Do you have to run leaded? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jeremy_5 · 08-31-2004, 04:21 PM

Since our engines weren't designed to run on unleaded fuel is it ok to do so. I read somewhere that if you are going to run unleaded you have to have the valve seats hardened. Is this true? What do you guys run? I don't even know of a gas station that sells leaded fuel anymore.

Joe67 · 08-31-2004, 04:23 PM

I've always ran 87 Unleaded in my '67 up to the time I pulled the engine a month or so ago with no issues

**Yukon Jack** · 08-31-2004, 04:47 PM

This was my first question on this board more than 4 years ago - most people say go for it and if you have a problem, then have hardened valve seats installed.

Blazer1970 · 08-31-2004, 07:55 PM

You will definitely not have a problem in a '72. The valve seats were induction hardened by then for sure in anticipation of the switch to unleaded fuel. They didn't just decide all of a sudden one day to go to unleaded and immediately screw over anyone who had bought a vehicle prior to that day.

**Stocker** · 08-31-2004, 09:01 PM

Quote:

Originally Posted by Blazer1970

You will definitely not have a problem in a '72. The valve seats were induction hardened by then for sure in anticipation of the switch to unleaded fuel. They didn't just decide all of a sudden one day to go to unleaded and immediately screw over anyone who had bought a vehicle prior to that day.

I'm not sure this is exactly correct. Unleaded gas became the norm for most passenger cars and the lightest light trucks starting in 1975 (primarily due to the introduction of catalytic converters), but leaded fuel was still widely available for a number of years - though I can't recall how many. Since both fuels were available, nozzles for unleaded were made smaller, and restrictor plates were added to vehicles to prevent putting in leaded gas. Years ago when I had the heads rebuilt on my '72, hardened seats were installed because leaded was disappearing.

*Slams_58* · 08-31-2004, 08:03 PM

Didn't know you could buy leaded gas. You can't buy it in Canada

JimKshortstep4x4 · 08-31-2004, 08:51 PM

You can buy lead additives to mix with unleaded gasoline. Unless you are pulling a trailer for example where you cause the valves to run hot, you probably will never have a problem. Normal everyday driving does not seem to hurt the trucks and as was mentioned, the 72's had hardened seats. I believe that the 71's had heads with hardened seats in the last 6 months of production.

Jim

Longhorn Man · 08-31-2004, 09:21 PM

I remember leaded fuel into the mid 80's here in ohio...I remember my dad had the cat removed from his 78 Aspen Station wagon (318 w/2bbl) so he could run the cheaper leaded fuel.

Loading down an engine with big loads, or running for extended periods of time over 3000 RPM are the two main problems running new gas in old engines. The military spent more money than you and I will ever make to confirm this when the lead started to disapear.

The actual lead substitutes are off the shelf now if I am not mistaken...now there are lead substitutes.

**'68OrangeSunshine** · 09-01-2004, 01:53 AM

The actual lead substitutes are off the shelf now if I am not mistaken...now there are lead substitutes.[/QUOTE]
Actually, The Paddock still lists "Max Lead"
in their newest catalog. Tetra-ethyl lead octane booster. 12 Oz. good for 20 Gals. Spendy: $9 for a quart or $33/Gallon.
Try:
www.paddockparts.com
They are also the only people to carry '68 interior silver fawn iridescent lacquer.

Chevelle454 · 08-31-2004, 10:09 PM

I have a '72 with the original 350. It was manufactured Nov. 1971. When I rebuild the heads last fall, the seats were badly pitted from running unleaded. I had a machine shop check and see if they were hardened seats, and they said that they were not. I installed new hardened exhaust seats...

*71 Blazer CST man* · 09-01-2004, 03:12 AM

Like longhorn said, if your going to run leaded, makesure you dont have a cat, so you dont burn it up/ melt it down.

**Zonaman** · 09-01-2004, 01:29 PM

Here's how Chevron weighs in on the topic.

boraxman · 09-01-2004, 03:53 PM

Quote:

Originally Posted by Zonaman

Here's how Chevron weighs in on the topic.

Good info.

