Porsche 944 | Engine Rebuild Pt 1 | Cylinder and Bearing Measurements

[@CJFusco]

These videos are an outstanding resource - you’re performing a valuable service! Keep ‘em coming!

[@944restore]

Thanks! Glad you like them.

[@andreasbeier2431]

Another one in the 944 gang, let‘s go. Really hope that your machine shop knew, that this is a silicon alloy block and you can not hone it with stones like normal alloy, and you have to etch the metal with a certain solution in order to properly hone it. There‘s Idiot shops everywhere that just hone it „normally“, and if that‘s what happened, you‘re in for a bad time. I‘m asking because of the cross hatch pattern that looks like a stone hone. Cheers mate

[@944restore]

Thanks. The shop is reputable and had quite a few 924/944/928 cars parked outside. I've never had an alusil block honed before so I didn't know what to expect. I might be in for a surprise.

[@RollingtreeNet]

@@944restorewere the bores scratched? What triggered the trip to the machine shop?

[@944restore]

Yep, 2 of the bores were scratched. I included pictures at the beginning of the video.

[@machinistrrt]

The original bore finishing process was less a honing operation, more accurately a lapping process where the aluminum is removed leaving the silicon.

[@andreasbeier2431]

It‘s not quite lapping. I don‘t actually know how shops remove scratches from the bore, but when you have a decent surface to be refinished, the aluminum is etched away, exposing the silicon crystals, which are pretty low friction. I guess the honing marks might be from scratch repair before etching.

[@davidkaehele8910]

If using the original hardware don't forget the girdle washers are cupped and need to go on in the correct way. If you look at your old rod bearings you should be able to see three scratches on each half (if they are not trashed) where Porsche used a micrometer to measure them. This is the difference between Glyco and Porsche branded bearings.

[@944restore]

That's a great tip about the washer orientation. I'll be sure to mention it in the next video. Thanks!

[@944restore]

I wish I would have kept the old bearings to check for measuring scratches. They weren't too trashed.