Re: IML: Lead additive

[sosmi@xxxxxxxxxxx]

Leaded fuel has been around for a long time. It started in the early years of aviation,(20's) with higher performance engines. The lead (TEL) was found to increase the octane permitting higher compression, supercharging, turbocharging, and the net effect was more HP. The lead also proved to aid heat transfer between the valves and seat, the valves run cooler. It also acted as a lubricant for valve stems and piston rings, unfortunately some was left behind for the engine oil to deal with. Anyone who has disassembled an old engine, and a post lead engine saw the difference. The Hemi engine, with it's inherent superior head design would be less susceptible to valve damage because of better valve cooling, the cross flow design removes more heat, and reduces the chance of detonation which raises combustion temperatures to the point of melt down. Us wedge head guys (413-440) have more to worry about, the flow through these heads is constricted much more. This leads to hot spots, carbon deposits, and more heat left in the combustion chamber. All this leads to is detonation, and much more heat for valves to handle. Todays additives are only new synthetic replacements, none have TEL. Do they help? I suppose anything that's a lead substitute and conditioner can't hurt(I use them as well), are there things you can do? sure, but that's another show. Ya'll have a nice day, Dave.

 

-------------- Original message --------------
From: PAUL WENTINK <randalpark@xxxxxxx>

> This post from Burt corresponds exactly with my understanding of the
> situation regarding unleaded gas and our cars.
>
> I will also add that I have been told that through 1955, Chrysler
> automobiles were able to withstand unleaded gas. This wasn't
> deliberate, but rather it was after that the engineers realized that
> since lead prevented valve and valve seat wear, hardened valves and
> seats were not necessary. Beginning in 1956, the cylinder heads were
> changed slightly as a cost saving measure. The engines built from then
> on required leaded fuel to prevent wear for extended high speed
> driving. I would like to know if anyone has also heard this or knows it
> to be true. Remember, lead wasn't added to prevent valve and valve seat
> wear. It was added to eliminate pre-ignition and increase the octane
> levels. The fact that it also allowed for a cost reduction in producing
> engines was a bonus for the bean counters.
>
> I drove various Imperials as everyday cars in the '70s & '80s, mostly
> my '56 & '65 models. It was in the late 1980's that leaded gas vanished
> from our area. I began using Bardahl Instead-o-Lead with each fill up.
> At the time, it was rated as a quality product. Also, the speed limits
> were Federally regulated at 55, so whether this additive actually
> worked or not, the engines were not working hard enough to cause much
> damage due to unleaded gas. I discovered that I was using too much of
> the product and eventually it caused the cars not to run well. I had
> the tanks drained and discontinued using it. There are probably two or
> three unused cases somewhere in my garage.
>
> These days, there are 75 mph speed limits, which means some folks are
> going to drive 80. I think driving our cars using unleaded gas for
> extended periods at these speeds will cause accelerated valve and valve
> seat wear. Rather than relying on an extra cost additive, I plan to
> take it easy on the road. When the cars require valve work, I'll have
> the cylinder heads reconditioned with hardened valves and valve seats.
>
> I believe that this is the only truly correct approach for me to take,
> particularly since most of my cars are around the point where they
> would be needing valve work as part of the regular maintenance of the
> engine anyway.
>
> Paul W.
>
> Paul W.
>
>
> -----Original Message-----