68w/sbc406 · 09-01-2004, 07:29 PM

how many of you guys have one of these:
"The problem can only occur in older engines when operating under sustained high speeds"

08-31-2004, 04:21 PM	#1
Jeremy_5 Truck addict Join Date: Sep 2003 Location: Lincoln, California Posts: 497	Do you have to run leaded? Since our engines weren't designed to run on unleaded fuel is it ok to do so. I read somewhere that if you are going to run unleaded you have to have the valve seats hardened. Is this true? What do you guys run? I don't even know of a gas station that sells leaded fuel anymore. __________________ 1956 Chevy Napco 1972 Cheyenne Super 1970 K20

08-31-2004, 04:23 PM	#2
Joe67 67 is sold Join Date: Apr 2001 Location: Troy, Michigan Posts: 6,738	I've always ran 87 Unleaded in my '67 up to the time I pulled the engine a month or so ago with no issues __________________ Joe - Formerly 67c10step ------------------------------- 1967 Chevy Stepside - ECE 4/6, fuelcell, 5lug - SOLD gr8lakes - My ebay auctions Click here to order forum apparel :: Click here to become a subscribing member

08-31-2004, 04:47 PM	#3
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,683	This was my first question on this board more than 4 years ago - most people say go for it and if you have a problem, then have hardened valve seats installed. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

08-31-2004, 07:55 PM	#4
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,510	You will definitely not have a problem in a '72. The valve seats were induction hardened by then for sure in anticipation of the switch to unleaded fuel. They didn't just decide all of a sudden one day to go to unleaded and immediately screw over anyone who had bought a vehicle prior to that day. __________________ Tim

09-01-2004, 01:53 AM	#9
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,189	The actual lead substitutes are off the shelf now if I am not mistaken...now there are lead substitutes.[/QUOTE] Actually, The Paddock still lists "Max Lead" in their newest catalog. Tetra-ethyl lead octane booster. 12 Oz. good for 20 Gals. Spendy: $9 for a quart or $33/Gallon. Try: www.paddockparts.com They are also the only people to carry '68 interior silver fawn iridescent lacquer. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not.

08-31-2004, 08:03 PM	#6
Slams_58 Account Suspended Join Date: May 2002 Location: I let ya know as soon as I know Posts: 3,593	Didn't know you could buy leaded gas. You can't buy it in Canada

08-31-2004, 08:51 PM	#7
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	You can buy lead additives to mix with unleaded gasoline. Unless you are pulling a trailer for example where you cause the valves to run hot, you probably will never have a problem. Normal everyday driving does not seem to hurt the trucks and as was mentioned, the 72's had hardened seats. I believe that the 71's had heads with hardened seats in the last 6 months of production. Jim

08-31-2004, 09:21 PM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	I remember leaded fuel into the mid 80's here in ohio...I remember my dad had the cat removed from his 78 Aspen Station wagon (318 w/2bbl) so he could run the cheaper leaded fuel. Loading down an engine with big loads, or running for extended periods of time over 3000 RPM are the two main problems running new gas in old engines. The military spent more money than you and I will ever make to confirm this when the lead started to disapear. The actual lead substitutes are off the shelf now if I am not mistaken...now there are lead substitutes.

08-31-2004, 10:09 PM	#10
Chevelle454 Registered User Join Date: Aug 2003 Location: MN Posts: 380	I have a '72 with the original 350. It was manufactured Nov. 1971. When I rebuild the heads last fall, the seats were badly pitted from running unleaded. I had a machine shop check and see if they were hardened seats, and they said that they were not. I installed new hardened exhaust seats... __________________ 1972 C10 1972 C20

09-01-2004, 03:12 AM	#11
71 Blazer CST man Account Suspended Join Date: Apr 2004 Location: Nor Cal, Sonoma Posts: 324	Like longhorn said, if your going to run leaded, makesure you dont have a cat, so you dont burn it up/ melt it down.

09-01-2004, 01:29 PM	#12
Zonaman Senior Member Join Date: May 2004 Location: Chandler, AZ Posts: 517	What Chevron says Here's how Chevron weighs in on the topic. __________________ 69 C-10 LWB, 350, 700r4, 3.73 posi-traction, front disc brakes. Built for the desert- She can take the heat! Vivat Rex Chevus!

09-01-2004, 07:29 PM	#14
68w/sbc406 Got Light Emitting Diode? Join Date: Apr 2004 Location: Newberg, OR Posts: 2,485	how many of you guys have one of these: "The problem can only occur in older engines when operating under sustained high speeds" __________________ 1968 1/2 ton 2wd lwb 6 lug disc and bags up front. Next c notch and rear bags '02 Chevy Silverado LT ext cab short bed 2WD 5/7 drop on 22's(the family car) 1993 Cherokee work ride/weekend wheeler



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