My 16v Engine Build

[Endat]

Finally doing my build.. 1987 Porsche 944S that had a timing chain failure.

The block and all internals have been to the machine shop.. dont remember the cost, a few hundred maybe.








The crankshaft is in place...

[mikepellegrini]

Very, very pretty!

[Endat]

Wrapped my pistons and rods and connecting pins in oil after the machine shop.. had the pin bushings replaced and got some new nuts as well.

[Endat]

Rings


Repeat 3x




To be continued...

[rsoles27]

I've all ways wanted to get in to the bottom end of mine, cool to see it all. best of wishes on the rest of the build.

[guru944]

Endat:

Nice Pictures. Looking forward to it being finished. Any upgrades?
Keep us updated, Thank you in advance.

Later...

[Techno Duck]

Were those cylinders honed for Alusil? Maybe its just the pictures, but the crosshatch on the bores worries me. They should look almost smooth.

[Jrboulder]

Originally Posted by Techno Duck

Were those cylinders honed for Alusil? Maybe its just the pictures, but the crosshatch on the bores worries me. They should look almost smooth.

That's what I was thinking

[Eric_Oz_S2]

Originally Posted by Jrboulder

That's what I was thinking

It does look rougher than normal. Bores normally look a little grey not silver.

[speedysprocket]

Just had my 3.0L 968 block honed (polished) and it has no cross hatching either...

[9FF]

Were those cylinders honed for Alusil? Maybe its just the pictures, but the crosshatch on the bores worries me. They should look almost smooth.

Looks like it hasn't had the AN-30 finishing after it was honed.

[Endat]

So is it going to explode?

Guru944: No upgrades except a little head work.. and wrinkle red powder coat for the intake and valve cover.

[9FF]

It will wear out very quickly if the silicone hasn't been exposed (AN-30 lapped & finished). If you need the KS engine repair manual for your builder pm me.

[Techno Duck]

Worse case scenario is a ring will break or a piston will seize. Best case scenario is the rings probably wont ever seat correctly and it will have low compression. This is important!

[wilkrod]

+1
Something ain't right!
Jeff

[Endat]

Seems like it's too late for that now...

[Jfrahm]

It might gall and gouge a cylinder wall just turning it over on an engine stand. It could wreck the block to not address this, although I do not know what your clearances will be like if it's taken apart and lapped properly now.

[Endat]

So it'll destroy the engine.. solutions anyone?

[tamathumper]

Sorry, man. The only solution is that it needs to be disassembled and done right. These cylinders can't be honed the conventional way. The silicon needs to be "standing proud" of the aluminum surface.

Honing Options for Hypereutectic Aluminum Cylinder Bores - Sunnen

[9FF]

I'm feeling the suckiness of this dilemma. The machine shop should have known if they had any engineering knowledge, but that doesn't help you I suppose.

First, you need a shop that either knows these engines or is willing to read-up and learn. Any shop with Mercedes, BMW, Porsche engine experience should know.

They need to have a diamond hone for a quick pass through to make sure everything is right.

After honing they need to lap AN-30 paste using felt pads to expose the silicone particles. Basically the AN-30 removes aluminum from the bore but leaves the silicone on the surface.

Get your piston skirts coated at Swaintech. It's relatively cheap and the coating is Alusil compatible. They can also apply a few coats to match the clearance you are left with in the bores.

Get some new rings and gap them accordingly, iaw the FWSM.