Tractorsport Flowbench Forum Archive

Posted: **Mon Oct 27, 2008 9:59 pm**

I haven't made this yet but I would like too. In the past I have filled the port with water and looked for a "weep leak" pass the valve into the camber. No leak, seal ok (I think). But it may not be the best approach since not much pressure is applied by the product and the viscoity is thicker than fuel. So I would like a better, cheaper, simpler DIY gimick that tests for valve seat seal. I thought of vacumn using the Mite Vac Pumper I have. Seal the port and see if it bleeds down. Then I thought the guide would leak away the vacumn and void the test. Then I thought of sealing the chamber side but that would require some clamping gizmo to secure the seal and if it leaked the vacumn, which valve is leaking, the intake or exhaust?

So am I stuck with the fill the port water test for now? Any DIY ideas.

Posted: **Mon Oct 27, 2008 10:37 pm**

Well there is one other way. What I did and I still have it. I made a .500" thick aluminum plate with the head bolt pattern of your head, mine is SBC. then right in the middle tap a hole that you can screw in an air fitting and then bolt this to your head. Plug in your air hose and fill the ports with slightly soapy water and see if you get bubbles coming out the port. That is what I do. Or you can just listen to the port see if it is noisy

John

Posted: **Tue Oct 28, 2008 10:32 pm**

Ok, that sounds like a practical design, thanks.

Posted: **Wed Oct 29, 2008 9:50 am**

Tom

Very simple design, go to the Goodson catalog on line and look they sell just this tool just a little more fancy. You can see the chamber test plate and all, this should get you there (the vacuum actually holds it in place). Also look at the valve guide leak tester for Harley its a good idea for any press fit guide I made one a while back and it works great.

Rick

PS.. I am not a salesman for Goodson I swear they just have done me right for 20 years.

Posted: **Sun Dec 28, 2008 6:30 pm**

This is the one we use

The pads seal on the manifold face and we make sure it reaches 600 mbar at least

It's super expensive $2000

So I was thinking of making one out of those small tire filling compressors using the suckion side and a gauge

Posted: **Sun Dec 28, 2008 7:12 pm**

It's funny but over the years I've seen a good many interference valve jobs done that show light past the valves after a fresh valve job. I've never agreed with that concept but I do know a lot of cylinderheads make it out the door of machine shops like that and onto engines. Best part is I never hear guys complain about the motors either.....

Posted: **Sun Dec 28, 2008 10:38 pm**

I have also used the air pressure deal with the plate but then dropped the head into a 55 gallon plastic soap container (using a simple block and tackle) No air bubbles no leaks. (just like testing a tire). The plate has an air distribution "manifold" on it that allows testing 4 intakes at the same time. I also have a plate for the exhaust ports. You can tell if you have "loose" valve guide clearances by the amount of bubbles too. I only play with Traditional Pontiacs so I don't need multiple fixtures.

Tom Vaught

Posted: **Sun Dec 28, 2008 11:20 pm**

Posted: **Fri Jan 02, 2009 11:32 pm**

I posted some details of a vacuum tester I made a few years back, very similar to the way the Goodson one works.

You can check the seal on your valve jobs or check for cracks from the cooling system.

Happy New Year.

Cheers,
Greg.

Tractorsport Flowbench Forum Archive

Cylinder Head Valve Leak Tester