This some kind of backyard head improvement?

[LanceM]

I was looking at an E-88 head that I was going to get rid of when I noticed something really strange. Around each intake valve there are 4 large punch marks in the head, looks like it was done with a punch and by hand as each chamber has the marks spaced differently. Looks like a good way to create hot spots in the head, anybody have any idea why someone would do this???

Or maybe I have some long lost high tech hi flow supersecret head here

[madkaw]

That's Weird!

[Arne]

I'm willing to bet that was someone's (rather silly) way of "staking" the valve seat, to hold it in place. Perhaps the seats were replaced, and the machine shop blew it ever so slightly when they cut the head for the new seats?

[Ed]

I'm willing to bet that was someone's (rather silly) way of "staking" the valve seat, to hold it in place. Perhaps the seats were replaced, and the machine shop blew it ever so slightly when they cut the head for the new seats?

I think Arne is correct. This method is used in a variety of different applications to "close" a hole. I've seen watch repair use this method to restore gears and mechanics use it to hold a freeze plug in place. As a matter of fact I think if you look at the underside of an intake manifold there are some of the same punch marks holding the freeze plug.

[LanceM]

You guys might be right but that sure is not the right way to do it on a head. None of them are smoothed down, they look like moon craters. The peaks would glow with the engine running I would think causing all kind of problems. It sure couldn't help performance in anyway. Another mystery of life

[Arne]

No, you're right, doing that on a head to hold the valve seats in is a very bad idea. And I'm sure that increased performance was not the goal - whoever did it just didn't want the valve seats to fall out.

[skyline_stu]

I can't believe some people repair heads like this. el cheapo & bodgy come to mind.They had loose valve seats and did that to try and tighen it up. don't even think of trying to expect any sort of safety with this setup. get it fixed before you drop a valve and get the detonation accelerators(punch marks) welded up whilst rewelding the seat area. better than new when done properly.

[MikeZcar]

The term for this is "peening", might be a crappy thing in this instance, but if you're broke you're borke, this may have been done 20 plus years ago by someone who just wanted to make it stay together long enough to get to work and back, something about "till you have walked in another man's shoes".

[Fun_in_my_z]

Mike alot of thease folks dont think that way...

[skyline_stu]

Yeah, i understand that may have been the way for an emergency or low buck fix, but long term durability ???????? I'd be more concerned about the sharp edges causing detonation. take a quick look at the photo. see how much carbon is in the chamber. those hot spots around the punch marks will ENHANCE the chances of detonation, so that's 2 good reasons not to do it. remember, we often run our motors hard and a dropped valve is going to ruin anyones day. I've seen people centre punch tailshaft yokes to do the same. More often than not it ends up in a big mess.

think, grenade with pulled pin.