Firstfives.org

Hello. I'm new to the forum, but have had my 1980 528i for a few years now, and spent a lot of time revisiting the FAQ section. i was my daily driver, until it blew a head gasket. Now I'm currently in the middle of a head swap, from the early casting [1 250 019] to a later casting, from a '86 635CSi [1 277 358]. Preparing for re-assembly, I'm comparing the two heads and head gaskets, and noticed a difference that I'm concerned may be an issue. The 3.5L head [and blocks] have a small water jacket passage way, approximately 6mm in diameter, tucked up between the cylinders on the exhaust side. There is also a corresponding space in head gasket, however, the 2.8L block is solid. I'm concerned this will cause problems if I don't block it off in some way. Have any of you seen / addressed this?
See attached pics, and thanks!

...and here is a pic of the block

Not to worry, just bolt it on up.

You do have the right cam in there or adapter nut, correct?

I notice piano head pistons, so thats a euro dirty engine?

Thanks Mike W. I had the machine shop swap cams, so yes, I have the correct distributor drive / cam.

maybeillbuyit - um, I dunno. This is my first BMW [car], so I still have a lot to learn.. Are piano tops only euro / high-compression? I know it's not the original engine, but haven't dug in deeper that that yet.

I'm not positive myself. I've always heard about piano top pistons in the high comp euro engines. No first hand experience myself. I didn't know they came in NA engines. Worth looking into.

OK so I was curious about those pistons and asked my BMW guru buddy and he said all b28s had those pistons so its nothing special. Sorry I got over excited. Another guy I know found a 528i in a yard a while back with the head off and asked me the same thing.
I'll be doing the same thing later on my car. I think the guides are worn and need replacement. Instead of redoing the old existing head I've got a head from an 81. Did you replace the valve guides?

US spec E12 2.8's had a small raised piano top crown, 2MM IIRC. Early US 2.8s, such as 69-71 E3s and E12 euro had higher compression, 9:1 pistons with a larger crown, ~6MM or so. The pic looks like more than 2MM but I can't tell for sure.

Measured my pianos: 6mm tall. Looks like I lucked into higher compression. Sweet!

maybeillbuyit wrote: Sun Jul 14, 2019 6:17 pm OK so I was curious about those pistons and asked my BMW guru buddy and he said all b28s had those pistons so its nothing special. Sorry I got over excited. Another guy I know found a 528i in a yard a while back with the head off and asked me the same thing.
I'll be doing the same thing later on my car. I think the guides are worn and need replacement. Instead of redoing the old existing head I've got a head from an 81. Did you replace the valve guides?

According to the machine shop, my new-old head was is pretty good condition already, so no valve guide replacement.

OK, lucky you. Saved some expense there. I had the same on a previous head redo

Sharky1980 wrote: Tue Jul 16, 2019 12:29 am Measured my pianos: 6mm tall. Looks like I lucked into higher compression. Sweet!
EA38B08F-2F27-426F-BB39-5574EA738F7A.jpeg

OH wow, thats awesome, Mike whats the HP difference in those engines?

maybeillbuyit wrote: Tue Jul 16, 2019 11:59 am

Sharky1980 wrote: Tue Jul 16, 2019 12:29 am Measured my pianos: 6mm tall. Looks like I lucked into higher compression. Sweet!
EA38B08F-2F27-426F-BB39-5574EA738F7A.jpeg

OH wow, thats awesome, Mike whats the HP difference in those engines?

Not a ton, euro 528i was 177HP, US 169HP. Still a little more fun.

On valve guides, in my experience the seals are more important than the guides, so I assume you are using new seals?

Thanks for the info Mike!

Yes, the shop installed new valve seals. Good to go.