1934 LA10 Oil Leak

[JT7196]

Hi Chaps, I have recently completed an engine top end overhaul, including fitting a replacement Camshaft and Followers.
Since completion, Oil appears to be spraying from behind the Starting Handle Nut, when the engine is gunning, the Nut was not disturbed during the changing of the Camshaft etc, so have no idea why this leak should suddenly have started.
Could this be due to excessive Crankcase compression , I appreciate that having overhauled the top end of the engine should/ would have increased the compression in the cylinders , so could this have such a dramatic effect on the Crankcase compression causing the Oil leak ??
I look forward to reading your observations .............

Cheers Al

[Norfolk Lad]

AL as no replies what about the breather but yet again should have been ok before , does seem strange could it be a new gasket blocking a vent hole .
Never worked on a LA10 so just a guess.

Peter

[JT7196]

Hi Peter, wish it was that easy mate, but very unlikely .
Looks like I’m gonna have to take another trip up to Gloucester to try and see what’s causing this prob.

Cheers Al

[frenchy]

Hi Al, might be worth trying, wash and clean the air silencer as this also acts as a crankcase breather. Cheers Frenchy.

[JT7196]

Hi Dave m yes this is exactly what what my old mate Geoff Millington has suggested , so will take a look when I’m up there next .

Cheers Al

[ranald]

Hi Al, Are any of the camshaft bearings are pressure fed? is it possible that the new bearings with a finer tolerance is resulting in increased oil pressure and this in turn is finding a weaker part in the pressure fed system. My 15/18 has an oilway through the rear camshaft bearing allowing oil to route to the rocker shaft etc. Are you happy that oil is reaching the rocker shaft? Can you adjust the pressure ? I know some cars have an adjustment on the external pipe before it enters the rocker shaft. I cant see how improved cylinder compression can result in more pressure building in the crank case. Another thought, was your new camshaft identical, oil scrolls etc. No answers....just thoughts. All the best, Ranald

[ranald]

Me again! Is the sump oil level full to the brim? Is it worth reducing the sump level to see if it still happens? Ranald

[JT7196]

Hi all, well Stella has contacted me and said that at the moment the “ leak” appears to have stopped .....very strange!
Oil level is correct and well below the Crankshaft level, oil reaching Rockers ok , no adjustment for Oil flow to the Rockers, you may remember from my own past experiences , that adjusting the oil flow resulted in oil started to leak past the Rear Main ! ! So not going there again !
So we will just have to wait and see what happens when we take the car up the road for a run.

Cheers Al