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winter Project - Fix Oil Burn


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Hi

At a guess I am eating about 1ltr of oil per 200km based on my last trip.  If I boot the TR and decelerate hard using gears I do get a nice cloud behind me (grey).  

I have read a compression test only tells you if the rings are good, and read this could be the valve guides.  As for dripping oil, well, it does leave a few drops but nothing serious, but maybe this is worse when driving?

Other factors:

 - when I got to my summerhouse, a lot a '****' on back bumper, so out came polish to remove it.

 - Oil pressure 3/4 over then just over halfway when cruising

 - New K&N oil filter - this seemed to help a higher oil pressure when starting, but maybe a red herring

  - using 20/50 Millers, mineral oil

I think one side of me wants a winter project also I really do not like having this oil eaten away so was considering a top end re-build and researching what it means to do that over coming months.  Does anybody have some thoughts or opinions on this?  I have an OK garage and am quite quite savvy but still learning a lot, but this forum for me has always been my go to place.

 

Richard

 

Edited by AarhusTr6
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How "old" is the engine. Is the oil consumption a new problem or has it been there for a while but deteriorating? Have you changed anything?

Have you got an external rocker oil feed fitted. If so remove it and see if oil consumption falls.

If it's not been apart for some time could be wear in bores, broken/worn rings, glazed bores or worn valve guides.

If it is relatively recently rebuilt the wear element is unlikely. If a compression test yealds poor results then you are likley to need to strip it down fully.

If the compressions are OK then you can examine the bores when you do take the head off to check the guides

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7 minutes ago, Andy Moltu said:

How "old" is the engine. Is the oil consumption a new problem or has it been there for a while but deteriorating? Have you changed anything?

Have you got an external rocker oil feed fitted. If so remove it and see if oil consumption falls.

If it's not been apart for some time could be wear in bores, broken/worn rings, glazed bores or worn valve guides.

If it is relatively recently rebuilt the wear element is unlikely. If a compression test yealds poor results then you are likley to need to strip it down fully.

If the compressions are OK then you can examine the bores when you do take the head off to check the guides

Hi Andy

No idea how old, very very little PO history but doubt that there has been a re-build for many years.  No external rocker feed fitted (should have mentioned that).  I am looking at doing a compression test next week but never done one before, so all the fun of the learning for me.

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Hi Richard,

I have just scanned a number of forums (mainly USA) and the answer to the same question is varied.

Hotter plug, valve guides. worn bores, broken/worm oil control rings.

How can you make a plan with that lot.

If it was me I would consider removing the engine and GB.

Get the pistons out to check the rings/bores.  This will give access to the big-end shells. Whilst there look at the main bearing shells and thrust bearings. Is the rear oil seal leaking !!!!

Consider a rebore/hone of the bores.

Obviously the head needs a good look. if the valves look good then consider the guides.

So basically plan for a complete overhaul and taker it from there. If the engine has many miles then it may all need doing.

 

AND then there is the GB.  The top cover selector rod hole seals have got plenty of posts as for a cure.

If you have an oil leak similar to the adaptor plate on the 'A' type then the OD is easily separated - new gasket and Welseal - unless it is cracked. 

Clutch fork Taper pin and extra pin

Rusty wings area  problem 

 

Roger

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Hi Roger

To be honest, I think taking the head off is my limit of my safety zone, more than that I am feeling I am in darker un-knowns, but I am an Engineer at heart so maybe the complete option is an option - and what else is there to do in winter right ?!

Richard

 

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Hi Richard,

unlike the diff, the engine does not have the same unknown gaps and tolerances that are needed. Most of it is bolt on/off.

On the 6 bore you do not even have the liner heights to set (that can be fun).

Roger 

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39 minutes ago, Mike C said:

A set of wet and dry set of compression tests will  indicate if you have wear in the valve guides. 

