Fuel Advice

[blackhawkdc]

I have a 1975 Volvo AQ170C in my Chrysler boat. On the motor it recommends 93 octane and leaded fuel. Should I still be running 93 octane in it these days. I also assume that I should be putting the lead additive in the fuel to avoid exhaust valve issues. Any thoughts or opinions on either of these issues?

Thanks!

Seth Petro

 

[am_dew]

Re: Fuel Advice

I have a Volvo AQ130C (factory rebuild purchased in 2002) and I also wonder if I should be using lead additive.

As for octane, I put in 91 octane and then add octane booster each time I fill up, otherwise I get slight pinging at high RPMs despite my ignition timing being set correctly.

 

[blackhawkdc]

Re: Fuel Advice

Thanks Am DEW.

Anyone else????

 

[180shabah]

Re: Fuel Advice

Should I still be running 93 octane in it these days. I also assume that I should be putting the lead additive in the fuel to avoid exhaust valve issues.

Seth Petro

Octane requirement is a function of compresion ratio and cylinder head design, So you should still be running premium gas "these days". As for the additive, in cars it was not 100% necessary if the car was driven gently, however, your boat is always under load and will probably require it.

am dew - your engine was rebuilt in 2002 and more than likely had hardened valve seats installed and thus would not require any kind of lead additive.

 

[am_dew]

Re: Fuel Advice

Thanks 180.

 

[bruceb58]

Re: Fuel Advice

Check your engine number. If the number is greater than 119687 you can run without lead. 1975 is the "grey area" year when unleaded gas was first coming in. Many engines had the hardened valve seats already.

 

[inwo]

Re: Fuel Advice

Check your engine number. If the number is greater than 119687 you can run without lead. 1975 is the "grey area" year when unleaded gas was first coming in. Many engines had the hardened valve seats already.

How about a 1976 Chris Craft 350 sbc/ 270 Volvo. I have no idea if it's original. Lead additive needed ?