OIL FILTER TUNNEL LEAKS...Some thoughts.

[Les Howard]

Some excellent posts here. Many thanks Groily for your comprehensive set of sizes, they are very useful and show the tunnel at 27mm and also shows how little metal is available around the hole, I have found a supplier on Ebay that sells 1 1/8" aluminium tube which is 28mm OD. Its a pity the tunnel isn't a stock size if one wanted the expedient fix of bridging the joint internally with say an inch long section of tube and Loctite 518.
Poul (ajsph) says the O ring size he has successfully used 29 mm diameter which must be very close to the hole itself and only 1mm thickness...Wow, I was picturing a fatter O ring so like Shaun I would love to see some photos...please? PS: How did you create the O ring groove...what machinery/tool did you use please?
Shaun. When I see your excellent gasket it reminds me so much of what I saw when I dismantled my engine. The paper gasket was all but invisible...if only I had made one like that on the first rebuild instead of thinking the one I bought was correct...great stuff chaps...this is all helping me for the next attempt However do you think the silicon content would cause a problem...I reckon silicon will reject water, but the surface tension of a solvent might well be OK...They used Wellseal originally. You could see if your chosen compound sits on the gasket without flowing off. There might be other sources of 0.002" paper around thou. Otherwise, the O ring seems best maybe?

[shaunstaples]

Les if you PM your address I can pop some in post for you to experiment with, I'm just reading about Japanese tissue paper (seen it used on repair shop by book repair man) but cant tell how thick it is, just gives a weight

[ChrisTheChippy]

Doh !!!! I just rebuilt my gearbox box and used the o rings from the club . I just literally sealed the front on today . I was sitting here feeling smug until I read your post Rob. I think I will leave it now and move on to the next bit of the build . If and when it leaks I will sort it in use .
Les I think the o ring solution definitely sounds the best especially since poul has used it 4 times with success.
What we need to know now is it a lasting solution?
Is he willing to share his method and experience?

[Groily]

very useful and show the tunnel at 27mm and also shows how little metal is available around the hole

Could be more meat on alternator cases Les, as no need to machine the dyn cradle across the front where it ends up thinnest - but don't have any to measure as I'm 'all dynamos' round here . . . But in whichever case, not a WHOLE lot to play with if thinking of reaming /sleeving across the joint.

[Les Howard]

Think I'm going for the O ring job...It HAS to be the correct way. With the correct "pinch", surely the tunnel cannot leak. I would however like to see how others have made the groove though. I show a perfectly feasible tool and might endeavour to get one made ( I don't have a lathe or welder) ...I and others would love to get more info from POUL from Denmark as he says he has done 4 and none leak afterwards..... SHAUN: very many thanks for your kind offer of the paper. As just said, I think this time (the THIRD!) I will go for the O ring.... however, I will attempt an expedient way for the time being at some time by trying an internal sealed tube joint bridge as discussed earlier. Thanks again

[shaunstaples]

No problem Les, just let me know if you need to.
I've just found some Wellseal (must be at least 30-40yr vintage! and still fluid) it has covered better than I thought, but like you would prefer the o ring in a groove.
I bought a full gasket set a while back and just measured the gasket that came with it and its just over 12 thou, so too thick.

[shaunstaples]

Just while I was typing it looks like the silicone is doing it’s job and repelling

[ajsph]

Her you have some pictures,

DSC02446.jpg

DSC02445.jpg

DSC02444.jpg

DSC02442.jpg

DSC02440.jpg

Poul

[Les Howard]

Thanks for experimenting Shaun. So the grease proof paper doesn't look suitable then...HOWEVER ha ha.one wonders if the natual repelling power of it would not be an asset in stopping oil passing by it? Think about it....you would have compound around the outer edge of the paper gasket when in situ but the oil would need to pass from the tunnel through the gasket that was being squashed absolutely flat and creating a solid oil resistant barrier of 2 thou thick...the oil could NOT pass by it, nor would it EVER dissolve away so would remain intact indefinitely. One problem is gluing it in place when doing the assembly but maybe something like Hylomar would do it...this is very sticky. Anyway, as said when I do the 3rd attempt, I reckon I'll go for the O ring job as long as I can the groove cut perfectly and easily...

[ajsph]

two more pictures

DSC02448.jpg

DSC02447.jpg

My experience: I assembled my 56 model 30 in 1999 with only a thin smear of Würth RTV silicone, without an O ring,after 45000 km. it is still leakfree between the cank case halves. I assembled my 1958 G11CS in 2013, with a light smear of Würth RTV silicone and an O ring after 24000 km. it is still leakfree, I have never used the round gasket, in any of the engines I have rebuild, I have 15 gaskets and they are all between 6 and 8 thou. Sorry for my poor english
Regards Poul