Author Topic: Oil leak  (Read 913 times)

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darmst6829

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on: September 12, 2022, 04:58:15 am
So doing maintenance on my 1977 350 Bullet I decoked the cylinder head, lapped in the valves, compression release and replaced all the top end gaskets and sealing washers. After a competition yesterday and to my dismay the oil pipe fittings to the cylinder head still leak. I used new (the same aluminum washers as original) and they leak as before. Could I use red fiber washers instead of the aluminum ones? What a mess.


AzCal Retred

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Reply #1 on: September 12, 2022, 05:31:44 am
A thin layer of Motoseal (grey flexible oil-proof engine sealant) and spraying off the sealing surfaces with carb cleaner worked a treat for me.
A trifecta of Pre-Unit Bullets: a Red Deluxe 500, a Green Standard 500, and a Black ES 350.


Mr_84

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Reply #2 on: September 12, 2022, 06:00:05 am
I had the same problem after my build and I used new genuine RE alloy ones , so I gave them a light coat of VHT copper gasket cement, problem sorted

https://www.vhtpaint.com/specialty/vht-copper-gasket-cement


darmst6829

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Reply #3 on: September 12, 2022, 06:02:56 am
A thin layer of Motoseal (grey flexible oil-proof engine sealant) and spraying off the sealing surfaces with carb cleaner worked a treat for me.

Motoseal on the washers?


darmst6829

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Reply #4 on: September 12, 2022, 06:04:18 am
I had the same problem after my build and I used new genuine RE alloy ones , so I gave them a light coat of VHT copper gasket cement, problem sorted

https://www.vhtpaint.com/specialty/vht-copper-gasket-cement

applied to the washer surface?


Mr_84

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Reply #5 on: September 12, 2022, 06:07:18 am
Yes to the washer surface both sides  , let it tac off then fit as normal , VHT copper is good stuff not all messy and everywhere


AndyMcP

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Reply #6 on: September 12, 2022, 09:04:04 am
I use Dowty washers (seals?) on the oil line unions.


Karl Childers

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Reply #7 on: September 12, 2022, 01:05:08 pm
Mine leaked from day one of my ownership. I replaced the washers and they still leaked. During a tear down of the top end for other reasons I took a close look at things to find two problems, there was casting flash on the cylinder head and also the area below the round portion of the banjo fitting that is bonded to the pipe, these combined would not let the surfaces completely lay flat on one another no matter how much I dared to tighten it. I carefully dressed these areas with a file and then used two copper washers to add a little more distance between the parts on each side. This solved the problem for me without having to use any sealant. After dressing the the parts I probably could get away with only one washer in between but I liked the added distance it gave and it has now been drip free for 5 months. I will also mention that for these joints I prefer copper over aluminum.


Adrian II

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Reply #8 on: September 12, 2022, 01:06:20 pm
Just a thunk, did you make sure all the oil ways in and around the rocker assemblies were nice an clean and not blocked or partly blocked with debris pumped up from the sump?  The screw-in mesh strainer plugs only screen out larger lumps of stuff. 

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stinkwheel

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Reply #9 on: September 20, 2022, 02:13:12 pm
I use Dowty washers (seals?) on the oil line unions.

I do too. I use them anywhere I can and I can't understand why they aren't more popular. They don't leak, withstand enormous pressure, don't need tightening down till you risk stripping to achieve that and are re-useable.

Only caution is they are slightly wider than most sealing washers so make sure they don't obstruct the oilway in the banjo.