Oh really? Our minivan pings all the time when you first start it up! So does our neighbor's.....she has the same van! :D


Run premium in it if its a gas mercedes. Like has been said, if you need to save that extra $2-3 a tank then you can't afford one in the first place. :D

I don't think our 80's Benzes have knock sensors. My sisters 04 mustang pings like theres no tomorrow if you get the RPM's up.

Just a bad idea. Dont be cheap and buy premium gas. The amount you will be paying in repairs will be alot more in repairs and premium gas will be cheap once you get the repair bill.

You wont save any money on the lower octane fuel. The gallon may be cheaper, but you'll use more of them to develop the same power that the car would have made with the high octane fuel. It might actually cost you money, depending on how you drive.

bottom line - why chance it - iffen you can't afford an extra $3 per week - you can't afford the car. there are plenty of nice cars out there that will run just fine on reg. (hondas, toyos, buick, chevy). why did you buy this car? i bought mine cause of the way it handles and runs (126 lwb, v8). if i wanted to save money i would have purchased a much smaller car.

my M117 powered 450SL-C gets a little bi+chy if I run her on 87. She'll live with 89 just as well as 93 though. This is just my observation over the course of ownership.

Thats strange, it sounds more like a timing issue. It takes heat and a good load to the the gas to go bang before it should. More so in a lower compression engine like that.

That is most likely a lubrication issue. Why would it ping in a no-load situation?

You're better off staying with the higher octane. I learned my lesson by periodically using 87 and it killed the Knock sensor. After I had it replaced for $200, I realized that the cost savings from going down to 87 octane still did not pay for the knock sensor replacement.

Knock sensor is a high tech mic attached to the engine block and the moment it senses ping, it retards the timing. If high octance is specified then using regular fuel will lead to knock. OTOH if a engine specified for regular fuel knocks or knocks with high octane there are other issues to be looked into from timing to excessive carbon build up.

Just filled up the 1st time since installing my new heads, advancing the timing and correcting the crankshaft/camshaft alignment. . .goddamn. . .what a difference over 89 (i can not imagine how poorly she'd run on 87). . . A few more miles to break in the head and an oil change to 20/50 from my 10/30 flush Im running and its track time!

Instead of 20W/50 try a HDEO like Delo 400 15W-40 and you will see even better results. Engines raced with Delo 400 hardly show any wear after tear downs. There are several threads on BITOG discussing this.

hmm thanks for the tip gurkha, I'll give that a shot instead, I still need to go get oil. . .brand spankin new heads. . .a world of difference they made. . .3 way cut and all new valve guides/seals. I reused my valves and springs as they were ok, but thoes new heads gave the sluggish US spec m117 (with emissions) a real wake-up. . .

Also since you intend to race, do consider a full synthetic ATF for your tranny and synthetic gear oil like 75W-140 for your diffs. Mobil-I work fantastic to my knowledge and also Chevron Delo gear oil works even better for MB trannies. Don't worry about the wear of soft metals, Chevron Delo gear oils are EP etching sulphur free and use far better boron instead which protects the tranny well under severe racing conditions.

Just to pile on on the mileage vs octane question: My Saab, per the manual, will run on regular with less power but premium is recommended. Tracking the car shows that premium produces over 10% better mileage, usually 11-12%, and the price difference these days is more like 5-6%; it's consistently cheaper per mile to use premium. I haven't tried it in the 560 cuz that's an old enough engine I don't trust the ignition system to be that sensitive, and the manual says use only premium, but for a car of the vintage of the original poster I strongly suspect the Saab experience should be instructive.