RE: Honda 50 4-stroke help!!!

Tony /
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Regarding lead in gasoline, the tetra-ethyl lead gasoline additive was developed at the General Motors Research labs back in the late 1930's-40's to improve the burning characteristics of gasoline, particularly under conditions of high pressure and temperature. This allowed 4-stroke cycle engines to operate at significently higher compression ratios than in the past (9,10, even 12:1 rather than 5-6:1 without TEL) without destructive dedonation occuring and therefore produce more power and increased fuel efficiency from the same displacement. This was a big deal for piston engine powered aircraft during WW-II. This technology naturally spilled over into the auto industry and led to the development and introduction of engines like the Oldsmobile and Cadillac V-8's in the late 1940's and the famous Chrystler "Hemi" and Ford "Y-Block" and Chevy "Small Block" V-8's, as well as similar engines from Studabaker, Packard, and Hudson, to name a few, during the mid '50's It was not until twenty years later that another advantage of the TEL additive was discovered, it acted as a higp pressure - high temperature lubericant. At this time, almost all engines had cast iron cylinder heads and the valve seats were machined from the parent metal and induction hardened and ground to finished form. Unknown to the industry, the TEL was preventing the steel valves from welding to the cast iron valve seat under the high temperature and pressure conditions in the running engine. Wjen vehicle exhause emissions regulations became so stringent that the only economical way to meet them was with "after-treatment devices, specifically exhaust catalyic comverters, the TEL had to be discontinued as a gasoline additive because even the minute ammount that was expelled from the engine in the exhaust would quickly destroy the effectiveness of the catalyst in the converter. It was then that "NO-LEAD" gasoline cam on the scene and not long after that serious valve problens began to occour in engines everywhere. New engine production was quickly addapted to include special valve seat inserts to prevent the problem, but the all the earlier engines were, and continue to be vulnerable to damage caused by the lack of the luberication that the TEL additive once provided. Many suppliers of modern un-leaded gasolines claim that they have included additives to replace the luberication of TEL, I am skeptical. Therefore, for my vintage 4-stroke cycle (and them only, NOT 2-strokers) machines like my 1948 Cushman and 1962 Honda Super Cub, I add an aftermarket "lead substitute" to the gas, there are several available at your local auto parts store, pick one from a reputable oil company like Valvolene, Texaco, Quaker State, etc. . I might not need it, but I don't want to find out that I did!

This single post is part of a larger thread. Start from the top or view this post in context.
Subject Written By Posted
  Honda 50 4-stroke help!!!Topic by: tim tim 11/15/00 12:13AM
  RE: Honda 50 4-stroke help!!!Re: Ivo Ivo 11/16/00 05:21PM
  RE: Honda 50 4-stroke help!!!Re: tim tim 11/16/00 07:26PM
  RE: Honda 50 4-stroke help!!!Re: Ivo Ivo 11/21/00 09:53AM
  RE: Honda 50 4-stroke help!!!Re: Ron Brown Ron Brown 11/16/00 07:31PM
  RE: Honda 50 4-stroke help!!!Re: Ivo Ivo 11/17/00 10:02AM
  leaded gas and dirty carb dirty carb dirty carbRe: Fred Fred 11/18/00 08:22PM
  RE: leaded gas and dirty carb dirty carb dirty carRe: Ron Brown Ron Brown 11/19/00 11:07AM
  Fogey's 'R' UsRe: Fred Fred 11/19/00 09:19PM
  RE: Fogey's 'R' UsRe: Ron Brown Ron Brown 11/20/00 12:44PM
  RE: Fogey's 'R' UsRe: Simon King Simon King 11/20/00 05:07PM
  RE: Fogey's 'R' UsRe: Ron Brown Ron Brown 11/20/00 07:57PM
  RE: Honda 50 4-stroke help!!!Re: Ron Brown Ron Brown 11/16/00 07:26PM
  RE: Honda 50 4-stroke help!!!Re: Tony Tony 11/18/00 08:43AM
  RE: Honda 50 4-stroke help!!!Re: Ron Brown Ron Brown 11/18/00 11:30AM
  Ritje : De 1e Oude Leidse Sluiproute RitRe: Mike Zwetsloot Mike Zwetsloot 01/14/01 03:11AM

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