Reg versus Premium Fuel experiament in 09 PT Cruiser
in [Cars]
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From: jim on 6 Nov 2009 12:07 Steve wrote: > > jim wrote: > The simple fact is that in order to make a 60's engine > > last as long as a modern engine you need to do a tune-up with the same > > frequency as you change oil. > > OK, let's separate the problem here. Theres the hard mechanical parts of > an old engine (rings, bearings, pistons) and then there's accessories > (carburetion, ignition). The internal hard parts are not terribly > different from today, but the accessories and lubricants ARE. That's my > real point. > That's more or less true, but the question was what causes the wear on internal engine parts. It has been shown that leaded gas at the levels used in the 60's causes significant increase in soot and ash and some increase in salts and acids in engine lubricants. And the difference is not anywhere near insignificant in terms of engine wear. > I use a 1966 engine as a daily driver. I rebuilt it several years ago > and went back to a very stock configuration in all regards. The biggest > deviation from box-stock is that it has electronic ignition (a $100 > investment and about 2 hours work) and that it has hardened valve seats > in the head (which only raised the cost of the overhaul by about $50) So these are just case hardened seats not stellite? > It now gets about the same maintenance schedule as my wife's 05 PT > Cruiser. I recently had an oil analysis done on both, and the old engine > only had one wear metal that was higher (iron), probably attributable to > the fact that it's a 7+ liter V8 with more than twice the > ring-to-cylinder friction area and has the same volume of oil. Its > copper and lead wear numbers were actually LOWER than the 2005. > > > Where is the evidence for these engines that burn or recess valves > > without leaded fuel? > > (raising hand...) That's not evidence. Hell I know somebody with a 2003 subaru that burnt a valve at 60k. What does that prove? > > I had another engine (1966 383) that I converted to electronic ignition, > but it still burned 2 exhaust valves. At the time I was doing a great > deal of sustained high-speed driving with it. From the other old car > drivers I've talked to and my own experience, sustained high speed > operation is *much* harder on non-hardened valves than city driving. > Especially if you're starting with a higher-compression higher-power old > engine than something like a base slant-6 or 318. The government of Thailand did some testing when they were deciding to switch over to lead free gas back around 1990. They ran engines from lots of different manufacturers (all asian and european) under high speed heavy load conditions (since that was the only circumstance where lead is supposed to make a difference). They found to there surprise that some valves in some engines without hardened valve seats held up better with no lead gas than others with hardened seats. Across the board they came to the conclusion there was no significant benefit to valves from lead. They also at the same time tested the additives that are added nowadays to European lead free gas that are supposed to replace the valve coating action of lead and found no significant benefit with those additives either. The only thing that has been proven conclusively is that lead raises octane. > > I had a third engine (1969 440) in a restoration project that didn't > have any burned valves and still had great compression, but when I > pulled the valve covers for some work (all the valve umbrella seals were > rotted from age) and laid a straightedge across the valve stems, they > were all at randomly different heights- lots of recession on many of the > exhaust valves. So my quick saturday morning valve seal swap turned into > a valve job and more hardened seats. Actually, it cascaded into months > of work I hadn't planned to do for another year or so, but that's pretty > typical for my projects it seems... ;-) I met a guy in the 70's that ran a volkswagon only repair shop. He was from germany and VW factory trained in germany. He had been working on VW bugs for 20 years. He claimed that none of his regular customers had ever burned a valve in a vw beetle engine that he maintained regularly. In fact he would guarantee it. Many of them getting over 200k without any engine trouble. His secret he said was a tuneup and oil change every 1500 miles. I told him that was a pretty tall claim given that those engines had a reputation for needing a valve jobs or more consistently at 60k . He said that was easy to explain: at about 60k the diaphragm in the vacuum advance would develop a leak. After that happens, drive it another 5-10k and the next stop is the junkyard or an engine overhaul. So the next time I was at a junk yard and saw a bunch VW bugs sitting in the same area and I ask if they would mind if I did a little snooping around in the beetle section. I checked about 20 vehicles and not a single one had a working vacuum advance. So after that whenever I happened to be at a gas station or a service garage or met anyone who claimed to be a mechanic I asked if they ever heard of a vacuum advance go bad on a VW or any other car for that matter. I never met a single mechanic who ever heard of a vacuum advance going bad. A few were honest and said they never had bothered to check if they worked or not. but the vast majority just blustered something like "oh No those never go bad they will last the life of the car" I guess that's sorta true. I can tell you for a fact that sustained high speed driving with a bad distributor or bad carb has a whole lot much greater impact on valves than lead or hardened seats. Running too much fuel or too little fuel or too advanced or to retarded spark at sustained high speed driving is going to make the issue of what kind of valves or seats or fuel additive completely irrelevant. The only significant effect that lead ever had on fuel was its effect on octane. -jim
