Overheating and venting oil

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TimM
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Overheating and venting oil

Post by TimM »

Hi, my Morris engine has been giving me lots of problems. Whenever the engine gets hot on a more 'urgent' journey it vents oil from underneath and then gets hot. The top of the engine has been rebuilt recently. When standing, there is no oil leak as such, only when it gets hot. Inside the oil cap is mucky with white cunk and I wondered if the head gasket had failed, though my mechanic thinks not, as he'd already had the top off to rebuild the engine. Any ideas? Many thanks for any suggestions.
simmitc
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Re: Overheating and venting oil

Post by simmitc »

Vents oil from underneath what? How hot is it getting - is the radiator boiling over?

A good mechanic should not "think" that it's not the gasket, it's simple to run compression tests and cooling system pressure tests; and also to test the cooling system for combustion gases.

For starters, DIY inspection: Is the water level dropping? Is there any sign of oil in the water? Id the oil level dropping, and is there any sign of water in the oil? Using the starting handle, with the ignition OFF, turn the engine by hand - do all four cylinders feel like they have full compression?

Remove the radiator cap (caution, take precautions if hot) and then start engine - are there bubbles appearing oin the water?

You could remove the rocker cover and clean way any emulsified deposits from the inside, and also clean the oil filler cap. Monitor to see if they were historic deposits or if problems recur.
TimM
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Re: Overheating and venting oil

Post by TimM »

Thank you!

So the water is still topped up and doesn't seem to have oil deposits in it. However, the oil cap nut was not sitting in the suction champer as if it had been raken out completely and not put back in. Could this have contributed?
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Re: Overheating and venting oil

Post by kennatt »

oil cap nut??do you mean the rocker cover nut,more info required.
/
TimM
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Re: Overheating and venting oil

Post by TimM »

On top of the suction chamber/dashpot of the carburetter. The dashpot plunger was just hanging out!
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Re: Overheating and venting oil

Post by Grumpy21 »

Hi Tim, there seems to be a lot of confusion here.

The dashpot should have light oil inside about half way to the top, then the (usually black) plastic cover should be screwed back down finger tight. There should be no gunk side at all.

The oil filler (on top of the rocker cover) should be clean apart from a little oil residue. If there is creamy foamy gunk here it’s likey your head gasket has failed but not certain, hence a compression test would help. The oil should be up to the FULL mark on the dip stick and no further

Water in the radiator should be clear or blue with no oil droplets or bubbles

If oil is coming out of the engine block itself (sump, gaskets, head, rocker or tappet chest) check you crank case ventilation system.

Hope this helps a little.
TimM
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Re: Overheating and venting oil

Post by TimM »

Thank you, it does😊
kevin s
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Re: Overheating and venting oil

Post by kevin s »

As above your symptoms fit if the engine breathers are blocked or it has the wrong combination of parts is fitted, there are various permutations of breather system and caps out there as the design changed over the years, what year is yours and some pictures of what is fitted would help.
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Re: Overheating and venting oil

Post by TimM »

Mine is a 1961but the engine is a newer one.
simmitc
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Re: Overheating and venting oil

Post by simmitc »

Tim, we're trying to help, but this is getting confusing with discussions about head gaskets and carbs, plus "a newer engine". Can we clarify the problem:

1) Is the engine overheating or not - is it simply getting to normal operating temperature? Overheating would suggest that the radiator was boiling over with steam and waster coming out. If I understand correctly, you have confirmed that it is not overheating.

2) What engine is fitted? Can you post a picture of the oil leak - I can't see that you have ever confirmed from where it is leaking.

3) A picture of the engine, carb and breathing arrangement would be helpful.

4) Check that the fan belt tension is correct, and report back.

5) Is the oil level correct on the dipstick?

6) You refer to the top having work done. What was done? Did the problem exist before the work was done, or has it happened since?

Please reply to the specific numbered points so that we can help you solve your problem.
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Re: Overheating and venting oil

Post by TimM »

Thank you everyone and so sorry for the confusion, I am no expert and so don't really know what I'm talking about, however here goes...

1. I am now not sure. What happens is that all is fine until after about 1o minutes of faster driving, such as on an A road or motorway. I'm a very careful driver so am not really going fast at all :o . At this point oil starts to leak from under the car, the car loses power, there is a smell of burning, the engine gets louder and then, of course, I pull over. On popping the bonnet the engine itself is hot, but the water is not boiling over and the level is fine. Oil is continuing to drip from under the car.

2. The engine is a 1098 engine. This car should have the 948cc engine as it is a 1961 car but I don't know why it has this in it. I have attached some pictures of the engine and the underside in the 'attatchments' section. It is impossible to see where the leak comes from, it's all oily underneath and the leak only happens when it gets really hot. I could stress the engine on the ramp and force it to blow oil, but would rather not. When I replace the oil, their is white gunky stuff on the lid of the oil filler cap and tube, lots of it.

3. Attached a picture.

4. The fan belt was loose but I think it is fine now. No screetching sounds or slipping.

5. Oil level is always fine and is checked regularly.

6. The work I had done last year or so was...

1 = CHECK COMPRESSIONS & LOW & HIGH TENSION SYSYTEMS. REMOVE CARBURETTA TOP, CLEAN & ADJUST MIXTURE & TICKOVER. REPLACE FUEL FLEXI PIPE FROM PUMP TO CARB WITH NEW PIPE.

