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2.5 petrol rebuild and conversion to EFI thread?


Gazzar

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You absolutely can over-cool oil and remember that LR fitted oil coolers to FFR trucks which would be running stationary for hours on end powering equipment, which is a different sort of scenario.

Temperature tell-tale labels will tell you if your oil ever gets too hot before you go to the effort:

temp_labels_2.JPGtemp_label.jpg

 

I have avoided fitting any oil coolers to my trucks on the grounds that every bit of plumbing you add is a new failure point... so far the labels show I don't need to worry.

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18 hours ago, lo-fi said:

The cam may be a result of the crank bearings failing. With the mains worn so badly, the oil can flow out far more easily, meaning there's less reason for it get pushed up to the cam and up top. Number 4 is furthest from the oil pump, so you can see the story unfolding. Teardown post mortem is one of my favourite parts of rebuilding broken stuff!

If the crank bearings are worn, would that mean there's oil squirting out on to the crank shaft? And available to be splashed onto the bores? There aren't under piston sprays in this engine, unlike a TDI.

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I'm going to work my way through the oil route and try understand it.

Should be a nice physical mental exercise.

I think I'll get some of those stickers and see how hot the oil gets when I get that far, but I'm happy that I'll not over cool the oil. If that happens I'll put a restrictor in the return banjo.

 

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I've been studying the parts manual on the oil cooler.

It looks like you replace the pressure valve in the oil pump with one in the oil pipe circuit, plugging the valves in the pump.

Did this mean it only cools when the oil pressure is excessive?

That would make make sense, as otherwise there'd be reports of FFR vehicles failing in a regular basis as a result of over cooling of the oil.

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15 minutes ago, Gazzar said:

That would make make sense, as otherwise there'd be reports of FFR vehicles failing in a regular basis as a result of over cooling of the oil.

Out of idle curiosity I've been emailing my mate in the oil business about this, he & his colleagues reckon there's no major risks to having an unnecessary oil cooler as you're never going to drag it down by very much if the engine itself is up to temperature (unless you've fitted a HUGE cooler).

The drawbacks are loss of efficiency, failure to boil/burn off condensation/fuel etc. in the oil, minor loss of performance of some of the additives in the oil, and the addition of weight, complexity, plumbing and opportunities for damaging an oil line / cooler off-road.

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38 minutes ago, Gazzar said:

I've been studying the parts manual on the oil cooler.

It looks like you replace the pressure valve in the oil pump with one in the oil pipe circuit, plugging the valves in the pump.

Did this mean it only cools when the oil pressure is excessive?

That would make make sense, as otherwise there'd be reports of FFR vehicles failing in a regular basis as a result of over cooling of the oil.

Correct, I alluded to this earlier in this thread, essentially the stuff that goes out the back of the pressure relief valve goes round the cooler back into the sump. 

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So, at tickover the circuit would be closed?  That makes sense, because I couldn't figure out how oil got to the lubrication circuit if it all went to the cooler and back to the sump, the pressure valve in the circuit only lets excess pressure into the cooler.  In normal use the circuit would be closed.

I'll ask the father in law about the cooling of oil, he wrote the book on automotive lubricants when he was at Esso, back in the day.

Oh, hopefully I've an experienced engine rebuilder coming around next week to assess the wear.  He rebuilds race engines and also some Porsche engines, so he should be able to point me in the right direction.....

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Yes. So, in general pottering about I'll be fine. In full throttle down the motorway with a trailer it will be cooling a lot more.

Fine. That's what I want.

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17 hours ago, lo-fi said:

I think you'll appreciate this channel:

Reassembly starts here on this engine:

 

 

 

A beautiful build, he makes great videos. 

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Oil cooler makes quite a difference on my V8, but that needs all the help it can get. 

Squatch has become one of my favourite YouTubers. His engine builds are inspirational. 

On a related note, I realised while driving home that I no longer need to farm out my basic engine work to a machine shop. I have a Bridgeport :D

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I think this thread should have me worried, as my ex Singapore military 110 with 18J motor came with a pretty big oil cooler fitted!  Then again, I'll just trust that they put it together in a way that doesn't require a tropical climate to keep the oil warm enough.  It would be interesting to know if there is any sort of thermostat in there though.

Other than that, I will follow this thread with interest.  No better way to learn than seeing worn items being pulled apart carefully.

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On 1/11/2020 at 9:48 PM, Gazzar said:

That's what I thought. 

Would a TDI filter mount, with stat, work with the series cooler, returning to the sump? Or is there such a thing as over cooling oil?

Yes, it would work.  It’s what I did with my 12J, using a Series oil cooler.  I was told the Series cooler (the same as fitted to FFRs) has too much internal resistance for full flow - they normally take only the “overflow” - but I had very healthy pressure readings at all rpms with the oil warm or cold, so I don’t think it’s an issue on these engines.  On a Tdi or 19J, with the oil demand for the turbo, I’d pay more attention to it.

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On 1/12/2020 at 10:41 PM, Gazzar said:

Could I use a tdi200 filter housing? That has a stat. I dimly recall reading that this was a bad idea, but can't figure why.

 

Yes, and and there is no trouble in doing so.  The 200 has exactly the same main housing, just the oil stat housing in place of a blanking plate and the other port open instead of plugged.

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On 1/14/2020 at 8:45 PM, Gazzar said:

I've been studying the parts manual on the oil cooler.

It looks like you replace the pressure valve in the oil pump with one in the oil pipe circuit, plugging the valves in the pump.

Did this mean it only cools when the oil pressure is excessive?

That would make make sense, as otherwise there'd be reports of FFR vehicles failing in a regular basis as a result of over cooling of the oil.

Not excessive, but adequate for running the main lubrication circuit and the cooling circuit in parallel, which does suggest that at low rpm, like an FFR at high idle, the oil flow through the cooler will be very low indeed.  Perhaps that’s why it’s so big.

You should never overcool oil if the system has a thermostat, like the 19J/Tdi housing.  I also doubt that the coolers embedded in radiators are better for being able to warm the oil - if the oil is cold, the thermostat is shut and there is minimal if any oil flow through the cooler (It bypasses the circuit within the filter housing) to pick up coolant warmth.  However, such coolers have much less cooling capacity in a warm rad, are more expensive to replace (as your replacing two heat exchangers and all the drained coolant too) and can easily cross-contaminate oil and coolant.  I don’t know, but I suspect LR and others do it that way purely for space saving and ease of engine bay design rather than any mechanical superiority.

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2 minutes ago, Gazzar said:

Ummmm, the return is key, isn't it? The TDI return is to the filter, the series is to the sump.

Get that wrong, and bad things happen!

 

 

Yes, but you use the plain sided sump (or blank the sump oil ports), so the return goes to the filter like on the Tdi.  Basically, you mimick the Tdi oil cooler circuit, just using your existing cooler and keeping the old SIII separate rad for the coolant system. 

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