EA71 with burned up valves question

[Claus]

I just bought a cheap spare motor for my 1980 Brat. It is an EA71 from 79, and the owner claims it was in a running vehicle years ago, and that it has low mileage (50k). When I got it home, I hooked a compression gauge to all cylinders and hand cranked the motor, no compression reading on the number 4 cylinder. I decided at that point to remove the head, and what I found was a lot of rust on the bolts that hold the head on, and the intake valve and seat chewed up with giant gaps. My question is, is it possible that this corrosion happened while the engine sat? Should I get the valve job done and use this motor, or assume that it is actually high mileage and forget about it. Any ideas or discussion are greatly appreciated, I am kind of at a lose on what I should do.

[DaveT]

Sitting in an environment where there is no humidity or temperature control can cause rust to happen. What does the cylinder wall look like? Top of the piston?

[Claus]

Hey Dave, thanks for the reply. I live in New Mexico, so there is definitely a lack of humidity. The cylinder wall looks pretty clean, and the top of the piston has some black soot, but no corrosion. I could post a photo but I am not sure how to do that.

[DaveT]

Trying to think of how a valve and or seat gets chewed up without there being scratches in the cylinder walls, and dents or marks on top of the piston. With they dry climate, I guess there is less worry as far as rings being rusted stuck and all.

 

If you use the full editor for the posting, one of the icons is to attach an image.

[Claus]

Thanks again Dave. Here is a photo of the pistons and cylinders.