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| | | | Joined: Jul 2008 Posts: 111 Shop Shark | | Shop Shark Joined: Jul 2008 Posts: 111 | 1957 235cui....
can I just put straight 87octane? or should I mix with lead-sub?
THANKS - John | | | | | Joined: Mar 2004 Posts: 3,068 'Bolter | | 'Bolter Joined: Mar 2004 Posts: 3,068 | As long as you're not pulling/hauling a heavy load, all day, everyday I wouldn't and don't use lead additives,
There's my opinion,
Scott | | | | | Joined: Dec 2006 Posts: 1,154 Shop Shark | | Shop Shark Joined: Dec 2006 Posts: 1,154 | I do, its cheap enough and will not harm anything. I also use Marvel Mystery oil in the gas for top end lubrication always have. I have the same engine same year. Just my opinion. T/C Sjb | | | | | Joined: Jan 2008 Posts: 4,960 'Bolter | | 'Bolter Joined: Jan 2008 Posts: 4,960 | Pre 1975 engines were built for leaded gas. The heads did not have hard valve seats, and using unleaded will erode away the seats in a hurry. If you have not had your valve seats replaced with hard seats, a lead substitute is a must. Using a top oil like Marvel is fine for keeping carbon buildup on the stems. However we are addressing two totally different problems. Self serve came of age in the 70's, and a lot of people bought unleaded because it was 2cents higher than leaded regular they thought they were getting premium with tetraethyl lead. And it wasn't long before valve seats eroded to the point where the valves burned. | | | | | Joined: Feb 2004 Posts: 29,743 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,743 | Just run 5% diesel fuel. (1 gallon diesel to 19 gal. gas) It will boost the octane as well as a lead substitute, and it's a lot less expensive.
Jerry
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| | | | | Joined: Feb 2006 Posts: 1,867 Shop Shark | | Shop Shark Joined: Feb 2006 Posts: 1,867 | You dont need it, unless as stated above, your working the motor extremely hard constantly or you plan on running a large amount of horsepower through the engine, in which case you probably have it torn apart and why not add hardened seats to the list?
Theres plenty of vehicles still on the road that were built with leaded gas in mind. If it makes you feel better it certainly couldnt hurt anything.
But after 55 years of abuse, I think my old 216 will speak for herself. She still runs great.
Jeff
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | Just run 5% diesel fuel. (1 gallon diesel to 19 gal. gas) It will boost the octane as well as a lead substitute, and it's a lot less expensive.
Jerry Doesn't Diesel fuel have a much lower octane rating rating than gasoline? | | | | | Joined: Nov 2002 Posts: 2,763 Carburetion specialist | | Carburetion specialist Joined: Nov 2002 Posts: 2,763 | I do not use any of the lead additives; and have never encountered problems in any of my collector vehicles.
If/when it becomes necessary to rebuild an engine (for other reasons) we have hardened seats cut in the head. Permanent fix.
Jon.
Good carburetion is fuelish hot airThe most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes!The Carburetor Shop | | | | | Joined: Mar 2005 Posts: 684 Shop Shark | | Shop Shark Joined: Mar 2005 Posts: 684 | I don't use it in any of my cars. Although they are not worked hard. | | | | | Joined: Mar 2005 Posts: 1,513 'Bolter | | 'Bolter Joined: Mar 2005 Posts: 1,513 | An old partsman tells me to put a cup of ATF with a fill up to improve seat life.
1952 1300 Canadian 1/2 ton restomod You Tube | | | | | Joined: Dec 2006 Posts: 1,154 Shop Shark | | Shop Shark Joined: Dec 2006 Posts: 1,154 | Crenwelge....I was just pointing out that I also use Marvel Mystery oil along with "liquid lead". Some people do not realize that it will work in gas and or diesel. We have used both in tractors, cars, trucks, and stationary engines. I use "liquid lead" along with 89 octane in my 235. Its all a matter of personal choice, life is short if it makes you feel better then why not! T/C Steve | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | John,
This topic is almost as entertaining (and frequent) as the recurring discussions on engine colors and oil filtration alternatives.
As long as your are not heavily working your engine (very high revs, for very long periods) there does not seem to be a valve seat "erosion" problem on old low compression engines.
If you are rebuilding a head, you might want to consider putting in hardened seat inserts. Many of us have asked this same question and have left the head as-is with no problems (I asked 7 years ago).
Oh yes, the best advice is to take heed to carbking - he's a pro.
Tim
Last edited by tclederman; 07/17/2008 3:53 PM.
| | | | | Joined: Dec 2006 Posts: 1,154 Shop Shark | | Shop Shark Joined: Dec 2006 Posts: 1,154 | Diesel oil is not Octane rated it is Cetane rated.....how would that help valve seat life?
LEAD SUBSTITUTE is a safe and
effective valve seat protection additive which is
designed for use in engines which require the
protection of lead. Tetraethyl lead was originally
designed as an octane enhancer, but it was soon
discovered that the metallic oxides which result from
combustion form a protective coating on valves which
prevent microwelding of the valve seat to the valve
face under high temperature operation. This welding
of the two hot pieces of metal causes the removal of
the softer seat metal and subsequent recession of the
valve into the cylinder head. Wear debris then
contributes to valve stem and valve guide wear. Valve
recession causes poor sealing of the compression
gases, which means loss of power and fuel economy,
poor idle and driveability, and the eventual need for
cylinder head replacemen | | |
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