Changing valve seals - putting air into cylinder - hear air leaking - help

Ok, I pluged all the other cylinders with spark plugs and am working with #1 cylinder. I hear the air leaking but cannot determine where it's leaking to. I don't feel anything at the tail pipe. I don't see bubbles in the radiator water. I can't feel anything at the dip stick. The only thing I haven't looked at yet is the intake. The only thing I know of that is.

I'm going to look at that now.

Maybe my valves are stuck open? If that were true I should be able to feel it somewhere, either intake or exhaust, yes?

Bill

Well I put my valve cover back on, pluged all the spark plug holes, and covered the holes in my valve cover. I'm hearing/feeling air though the pcv valve. This is due to rings, yes?

Thanks,

Bill

probably! squirt some oil into the cylinder and turn the engine over a few turns (can be done by hand if necessary).

Poured about a table spoon down #1, cranked it over a few times by hand (found TDC twice) and tested again. Still I'm hearing the air.

I should not be hearing air, right? It sounds like I'm filling a tank with air.

Just to let you know, I'm finding the compression stroke by sticking my finger in the spark plug hole and turning the crank. When I feel pressure against my finger then I know I'm on the compression stroke and then look for the timing mark to reach TCD or just before.

So, am I worrying about nothing then? Just because I'm hearing air and feeling air out the pcv valve hose then this is ok. In other words, the cylinder should not completely contain the air. This is normal? I'm freaking and thinking all the rings are bad because I hear air. Please correct me.

Thanks,

Bill

You'll always get some leaking by the rings, even in a brand new engine. There is a small gap of .020-.030" left where the ring ends almost come together. If you do a leakdown test as per my earlier post, it will tell you how much you are losing. A stock type rebuild will have as much as 8% leakdown when it is brand new. This doesn't mean that anything was done wrong, it's just the way it is. A racing engine will have less leakdown (usually 2-3% for a well built race engine) when the engine is new because they use tighter ring end gaps and a smoother bore finish when the engine is honed. Now if you hear a large rush of air coming out the tailpipe or intake and the valves are closed, then there is a problem. Also, your radiator shouldn't look like Old Faithful either. ;).

Chris

The valves can leak too....

When you have the old seal off, dab a little oil around the valve stem to see how many bubbles come up.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

"L.W.(ßill) Hughes III" wrote:

Yeah, I'm working on building my own Leak Down Tester. Bout halfway there.

Thanks,

Are you sure you're not on the exhaust stroke? I'd pull the rockers off before airing up - then it doesn't matter what stroke you're on.

-Brian

Thanks guys.

What I'm hearing is like I'm filling a tank with air if that makes any sense. It's hard for me to determine how much is not much and if it's too much.

I'll try it again tonight with the arms off, put the air in and see if I can get the keepers out.

Thanks again,

Bill