Just wandered if anyone wanted to help me out and play “What’s that noise”. I have a stock 73 1.7 with FI. Under hard acceleration after getting back on the gas after changing gears, the engine makes a noise that sounds like something between flicking water on a hot stove and a piece of aluminum foil shaking around in a tin can. Thanks in advance for all your help. I’ve been having a great time driving this thing around for the last 4 months and want to keep it as healthy as possible.

Could it also be described as a "spitting rattle" sound? That was how I described the sound of pinging (detonation) in my old 1.8 a ways back. It went on for quite a while before blowing a hole in a piston.

--DD

I think that’s the noise. And from what I've been seeing online it’s happening at the right time to be pinging (under load or acceleration). I'm running 87 octane gas (the less than 10% ethanol crap, can't find any ethanol free in the area). Would bumping up the octane help? Any additives? If I have to rebuild an engine I’m hoping to at least put it off tell wintertime…several years from now.

You may want to double check your timing. Sounds like it may be off.

keith

Can't hurt to check the timing. Try running high-octane fuel in it, too. If the timing is OK and the high-test stuff prevents the problem, figure you have high compression or carbon deposits and keep running the more expensive fuel.

--DD

A couple of gallons of 93 octane ethanol-free fuel and half a bottle of Lucus injector cleaner/top end lube, and it seems like the pinging sound is gone. I'll be happy to spend some time tomorrow just to make sure though. Thanks everyone for the suggestions!