Fuel additives

[MikeCT 70]

Hi All,

I have a simple question about fuel additive. Is it a common practice to alter today's unleaded fuel with anything since these were set up to run on leaded gas? Sorry, just curious.

thanks for your thoughts,

[bugeye88]

Mike,

The has been a lot of discussion on this on this site and other vintage auto sites on this subject, but my feeling is the alcohol in todays fuels have many negative effects on our old trucks and cars. That said, adding a ehtynol neutralizing additive is a very good idea in my opinion. I also add a fuel stabilizing agent if the car is in storage for over 1 month or so. I also add a lead substitute to fuel used in car without valve guides made for unleaded gas. I also suggest oil with high ZDDP content for old flat tappet engines found in many vintage cars and trucks. I know this sounds like a lot of additives and stuff, but these cars were not made to run on the fuel and oils used on modern vehicles.

Cheers,
Rob
Bugeye88

[ybt502r]

This may be strictly my experience and is subjective (of course), but I've found that Marvel Mystery Oil has made a difference. I've had my S3 for twelve years, ten of which I just put in unleaded. It had been fitted with an "unleaded head" when I got it, so I just put in gas. That said, mileage was never that great and I fiddled with carburetors and adjustments and the like for years, trying to get a nice relaxed engine. I started putting in MMO on the advice of an old mechanic (and some notes on such here at one point), and it has helped. Mileage is better, and idling / throttle response seems better; the general word I would use is that it all feels "less harsh" than before. So I keep using it.

[o2batsea]

I wouldn't worry even if you have an old engine. Unless you run the engine at WOT for long periods, you're fine.

[bugeye88]

@sea is an optimist as to ethyl alcohol fuels. Although he is generally right. Really, ethyl alcohol fuels are evil for anything in the fuel intake systems of these and other cars! MUST BE NEUTRALIZED. This stuff eats fuel lines, carb washers, fuel pumps, and anything else it comes into contact with, as it was never intended to be used in the fuel intake system of these or any vehicles of the era they came from.....Other than that I'm quite good with other additives to lubricate upper cylinder areas, valves and such if they are used in moderation. I do admit to using a bit of Marvel Mystery Oil in various areas, if for nothing more than the name. Seriously, I do feel we need to 1. neutralize ethanol 2. lube tappets with proper oil for older cars. 3. use a led substitute for non lead valve guides. Other than that, go for it.

Cheers,
Rob
Bugeye88

[Star27buck]

A zinc additive can help with the type of camshaft/tappets on the 1.6 and 2.0 liter engine. An engine with roller tappets should not require it except for run-in on a freshly built engine.

http://classiccars.about.com/od/maintenancetips/a/Zddp-Debunking-The-Urban-Legend-This-Motor-Oil-Additive.htm

The views expressed in the attached article are not without detractors, but flat tappet engines seem susceptible to early failure without ZDDP additives.

[SafeAirOne]

A zinc additive can help with the type of camshaft/tappets on the 1.6 and 2.0 liter engine. An engine with roller tappets should not require it except for run-in on a freshly built engine.

1.6?? 2.0??

What vehicle are we talking about here?

[Partsman]

This may be strictly my experience and is subjective (of course), but I've found that Marvel Mystery Oil has made a difference. I've had my S3 for twelve years, ten of which I just put in unleaded. It had been fitted with an "unleaded head" when I got it, so I just put in gas. That said, mileage was never that great and I fiddled with carburetors and adjustments and the like for years, trying to get a nice relaxed engine. I started putting in MMO on the advice of an old mechanic (and some notes on such here at one point), and it has helped. Mileage is better, and idling / throttle response seems better; the general word I would use is that it all feels "less harsh" than before. So I keep using it.

I agree with 502, MMO is the only thing I add to my fuel, I add 4ounces per fill up, and the engine seems to run smoother, accelerate better, and get better mileage over all than without it.

[PavementEnds]

1.6 and 2.0: Series 1