Todd found turbos and never looked back.

If we go back in time, it wasn’t just wet sleeve motors cracking it was just strokers. Back then if you exclude Bob Devore & Co, there was no wet sleeve engines. I made the claim, I do say claim because I can’t prove it, that is, that mass forces were cracking the blocks. These were engines that had cracks appearing around the crankshaft web.

I said (at the time) I planned to reduce these forces by reducing the using a Honda rod journal sized crankshaft. I had that made and it’s bob weight was 1594 grams. I also reduced the stroke to 3.55” versus the nominal 3.75”. Unfortunately I got into a bad accident and sold that project so I didn’t see it through. Now we have take two. More on that later.

I’ll just make a point about testing, we can’t afford to truly test any product or project like an OEM can, it’s just impossible. If you recall back when Mark Anderson had a few write ups in Excellence and he was blowing up motors due to rod bearing failures. We (the outsiders) were told the engine even had dry sump. Well it wasn’t till about a decade or so later that we learned it was only two stage and that you need a very large oil storage tank to compensate. Chances were that the engine was running dry from oil starvation. We now know that the 928 pumps extreme volumes of oil at very high pressures, hence the need for a very large scavenge pump. So in the early days, when there was so much talk of drilling the crank and using 360 degree main bearings we know much more these days.

‘’You mention the the 944 block, we’ll we know that Porsche then raised the level of the aluminium in the water jacket. There is far more metal in that block. So maybe the 944 was too small to start with, maybe it had something to do with the inherent vibration produced by 4 cylinder engines?

I would also say there is problems with almost every major engine mod on the 928. A lot of these problems are execution risk, that is the risk that the operator cocks it up. Even with Nicasil there is potential for problems with the fuel purity and delamination of the Nicasil especially given that the Alusil is a poor parent material to attach Nicasil due to its silicon content. Silicon doesn’t conduct electricity as such the atomic bonding can be problematic.

You can try piston coating, yes some 944 people has success, is it success in the moment or will it be short lived? You can thin wall sleeve the block with cast iron sleeves. Even the 991 models are getting that done now. Porsche’s current models still have bore problems. Execute that properly and you will probably have success. Wet sleeves are riskier, but I think with light components and a grout filled block the risk is present but hopefully controllable.

For myself, my sleeves only have 95 mm exposed to the water, the remaining length is all to be grout filled. So that means 50 mm of the bore is filled with either parent material or epoxy and should be stiff. It needs to be stiff as any flex will end badly. The components are light and super strong with a bob weight around 1500 grams. Time will tell.......

https://www.youtube.com/watch?v=hVXsL7kDrsE

Hopefully I can guide us back on topic,

from the discussion it seems that the wet liner approach is a step further than a dry liner solution.

Larger capacity does appeal to me but there is not a lot of information being shared to help drive forward more builds- a more open source approach might help give people confidence to attempt more builds adding to the overall development of the engine.

Reducing the mass of the rotating parts must help reduce overall forces on the block which could help with perceived weaknesses in the block. More information on this would be very interesting.