Ringing Rattle

Datsa 66 · Post by **Datsa 66** » Wed Mar 09, 2005 8:11 pm

Recently, I have noticed a ringing sounding rattle that only happens when I take my foot off the gas. Under load it does not happen. It's not a timing chain thing, those were all replaced when the engine was rebuilt less than 4000 miles ago. I am thinking something is loose, but try as I might I cannot find anything. Alternator bearings? Water pump was brand new when the car was redone as well.

I've checked the exhaust system from manifold to tailpipe and it is all tight too. Tranny connections checked. Everything I can think of.

Ideas?

Andrew Murphy
1967.5 2000

DELETED · Post by **DELETED** » Wed Mar 09, 2005 8:21 pm

DELETED

glennhuff · Post by **glennhuff** » Wed Mar 09, 2005 9:54 pm

Andrew,

It could be pinging. Most people say it sounds like rocks in a coffee can. It will probably sound like it's right under your feet, or out in front of you. The reason that it will ping when you let off the throttle is that the engine is at a high rpm (all mechanical advance in) and when the throttle shuts, vacuum goes up causing the vacuum advance to come in. If there is enough load, this will cause the engine to ping (preignition). Taking a little bit of timing out will usually solve this problem. Then again, it could be something else entirely, in which case I am just rambling. Good luck.

Glenn

Datsa 66 · Post by **Datsa 66** » Wed Mar 09, 2005 10:25 pm

Didn't think that solexes had vacuum advance...

impinhigh · Post by **impinhigh** » Wed Mar 09, 2005 10:46 pm

Andrew,
I have the exact same problem on my Spl, it only happens when you back off the throttle at speed and in gear. I can't figure it out exactly but I'm pretty sure it either tranny or rear end. I changed the fulid in both and going to let it ride!!

Try removing the rubber shift boot and you'll really get an ear full.

Matt

Post by **itsa68** » Thu Mar 10, 2005 7:40 am

My spl had a similiar sounding ringing rattle.
I found that the carb heat shield had a cracks from the bolt holes.
Tig welded up the cracks and fillet welded a washer over each hole and included a few weld beads radiating from the washers to stiffen it.

Rattle went away.

Ray B.

bengelhardt · Post by **bengelhardt** » Wed Mar 16, 2005 9:37 am

My '70 SRL does it too, although I'd say that mine is a tin sounding rattle. I think it's either the carb heat shield (like itsa68's) or the alternator bearings. The sound in my case sounds like it's coming from the engine compartment. In fact, I can get mine to do it a little by pushing the throttle linkage and letting off while I have the hood off. Can't completley pin point the location though, because alt. & heat shield are in close proximity to each other.

Post by **Datrock** » Wed Mar 16, 2005 10:35 am

Hi Andrew, this is shot in the dark on your ringing sound.
I've experience a ringing sound a few different times, once coming from the pulley and belts. Not that they were to tight, I believe it was from painting the pulleys. Try and drop a few drops of water on the belts while idling, if the sound goes away you may have found the source.
Another thought comes to mind is the driveline ringing. It could be from lack of grease in the u-joint, spline or loose u-joint bolts.
Could also be a harmonic ringing from the rearend being low on fluid or in need of a change of gear oil. What oil weight are you using in your differential?
Just thowing a few troubleshooting ideas your way while trying to help... Bill

Redtail · Post by **Redtail** » Wed Mar 16, 2005 12:05 pm

Same problem here. usually at around 3000 to 3500 rpm when I let off the gas, sounds like it's coming from the right side of the engine compartment, but I have not been able to find exactly where.