LT-1 Fuel Requirements

[George J.]

Pump Gas

For what it's worth, I had my '65 fi engine rebuilt last year by a reputable race shop and had the compression physically measured before bolting everything together. With the thicker Fel-Pro gaskets it measured 10.3:1. All internals were stock replacement with the exception of roller tip rockers. I have since set the timing to 40 degrees total advance and have not had any problems running 93 octane pump gas. George #31887

[George J.]

Pump Gas

For what it's worth, I had my '65 fi engine rebuilt last year by a reputable race shop and had the compression physically measured before bolting everything together. With the thicker Fel-Pro gaskets it measured 10.3:1. All internals were stock replacement with the exception of roller tip rockers. I have since set the timing to 40 degrees total advance and have not had any problems running 93 octane pump gas. George #31887

[Joe L.]

Re: LT-1 Fuel Requirements

Jeremy-----

Let's "boil all this down" to the simplest of terms:

1) Empirical evidence is always better than theoretical. If you are running your engine currently using unleaded premium and are not experiencing significant pre-ignition or detonation (as evidenced by mild or severe "pinging" which, if severe, will be VERY audible), then you have enough octane. In fact, you might even try using a mid-grade to see if you still stay out of detonatation. Some of this may change with higher ambient teperatures, though, as, with higher temps, there may be more of a tendency to detonate.

The simplest fact is this: higher octane fuel serves only to prevent pre-ignition or detonation. You don't need any more octane than it takes to accomplish this. Higher octane and/or "premium" fuel is NOT otherwise beneficial for your engine. Period.

2) Tetraethyl lead was added to gasoline for TWO reasons only. (1) To provide an inexpensive means of increasing the octane of fuel and, (2) to provide protection for exhaust valve seats.

There are other ways of increasing gasoline octane and, today, those are used to provide moderately high octane fuel commonly available. So, if you can use 93 octane pump gas without detonation, then you don't need lead for its octane increasing properties.

If your engine has not been fitted with hardened exhaust valve seat inserts, it's very unlikely that any harm will come to your engine as a result of the use of unleaded gas under any condition that you're likely to encounter. But, if it makes you feel better, you can add a lead substitute. I recommend those containing Powershield. These include Alemite-CD2, Unocal, Red-Line, and many others.

If your engine has been fitted with hardened exhaust valve seat inserts, then there is absolutely no reason, at all, to use any lead substitute.

Also keep in mind: while lead is GOOD for increasing octane and preventing valve seat recision, it's BAD for everything else in the engine. If you can achieve the necessary octane and necessary valve seat protection in other ways (which you can), you're far better off without lead in your fuel.

[Joe L.]

Re: LT-1 Fuel Requirements

Jeremy-----

Let's "boil all this down" to the simplest of terms:

1) Empirical evidence is always better than theoretical. If you are running your engine currently using unleaded premium and are not experiencing significant pre-ignition or detonation (as evidenced by mild or severe "pinging" which, if severe, will be VERY audible), then you have enough octane. In fact, you might even try using a mid-grade to see if you still stay out of detonatation. Some of this may change with higher ambient teperatures, though, as, with higher temps, there may be more of a tendency to detonate.

The simplest fact is this: higher octane fuel serves only to prevent pre-ignition or detonation. You don't need any more octane than it takes to accomplish this. Higher octane and/or "premium" fuel is NOT otherwise beneficial for your engine. Period.

2) Tetraethyl lead was added to gasoline for TWO reasons only. (1) To provide an inexpensive means of increasing the octane of fuel and, (2) to provide protection for exhaust valve seats.

There are other ways of increasing gasoline octane and, today, those are used to provide moderately high octane fuel commonly available. So, if you can use 93 octane pump gas without detonation, then you don't need lead for its octane increasing properties.

If your engine has not been fitted with hardened exhaust valve seat inserts, it's very unlikely that any harm will come to your engine as a result of the use of unleaded gas under any condition that you're likely to encounter. But, if it makes you feel better, you can add a lead substitute. I recommend those containing Powershield. These include Alemite-CD2, Unocal, Red-Line, and many others.

If your engine has been fitted with hardened exhaust valve seat inserts, then there is absolutely no reason, at all, to use any lead substitute.

Also keep in mind: while lead is GOOD for increasing octane and preventing valve seat recision, it's BAD for everything else in the engine. If you can achieve the necessary octane and necessary valve seat protection in other ways (which you can), you're far better off without lead in your fuel.

[bruce11495]

Clem..Check out the Dukes message!!! *NM*

[bruce11495]

Clem..Check out the Dukes message!!! *NM*