Forum member ysifl2 sent me this - probably because I complain about my VW heads a lot lately! I’m going to make one.
Also I’m going to try and tag it in the Firewall Forward > Aerovee category.
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It didn’t really cross post like we were hoping, oh well. Here is a very similar tool posted some years ago in the old forum:
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This is a great idea. I’m going to build one as well. Thanks for posting!
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It didn’t post to Categories → Aerovee, but it can be found by looing in: Tags → Aerovee
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That’s a great idea. Do you think it will need something to form a seal between the PVC and the head? I guess as long as your tolerance is tight enough, you shouldn’t.
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If you look at the picture in the first post, the article says to make a rubber seal from an inner tube.
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Here it is in action:
One sealing issue is that there are deposits on the head and that can interfere with the seal I think. In that way, Graeme’s tester is better. I did have to mess around with it to get it to seal well.
I’m seeing 80/78 on both sides here, with leaks through the exhaust valve. I pulled the exhaust valves out and lapped them more aggressively, no real change. Technically passing, and might be slightly lower given leakage past the rings, but I hate hearing the air shoot out the exhaust valve. Trying to decide - should I:
- Go with it as is
- Try and lap some more
- get out the Neway cutters again and take another pass
Bryan,
Have you tried to (remove pressure and) rotate the valve(s) a few degrees to see if you get any change in leak rate? A bit of run out in either (or both) valve or seat, and maybe you could be chasing a non-repeatable ghost here, right?
“Perfection is the enemy of good…” or something like that
- Voltaire
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I staked the valves, meaning whacking them with a plastic hammer while under pressure. They were likely rotated when I tried lapping them again. But I’ve not just rotated them.
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Since you’re pretty close already, I’d probably start with lapping and see if it changes for the better.
I probably wouldn’t just go as is. It in spec now, but your leak down test is bound to be worse with a fully assembled engine where you’ll lose some pressure thru the rings.
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After cutting and lapping, #3 was 80/74 which was a little worse. I lapped it some more, 80/80.
Between the bench leakdown test setup, and the insanely awesome valve compressor, each iteration goes really fast!
Edit: just finished the other head. 80/80 all around. I’m done.
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Awesome!
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