From: Steve on 6 Nov 2009 12:54 Bill Putney wrote: > Scott Dorsey wrote: > >> ...And yes, everybody knew lead was toxic, but I don't think anyone >> had any >> notion just how toxic it was. Remember only 20 years before, lead >> acetate >> was a common ingredient in cakes and candies... > > I bet most people aren't aware that today, lead is one of the powdered > ingredients in many brushes in the d.c. motors and alternators on our > cars. I was amazed to learn that when I worked as an > engineer/engineering manager in a brush manufacturing company supplying > 60% of the brushes to the U.S. auto industry. > > Think about it - lead in the brushes - brushes that wear and create dust > that gets blown about into the air. Who'd a thunk that they would allow > that - but it's a fact and you never hear anything about it. Whyizthat? > And of course elemental lead and mercury have an entirely different toxicity level than lead and mercury compounds. Handling or working with metallic lead is very different from eating lead compounds in paint, for example. A senior co-worker tells of how he used to bite the end of leaded solder wire to flatten it when he was fabricating circuits back in the 50s, and in my own generation we used to play with balls of mercury dipped from the open-beaker barometer in the school science lab. I don't recommend either practice and I'm glad we're more aware of toxins these days, but it does make me laugh my head off when someone panics and practically calls in the hazmat squad over the breaking of a compact fluorescent lamp. :-p
From: Steve on 6 Nov 2009 12:59 Thomas Tornblom wrote: > Steve <no(a)spam.thanks> writes: > >> jim wrote: >>> Ashton Crusher wrote: >>>> On Mon, 02 Nov 2009 10:25:45 -0500, elmer <e(a)f.udd> wrote: >>>> >>>> I don't understand you claims of "junk" engines. Today's engines are >>>> far better in pretty much every way then everything that came before >>>> them including durability. That's a general statement, there will >>>> always be a few bad designs. Up until the mid/late sixties, engines >>>> were so weak that it was common for them to need valve jobs before >>>> 100K and for many of them they needed both rings and valves before >>>> that point. There used to be a thriving industry doing ring and valve >>>> jobs there was such a demand for it. >>> But that has nothing to with the engine itself. To claim that burning >>> rings and valves is evidence of a "weak" engine is silly. >> Also left out of the discussion is the fact the the VERY BEST motor >> oil you could buy in the late 60's wouldn't qualify as chainsaw bar >> oil today. Lubricants have come WAY further than engine design- at >> least in terms of bearings, rings, and other "hard" parts. Fuel >> managment systems have come as far as the oils or even further. If you >> could find a "pickled" (preserved, never run) factory engine from 1965 >> and put it into use with today's synthetic oils > > I don't know what you intended to write here, but I can tell you that > the cam would likely fail in very short time due to the reduction of > ZDDP additives in todays oils. THAT is the single most overblown piece of misinformation out there. A substantial percentage of the cam failures initially attributed to inadequate ZDDP were in fact probably related to substandard material and processing of a whole lot of lifters and cam blanks. That's a risk when you're down to only one or 2 vendors still making flat-face lifters... I'm running my flat-cammed Jeep and 1966 440 on SM-rated modern motor oils just fine. So long as the cam is properly broken in (the first 20-minute run-in) with the proper break-in lubricant, ~800 PPM of ZDDP is PERFECTLY good for everything short of extremely high-lift high spring-pressure cams. And there are other additives now being used to compensate for ZDDP. Don't forget that there is *still* a flat-tappet cam test required for any oil to get an API rating, including the "low phosphorous" SM rating.
From: Steve on 6 Nov 2009 13:08 jim wrote: > > Steve wrote: >> jim wrote: >> The simple fact is that in order to make a 60's engine >>> last as long as a modern engine you need to do a tune-up with the same >>> frequency as you change oil. >> OK, let's separate the problem here. Theres the hard mechanical parts of >> an old engine (rings, bearings, pistons) and then there's accessories >> (carburetion, ignition). The internal hard parts are not terribly >> different from today, but the accessories and lubricants ARE. That's my >> real point. >> > > That's more or less true, but the question was what causes the wear on > internal engine parts. It has been shown that leaded gas at the levels > used in the 60's causes significant increase in soot and ash and some > increase in salts and acids in engine lubricants. And the difference is > not anywhere near insignificant in terms of engine wear. Probably true, but then that falls in the same category as 60's oil not being good enough to use in a weed-whacker these days. My whole point was: given that these engines lasted >100k miles back then, it should be no surprise that modern engines last even longer. Furthermore, OLD engines built to OLD ENGINE SPECs also last far longer on today's fuels and oils, even with carburetion still in play instead of fuel injection. > > >> I use a 1966 engine as a daily driver. I rebuilt it several years ago >> and went back to a very stock configuration in all regards. The biggest >> deviation from box-stock is that it has electronic ignition (a $100 >> investment and about 2 hours work) and that it has hardened valve seats >> in the head (which only raised the cost of the overhaul by about $50) > > So these are just case hardened seats not stellite? Beats me, I subbed that out to the machine shop. They're an over-the-counter part specifically for vintage engines. Pressed in, just like modern hard seats are done. >> >>> Where is the evidence for these engines that burn or recess valves >>> without leaded fuel? >> (raising hand...) > > That's not evidence. Hell I know somebody with a 2003 subaru that burnt > a valve at 60k. What does that prove? There are plenty of burned valves out there, not just mine. There is also a known, understood, and well-described failure mechanism when the valve seats are not sufficiently hard (microwelding leading to roughness and erosion, leading leakage, leading to "torching" through the valve/seat junction under peak combustion pressure). The fact that SOME engines (probably the majority, in fact) never had trouble with unleaded fuel doesn't invalidate the need for hard valve seats.
From: Steve on 6 Nov 2009 13:11
E. Meyer wrote: > > > On 11/5/09 3:56 PM, in article > 1bd43wocta.fsf(a)snowball.wb.pfeifferfamily.net, "Joe Pfeiffer" > <pfeiffer(a)cs.nmsu.edu> wrote: >> In fairness, Y2K was a huge problem, but it was seen coming just barely >> far enough away that companies were able to put a huge amount of effort >> in and fix (or band-aid) their code so that almost nobody outside was >> inconvenienced. Had the work not gone into fixing it, the dire >> predictions would have come true. > > You can't possibly believe that. Having worked with software engineers who previously spent a fair chunk of their career fixing Y2K problems before Y2K, I not only believe it I KNOW it. Anyone that thinks Y2K wouldn't have been a problem if corrective measures hadn't been put in place is, frankly, clueless. It wasn't a problem because a huge effort was committed to fixing it in time. |