I just bought my first Ford Truck. It's a '94 F-250 460. Do you guys recommend I use high octane gas or does it really matter. As you can imagine, the gas mileage is pretty poor, and it would be nice if I wasn't hurting my truck using lower octance gas.

Bill.

 

In my '92 351, I have to use minimum 89 octane otherwise it pings. If yours doesn't ping on the 87 gas, then you should be fine using it.

 

--socal, your truck, along with everyone elses car or truck, was engineered and designed to run on 87 octane fuel. The only case you would need to go higher is if you were hauling and exceptionaly heavy load and did notice a pre ignition (pinging) problem. At that it would probably only be noticed when going up hills.

Outside of ripping the motor apart and putting 3000:1 pistons in it, there is no need to run a high grade of fuel.

Hats off to marketing i guess....

my 2c's

 

Not so with needing to rebuild and put in said rediculous compression ratio. I rebuilt a 390 a few years back that would only run on premium at stock timing on mostly stock 2 brrl carb and a mild rv cam, and only put in 10:1 slugs. A high mileage engine will likely have some carbon build-up. Assuming this, carbon holds heat, and tends to get hot-spots, which in turn, create ping, as these hot-spots try ti ignite un-burnt fuel on idle strokes of the piston. Running premium, will help this problem. How ever, your problems with ping and a high mileage engine might also lay in a worn timing chain/gear assembly and worn distributor as well. The first thing I'd do is put a fresh ignition tune-up on it(cap, rotor, wires, plugs) and see where it goes from there. Try re-timing the engine to correct specs, and if it still proves to be a problem, then look at the timing gear/chain assembly. A distributor drive gear wouldn't be a bad idea at this time either, as it's designed to wear long before the cam drive gear is. Process of elimination, do the cheap stuff first.

 

The octane number represents a fuel's ability to resist pre-ignition. The higher the number, the higher the resistance to pre-ignition. Pre-ignition is what you'll hear refered to as pinging. It kind of goes hand in hand with compression. A higher compression engine is more likely to pre-ignite (burn before spark from spark plug) fuel because increased pressure is the equivalent to a higher temp. Sports cars tend to call for the higher octane stuff. I had a buddy whose Corvette needed 91 octane. Anyway, your owners manual will tell you what octane fuel it should have in it. Putting higher octane gas in there doesn't hurt but it also doesn't help.

Here's some readin:
http://www.cartalk.com/content/columns/Archive/1995/July/01.html
http://www.cartalk.com/content/columns/Archive/2003/August/03.html
http://www.cartalk.com/content/colum...ctober/11.html

Here it is straight from the FTC:
http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm

 

Thanks for the help guys. I appreciate it.

Bill.

 

It would be nice if I could run 87 octane in my stock 351 engine with 45K original miles, but the fact remains that it does ping under alot of circumstances when I run 87 in it. Maybe it's the oxygenated gas used here in California year-round, but it pings anytime it's warm out and any time the truck is loaded. Since it is often warm here in southern California and I use my truck primarily to haul a camper and pull a trailer out to the desert for motorcycle riding trips as well as for hauling anything else I need to move, I run 89 octane gas in it and it doesn't ping.

I notice our '98 Taurus also pings sometimes with 87 octane as well as our 2000 E150 4.6L. Our old '97 Chevy G1500 V6 van also did it, as does the little '87 Dodge 4-cyl I drive to and from work. Except for the Dodge, these were all puchased new, maintained very well, and pinged on 87 from day one.

By contrast, my old '82 Chevy 454 did not ping with 87 and neither did my '77 Chevy 350 or my old '78 Dodge 318. They all ran the same no matter what kind of gas I put in. In my bikes, I don't even mess with pump gas at all and only run 110 octane leaded race gas .

 

SoCal, that's kind of odd. I thought the newer vehicles had ping sensors and that they'd not ping even if you had in the wrong gas. From what I've read on Click and Clack, the sensors detect the ping and adjust timing or something to compensate for it. They say that prolonged use of the wrong octane fuel will lead to damage even if these sensors are doing their job so they advise to use the correct octane fuel. I have a 98 Taurus and I put in 87 octane cause that's what the book says. It runs fine. We also use oxygenated fuels here in CO. Start buying gas from a different station. Maybe you're getting some rotgut stuff.

 

socal, your truck, along with everyone elses car or truck, was engineered and designed to run on 87 octane fuel. The only case you would need to go higher is if you were hauling and exceptionaly heavy load and did notice a pre ignition (pinging) problem

Sorry but this is not correct there are a lot of cars designed to run on high octane gas. the amount of compression and timing play a big part.
My 96 ranger needs to run 89 octane or it pings. Why? Probally because there is so much carbon build up on the pistons that it raised the comp. ratio. The reason they ran such a high comp. ratio in the 60's cars was because the lead in the gas raised the octane. Take one of those cars with 11 to 1 comp. ratio and run it on 87 octane and you will blow it apart. By the way I run 87 octane in my f-150 and it does fine.

 

On the knock sensor: As far as I know, the 302 (5.0L) EFI has a knock sensor. I don't know if the 351 has one or not, but if it does, mine isn't working too well or it wouldn't be pinging on 87.

The engineers may have designed the thing to run on the 87 octane gas that was available in '92, but it does not run without pinging on the 87 octane gas currently availabe to me here in CA. I do not like pinging and do not want my engine doing it and I am not going to run gas in my engine that causes it to ping, regardless of who said what about what the engineers did or did not do some 15 years ago, so I will continue to run 89 octane in it and be happy to not hear any pinging.

We buy gas from several different stations, all brands, but I try to stay away from Exxon/Mobile for other reasons. It doesn't matter the station or the brand, it's the octane rating that makes the difference.

 

Forgot to say the first part of my last post was a quote.

I agree run the gas that doesn't make it ping. When I was younger and didn't know that I put a half dollar size hole in a piston now I know better.

 

runn the mid grade 89 octane 91 will get you better performance but i dont know about mileage( 91 is more expensive) so ithink it would be a toss.

 

You get no more performance from running 93 in a vehicle that runs fine on 87. The higher the octane the harder it is to ignite. The harder it is to ignite the less fuel gets used and the slower it burns, unless your car is producing the heat and compression needed to sufficiently ignite the fuel. The only vehicles i notice that say you should run "premium" gas are mercedes, jag, BMW, etc. right on the gas door (I work at a fullserve gas station). 90% of people with these cars just ask for 87 and they run perfectly fine with no ping.

 

uh ok whatever you say - guess working at a full serve gas station means your an expert on fuel systems - by the way try running premium fuel in a car that pings on acceleration listen the pinging is gone

 

[QUOTE=FordPerf300]You get no more performance from running 93 in a vehicle that runs fine on 87.QUOTE] Maybe you should try reading first. If your car is pinging on 87 that means it isn't running fine on that fuel and the higher octane will stop the ping.