block to crankcase joint - external seal?

[Ruairidh Dunford]

Spot on Tony.

[andrew34ruby]

......... I have wondered about fitting a silicon gasket with the engine in the car - by lift in the block slightly and pulling the gasket over the block from the top, having snipped the connections between the cylinders as they don't need to seal.  Is this sensible?  Has anyone tried it?

I had also wondered about this. Can it be done? All comments are welcome.

[JonE]

Re, snipping, I would have thought that any structural elements that keep the sheet from distorting were vital, for IF oil penetrates on less flat surfaces and makes it skate about. Would you be able to get the surfaces properly oil free clean with the slight block lift?

[Colin Ayre45]

Some years ago my chummy developed a serious leak on the block joint.  I had promised to take the car to an event and there was no time to do the job properly.  I removed the tappet cover and removed the Dynamo.  The crankcase and edge of the block were thoroughly cleaned starting with Jizer and finishing with cellulose thinners.  The car was left overnight and recleaned with cellulose thinners  the next day.  A thick bead of clear bath sealant was then applied, as large as I could make it continuously around the block. Once the sealant had cured the various bits were reassembled.  The idea was for it to last for a day.  In practise it was still in place and working 500 miles later.  The seal was almost invisible and achieved a satisfactory temporary repair.  To make it work the surfaces must be scrupulously clean, but it is only a temporary repair.

[Dave Mann]

I should add for the last 40 years the engines in our cars are secured by just two bolts (FNS & ROS) with 1/8" washers between crankcase & chassis which many other owners have commented on. I see no future in bolting a rigid block to a flimsy crankcase and then bolting the assembly to a torsionally flexible crankcase.

[Colin Morgan]

I feel such an amateur asking about short cuts - but everything is running fine and the engine hasn't been out since before 1970 so there is much that would be disturbed if I did the job properly.  And the car is only used to potter around.  It is knowing when to give in.  But nearly every job I tackle these days is something I have done before - should tell me something?!

[Howard Wright]

Hi Colin

I would leave well alone….Oil is relatively cheap and helps rust proof the chassis. Unless your getting grief for oil on the garage floor….in which case put a tray under the car  .

Cheers

Howard

PS Unfortunately I’m a compulsive tinkerer and rarely follow my own advice  .

[David Stepney]

Contrary to much of the advice given both in this thread and in others concerning oil leaks, I use a paper gasket lightly smeared with a proprietary silicon gasket sealer on both sides, making sure that both the upper surface of the crankcase and the lower surface of the block are perfectly clean when being assembled. I should add that my engine (being the 'non rubber' mounted type) is fully bolted down at all four mounting points as I suspect it was from the factory.

The engine leaks oil from the nearside rear (although this might be from the tappet cover) and a bit from the offside front just under the dynamo. However, oil consumption is in the region of 250 miles per pint, although this tends to vary depending on the type of work the car is doing. It seems to use more scrambling up and down hills than it does on long flat runs.

Given that the engine is running very sweetly and bowls along on the flat at between 40 to 45 mph as its natural gait, I am leaving things alone, convinced that the engines probably all leaked oil from new. However, I keep a piece of rag on the top of my toolbox in the garage to wipe the dribble of oil from the crankcase every time I do the pre-drive check of oil and water.

[Colin Morgan]

Hi Howard

Enjoy both tinkering and driving - it can be hard to get the balance right? The aim is 'continuous improvement' whilst keeping the car on the road. I already carry a tray that goes under the car on fussy friend's drives - had it for years - but if there is a possible technical quick fix then it might be interesting to try.

Regards,
Colin

[dickie65]

I am of the Paper Gasket and Blue Hylomar Religion.
The block nuts get checked for tightness every so often, the one behind the dynamo is the only awkward one to do as it it means taking the dynamo housing off to do it.