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What Happens if You Don’t Change Your Oil For 60,000 Miles


Tony
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complete strip down and deep clean to get things back to normal?

I would agree.... It would be assumed the oil ways are blocked and the oil level low due to the sludge

 

 

Is it true that a 50/ 50 oil and paraffin mix acts as a flush?

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Is it true that a 50/ 50 oil and paraffin mix acts as a flush?

Well,

mineral oil (the "old" type of engine oil) is a long chain hydrocarbon molecule; paraffin is a much shorter chain hydrocarbon, so paraffin will dissolve mineral oil. Whether it will have any effect on modern synthetic oils is a bit trickier...

 

If you're going to flush an engine, I'd suggest using one of the commercial products, they will contain other compounds to assist cleaning the dirt out of the engine. (detergents etc., and you can run the engine with them - no load!)

 

To remove this level of grot, you would probably be looking at a complete strip down and steam cleaning every oilway. That really makes it a labour of love, 'cos economically it's not worth it.

 

Modern oils are much better than the old ones:-

recommended oil change intervals for my Minor were 3000 miles (using SAE 30 - and changing to a thinner oil for the winter)

using the early 20W/50 multigrades it went to 6000 miles.

The A series was notorious for condensation in the rocker cover - each oil change required scraping out the rocker cover emulsion, but the used oil was free flowing (though black).

 

Modern oils are that much better (and more expensive!) that I wouldn't be surprised to find some manufacturers recommending 20 000 mile intervals... rather depends on how you use the car.

 

There's a number of reports that the Luftwaffe in WW2 Eastern front used to dilute the crankcase oil with paraffin so that the aircraft engines could be started in sub-zero temperatures. Apparently, as the engine warmed up, the paraffin would vaporise (boil off), rather you than me.

 

Colin

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I had no idea that you needed different oils for summer and winter in the old days. Also changing every 3,000 miles is a pain (as well as expensive). Do you still have to stick to this service interval using modern synthetic oil with the Minor?

 

 

 

 

Is it true that a 50/ 50 oil and paraffin mix acts as a flush?

 

Modern oils are much better than the old ones:-

recommended oil change intervals for my Minor were 3000 miles (using SAE 30 - and changing to a thinner oil for the winter)

using the early 20W/50 multigrades it went to 6000 miles.

The A series was notorious for condensation in the rocker cover - each oil change required scraping out the rocker cover emulsion, but the used oil was free flowing (though black).

 

Modern oils are that much better (and more expensive!) that I wouldn't be surprised to find some manufacturers recommending 20 000 mile intervals... rather depends on how you use the car.

 

Colin

 

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Fuel injection has made a huge difference to service intervals , carburetors (Described by a mate of mine as an organised fuel leak) usually ensure the oil in contaminated by petrol by 6000 miles, more if they car is used for short trips  

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I had no idea that you needed different oils for summer and winter in the old days. Also changing every 3,000 miles is a pain (as well as expensive). Do you still have to stick to this service interval using modern synthetic oil with the Minor?

 

Used to have only "straight" grade oils-e.g.SAE20,SAE30,SAE90 (SAE 20 is used in the SU carburetter for the piston damper - roughly the same as "3-in-1").

Once Multigrade oils were available, these were used and were much easier to maintain - however, even today I note that some manufacturers recommend different viscosity multigrades depending on the expected ambient temperature.

 

There's been a lot of debate about synthetic oils in the old engines. There seems to be a consensus (or there was when I had my Minor - about 7 years' ago) that synthetic oils were not recommended. The protection offered was slightly better for starting (better oil film on bearing surfaces, but they also seemed to creep well - this includes a bit through the old cork gaskets... 

Another problem with synthetic multigrades is that they aren't readily available as 20W/50 - only thinner grades. This means that the oil film is slightly thinner. It leaks down the valve guides and past the piston rings better!  Also the A series engine was designed to drip lubricate the read crankshaft bearing - just a little, but the clutch bell housing has a drain hole and "giggle pin" as part of the design.

