If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#131
|
|||
|
|||
On Fri, 24 Dec 2004 16:49:54 +0000 (UTC), "Coyoteboy"
> wrote: >> 2. you go ahead & change your oil anyway - you just send a sample of the > >old oil at change time. the resulting report tells you whether you're >> about to encounter a problem. or, and this is the whole point of this >> conversation, whether you're changing oil ahead of it being necessary & >> thus wasting money. > >I dont really want to know if I'm about to encounter a problem lol. Looking >at the things it can diagnose, I can diagnose most of them shortly before >they go critically wrong anyway by ear/feel etc. If they take out something >else when they go, they were probably wearing it excessively anyway and so >I'd replace that while i was changing it. If I were to know about it I'd >worry about when was the best time to change whatever was failing etc I >guess that since I do all my own work im less worried about the costs of >labour if things go wrong. > >But a)I'm not too worried about environmental issues regarding a couple of >gallons of oil, b) I know 3K miles is a nice short interval on top Q synth >oil, c) my differing driving habits from one month to the next would mean I >couldnt really use one change's analysis results to predict the rest - which >nullifies the point of doing the test. > >TBH it is just too much faffing to be bothered with, and with the fact that >the vehicle is sometimes thrashed, sometimes pampered, the cost of repeated >analyses would vastly outweigh the benefit. The oil testing companies *are* >out to sell you stuff - the next analysis - they dont do it for fun. I can >see its a great idea for a normal vehicle under fleet use conditions, and if >I were to be running 10 cars I'd consider it to reduce oil change costs, but >really its over-analysis for the normal user when all thats required is a >safety buffer of maybe 1 extra oil change. > >Due to its long term racing/drag/street history the 3Sgte engine is well >documented, and the known 'good' change interval is accepted as 3K as per >the manufacturer specs, unless the car is track-abused. > >I'm not saying its a bad idea, just that it doesnt suit all cases, and >really in my case its a waste of cash and simply serves to scare the hell >out of me warning me of the next failure - why worry about things you cant >alter. . You only can't alter them when you don't know about them. You're a bit keen on the "i'm SO good i can tell by ear if somethings wrong - oblivious to the point that it's already a fair bit broken if you can hear it. My father used to rally, (was a road legal escort mexico iirc) and he used to get the analysis done. A place up by the whats now the Jag plant in halewood used to do ti. He managed to catch a head gaskett just in time, before a race, thanks to analysis, would ahve cost him a race, and thus the championship. However, he also does it on his daily drivers. he had an a-reg cavalier he bought about 15 years back, and the first thing he did was take a sample of the oil, for analysis. unfortunatly, on the day the results came back, he was on his way back from work in runcorn, and the engine siezed right on the runcorn bridge (and that was before it was widened) The results waiting for him at home told him that was likely to happen. Engine SOUNDED fine, FELT fine (it wasn't his first cavalier) and had he gotten the results back a day earlier, he'd have taken my 340, and made sure te engine didnt sieze. 5 months I think it took him to fix that engine. He even did one on my last 340, and its now at 20,000 miles between changes, and the oil's still pretty good. (its running synthetic, and is mainly a motorway cruiser for me, when i'm in the UK) As i've tried to explain, the analysis CAN make it worth your while. You, however, seem to be the sort of person that never checks their hoses and belts. You can't hear a cambelt thats about to snap, you can often SEE it though, but if it's oing to go, and takes out some valves, well "they were probably wearing it excessively anyway and so I'd replace that while i was changing it" Do you even use your dipstick(s) at all, or can you tell if you're low on oil by feel/ear too? |
Ads |
#132
|
|||
|
|||
No, but if they happen to tell you you need to worry about something you are
bound to get more tests done next time. I trust no-one - i trust my own knowledge more than 99.99% of other people, being a design/research engineer, having worked in most aspects of the industry and having experienced the other areas first hand i know i trust me more than anyone else in these areas - everyone has an ulterior motive but yourself, But the point is - at what point do you decide to fix whatever is wrong from the results? Also, when its not a daily driver and covers no more than 8K miles a year, what difference does it make? If it goes breasts up I call breakdown and get carried home - who cares? And then i know whats gone wrong, what needs repairing and how to do it myself. J |
#133
|
|||
|
|||
"Coyoteboy" > wrote in message
