Building oil pressure prior to starting the engine

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Post by Kitch »

rmattila wrote:
Kitch wrote:I think trying to fix a problem that isn't there is a bit of a waste of time. Even high performance engines don't have anything like that, and the XUD is about as far removed from a high performance engine as is possible without getting into plants buildings.
..but on the other hand, low-performance naval diesels that are designed for long-lasting service, do.. :wink:
I think the line between submarines and a mass-produced Frencgh diesel hatchback is quite a large one.
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Post by rmattila »

Kitch wrote:
rmattila wrote:
Kitch wrote:I think trying to fix a problem that isn't there is a bit of a waste of time. Even high performance engines don't have anything like that, and the XUD is about as far removed from a high performance engine as is possible without getting into plants buildings.
..but on the other hand, low-performance naval diesels that are designed for long-lasting service, do.. :wink:
I think the line between submarines and a mass-produced Frencgh diesel hatchback is quite a large one.
I don't care for hatchbacks either. 8)

But in the few-hundred-kilowatt class, it is quite usual for a diesel engine to have an interlock preventing start-up if there's no oil pressure. I don't see any principal difference, why it would not be benefitial for the smaller engines as well to have a good lubrication all the way from the start-up.
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Post by Kitch »

rmattila wrote:
Kitch wrote:
rmattila wrote:
..but on the other hand, low-performance naval diesels that are designed for long-lasting service, do.. :wink:
I think the line between submarines and a mass-produced Frencgh diesel hatchback is quite a large one.
I don't care for hatchbacks either. 8)

But in the few-hundred-kilowatt class, it is quite usual for a diesel engine to have an interlock preventing start-up if there's no oil pressure. I don't see any principal difference, why it would not be benefitial for the smaller engines as well to have a good lubrication all the way from the start-up.
It'd be beneficial yes. But it'd also be beneficial to remove the camshaft before each start to manually oil all the lobes, and to remove the pistons and de-glaze the bores after each long journey. Doesn't mean you need to do it! :wink:

A mass-produced car like this is engineered with a certain amount of neglect in mind. The tolerances aren't strict enough to require any special treatment. A mass-produced automotive diesel engine isn't in the same catagory as the diesel engine in an old sub - period.

That's not to say you shouldn't do it. Who's to tell you what you can and can't do? But if it were me, I'd concentrate on doing something you'll actually benefit from! You'll never notice the difference with it.
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Post by rmattila »

The original design was not meant to run for over a million km, which is what I'm aiming at, and therefore the original design justifications are not necessarily directly applicable. If you look at the things causing excessive wear, the top three I've come up with are:
  • suboptimal oils (already taken care of by changing to good one every 7500 km)
  • running a cold engine (already taken care of by the electric block heater whenever it falls below +5)
  • running dry until the circulation starts (currently not taken are of)
I'm not aiming to stay within what the engine was expected to normally endure, but really running it as long as possible, and therefore looking for things to do to make sure the wear keeps as low as practically attainable.
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Post by Kitch »

What mileage are you at now? I would have thought it would be more interesting to see how long an unmodified, straight out of the box engine will last. Looked after, of course!
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Post by rmattila »

Kitch wrote:What mileage are you at now? I would have thought it would be more interesting to see how long an unmodified, straight out of the box engine will last. Looked after, of course!
.
Just had an engine failure at 730 000, but that was not the engine's fault: http://www.rmattila.com/images/remontit ... ne_change/

I'm rotating engines so that I do the timing belt change in the shop, so the engines move from car to car. The one with the largest mileage is currently at 620 000 km, the other 3 are quite fresh.
Last edited by rmattila on Sun Feb 12, 2012 12:44 am, edited 1 time in total.
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Post by Kitch »

See at that mileage I wouldn't begrudge them going bang :lol:
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Post by Defender110 »

rmattila wrote:.
Just had an engine failure at 730 000, but that was not the engine's fault:
exactly, 'not the engines fault' so although I admire your attempt to increae engine life how would having a pr-oiled engine of prevented this and increased the mileage of the engine? It won't increase combustion damage to pistons etc. neither will it? I'm sure there are all sorts of other engine components that would eventually give up out of pure fatique even if perfectly lubricated do you not think?
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Post by electrokid »

I've wondered about fitting an extra oil filter - one that draws oil from the sump and passes it through a very fine filter then back to the sump or to above the camshaft. Since the filter doesn't have to operate a full flow it can be as fine as you like - experiments with this type of system have used filters something like a toilet roll where the oil flowed 'across' the roll - aparently this provided the best filtration.
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Post by Oilyspanner »

electrokid wrote:I've wondered about fitting an extra oil filter - one that draws oil from the sump and passes it through a very fine filter then back to the sump or to above the camshaft. Since the filter doesn't have to operate a full flow it can be as fine as you like - experiments with this type of system have used filters something like a toilet roll where the oil flowed 'across' the roll - aparently this provided the best filtration.
A company called Cresco used to sell a by-pass oil filter, basically a bog roll in a casing, plumbed into a T piece screwed into the oil pressure switch hole, it returned the filtered oil via a fitting drilled into the rocker cover, they reckoned a 60,000 mile oil change interval, a colleague fitted one and his oil always looked new, I dont know why they never took off but I believe they were too good at filtering and were removing the additive pack from the oil.
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Post by electrokid »

I guess if the oil stays clean for that length of time one would need another way of judging whether it was still fit for use - good point.
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Post by MULLEY »

Wouldn't adding another oil filter possibly cause oil starvation as the flow of oil could be less due to the extra resistance of having more than one filter in the system?

I must admit, everytime i've done the oil change on my txd, which i do every 6k, the oil is black, even after an oil change & only a few day's driving its black? Why does this happen?
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Post by Oilyspanner »

The Cresco system was fed from the oil pressure switch hole, only a small bore pipe and not affecting flow through the standard filter, which did not need changing again, it probably took a good while for the entire contents of the engine to go through, but it would, I think the additives have become more important, it looked very good at the time (late 70s).
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