Hitchcocks Forum

Mark 1A Inter timing side leak which has annoyed me for some years and I have had several attempts at quick fix. new gaskets, gasket sealer and all to no avail. Yesterday I decided to have a really fair dinkum look to see what I could find. Timing cover on the wet and dry on the glass sheet trick showed the timing cover to be good. On fitting the timing cover to the engine case I have a 54 thou gap up around the top area above the tach drive and exhaust cam. Nothing in there is touching the cover to hold it out. Obviously the case is distorted and the correct way would be to split the cases and remachine the timing cover face but 54 thou is a lot of ally to remove and I'm not sure if this would cause me other issues. I am thinking of making a nitrile type gasket but I am concerned that by compressing the nitrile it might block the oilway holes. Anybody have any thoughts?

Hi Norm----------- are you sure it's 0.054" ?? That's nearly 1/16" (0.062" for those not "in the know") I not doubting you at all matey but, bloomin 'ek thats like the gap in my front teeth!! Yes, machining back to give an all-round flat surface would loose a lot of Aluminium to be sure. So that leaves you with "filling-in" the gap somehow. Do you have access to a good TiG welder ?? Build up and file back. I repaired a VOLVO PENTA MARINE 2-stroke piston like that where one of the ring pegs had torn loose and damaged the lands and down the side of the piston. Tig weld----rotary table & vert. miller + hand fettling saw it back in service. OR ----- build up the area using epoxy resin & file back------- I understand about the flexable nature of Nitrile rubber ( we use it in the steam locos in 5" gauge railways )Is there enough room to drill the matching oilways slightly oversize and fit a hollow pin such that the rubber would not be able to spread across the oilway ??

Hi Alan,
No doubt about it being 1/16 inch, it's big enough for me to see the chain through it. Little sleves in the oilways had crossed my mind but I'm concerned swarfe might end up stuck in there somewhere. I would prefer not to have to split the cases if I can avoid it, leave that till I really have to. What appears to be happening even though the gap is up high, once it is tightened up it obviously distorts the timing cover and this causes it to leak down above the oil filter somewhere.I might try using the paper gasket and then a nitrile piece around the top where the gap is and see if that will work.Not the best option but might be worth a try

Hi Norm, I'm no expert and you have probly already considered this but here goes. After fitting the cover and only tightening the screws to give a good joint at the bottom and the top screws just enough to "bite" seal the top gap with clear silicon sealant and clean off. Just an idea.

Norm if you were an Amaerican astronaut or similar you would merely do what John suggests and then after cutting it flush with the outer surfaces simply apply some Duck Tape. Duck Tape is after all the American solution to all mechanical ills, including Apollo spacecraft, hence my allusion to astronauts. Sorry about that......feeling frivolous today.

Sounds like a job for silicone to me alternatively there is also quite a good loctite product that you can mix with aluminum dust and clamp into place which will anerobically set. Then you can fettle the squeezed out excess. I used it on a blow hole I revealed when fettling the castings on my 350. The was a big bubble hole just above the oil pump which is impossible to see now.

Thanks Mike I did think of the duct tape but then I though about the very sticky aluminium tape we have here and I thought it could be polished up to match the case. Anyway I got a sheet of 3mm nitrile and cut a gasket fitted it up and low and behold the bastard thing still leaks and I have spent most of the day messing with it. Anybody got a match

JohnR has the answer, seconded by His Madness & thirded by me. Done it may 2006 on the Flash rear cylinder/ crankcase joint, still oiltight today. Didn't do any duct tape or anything else, just the clear silicone

JohnR or JohnJ I know who i mean

Norm, could something be holding the case proud? The idler/chain tensioner spindle or the wrong thickness of washer on this spindle for instance?
REgards, Mark