... <snip> > But the point is - at what point do you decide to fix whatever is wrong > from > the results? Also, when its not a daily driver and covers no more than 8K > miles a year, what difference does it make? If it goes breasts up I call > breakdown and get carried home - who cares? And then i know whats gone > wrong, what needs repairing and how to do it myself. > > J > > That is a good point. The last engine I was involved with that failed internally was in my #2 son's '82 Corolla. The oil light started coming on at idle, and we brainstormed a course of action. The upshot was that the car wasn't worth any of the investigations or potential repairs (like oil pump replacement) that would have made a difference. Eventually a rod threw - big surprise - and the matter was settled. Oil analysis probably would have shown the problem earlier, but it still would have required a prohibitive amount of work to investigate further. The same could probably be said about any car that is more than a couple years old. For a car that is under some sort of warranty... the report within the warranty period would support a claim if the engine failed after the warranty expired, but you can be sure the warranty won't support any action be taken on the basis of an oil analysis. I used to work in general aviation, and oil analysis is very common there. With such expensive engines and scary prospects in case of internal failure it is a sure winner. For most cars I don't see a path forward if the analysis shows a problem, unless you count selling the car without notifying the buyer. Mike |
#134
|
|||
|
|||
Philip wrote:
> I recall well ARCO Graphic and a similar Kendall product. Lost a > camshaft to ARCO graphite back in 1978. Too bad that stuff was not > pulled from the market sooner. Typo correction: That's ARCO Graphite ... although the stuff was graphic black in color right out of the can. LOL -- - Philip Merry Christmas and all that rot. |
#135
|
|||
|
|||
"Coyoteboy" > wrote in message ... > Here in the UK there's no such thing as oil analysis - certainly I cant > find anyone local (i.e. in the north of the country) that does it, and the > only place i found in the whole country quoted £10 and 3 days wait. Whats > the point? I'm in the UK and can assure you that most oil companies provide the service as well as some engine and equipment manufacturers. It really is cheaper and less time consuming to change > over-regularly than to run tests and waste time that way - takes me 10 > mins > to change oil at the most, i spend £50 a year more than most people, but i > know im running golden honey all year round, no matter how hard i've > thrashed the engine, and most particulates from an older engine are > cleared > out with each oil/filter change. > This type of oil analysis not cost effective for light duty cars and vans. The more vehicles you own, the bigger they are, the higher their utilisation ratio and the higher the cost of their downtime then the economics of true analysis for oil changing and early detection of potential overhaul or preventative maintenance becomes more attractive. Latest technology allows the car's internal systems to appraise and advise the service intervals and this is now routinely fitted even to fleet cars in Europe e.g. VW and Opel/Vauxhall. This effectively makes a long [optimised] flexible service interval based on driving cycles and crude oil condition analysis become economically viable for almost everyone. Huw |
#136
|
|||
|
|||
Coyoteboy wrote:
> No, but if they happen to tell you you need to worry about something you are > bound to get more tests done next time. I trust no-one - i trust my own > knowledge more than 99.99% of other people, being a design/research > engineer, having worked in most aspects of the industry and having > experienced the other areas first hand i know i trust me more than anyone > else in these areas - everyone has an ulterior motive but yourself, two things: 1. how does an engineer/researcher have no interest in science-based decisions??? 2. inability to qualify those you need to trust is a function of your upbringing, not your education. the day you get over that is the day you'll start getting more from others as well as yourself. > > But the point is - at what point do you decide to fix whatever is wrong from > the results? Also, when its not a daily driver and covers no more than 8K > miles a year, what difference does it make? If it goes breasts up I call > breakdown and get carried home - who cares? And then i know whats gone > wrong, what needs repairing and how to do it myself. > > J > K'Tetch gave you the perfect example - analysis could have prevented an expensive time consuming siezure. who willingly flys blind when they can hit the 'on' switch on their radar? |
#137
|
|||
|
|||
jim beam wrote:
> Coyoteboy wrote: >> No, but if they happen to tell you you need to worry about something >> you are bound to get more tests done next time. I trust no-one - i >> trust my own knowledge more than 99.99% of other people, being a >> design/research engineer, having worked in most aspects of the >> industry and having experienced the other areas first hand i know i >> trust me more than anyone else in these areas - everyone has an >> ulterior motive but yourself, > > two things: > > 1. how does an engineer/researcher have no interest in science-based > decisions??? > > 2. inability to qualify those you need to trust is a function of your > upbringing, not your education. the day you get over that is the day > you'll start getting more from others as well as yourself. What do you do when your education compromises your ability to "qualify" those who one might trust? -- - Philip |
#138
|
|||
|
|||
Philip wrote:
