Installing valve springs.....question????

[Biggin0822]

I'm using compressed air in the spark plug hole for each cylinder to hold the valves up. The question is, should I hear any air leaking inside the head? I do hear it and I wonder if I need a valve job or if it is normal?

 

[Honky Kong jr]

I'm using compressed air in the spark plug hole for each cylinder to hold the valves up. The question is, should I hear any air leaking inside the head? I do hear it and I wonder if I need a valve job or if it is normal?

Wash line rope in the cylinder is how I do it no chance of engine roll over and dropping a valve in just leave a tail so you can get it out.

 

[chengny]

If you are concerned about the condition of your valves/rings do a leakdown test. It gives you a far more definitive picture of the condition of your valves/rings than a compression test does. It requires a compressed air supply, which - from reading your post - I see that you have. I could try to explain the theory and how to do the procedure, but it might easier on everyone if you just googled it.

I made my own, but you can pick up a reasonably priced leakdown test kit at Harbor Freight for $40. It's far from "professional grade", but should be okay for a few tests.

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https://www.harborfreight.com/cylinder-leak-down-tester-62595.html

 

[vkh]

Wash line rope in the cylinder is how I do it no chance of engine roll over and dropping a valve in just leave a tail so you can get it out.

Same here with the rope, easiest way I know of with the heads on.

 

[vkh]

Far as whether you need a valve job I think you should do a compression test or leakdown test like chengny suggested to get an idea of how your valves are doing.

 

[gpmorgan]

Whichever cyl you are doing, make sure both valves are closed on the compression stroke before putting air on it.

 

[SkinnyG]

There will always be some leakage if you are pressurizing the cylinder. No engine is 100% air tight.

A really good engine might leak 5%. Most engines will leak a lot more. But there will be some leak.

I like the nylon rope through the spark plug hole a lot better than merely air.

 

[Biggin0822]

I got the leak down tester and looks like all the cylinders are good.

 

[Green79Scottsdale]

The air you were hearing was probably air going through your ring gaps.

 

[MikeB]

Even if you have new broken-in rings, you will still get leaks. I have always used compressed air, but next time will try the rope method mentioned by HK above. A buddy mine who worked as an aircraft engine mechanic swears by it. Just make sure you remove all the spark plugs and turn the crankshaft by hand to TDC for the cylinder you're working on.

If this were professional advice, I'd have to post 10 pages of safety and hazardous material precautions. Such as disconnect the battery, block off the wheels, wear gloves & goggles, and don't drink motor oil.