Unleaded valve seats??

[tsa]

R80/7 1978.
I recently got myself a spare set of cylinder heads, with the aim to have one pair that can be machined for dual plugging. Whilst looking at the valve seats, I see that the inlet and exhaust valve seats are different, the latter having a bronze-ish tan colour whilst the inlet is "shiny steel".

I have no idea what these valve seats looked like when new, and also considering that all such heads I've seen may have been worked on at some time - can anyone tell me if the exhaust valve seat in the picture below is an aftermarket unleaded replacement? Exhaust port to the left. Many thanks.

UPLOAD FAILURE: <Sorry, the board attachment quota has been reached.>

EDIT: link to picture below, in my reply to Major Softie & bbelk

[Major Softie]

UPLOAD FAILURE: <Sorry, the board attachment quota has been reached.>

As a relative newbie on this forum, is there a special limit on attachment file sizes?

Nope. It's just that the board's storage space for attachments is full, and no one has done anything about that. So it doesn't matter how small the attachment might be, it won't work.

[bbelk]

UPLOAD FAILURE: <Sorry, the board attachment quota has been reached.>

As a relative newbie on this forum, is there a special limit on attachment file sizes?

Nope. It's just that the board's storage space for attachments is full, and no one has done anything about that. So it doesn't matter how small the attachment might be, it won't work.

True - but it is still easy enough to post a picture. Post it anywhere that will except it like some other forum or one of the many photo places (I use Google Picasa) - get the address for the picture hit the "Img" button in the heading above your reply and paste in the picture address.

[tsa]

UPLOAD FAILURE: <Sorry, the board attachment quota has been reached.>
As a relative newbie on this forum, is there a special limit on attachment file sizes?

Nope. It's just that the board's storage space for attachments is full, and no one has done anything about that. So it doesn't matter how small the attachment might be, it won't work.

True - but it is still easy enough to post a picture. Post it anywhere . . .

Fair enough. URL for picture uploaded to flickr:
http://www.flickr.com/photos/55376586@N ... /lightbox/

(tried the "Img" button, but it only resulted in "Image" shown, as text, instead of the picture)

[enigmaT120]

I selected a size (medium this time), and right clicked on that picture. I right-clicked and copied what it shows after "properties" in the menu, and inserted that text in between the Img brackets.

I use Flikr, too. Some browsers have better options, so that if you right-click on a photo it gives you the option to "copy image address" which is a lot easier.

[tsa]

Many thanks for posting the picture.

I use Flikr, too. Some browsers have better options, so that if you right-click on a photo it gives you the option to "copy image address" which is a lot easier.

The most recent user interface "update" of flickr makes it work horribly with my browser; I copied the image URL that flickr provided, but I see the URL is very different from the one you were able to find.

Anyhow, after a bit more searching I've seen mentioned that unleaded seats should have two parallel lines along the inside of the seat. However, I have no idea whether that only applies to OEM unleaded seats provided by BMW - ?

[Kurt in S.A.]

Something I remembered from what Tom Cutter said. He wrote that the OEM new metallurgy exhaust valve seats used on all 1985 and later models had two grooves machined around the ID of the seat. Not sure if that helps or applies here.

Kurt in S.A.

[tsa]

Something I remembered from what Tom Cutter said. He wrote that the OEM new metallurgy exhaust valve seats used on all 1985 and later models had two grooves machined around the ID of the seat. Not sure if that helps or applies here.

In a way, yes. Whilst searching further for info on this, I came across this thread in a sister/competing airhead focused forum:
http://www.advrider.com/forums/showthread.php?t=787793

- where two grooved along the inside of the seats should indicate an "unleaded valve seat". However, that seems to only apply to BMW OEM valve seals, and if cylinder head engineers here in the UK also use generic unleaded seals (without those grooves) for their modifications, it can be hard to tell what is installed. Unfortunately my photo showed the ID a bit dark (and it was also covered by a generous layer of soot), but further cleaning showed no groove(s).

I think I'll just put the heads back to service, and keep an eye on the tappet clearances.

[Kurt in S.A.]

Seals or seats? There's something other than OEM?

Kurt in S.A.

[tsa]

Seals or seats?

Doh. [colour=#FF4000]Seats[/colour]. Perhaps I may have to come back to the potential use of oil seals on the valve stems . . . .

There's something other than OEM?

Officially, no. But then again, several of the "BM bits" (or "bits for BMs") suppliers in the UK purvey parts made to fit BMs . . .