Cleaning up the heads and saw these marks on the valve face... ate they a worry?.. at least the heads don't seem to have any damage!!! (So far...)
The valves look to be recessed into the valve seats to me but maybe that’s my eyesight or the angle of the pic. I’d at the very least replace the exhaust valve. Just out of interest what’s the part number of the head and what are the valve sizes?
Replace the valves and check the wear on the guides Agree with @77 Westy something looks odd with the inlet seat
The marks on the inlet valve are just from the forging process, the exhaust is just carbon build up. The marking around the seats are the original VW machining of the valve seat. Unlike the Type 1 valve seats they are not peened in after fitting, they are machined to the correct depth, this can make you think that the seat has sunk in the head. The seat first comes loose and is then forced deeper into the head, you will see the damage and it will not leave a perfect circle as you see in the pics.
Ta...it was those creases in the inlet that looked funny..just photo that makes valves look like not seated... Barely a waggle in the stem.. Seat nice and shiny under valve
Yes, ‘79 only, square port, intake valve 39.3mm and the exhaust 33mm EDIT: Intake valve size is 37.5mm
029's have the 37.5 intake and 33 exhaust.. it's the 071's that have the 39.3mm.... As I now know! Does anyone have any idea if the extra 1.8mm of intake is of much benefit... I've got one and might consider a second to match..
You’re right, same inlet valve size as the 1700. If you can find another you might as well use it, the slightly larger valve size is a benefit with an engine with carbs and although it’s not a big difference it’s a step in the right direction.
I would replace the exhaust valve as that may well have been heated to the point where the face has softened and started cracking. Especially as its a T4 head where high head temperatures are a greater risk than on a T1. I have an exhaust valve in my collection which shed chunks following cracking leaving a hardened ring in contact with the seat. I will post a picture if I can find it.
As Robert pointed out earlier, it's just carbon deposits on the valve... it comes off with the wire wheel in the bench grinder
Yeah those cleaned up nicely. .. then made a mess of the guides... got a nice later head with 39mm inlets that I might splash out on a partner for to get the long block finished.. then practice on putting my head collection back together as i have guides valves etc already in the collection of bought bits
