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+--- Thread: A QUESTION OF CLEANESS (/showthread.php?tid=4334)
A QUESTION OF CLEANESS - Rpm - 07-05-2020
Good afternoon forum members. Firstly thank you for sump gasket confirmation. The reason I have a few questions is that I currently have the engine out of my car and on the bench.
This question is how clean does an engine need to be in switching over to muligrade oil. My engine was rebuilt 5k ago and on removing the sump was very clean. The internal case was stained the usual brown but no sludge and roughly haft an egg cup of sludge in the sump, the car has been running on straight 40 oil no remote filter and not intending to fit one at this time due to drilling required. What are your thoughts guys?
Rob RPM
RE: A QUESTION OF CLEANESS - Colin Wilks - 07-05-2020
I had my crankcase vapour blasted (aka aqua blasting). Main reason was to get the oil galleries clear. It cost about £100 but I reckoned it good value, given that I'm hoping not to rebuild the engine again. I'm sticking with non detergent oil, but that's a different discussion which has been done to death!
RE: A QUESTION OF CLEANESS - spannerman - 07-05-2020
Many years ago I was.told by a chemist at
castrol oils straight oil no filter multigrade oil filter ?
He said use that rule and you won't go wrong !
I believe the expert
RE: A QUESTION OF CLEANESS - John Mason - 07-05-2020
Spannerman I think you are missing the point of the previous thread when fitting an oil filter was the question,. It’s all personal choice about what to use however a number of us stated that we use multi grade detergent oil but change it regularly. This of course means the engine has to be clear of sludge in order that the detergent oil does not flush it into the oil jets etc.
RPM. With my engine I removed all the brass blanking studs to the oil passage ways. The oil relieve valve spring and steel ball and thoroughly clean everything with engine cleaner and a suitable long handled bottle brush. There was some staining to the inside of the crankcase but that was just that nothing that if it came away would block anything. All that was about 20 years ago and the engine has been running on multi grade detergent oil ever since without problems.
John Mason
RE: A QUESTION OF CLEANESS - Chris KC - 07-05-2020
I listen to experts but then I ask them to explain their logic so I can judge for myself!
Straight oil = way too thick when cold, leaving the engine dangerously poorly lubricated for the first 5 or 10 mins of each run. Add a filter in there and you'll have even less oil flow when cold.
Multigrade oil = still a bit too thick when cold, but considerably more flow than with a straight oil, giving a bit of latitude to filter the dirt out of it too, including any dislodged by the detergents in the oil.
I know which I choose.
In answer to RPM's question, it rather depends how well the engine was cleaned when rebuilt.
If only 5000 miles since it should not need stripping down for deep cleaning, unless it wasn't cleaned thoroughly when rebuilt.
A lot of crap is generated during running-in but that should drain out with the old oil. If in doubt run some flushing oil through it.
If you have confidence that it was thoroughly cleaned when rebuilt then I for one wouldn't have any qualms about refilling it with 20W50, just stick to the oil replacement schedule.
But don't blame me please...
RE: A QUESTION OF CLEANESS - spannerman - 07-05-2020
Yes I see all your points oil pump and filter
Sludge I believe is formed mainly because engine
Not getting hot to boil off all the acids and other nastys
That are formed but changing oil regularly is the way to go ? But oil ways must be clean when using multigrade oil.
RE: A QUESTION OF CLEANESS - Rpm - 07-05-2020
Thank you guys, will check clean and check again before pouring multigrade into my seven engine. Don't know about other members , but hate seeing black oil running out my sump even after little milage feels like neglect.
John Mason thanks what to focus on.
RPM
RE: A QUESTION OF CLEANESS - Tony Press - 07-05-2020
"I listen to experts but then I ask them to explain their logic so I can judge for myself!"
Oooooh !!
Is this why virus control is going so well in UK and USA ?
RE: A QUESTION OF CLEANESS - Dave Mann - 08-05-2020
Detergent oils were developed to solve the problems experienced on diesel engines, piston rings stuck in their groves with carbon build up, valves sticking for the same reason and oil changes were done with a shovel. In the 1950s attending to an engine for an oil change would reveal the sump full of sludge with troughs cut in it by the cranks, the whole lot had to be shovelled out. I can remember in the mid 1960s doing piston exams on marine diesels which ran on diesel fuel, we could have a piston out in an hour or so then it would take the rest of the day to clean the ring grooves of the carbon build up. Today a similar engine running on modern oils and residual fuel oil, which resembles tar when cold, and the pistons are wipe clean. Detergent oils keep the carbon in suspension to be removed by a filter, which we don't have, so regular oil changes are the order of the day. I do my oil changes when the oil is hot immediately after a long run so that there is less risk of the clag settling out.
RE: A QUESTION OF CLEANESS - Chris KC - 08-05-2020
Apologies if that sounded a bit blunt. Experts themselves often own up to knowing a great deal about very little; to understand their pronouncements properly it's important to understand their perspective.
As for virus control in the UK, as far as I can see they have left it to the supermarkets?