Reproduction Parts for 1916-1964 Chevrolet Passenger Cars & 1918-1987 Chevrolet & GMC Trucks


Previous Thread
Next Thread
Print Thread
Rate Thread
Joined: Sep 2008
Posts: 28
Aldo Offline OP
Grease Monkey
OP Offline
Grease Monkey
Joined: Sep 2008
Posts: 28
I herd that using today’s gas in a old car will damage the valves so I was wondering what type of additive can I use to reduce the octane level?

Someone told me I can add diesel fuel to my regular gas to reduce the octane but I don’t know if this is recommended.

It's for a 1927 Chevy.

Any thoughts?



Filling Station - Chevrolet & GMC Reproduction Parts


Filling Station


Joined: Dec 2001
Posts: 11,162
ChatMaster - 10,000
Offline
ChatMaster - 10,000
Joined: Dec 2001
Posts: 11,162
Idon't think that is necessary. I usually add some Seafoam to keep the new gasoline from screwing up my carb , also add some Marvel Mystery oil for upper lube.


Life's a long winding trail, love Jesus and ride a good horse!
Joined: Sep 2006
Posts: 731
Oil Can Mechanic
Offline
Oil Can Mechanic
Joined: Sep 2006
Posts: 731
today's gasoline will not damage these old vehicles. there's a myth the absence of lead in modern fuel will damage valves. but it's just that, a myth. octane will not damage an engine in any way, shape, or form. filler up, add a little MMO if you prefer and drive to your heart's content.

I put 80,000 miles on a set of heads that were manufactured long before unleaded fuel and they showed no ill effects. and I worked that old truck hard


Chevrolet

Valve In Head, Ahead In Value
Joined: Mar 2004
Posts: 1,290
ChatMaster - 1,000
Offline
ChatMaster - 1,000
Joined: Mar 2004
Posts: 1,290
I know that I have not put anything in my 31 coupe since the rebuild and it runs fine. But I was wondering about my new project the 67 El Camino. Should that have something added to the gas?


Sal Orlando
Chat Group Region Member
Joined: Feb 2009
Posts: 597
Oil Can Mechanic
Offline
Oil Can Mechanic
Joined: Feb 2009
Posts: 597
Burned valves on older engines that have not been rebuilt with hardened ones will only happen with sustained high speed driving, like a lot of long road trips between cities. the driving most of us do cruising, going to shows, etc. should not pose a problem. If you are really paranoid, you could rebuild the engine with hardened valves. I personally would not bother. And don't even bother with the lead substitutes found in the stores. It has minimal value raising octane and has nothing in it that will protect the valves. One more thing, I did read an article that said that if the car was run on leased fuel for any amount of time, the valves will typically be 'protected' for the life of the engine. However there is no way to substantiate this claim.


It's not how fast you can go, but how good you look at 20 MPH.
Joined: Mar 2009
Posts: 184
Shade Tree Mechanic
Offline
Shade Tree Mechanic
Joined: Mar 2009
Posts: 184
There is absolutely no relation between octane and valve wear.

Tetraethyl lead supposedly has two purposes: raising octane and lubricating the valve seats. Only the lubricating property could have any effect on the valves. As far as I know, excess valve wear from lack of lead has never been proven.

Adding diesel is a crude way to raise octane. There is no conceivable reason to raise octane for that vehicle.



Joined: Jan 2002
Posts: 30,700
Likes: 141
ChatMaster - 25,000
Offline
ChatMaster - 25,000
Joined: Jan 2002
Posts: 30,700
Likes: 141
When your 1927 was new the majority of gas was unleaded. Lead did only one thing to gas and that was to make it burn slower. It had nothing to do with the valves. Today better refining raises the octane. The removal of lead can actually make the valves last longer because it prevents lead deposits from forming on the valve seats and preventing the valves from closing tight. The lead also shortened the life of the bearings, exhaust system and spark plugs.Modern engines would never go 200,000 or more if they used leaded as. Years ago it was common to grind valves by 20,000 miles.

Last edited by Chev Nut; 08/16/09 09:32 PM.

Gene Schneider
Joined: Mar 2009
Posts: 184
Shade Tree Mechanic
Offline
Shade Tree Mechanic
Joined: Mar 2009
Posts: 184
Really, so even the commonly mentioned effect of lubrication is false? Who started all of these rumors? Lead companies?



Joined: Nov 2001
Posts: 29,848
Tech Advisor
ChatMaster - 25,000
Offline
Tech Advisor
ChatMaster - 25,000
Joined: Nov 2001
Posts: 29,848
I will join the dudes above and also say that lead additive is not necessary! Your car will run just fine without it....period!

laugh wink beer2


The Mangy Old Mutt

"If It's Not Junk.....It's Not Treasure!"
Joined: Feb 2007
Posts: 570
Oil Can Mechanic
Offline
Oil Can Mechanic
Joined: Feb 2007
Posts: 570
What about the lead paint we ate as children? Do they make a lead substitute paint chip?