2= REPLACE ROCKER COVER SECURING BOLTS WITH SHORTER UNITS TO SECURE COVER TO HEAD & STOP OIL LEAK. RUN & TEST.

3 = REMOVE CYLINDER HEAD. FIND VALVE OIL SEAL RINGS MISSING OR HARDENED. REMOVE ALL VALVES. LIGHT BLAST HEAD, CLEAN & LAP IN ALL VALVES, FITTING MODIFIED VALVE STEM OIL SEALS & OIL RINGS. REFIT TO CAR , START ENGINE, NO SMOKE TILL WARM.

4 = REMOVE HEAD AGAIN. DRAIN OIL. REMOVE ENGINE SUMP. REMOVE ALL 4 PISTONS. FIND OIL CONTROL RINGS STUCK.
REMOVE ALL RINGS FROM PISTONS. LIGHTLY BLAST PISTONS CLEAN. DRIL OIL HOLES TO CLEAR CONGEALED OIL. .FIT NEW PISTON RING SET.
CLEAN & HONE BORES PRIOR TO REFITTING PISTONS. REFITTING ALL REMOVED PARTS.

RUN UP & TEST OK.

I hope that makes sense and thank you again!
Attachments
Morris 3.jpg
Morris 3.jpg (1.5 MiB) Viewed 795 times
Morris 2.jpg
Morris 2.jpg (1.44 MiB) Viewed 795 times
Morris 1.jpg
Morris 1.jpg (1.79 MiB) Viewed 795 times
Sleeper
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Re: Overheating and venting oil

Post by Sleeper »

Blown head gasket??

Can you do a leak-down test / compression test ?

John ;-)
KeithL
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Re: Overheating and venting oil

Post by KeithL »

TimM wrote: Tue Apr 19, 2022 1:27 pm 5. Oil level is always fine and is checked regularly.
The oil's not coming from the gearbox is it?

TimM
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Re: Overheating and venting oil

Post by TimM »

I have booked it in for a compression test next week. I don't think oil is coming from the gearbox. When it blows oil it definately comes from the engine as it needs refilling.
simmitc
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Re: Overheating and venting oil

Post by simmitc »

5. Oil level is always fine and is checked regularly.
When it blows oil it definately comes from the engine as it needs refilling.
Sorry, in my mind, they cannot both be true :-?
TimM
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Re: Overheating and venting oil

Post by TimM »

After it has blown oil, the dipstick level is down, so the engine oil needs filling up again.
ManyMinors
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Re: Overheating and venting oil

Post by ManyMinors »

It perhaps doesn't help that you seem to have the later engine with the closed breather system allied with an early carburettor and manifold, so that you have neither one system nor the other?
TimM
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Re: Overheating and venting oil

Post by TimM »

It perhaps doesn't help that you seem to have the later engine with the closed breather system allied with an early carburettor and manifold, so that you have neither one system nor the other?
That's interesting, I did wonder if the parts bin had been plundered when putting it all together.
simmitc
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Re: Overheating and venting oil

Post by simmitc »

I think that we're making progress.

Converted from 948 to 1098 but without the correct ancillaries. The work that was done to the top end sounds like it was by a competent person who knew what they were doing. That just leaves another few questions:
1) Why was the work done? Presumably the exhaust had blue smoke when the engine was running and possibly a high oil consumption?
2) Are any of the brakes getting hot after your high speed run? Remove hub caps and feel the centre of the wheels.
3) Is performance of the car generally good?
4) What sort of mpg are you getting?
5) What's the history of this - how long have you owned the car - was it running well and then the faults developed, or was the work done for a previous owner and the car has had the current fault since you bought it?

Sorry for so many questions, just trying to narrow things down. The more information you can provide, the better the answers we can offer.

As an aside, when the 1098 was fitted, were the gearbox and back axle changed as well, and were the front brakes uprated? To check this:
a) Is the gearbox ribbed or does it have a smooth case?
b) Does the back axle have a drain plug in the centre and a filler plug near the top of the rear, or is the filler in the nose of the diff, near the prop shaft?
c) Is the diameter of the front brake drums 7 inches or 8 inches?
These won't affect your current problem, it's just to see whether the rest of the conversion was done well.
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Re: Overheating and venting oil

Post by kennatt »

Could you do this test and report back,with the engine hot,take oil filler cap off hold your hand over the hole and rev the engine . On a good engine you should feel very little out flow of air/ engine fumes,(there will always be some,)on a slightly worn engine there will be a noticeable
/ flow, on a very worn engine you will see it even without your hand over the hole.
The test shows the amount of blow past the pistons,the more there is the more wear there is between the piston rings and cylinder wall.(it is a simpler test than a compression test but no way as good ,an indication is a better description), new piston rings don't always cure wear in the combustion chambers.

This blow past causes a build up of pressure in the crank case .If this pressure build up beyond that which the breathing system can cope with, then it has to go somewhere .It vents out of the rear scroll seal or any other gap it can find,taking oil with it ...oil leak. In a good engine it also indicates a blocked or wrong breathing system .
Obviously the hotter the engine get everything expands and any wear is exaggerated
Wouldn't worry too much about head gasket failure (Comp test will confirm or otherwise) Mayonnaise in the rocker cover is common on the a series its caused by the cold air flow over the long rocker cover, which condenses moisture and leave the white gunge. a deflector can be made to fit on the front cover bolt to direct the air up away from the cover.
good luck
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