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2.5 petrol rebuild and conversion to EFI thread?


Gazzar

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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?

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Lots of cleaning and measuring today.

The block has no obvious damage, the core plugs were uncorroded, so their removal was in retrospect, of no benefit. Chasing the tapped holes with a tap produced no surprises.

I don't think the cam shaft bearings are worn, but I need to read the manual again.

I found that measuring the bearings was difficult, but ended up getting consistent measurements that suggested that there was no ovality in them. 

The piston bores still have cross hatching throughout, so again, I'm thinking that there's little work to be done there.

 

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The crank shaft bearings are worn. I think. I can see brass ( or is it bronze ) on all of the bottom shells. And the top of No 1. bearing is also worn.

 

Or is this normal? I'll change them regardless.

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 Bearings look normal for very worn out bearings, no major grooves, so nothing terrible , but definitely need replacing. 

Cam bearings rarely wear, they are probably fine. 

Word of caution on the bores - cross hatching can still be present but the bores can still be out of round/tapered wear etc. If you put new rings on that, they won't seal properly and will smoke/use oil. 

I'd check the bores with your internal dial gauge, I expect you'll find you need to get it bored oversize, but will wait to hear from you :)

As for the oil cooler, I did some digging, Snagger is somewhat correct, there is no thermostat in the system on a series vehicle. The oil cooler take the 'rejected' oil from the oil pressure relief valve, circulates it up through the cooler, and back into the sump. 

Having thought a bit more, I'm going to stick my neck out and say there is no chance of you needing an oil cooler on this engine. As you know, the series motors run quite cool, and have mahoosive radiators to keep everything under control. This leads to lower running, and therefore oil temperatures. 

In the optional parts catalogue, the stated use for the oil cooler when using 24 HP or more at 1500rpm when stationary, and that oil temperature should never go above 90C. With modern oils you can raise that temp limit a bit higher.... 

Are you planning on using you land rover as a pumping station with a huge pump hanging off your PTO? No? Then I don't think you need it. 

You can over cool oil, if it doesn't get warm enough you start accumulating mayonnaise from condensation in the top of the engine, leads to all sorts of problems aside from the mess. So if you do go with a cooler, make sure you use a thermostat. 

You could of course build it up without one, and use those tell-tale temp stickers to see if you do need one, and then fit one at a later date. I assume there's no desperate rush to get on one it now? 

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I think I'm going to fit it anyway.  The reason being is I can see a scenario when I'll be somewhere hot, be late and having to hammer it for the ferry.  And be full of duty free booze, which is why I was late.

And I like the idea. Donno, maybe it's a hang up from my childhood. We always had cars and tractors that were overheating. 

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Hammering down the autoroute is not really what land rover had in mind with their setup :)

Perhaps you could get a tidier solution with a smaller more efficient oil cooler (the series item is hardly an efficient design....), and use a take off plate with thermostat, as you suggest. 

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40 minutes ago, Gazzar said:

I think I'm going to fit it anyway.  The reason being is I can see a scenario when I'll be somewhere hot, be late and having to hammer it for the ferry.  And be full of duty free booze, which is why I was late.

So what turbo are you fitting then? 😁

Edited by daveturnbull
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Yes, all v good points. You make good sense.

I'm still fitting the mad series oil cooler. I like the look of it, it's cool!

I like long road trips.

I do occasionally tow quite heavy loads long distances. Doing crazy things like cross Britain with an 88" on the trailer, or collecting a chassis from the Highlands. 

And it's a high compression cylinder head, so might be running hotter than a normal series, plus God only knows what they'll put into petrol next, so best design for extreme and not need it. 

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I've measured the cylinder bores at sixteen points. 

I may not using the micrometer right, and my calipers may not be sensitive enough, but there's no difference between the measurements at the top, measuring at 90 degrees, and the bottom of the bores are 0.01mm different from the top, if that, and identical to reach other at 90 degrees

I'll take more measurements tomorrow, as I am not confident that I'm doing it right, and I think I might borrow an engineer that owes me a favour to check what I'm doing.

