Crank case to block studs

[Ian Williams]

I see Alan, as I said I was also concerned about introducing something soft into the equation however I respected Rory's early experiences and decided to try them for myself. All I can add to this is that on the engines I have built with silicone base gaskets I am not aware of any loosening of the nuts and some have now done reasonable mileages. I guess the jury is still out on longterm effectiveness but so far they are more oil tight after a few thousand miles than gluing the joint and with no apparent problems to date. I should add I am meticulous about the case faces being true and absolutely spotlessly clean, these points are vital to success which ever method of sealing the joint one uses in my opinion.

[AustinWood]

I also am a believer in gluing the block to the crankcase. I use ThreeBond 1184 which holds really tight. This makes the entire surface a fixing and makes any movement impossible. As soon as thing move, however slightly, the forces separating the joint increase dramatically.
The downside is that it's very difficult to split the joint. I have an old carbon steel chef's knife. hammered into the joint it does the job.

[Greig Smith]

ThreeBond 1184 is the equivalent of Yama-Bond or Honda-Bond which are Brand specific sealants used and sold by the various motor cycle manufacturers. They are specifically designed for sealing aluminium surfaces without a gasket, I use them in my early Alfa gearboxes with machines flange surfaces.

Probably not relevant to the average 7 restorer, but I went a size up on the block-to-crankcase studs for the race cars, in my case 10mm cap screws fitted in from underneath the crankcase. Some light machining was required as was trimming the head of the cap screw. I documented this in my 'Supercharged single seater' thread.

I also made up 2 additional hold down studs using aluminium square bar at either end of the block on the valve chest side, also detailed on the same thread.

Aye
Greig

[AustinWood]

I don't use any gasket with ThreeBond. It works very well.

["Slack Alice" Simon]

I hoped this thread would trigger discussion beyond my original question.

May I ask the "bond" users how you stop excess goo breaking off and floating around the engine, potentially able to block jets?

However thinly spread, that must always be a risk, mustn't it?

Simon

[Chris KC]

Apply carefully! I weave an approx. 3mm bead around all the 'features' on the joint face, keeping it shy of the internal edge as far as possible.

I run a full-flow oil filter so if a bit were to fall in it wouldn't get past there. And if it did I don't have any jets...

[AustinWood]

ThreeBond doesn't produce the same 'blobs' as silicone. It sticks to the metal and stays stuck.

[Dave Wortley]

I have been using Seven Workshop big end bolts for 2 engine rebuilds recently. They have been used as big end bolts for only a low mileage after water ingress into the sump. Also used Seven Workshop silicone block to c/case gasket which is leak free.