Joined: Dec 2001
Posts: 11,162
ChatMaster - 10,000
Offline
ChatMaster - 10,000
Joined: Dec 2001
Posts: 11,162
My 1968 Impala Sport Coupe with a 275HP 327 and 400HT runs fine on tours and Interstate driving on regular and also premium unleaded, sometimes I will treat it to a tankful of premium, without any extra additives , It is an original engine with 104,000 actual miles on the odometer. It uses a bit of oil (a Qt about every 800 miles.) "Betsy" will burn rubber any time you want to. Of course the real owner (the boss lady) jumps on the old hotrodder driver for any street raceing. Sometimes I just gotta blow away one of those Dodge Rams. Ha!


Life's a long winding trail, love Jesus and ride a good horse!
Joined: Dec 2001
Posts: 11,162
ChatMaster - 10,000
Offline
ChatMaster - 10,000
Joined: Dec 2001
Posts: 11,162
Yeah, Home Depot had a liquid paint kit for anyone addicted to lead paint chips (window sill) and it has to dry for 5 years to mature, it is not really lead, but tastes good anyway!


Life's a long winding trail, love Jesus and ride a good horse!
Joined: Sep 2006
Posts: 731
Oil Can Mechanic
Offline
Oil Can Mechanic
Joined: Sep 2006
Posts: 731
after a highway run back in the day, tail pipes would be light gray to almost white due to the lead. it would be used as an indication of the condition of the engine. plugs would have small globs of lead on them.



Chevrolet

Valve In Head, Ahead In Value
Joined: Feb 2007
Posts: 570
Oil Can Mechanic
Offline
Oil Can Mechanic
Joined: Feb 2007
Posts: 570
I knew I could count on Mack to catch that.

Joined: Feb 2009
Posts: 597
Oil Can Mechanic
Offline
Oil Can Mechanic
Joined: Feb 2009
Posts: 597
I know the thread is about lead and burnt valves, but for completeness of information, here is another tidbit.

When I got my 28 in Feb, I too had the same questions since the PO had mentioned the engine knocked and gave me some 'lead additive'. Actually, it was the clutch that was thunking away. None the less, in my quest for info, I found a good article on the history of gas that said that back in the 20's the octane was around 40-60. Needless to say today's 87 is more that sufficient.


It's not how fast you can go, but how good you look at 20 MPH.
Joined: Dec 2001
Posts: 11,162
ChatMaster - 10,000
Offline
ChatMaster - 10,000
Joined: Dec 2001
Posts: 11,162
Yes, I would say that the old 4 cylinder (roaring fours!) are quite adaptable to fuel octane quality, The new unleaded will do a job of gunking up the fuel supply system if it is left in for a while without running the car. I am using Seafoam to counteract the detiriation and short storage life of the gasoline. I haven't been using it in the 28 very long, but I use it in the tanks of the outboard boats. Marine use is what Seafoam was originally made for.


Life's a long winding trail, love Jesus and ride a good horse!
Joined: Mar 2004
Posts: 1,290
ChatMaster - 1,000
Offline
ChatMaster - 1,000
Joined: Mar 2004
Posts: 1,290
Thanks to all for the answers to my question. I thought so but it never hurts to ask. Thanks again. :vcca:


Sal Orlando
Chat Group Region Member
Joined: Sep 2008
Posts: 28
Aldo Offline OP
Grease Monkey
OP Offline
Grease Monkey
Joined: Sep 2008
Posts: 28
Thanks everyone for your help. I will just add MMO & Seafoam to the gas.


Link Copied to Clipboard
Support The VCCA!

Enjoy the forum? Become a VCCA member! The World's Best Chevrolet and GMC Club!


Member Photos
1964 Chevrolet Impala SS
1964 Chevrolet Impala SS
by DreamChevy, February 17
My 1933 Chevy 2 Dr. Sedan
My 1933 Chevy 2 Dr. Sedan
by 1939Chevy1, November 24
Back on the road 79 years later
2 1927 Chevrolet Trucks
2 1927 Chevrolet Trucks
by 1927TRUCKS, June 7
Who's Online Now
2 members (Chipper, fonz8261), 70 guests, and 21 robots.
Key: Admin, Global Mod, Mod
Newest Members
NeilA, Jayhicks, Tomvanhouten, Dads29Chevy, Tractorman
18,308 Registered Users
Today's Birthdays
SabrinaKarras, Speedy1
Forum Statistics
Forums58
Topics59,072
Posts429,075
Members18,308
Most Online1,133
Jan 22nd, 2020
 

Notice: Any comments posted herein do not necessarily reflect the official position of the VCCA.

Powered by UBB.threads™ PHP Forum Software 7.7.5