Darklands

My friend Jochen says CIS euro engines fail because the vacuum ignition timing mechanism doesn’t work properly.
Than ppl in an recent Facebook discussion are arguing their S don‘t need high octane fuel, no wonder a lot of the engines are broken.
Pinging destroys the pistons.

Rob Edwards

If you bore that block oversize, then you need oversize Porsche pistons- I'm not sure that Porsche has any 97.5 mm or 98 mm Euro pistons available. So the other option would be sleeving and running aluminum pistons.

For the time and money involved, I'd probably go find another good (I know that's a tall order...) M28.11/12 short block and build up a motor around that. I think James Izzo may(?) have one. Or you can check with 928Intl but I'm not sure Mark has any right now.

camelman

I’m open to sleeving and running different pistons. Are there drawbacks to doing that? Does it open up more options for pistons?

Rob Edwards

Yes, cast iron sleeves allows the use of uncoated aluminum pistons. Dry iron liners plus aluminum pistons modeled after the originals, with the same compression height would allow you to use the original rods. Not sure about how lighter pistons would affect balancing the motor.

PK68

For what it's worth, I have seen a couple of M28/11 blocks for sale - in Europe.No idea on their actual condition however.

gbgastowers

Are you saying you were driving the car and it was just running a little rough with several broken piston ring landings? I don’t see how it wasn’t just pouring out smoke with oil blow by and no compression/no start and GB says all the Euros pistons have broken ring landings? Does not seem possible. Gunar

camelman

It smoked at full throttle at the top of second, and it was bad. Regular driving it didn't have any obvious smoke though. I lapped the valves and changed all of the valve guide seals last night, and they were all supple and new (changed 8 years and 10k miles ago). One valve guide seal was completely missing though, just not installed by the previous mechanic. The engine has never run well since I've owned it, so I don't think the cracks were within the last few miles of driving. After seeing the state of the rings and pistons, as well as the missing guide seal, I'm amazed it didn't smoke more.

I did a compression check before the tear down and the two worst cylinders were at 120psi while all others were 135 or so. The gauge is old, so I was only looking for correlation between cylinders. After seeing the pistons I bet the compression numbers were actually correct.

camelman

I reached out to Greg Brown to see about repairing it. He apparently does a nicasil spray coating on damaged walls, so hopefully that can recover my bores. Will learn more this coming week. I wonder what he'll try to talk me into though. I see he can build a 6.6L stroker out of these engines!

Rob Edwards

Greg can certainly repair this engine, you'll end better than new- Bore the block, Nikasil plate the cylinders (Nikasil is a plating process, not a spray process), spec custom pistons (and rods, and crank, and cams, and valves, depending on your WYAITitis), then rebuild the whole motor. The slippery slope is that you end up with a full-on stroker motor . Nothing wrong with that.

camelman

Rob, what else needs to be done if I upgrade the engine like that? Will I need a different fuel injection system, or mods?

camelman

My smog pump is shot, and I want to replace it with a new or rebuilt one. I can only find them on eBay. Does anyone have experience running one of these?

https://www.ebay.com/itm/33408502746...3ac5ac465451cd

https://www.ebay.com/itm/36150095048...9aceeb0f431c19

Rob Edwards

Not familiar with the Oregon rebuilder. Mark has good rebuilds in stock: https://shop.928intl.com/Rebuilt-Smo...13%2D017%2D00/

RE: engine rebuild, you don't really _need_ to change anything other than having the block bored and Nikasiled, and get custom pistons that match the original rods (I imagine Greg is very familiar with the specs for replacement Euro S pistons). Everything else could get bolted back together. The question is always A) what other wear items will you discover along the way while you're that deep in the motor, and B) what upgrades do you talk yourself into while you're there?

Mark Anderson

We do have a 4.7 US short block available

camelman

Mark, would I be able to swap my 928S euro parts directly to that block, or would it need US parts?

camelman

Thanks for the link. I'm replacing all bearings and will check for thrust bearing wear while I'm there. I rebuilt the fuel system a while back, am re-coating all fasteners and brackets, new engine mounts and shocks, new wiring harness, new air splitter, and every gasket and hose I can find. Anything else you can think of other than belts and water pump? If Greg Brown comes back with a wicked build plan I just can't pass on, then I'll do it!