> From: Burt Bouwkamp
> To: mailing-list@xxxxxxxxxxxxxxxx
> Sent: Mon, 29 Oct 2007 12:42 pm
> Subject: Re: IML: Lead additive
>
>
>
> Michael,
>
> Â
>
> When we developed and tested the Chrysler engines in the 1950's and
> 1960's we did it with a tetra ethyl lead additive (3 cc's per gallon I
> think) in the gasoline. It worked - in fact the engine relied on the
> lead deposits to avoid valve seat wear at high engine HP outputs. (Wide
> open throttle at high engine speeds results in high valve temperature
> and high speed valve action.)
>
> Â
>
> Young engineers - such as myself - did not know that lead was providing
> this benefit until we started testing engines with "no lead" gasoline.
> Valve seat recession during testing due to wear required us to
> harden valve seats or add hardened inserts to production engines to use
> unleaded gasoline. You probably remember that the auto and petroleum
& gt; industry used a lead additive - until it was banned - because it was
> the cheapest way to produce gasoline with the octane rating that we
> wanted.
>
> Â
>
> I don't know what happens to valve seat wear when you add Marvel
> Mystery Oil or ATF to the gasoline. I use am STP Lead Additive in the
> gas tank of my old cars but they are driven so few miles - and usually
> below 60 MPH - that I doubt that it makes any difference. I only do it
> because I have personally inspected durability test engines (with
> around 1,000 hours operation) with more than 1/4" of valve seat wear
> due to testing with unleaded fuel. If I ever have the engine rebuilt in
> my 1968 Dodge Charger I will have hardened valve seat inserts added.
>
> Â
>
> Burt Bouwkamp
>
> Â
>
> ---- Original Message -----
>
>
> From: Michael Alexander
&g t;
> To: mailing-list@xxxxxxxxxxxxxxxx
>
> Sent: Monday, October 29, 2007 1:01 PM
>
> Subject: RE: IML: Lead additive
>
>
>
>
>
> I just bought a bottle of Lead Additive at Advance Auto, which says on
> the bottle â??for older cars which need leaded gasâ??. Anyone have any
> experience with this product?
>
> I guess my choices for the 1952 Imperial are: Marvel Mystery Oil, ATF,
> or this stuff. Online voting begin!!!
>
> Seriously though, thanks,
>
> Michael Alexander
>
> Â
>
>
> ------------------------------------------------------------
>
>
> From: mailing-list-owner@xxxxxxxxxxxxxxxx
> [mailto:mailing-list-owner@xxxxxxxxxxxxxxxx] On Behalf Of Gary Wilson
> Sent: Thursday, October 25, 2007 10:01 PM
> To: mailing-list@xxxxxxxxxxxxxxxx
> Subject: Re: IML: Reces sion Unleaded Gas: MMO vs. ATF
>
>
> Â
>
>
> I don't know about running a qt of oil thu the tank but ATF works real
> well because it is a high detergent and helps coat the valves seat like
> leaded gas use to do.
>
>
>
>
> ----- Original Message -----
>
>
>
> From: YBSHORE@xxxxxxx
>
>
>
> To: mailing-list-owner@xxxxxxxxxxxxxxxx ; mailing-list@xxxxxxxxxxxxxxxx
>
>
>
> Sent: Thursday, October 25, 2007 6:17 AM
>
>
>
> Subject: IML: Recession Unleaded Gas: MMO vs. ATF
>
>
>
> Â
>
>
>
>
> Fellow Imperialists:
>
>
>
> Â
>
>
>
>      On my 1956 Imperial w/354 Hemi/Torqueflite 3 speed combo, I run a
> Marvel Mystery Oil blend through the fuel tank at every fil l-up
> according to the specs on the bottle and have had great luck with it [I
> use it as well in the motor oil] and change the oil quite often, every
> 1500 miles. I wonder, though, if it is providing the same degree of
> 'engine maintenance' that the ATFÂ does/would do with a periodic run
> through. Any thoughts?
>
>
>
> Â
>
>
>
> Jack
>
>
>
> Â
>
>
>
> Â
>
>
>
> Â
>
>
>
> In a message dated 10/25/2007 9:03:11 A.M. Eastern Daylight Time,
> randalpark@xxxxxxx writes:
>
>
>
> like the idea of running a quart of oil through the gas once in a
> while. I have found that it does improve performance.
>
> Paul W.
>
>
>
>
> Â
>
>
>
>
>
>
>
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