 

Modern engines are usually drip free

 

As liner 33 says, at 6000 miles the old petrol engines would need an oil change to get rid of the contamination (if nothing else, synthetics are expensive!), and I don't think anyone's run their engine for longer without changing the oil (oil's cheap compared with any engine rebuild!)

 

One technique that's more difficult these days is to use a thicker than standard oil to "quieten" an engine/gearbox/rear axle.

 

If the pistons rattled a bit - or the valves chattered, using (say) SAE 40 oil instead of SAE 30 would quieten them down - same for worn gearboxes and differentials..

Useful when selling (and I'm sure that doesn't happen today)

 

Cheers.

 

Colin

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I understand that synthetic oils are less tolerant of petrol contamination, its also less able to cope with shearing that you get in gearboxes due to the long molecule strains 

 

This used to be spoken about a lot when fully synths came in for motorcycles since they share the same oil for engine and gearbox and people thought it was an issue 

 

I used to use a mineral oil in my dragbike  

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I take it that the modern gasket kits for the morris minor do not leak?

 

The Morris Minor gasket sets are made to the original specifications.  If it leaked originally, it'll leak now....

 

The main gaskets (rocker cover, sump gasket, timing chain cover) are about 1/4" cork. They need to be somewhat "squigy" as the surfaces of the block and the covers are not machine perfectly flat (and it's easy to distort them by tightening the retaining bolts unevenly).

As I noted above, a little seepage is not only normal for the crankshaft bearings, but really required to keep the bearing and gasket working (modern engine designs are much better for leak tightness).

 

For a better - and more up-to-date discussion, try the MMOC (Morris Minor Owners' Clob) web forum - they'll be morecurrent then me.

 

 

 

Cheers,

 

Colin

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Cheers Colin. I've never owned a classic and the more I read the more I realise that you need to be pretty handy with a spanner and grease gun to not end up spending a fortune in maintenance bills

 

 

 

I take it that the modern gasket kits for the morris minor do not leak?

 

The Morris Minor gasket sets are made to the original specifications.  If it leaked originally, it'll leak now....

 

The main gaskets (rocker cover, sump gasket, timing chain cover) are about 1/4" cork. They need to be somewhat "squigy" as the surfaces of the block and the covers are not machine perfectly flat (and it's easy to distort them by tightening the retaining bolts unevenly).

As I noted above, a little seepage is not only normal for the crankshaft bearings, but really required to keep the bearing and gasket working (modern engine designs are much better for leak tightness).

 

For a better - and more up-to-date discussion, try the MMOC (Morris Minor Owners' Clob) web forum - they'll be morecurrent then me.

 

 

 

Cheers,

 

Colin

 

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It's certainly not good to own a classic car unless:-

 

either - you're handy with a spanner & possibly welding sheet steel (plus spray painting - with workshop)

or - bags of money

 

After a certain age, laying on my back under an oily engine trying to thread an oil filter cartridge in the rain, with old engine oil going up my sleeve loses its appeal.

 

Having said that, I could carry out the 6000 mile service on the Moggie in under 2 hours (including topping up the dampers, greasing all the grease nipples etc.  Cost of materials was about £15 or so (new plugs, points distributor cap, condenser, fan belt, oil gaskets and both filters) plus oil (a reputable 15W/40  - or if I could find it 20W/50).

 

Cheers,

Colin

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When you own a classic the maintenance and tinkering is half the fun 

true

 

It's certainly not good to own a classic car unless:-

 

either - you're handy with a spanner & possibly welding sheet steel (plus spray painting - with workshop)

or - bags of money

 

After a certain age, laying on my back under an oily engine trying to thread an oil filter cartridge in the rain, with old engine oil going up my sleeve loses its appeal.

 

Having said that, I could carry out the 6000 mile service on the Moggie in under 2 hours (including topping up the dampers, greasing all the grease nipples etc.  Cost of materials was about £15 or so (new plugs, points distributor cap, condenser, fan belt, oil gaskets and both filters) plus oil (a reputable 15W/40  - or if I could find it 20W/50).

 

Cheers,

Colin

I did a mechanics course in my teens but that is 35 years ago now.... need to do a refresher course somewhere. welding I have not done but I think I could pick it up

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