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Is this a crack in my Cylinder head?

PostPosted: Thu Jul 04, 2024 1:24 pm
by Art Tiller
Hello all,
I did not do a good job of repairing the upper spark plug threads in the number 3 cylinder using a back-tap. I also left some metal shavings in the cylinder. I attempted to blow them out using compressed air. Looks like they want to stay in there. I am prepared to remove the head and attempt another repair using the Time-Sert I just bought.
How ever, I captured an image of what I believe is a crack between my intake and exhaust valves. Using the boar scope which I also recently bought. I seem to be buying a lot of stuff.
In the attached picture you can see what I think is the crack. There is also a metal shaving stuck in the crack. I think I should remove the cylinder head clean and more closely inspect the suspected crack. If it is not a crack I can repair the spark plug threads, clean up the left over metal shavings and re-install the head. Or, buy a new head. Since the head will be off perhaps I should just go ahead and buy a new one.
I think I can get a new one from Sonex for about $500.
Got any advice for me.
Thanks

Re: Is this a crack in my Cylinder head?

PostPosted: Thu Jul 04, 2024 1:48 pm
by Bryan Cotton
I have a pair of new heads on order from Sonex. Their machine shop is a little backed up and I don't have an estimated ship date yet. As mentioned elsewhere, I think by Dale, having a second set of heads to swap in is a good idea. I also have a crack between valves - and a dropped #3 intake valve. Picture as shown in my photo album thread:
Image

It's hard to tell from your picture but I wonder if those could be lead balls from 100LL fouling.

Re: Is this a crack in my Cylinder head?

PostPosted: Thu Jul 04, 2024 3:45 pm
by Art Tiller
I think I shall pull the head off and see what is going on. Lead balls? I don't think so. I have looked in the other Cylinders and they are clean. Thanks

Re: Is this a crack in my Cylinder head?

PostPosted: Thu Jul 04, 2024 9:23 pm
by mike.smith
Those cracks are VERY common in VW heads. It's a design flaw from its inception by VW way back when:

http://bobhooversblog.blogspot.com/2006 ... -head.html

Re: Is this a crack in my Cylinder head?

PostPosted: Sat Jul 06, 2024 5:18 pm
by Art Tiller
I got the head off today. It was a pain getting it past the baffles. I looked for an easy way to take front and rear ones off, but in the end I just man-handled the head past them. Some bending required. I am sure I must have missed something simple. I will do the time-sert spark plug repair tomorrow.