Forum

[another Allan]

Well, I'm making progress (I think) with the fettling of my 2003, 900km 350T with a 625cc engine. The next challenge is an oil leak that shows-up after a run, on the top cylinder head fin adjacent to the spark plug. (I mean the top complete fin, before the staggered ones surrounding the inlet & exhaust.) The rocker cover seals are perfect, as are the rocker oil feed banjos, yet there is oil on the top fin. The oil spreads across the surface of the top fin (on the spark plug side,) so the only conclusion I can come up with is porosity in the head casting between the top fin and the short fin above it. I would guess that it is on the exhaust side, because the oil is between the fins there, as well as the inlet side (and of course it would blow backwards anyway.) There is a cylinder stud next to the spark plug, but it seems unlikely to me that oil could be travelling up there to find its way out under the washer and nut. Has anyone had this problem, and if so, how did you pinpoint the source, and how did you cure it? If it were a standard head, I would just find another, but I understand that mine has bigger valves so a swop would also include re-machining etc.

[Hemant]

Alan, I have the same problem in almost the exact spot. First when it happened I thought oil was coming from the head nut. I put a posting on here last year seeking advise. Comments were to clean the area with Acetone and seal it. So far I have lived with it by stuffing the gap between fins with folded kitchen towel, and replace this when it gets soggy and leaks.... I will get round to sealing it off one day !!
Hemant

[Alan R]

Hello "Mr Me" ------- I used to be employed (nearly said "worked" then !!) as a civilian Senior Craft Technician with the MoD repair depot here in Telford on the Army's APC's. The body and engine/transmission units are all Aluminium/Duralumin which are v. highly stressed (especially after a land-mine incident). We used a ROCOL leak detector spray which, along with it's de-greaser proved highly effective. Go onto Google-----Rocol leak detector spray-------(ignore the gas detectors). It's in a red or light maroon colour. Can't advise on cost as we got it by the crate-load, literally. Also 1/2 litre bottles of Loctite-------- 1 each, free on demand!!! Sometimes I wish I was back at work--- but not for long.

[Alan R]

ALLEN------- I MADE A SLIGHT ERROR-----------I should have put Rocol CRACK DETECTOR spray. Sorry!

[another Allan]

Hi Alan. Thanks for the clarification. I found the stuff on Rocol's website, and it looks the business. I can't find a supplier for it, but there's something very similar on Ebay, item no. 280729073858. I might try Hemant's suggestion of acetone first (it's cheaper!) The leak is substantial enough so, if I can get the whole area clean, I should be able to find the leak by running the engine briefly.
I'll let you know if I have success.

[Alan R]

Hi Allen------------ yes that's the same sort of stuff----a 3-pack. The penetrant (OOhhh--Alan Bennet ?-----there's a lovely word !!) reacts with the spray and very clearly shows the fault line. Be v. careful when handling ACETONE as it's a strong de-greaser and acts as a solvent for plastics etc.

[Barry N]

I had a similar problem with my Sixty-5. It turned out to be a porous cylinder head casting, which weeped oil, ever so slightly, between two of the fins. It took a while to pinpoint and the precise location was around one of the cylinder head stud tunnels. Someone on the American Enfield site had experienced the same thing, and offered two suggestions for a cure. The first was to apply heat-resistant exhaust paint to the area, which I found only worked for a short while. The second - and successful - suggestion was a tiny splodge of "JB Weld" (a magic compound in a tube, widely available on Ebay) which I applied with a cotton bud after thoroughly cleaning the area with acetone (nail varnish remover). It is a very discreet repair, not noticable deep in the fins and it is has been totally dry now for over a year (2500km).

[Alan R]

Hi guys--------yes,that name is a bit of a misnomer really as there is NO WELDING actually involved. It's an epoxy resin 2-pack similar to our ARALDITE.Not so much "magic"--- more a case of marketing.But they do the job asked of them and that's what counts.

[MHSILVERW]

Wonder if I am experiencing this on my 1990 350 Bullet. After a short run I am getting oil on the full width fin at sparkplug level on the spark plug side of the engine. No obvious source: not the rocker boxes; not the oil pipes (thats on other side anyway); doesnt seem to be coming from the stud infront of the spark plug....but it's there a leak of "clean" oil - but cant see exactly where from; just that it's on the fin when I stop.
With the engine warm and running I can't see where the oil is coming from - but this thread might be an answer....how to track the leak/porousity down, any suggestions?
Any suggestions on tracking down the leak (or porous) area - would talc/baby powder help locate this if sprinkled on the fins?
Any suggestions appreciated AND if it is this which JBWeld product (or suchlike) is recommended to have a go fixing BEFORE I do something drastic like change the head!
Mark

[Norm]

Every shed should have JB Weld at the ready, best stuff I have found for a million repair jobs