danglerb

woohoo!

heinrich

Great news Jim

Rick Carter

That's what I did, then balanced them to .001 gm. It's a little tricky at first, it helps to cut the pistons with serrations to make a stronger weld.

GregBBRD

Here's an idea, Mike:

Rob Edwards has a pretty "hurt" GTS crank that isn't ever going to be normal again. It has one journal worn to about .080 undersize.

Since you are going to need to "create" a custom rod for this engine, anyway....

Give Rob a few bucks for this crank and have it machined down to a chevy rod size. Pick up a "little bit" of "economy" stroke, for this project.

This would be really unique and interesting!

GregBBRD

BTW

Used pistons should always be custom fit to bores, anyway. I've seen used "group 2" pistons that measure the same as used "group 0" pistons.

.01mm or .02mm is not very big....I'm not sure many people can bore and hone an Alusil block this close anyway!

danglerb

So bump the stroke from 78.9 to 85.9, plus whatever offset grinding to a smaller journal rod?

Very tempting, sending Rob a PM.

James Bailey

Good point and many can not even measure to that accuracy.....

SLEI

I have -85 S3 and cylinder tubes are min 115,5mm measured at top, don't seem to be very thick walled block.
I got very cheap 4,5L block and 4,7L crank, could I wet sleeve it with MID steel tubes and stroke the crank with Carrillo Nascar 6" rods which have 48mm big end bearings? I need custom pistons with 22mm pin and rods centered at top but it's much easier to get pistons for steel bores than alusil and maybe also easier to get some company to wet sleeve the block than get a good bore to alusil at my country. Rods are very light and have bore for oiling to the piston pin ( DLC coated).

danglerb

All that stuff "might" work, how long its hard to say since very few have tried and then driven the results for many miles. I don't follow the "easier" part, surely they have zero experience with sleeving a 928 block, whats "easier" about having some shop experiment using your money?

If you have the budget to try some things, then toss them in the trash if it doesn't work out and start over, I say give it a shot and see what happens. Otherwise I would keep to a narrow path of what others have done in the past and is known to work.

What country are you in?

What are your goals for this motor?

SLEI

"What are your goals for this motor?"

More cm3, about 250g lighter rods, steel cylinders = almost "limitless" choices of pistons.

I would prefer supercharger but impossible to register on street.

I have learned today that only one company bores and hones alusil in Finland about 210$ per hole.
Many companys make wet and dry sleeves, 928 block can't bee very different to work. I'm thinking to fill bottoms of water space with epoxy.

Vilhuer

Who said that? R-Koneistus asks around $150/cylinder to make 104mm bore unless they have raised price lately. In case you want to go that route I have source for deck plate which has 106mm holes. Its use is mandatory or block is useless. Even when using it R-Koneistus can screw up by making bores )( shape for example. Don't ask how I know. My next large bore build will have dry steel liners for sure. I'm done with Alusil.

There are few places besided R-Koneistus who have installed dry sleeves into Alusil cylinder towers on 928 engine. I think normal 100mm block can be taken up to 102-103mm bore using 2mm thick dry liners. I would not try to do Darton style wet liners in Finland. There isn't any place which can make it happen properly. R-Koneistus has tried that with 951 block and there has been enough problems in those builds. Other places have even less experience.

I tried eboxy to make deck support on top of water jacket. No use what so ever in strenghtening towers. We are looking into having support rings made locally from jointless steel pipe. Some dry liners have caused cracks into remaining cylinder tower destroying block. Thus idea to try to prevent this by adding another support around Alusil.

Check http://www.9xxfin.com for local Porsche discussions.

Jim Nowak

I've got 7 - 104 mm J&E forged & coated for use in the Alusil bore if anyone is interested. The pistons are out of a 2 valve 928 engine.

danglerb

Coated with?

Any idea on what one more done the same might cost?

jleidel

i'm in the process of researching a 'fun' 16v project.

Has anyone used the OEM 104mm 944s/968 pistons [as opposed to the J&E-forged variants]? I was checking Pelican and they list for $370 for a set of 4.

danglerb

Yes, several have, mostly good, but not 100% good results is my take on the info so far.

I've bought (4) 968 pistons for my project motor, still looking for another 4.