But I don't think there's much wear on the bores at all.

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Where the rings are in the bore, as they are the bits of the bore that wear. The piston skirt won't wear the bore at all. 

Essentially you need to take two perpendicular measurements at the top, two half way down, and two at the bottom. I tend to take each three times to make sure I have it accurate. 

You then end up with a bore size at the top, middle and bottom, but also you have the difference between across the piston gudgeon pin, which should wear very little, and perpendicular to the pin, where wear is more likely due to the sideways thrust of the crank. The difference between the parallel and perpendicular figures shows you the ovality of the bore. 

Sideways thrust is greatest when the piston is half way up, hence the need to measure it at more than just the top and bottom of bore. 

Workshop manual should have maximum figure for ovality, the Rover V8 is somewhere around 3 thou, from memory, so have to be pretty close. 

The reason I suspect you will need a rebore is the state of the bearings which are completely worn out. If they are like this, then likely the bores will be work as well. 

Can hope though :)

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It depends, I think, on how the engine has been treated. Low oil pressure even with decent, frequently changed oil will wreck bearings and rings won't care. They don't need pressure, just enough splash with an oil film that holds up. Good oil pressure with bad oil seems to be the other way round and does bores no favours. A consistently over fueling petrol engine also tends to wear bores, as does lots of heavy towing. Don't have any data to to back that up, just trends I've noticed when stripping engines. I'd certainly be carefully checking - or more likely replacing - the oil pump and relief valve on that engine. 

Calipers are ok for checking bores, but you'll want to use a micrometer for the crank journals. Not many people have 4 or 5"+ micrometers laying around(!), but 0-2" are definitely handy to have in the tool box. 

Keep up the good work :)

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if you *must* fit an oil-cooler, combine it with a thermostat - otherwise, as others have noted, you will probably spend 99% of the time with over-cooled oil which means a buildup of condensation and acidic combustion-products in the oil which is really-not-good-news.

The best 'oil-coolers' are those that fit into the existing cooling-system [oil/water intercoolers] - they help get the oil up-to-temperature quickly after a cold-start by transferring engine-heat from coolant-to-oil - but then when the bulk-oil temperature's getting a bit hot they dump oil-heat into the coolant and let the coolant-radiator deal with it.

Truth is, modern synthetic multigrade oils are *vastly* better than the SAE30 monograde-stuff Land-Rover were designing-to-use in the 50s/60s/70s. Back then, an engine rebuild/rebore-every-50,000-miles was considered normal.

Edited by Tanuki
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As the cam is so badly worn at number 4 cylinder, I was planning on replacing the oil pump as a precaution. I've found no blockage in the oil ways, so I can only assume the engine wasn't circulating enough oil toward the top of the engine.

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12 minutes ago, 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.

 

Yep, I knew there was a problem:

 

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1 hour ago, Gazzar said:

As the cam is so badly worn at number 4 cylinder, I was planning on replacing the oil pump as a precaution. I've found no blockage in the oil ways, so I can only assume the engine wasn't circulating enough oil toward the top of the engine.

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!

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6 hours ago, lo-fi said:

It depends, I think, on how the engine has been treated. Low oil pressure even with decent, frequently changed oil will wreck bearings and rings won't care. They don't need pressure, just enough splash with an oil film that holds up. Good oil pressure with bad oil seems to be the other way round and does bores no favours. A consistently over fueling petrol engine also tends to wear bores, as does lots of heavy towing. Don't have any data to to back that up, just trends I've noticed when stripping engines. I'd certainly be carefully checking - or more likely replacing - the oil pump and relief valve on that engine. 

Calipers are ok for checking bores, but you'll want to use a micrometer for the crank journals. Not many people have 4 or 5"+ micrometers laying around(!), but 0-2" are definitely handy to have in the tool box. 

Keep up the good work :)

Yep, I'd go with that, I am just taking an overall picture where the cam is trashed, the crank bearing are gone.... Seems a higher miler engine so likely the bores will be worn. 

Be very happy to be proved wrong, of course :)

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