a bit, not after a fresh start.

[tram]

Originally Posted by Topher39

I do all my own service, have noticed this over the last month or two, no change in anything to trigger. As to the starter, it does not sound like it comes from down low, or the rear of the car, and sound developers after running for a bit, not after a fresh start.

Just for fun, check the little bracket that bolts to the front of the engine around/ below the crank pulley and the little engine shock/ grommets right there.

[Topher39]

I need to replace the lower mount/buffer but I don't think it's hitting, either way, it would hit/vibrate all the time, and turning the ignition off then back on should not effect.

A for effort! Much appreciate your thought. I do need to replace my engine mounts too.

[Topher39]

I'm going to check the water pump and the alternator for the sound by removing the belt when I usually hear the sound.

Chris