> Do reveal how higher combstion pressure and temperature result in more soot. > Simply re-read what I wrote, quoted below. Don't worry, I'll explain it again when we get down there.... > >>(and other undesirable combustion byproducts) > > > The primary byproduct here is your vague reference to NOx? I for one never said or implied a word about NOx. > > >>being pushed past the rings into the LUBRICANT, even though the total soot >>produced and sent out the tailpipe is much lower. Thus, poor >>wording aside, the statement is correct in the context of soot loading >>of the oil. > > > Are you aware that NOx contaminates the lubricating oil? I am not. If > less soot is being produced, then how is -more- soot being "pushed past the > rings into the LUBRICANT" Ring sealing technology has improved since 1960, but only very slightly compared to improvements in other areas, such as fuel delivery management and forced induction pressures. Combustion pressures tend to be much higher with direct injection, hence there's a bit more blow-by. So even though the combustion gasses may be cleaner, more volume (albeit of cleaner gas) passes through the crankcase. Also, the higher pressures result in higher piston underside temperatures, and that too stresses a lubricating oil. |
#139
|
|||
|
|||
Steve wrote:
> Philip wrote: >> Are you aware that NOx contaminates the lubricating oil? I am not. >> If less soot is being produced, then how is -more- soot being >> "pushed past the rings into the LUBRICANT" > > Ring sealing technology has improved since 1960, but only very > slightly compared to improvements in other areas, such as fuel > delivery management and forced induction pressures. Combustion pressures > tend > to be much higher with direct injection, hence there's a bit more > blow-by. So even though the combustion gasses may be cleaner, more volume > (albeit of cleaner gas) passes through the crankcase. Also, the higher > pressures result in higher piston underside temperatures, and that > too stresses a lubricating oil. Nissan SD22 (debuted in 1964), indirect injection, advertised compression 21:1, non turbo. and oil cooled pistons Ford and Dodge Cummins of late ... direct injection, advertised comp 17.5:1 with turbo, 21.5:1 without, and oil cooled pistons. From these stats, your claim of "Combustion pressures tend to be much higher with direct injection" is not supported. Perhaps you'll clarify. In the case of the SD22, there are pistons with three compression rings and those with two compression rings. Depends on application. It is known that indirect injection while quieter, does result in more soot production. AS I see it, less soot production due to chamber design and better fuel management ... MORE than off sets your claim of greater oil contamination due to compression ring blow-by so far as oil service life is concerned. Is there disagreement? -- - Philip |
#140
|
|||
|
|||
..Philip. wrote:
> Steve wrote: > >>Philip wrote: >> >>>Are you aware that NOx contaminates the lubricating oil? I am not. >>>If less soot is being produced, then how is -more- soot being >>>"pushed past the rings into the LUBRICANT" >> >>Ring sealing technology has improved since 1960, but only very >>slightly compared to improvements in other areas, such as fuel >>delivery management and forced induction pressures. Combustion pressures >>tend >>to be much higher with direct injection, hence there's a bit more >>blow-by. So even though the combustion gasses may be cleaner, more volume >>(albeit of cleaner gas) passes through the crankcase. Also, the higher >>pressures result in higher piston underside temperatures, and that >>too stresses a lubricating oil. > > > Nissan SD22 (debuted in 1964), indirect injection, advertised compression > 21:1, non turbo. and oil cooled pistons > Ford and Dodge Cummins of late ... direct injection, advertised comp 17.5:1 > with turbo, 21.5:1 without, and oil cooled pistons. > > From these stats, your claim of "Combustion pressures tend to be much higher > with direct injection" is not supported. Perhaps you'll clarify. from http://www.chevron.com/prodserv/fuel.../L2_6_3_rf.htm "Since rapid fuel autoignition requires a certain air temperature, an IDI engine needs a higher compression ratio to achieve the desired air temperature in the prechamber. IDI engines operate at compression ratios of about 20:1 to 24:1; while DI engines operate at ratios of about 15:1 to 18:1. The heat losses that necessitate these higher compression ratios have another, more important effect: they decrease the efficiency of the engine. IDI engines typically achieve fuel efficiencies that are 10% to 20% lower, on a relative basis, than comparable DI engines." this text appears to be from the bosch automotive handbook - a superb publication. > > In the case of the SD22, there are pistons with three compression rings and > those with two compression rings. Depends on application. > > It is known that indirect injection while quieter, does result in more soot > production. > > AS I see it, less soot production due to chamber design and better fuel > management ... MORE than off sets your claim of greater oil contamination > due to compression ring blow-by so far as oil service life is concerned. Is > there disagreement? |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Rotary Engine FAQ 0501 | Felix Miata | Driving | 0 | January 1st 05 01:27 PM |
3.3L downshifting by self after replacing Engine | Bob Warmen | Chrysler | 8 | October 12th 04 05:39 PM |
Switching between Engine Oils Synthetic and Regular? | Tavish Muldoon | VW water cooled | 9 | September 29th 04 04:41 AM |