Hole in Head Gasket Surface

Maintenance/Repairs
1

Hi Guys!

Today, big drama in the garage: my valve spring compressor slipped!
(my ego doesn’t want to say that I missed the valve so yes, it slipped!)

I poked a small hole on what appears to still be the combustion chamber, not really the gasket surface. See the grandiose picture:

valve%20gasket%20surface
valve gasket surface.jpg3024×4032 2.1 MB

That’s my way of getting more compression I guess!

More seriously, how can I repair this? The valve seating surface is not damaged, it looks like it on the picture but it isn’t.

I doubt good ol’ JB Weld + sanding is gonna do the trick…

Thanks!

2

What about just getting a new head?

3

Take the head to a machine shop that can TIG weld and machine the head.

Tester

4

A new head is out of the question, my wallet (and wife) would not approve!

Machine shop sounds reasonable; I wish I could do something myself…

Thanks guys!

5

I had a channel in a piston wall that kept blowing through head gaskets, jb weld did not work, FYI

6

What would happen if you didn’t do anything, other than file the raised edges of the gouge down level? Just curious.

7

It would create a hot spot and melt the aluminum head in that area,

Tester

8

Hot spot, I kind of guessed. But it will melt the head? Yowsers. Did not anticipate that.

9

Thank you all for your comments and help!

I’m so pissed at myself, I was waiting for all parts to come for weeks and now I’m going to wait even more for a machine shop to work on it.

This head is from a motorcycle (04’ Honda CB600RR) but it doesn’t really matters…

10

Hard to tell in pic, is that a little hole at the bottom of the dent or just carbon?

If it’s a hole, no question it needs to be filled and smoothed.

Before I had a welder for this kind of thing I probably would have dressed the edges to flatten and round them and called it a day. There is crevice volume by the plug, head gasket and other areas. They just round it off to reduce hot spots. Depends on your tolerance for risk…

1 Like
11

Just looked on eBay. Bunch of heads for $75-100. 2 weeks beer budget.

3 Likes
12

Bikes like this are very high hp/cc, any irregular bump like this, even sanded down, could cause a problem. I’d see what a machine shop would charge to fix it the right way.

13

While you’re at it, you might get a price on a complete top end job. They will probably remove the valves and associated hardware before machining the head anyway.

1 Like
14

Yeah I found a head for $60 on eBay indeed! Cheaper than contacting a machine shop! Love the internet lol

15

I think a replacement head is the best option. Welding that hole up will quite likely distort the exhaust valve seat which is next to it. That will in turn lead to a burned valve/seat.
The only way around that is to perform a complete valve job after the welding is done.