Fuel question

["Christopher Middlebrook" <delamothe@xxxxxxxxxx>]

I don't think the changes of formulation affect vapor locking in modern fuels.  
There is a bigger problem however, and that is the lack of tetraethyl lead.  
Leaded fuels would provide a deposit on the valve seats over time which would 
reduce valve wear at the seat.  Modern motors (after about 1974) have hardened 
steel valves to counter this problem as a result of unleaded fuel. 
Chances are that if your vintage motor was rebuilt recenlty, the valves will be 
up to date for our current fuel.  If this is not the case, there are several 
lead substitutes out there on the market which will help maintain  valvetrain 
health.
I recommend diluting the substance per directions, and use it every other tank 
full.  Unfortunately, the deposits that the substitute generates can affect the 
performance of the carburetor (jets and metering rods) over time if used all 
the time.

Also, another issue with modern fuels is stability.  Gasoline today has a 
limited shelf life (just a couple of months depending on temperature) before it 
becomes unstable. (bad personal experience) When gasoline becomes unstable, it 
has a tencdency to create a varnish which will "gum up" the works for lack of a 
better description.  This can be very costly on motors that have very tight 
clearances from the valves to the pistons, as gummed up intake valves will 
probably get more help from the piston on its way up than the spring...

So if you are putting yopur car up for storage, or drive it infrequently, make 
sure you have some gas stabilizer in the tank.  New or old, this can happen to 
any gas motor, and that includes lawn care equipment.

Chris


 --- On Fri 02/21,  < dardal@xxxxxxxxxxxxxxx > wrote:
From:  [mailto: dardal@xxxxxxxxxxxxxxx]
To: mailing-list@xxxxxxxxxxxxxxxx
Date: Fri, 21 Feb 2003 08:20:13 -0600 (CST)
Subject: Re: IML: Fuel question

The volatility also depends on the season.  I the winter, they produce more 
volatile fuels for easier cold starts.  In the summer, they blend lower 
volatility fuel to redce evaporative (sp?) emissions.  So, if your car 
overheats in the winter, it may be more likely to face vapor lock.
D^2

Quoting Christopher Hoffman <imperial67@xxxxxxxxxxxxx>:

> Additives in modern fuel eat rubber, so fuel lines tend to soften and
> weaken
> and seals tend to degrade. It's advisable to replace all the fuel lines
> in
> any older car.
> 
> Whether this contributes to vapor lock, I dunno. But the volatility of
> modern fuel is different and that could cause it. Are you sure it's
> vaporlock and not a collapsing fuel line preventing the pump from being
> able
> to suck fuel from the tank to the carb?
> 
> I live in a hot climate and drive the car in hot weather and have yet
> to
> have a vaporlock problem in nearly 15 years, knock on rare genuine
> walnut...
> 
> Chris in LA
> 
> Currell Pattie (currellpattie@xxxxxxxxxxx) wrote:
> > Is there something about modern gasoline formulations that makes older
> cars,
> > like our Imperials with mechanical fuel pumps, more prone to vapor
> locking?
> 
> 
>