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Cleaning oil passages.
Posted: Sat May 17, 2025 1:09 pm
by Joeck
I am enquiring about the procedure for cleaning the oil passages in a 1098 engine block.
There are several brass bungs in the ends of the passages which I assume need removing to do a thorough clean.
I have thought of drilling and tapping the bungs so that a bolt can be inserted and slide hammered out and, after the cleaning process, replacing these bungs with some suitable threaded plugs.
I have looked at a set of long handled brushes in various sizes that look suitable for rodding out the passages and am thinking of suitable flushing liquid maybe brake cleaner?
Any advice would be great.
Thanks in advance.
Re: Cleaning oil passages.
Posted: Sat May 17, 2025 9:24 pm
by philthehill
You can fit threaded bungs into the ends of the main horizontal oil passages.
There are also a couple of other oil passages that need to have the bungs removed, the passages cleaned and threaded bungs fitted.
Those passages are relating to the oil pressure relief valve and oil pressure relief valve bypass passage.

- Oil gallery plugs 1.jpg (94.51 KiB) Viewed 11115 times
I use paraffin in a air gun and wash it all down with a hose pipe followed up with a good blow through with a air gun.
Re: Cleaning oil passages.
Posted: Sun May 18, 2025 2:00 pm
by Michiel
If using an air gun, beware of oil sludge spray flying in unexpected directions from various oil ways.
Re: Cleaning oil passages.
Posted: Sun May 18, 2025 5:36 pm
by Joeck
Thanks for the replies, it looks like I am on the right lines.
I will locate the passages as described and remove the original bungs.
Is there a specific supplier of the threaded bungs or are they a standard plumbing part ?
I am assuming they will be BSP thread ? I have a set of BSP taps in my collection.
Are the threaded bungs fitted dry or with some type of thread seal ?
When the passages have been brushed through and flushed with paraffin, is the hose used to pass water through the passages before drying with compressed air?
Apologies for the many questions, just want to make sure I get it all right .
Many thanks.
Joe.
Re: Cleaning oil passages.
Posted: Sat Jul 05, 2025 5:06 pm
by Joeck
Having now cleaned all oil passages thoroughly and tapping out for threaded bungs, can anybody recommend a thread sealant for the bungs ?
I am wary of using ptfe tape as any broken off tape may bung up passages and defeat the initial object.
Thanks.
Joe
Re: Cleaning oil passages.
Posted: Sat Jul 05, 2025 9:39 pm
by philthehill
Re: Cleaning oil passages.
Posted: Sun Jul 06, 2025 4:37 pm
by Joeck
Brilliant.
Thanks Phil I shall get some ordered up.