The wet test uses oil to seal the bores better confirm if the rings are leaking or the valves, pistons ( hopefully not)  etc:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiHi9jC1tHqAhWOxzgGHXt3D6wQFjAAegQIAxAB&url=https%3A%2F%2Fwww.freeasestudyguides.com%2Fcompression-test-injecting-oil.html&usg=AOvVaw1L54lfN9dnOHUSuB1ksiHs

I just don't like disassembling engines more than I have to.

 

 

 

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1 hour ago, AarhusTr6 said:

Hi

I thought the compression test was to help you know if there was wear on the piston rings??

Rich

Richard, I had similar issues a couple of years ago. The compression test was fine but it was still burning oil. It was only after doing a leakdown test that worn bores were diagnosed which resulted in a full rebuild. This consists of pressurising each cylinder with air and seeing how quickly the pressure leaks out.

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3 hours ago, DRD said:

Richard, I had similar issues a couple of years ago. The compression test was fine but it was still burning oil. It was only after doing a leakdown test that worn bores were diagnosed which resulted in a full rebuild. This consists of pressurising each cylinder with air and seeing how quickly the pressure leaks out.

Hi

Can you run me through the leak down test?  Is that when you remove head and do pressure tests for leaks on the valves or look for cracks on the head?

Rich

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15 minutes ago, AarhusTr6 said:

Hi

Can you run me through the leak down test?  Is that when you remove head and do pressure tests for leaks on the valves or look for cracks on the head?

Rich

 

15 minutes ago, AarhusTr6 said:

Hi

Can you run me through the leak down test?  Is that when you remove head and do pressure tests for leaks on the valves or look for cracks on the head?

Rich

No, its a bit like a compression test in that you remove the spark plug and pressurise the cylinder. However this looks at how well the engine holds a pressure rather than the absolute value obtained from cranking the engine. 

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Hi Rich,

I would do a standard compression test first: remove all plugs, While the engine is still warm; ask a 2nd person to crank the engine with pedal full throttle so the cylinders can fill properly.
 Disconnect pump and coil first I forgot to say, and then measure the CR of say cyl. 1 until it moves no further up on the gage, typically 5-15 revolutions. Then proceed to cyl. 2-6; record all numbers.

Now squirt some oil in each cyl, like 3 squirts from an oil can. This will seal the pistons in the bores, but not the valve guides.
Do the same compression test again.

If CR has raised, the bores/rings are worn. 
If it does not, you have leaking valves. This could be a burnt valve(s) but very worn guides may give the same.

Next comes the blow down test: basically you connect compressed air to a cylinder and see (listen) where it goes. Head or bottom. Google blow down test for details.

If it is Just head related, you could consider to fix just that, as a first step. If you find nothing during the head off phase, probably wise to remove the engine (and as Roger says), the GB too. 
Choices choices.

Good luck and learn,

Waldi

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10 hours ago, AarhusTr6 said:

Hi

At a guess I am eating about 1ltr of oil per 200km based on my last trip.  If I boot the TR and decelerate hard using gears I do get a nice cloud behind me (grey).  

I have read a compression test only tells you if the rings are good, and read this could be the valve guides.  As for dripping oil, well, it does leave a few drops but nothing serious, but maybe this is worse when driving?

Other factors:

 - when I got to my summerhouse, a lot a '****' on back bumper, so out came polish to remove it.

 - Oil pressure 3/4 over then just over halfway when cruising

 - New K&N oil filter - this seemed to help a higher oil pressure when starting, but maybe a red herring

  - using 20/50 Millers, mineral oil

I think one side of me wants a winter project also I really do not like having this oil eaten away so was considering a top end re-build and researching what it means to do that over coming months.  Does anybody have some thoughts or opinions on this?  I have an OK garage and am quite quite savvy but still learning a lot, but this forum for me has always been my go to place.

 

Richard

 

When you say a lot of !!!! on the bumper was it black soot or spots of oil?

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