Octane gas?

[sleam]

Just a quick question again! I've been reading that for old engines like my 72, the best gas is low octane. I live at 7000 ft. It's a 2.5 engine. About 112K miles on the engine. Over summer I had problems with vapor locks. Now not so much.
Any thoughts?
thanks

[SafeAirOne]

There are a few threads on this board regarding vapor lock cures, including fuel line routing, and the use of electric fuel pumps to recirculate the fuel. I can't remember all the details, but if you search 'vapor lock' I'm sure you'll find all the gouge.

[I Leak Oil]

I've noticed NO difference when running any regular pump gas. 87,89,92 octane.....no diffrence at all.

[sleam]

Good to know! I won't worry about it then. Thanks folks

[thixon]

You can time your truck to run well on whatever octane fuel you desire to use. I recommend regular since its the cheapest. Simply put, the higher the compression engine you have, the more pre-combustion becomes and issue requiring higher octane fuel. 7:1 or 8:1 (typical for a rover motor) = no trouble on low octane pump gas. Do a google search for a more detailed explanation.

The vapor lock had nothing to do with the octane fuel you used, and more to do with ambient temperature or possibly how you're fuel lines are routed (close to a heat source). Mark gave you some great advice to cure vapor lock (electric pump).

[busboy]

Years ago I struggled with a vapor lock that was very annoying, I tried all kinds of things to cure it and some worked for awhile but then it would come back. I eventually replaced the fuel pump and I've never had another vapor lock since.

[Billy5]

I have had no issues with vapor lock, but then again I live in flat land long island. I run premium once in a while, regular most of the time. I do notice a difference in the way it runs. Worth the extra cost? Most likely not. As its been said, these were designed to run on awful third and fourth world country stuff.

[sleam]

I did get another fuel pump so I can trade it out. As soon as i have time, I'll go ahead and let you know what the difference is. Thanks,
s

[SGS714]

Years ago I struggled with a vapor lock that was very annoying, I tried all kinds of things to cure it and some worked for awhile but then it would come back. I eventually replaced the fuel pump and I've never had another vapor lock since.

I went through the same senerio and ended up with the same solution after the 3rd fuel pump and finally got one that cured the issue. Now I am still running the pump that worked and have an electronic one on the shelf if needed down the road.

[Lance]

I had this happen to me this last summer but haven't done anything about it yet. Did you guys replace the fuel pump with another machanical pump? If you did what about a rebuild kit?

[busboy]

Yes I stayed with the mechanical one, the aftermarket replacement parts are so cheap nowadays you can buy the complete pump with or without the sediment bowl for around $40, I have used "rebuild kits" before for other things and even though the kit is sealed there will be a seal or a part missing, now I replace the complete item and no worries about internal corrosion.