Comments on these leak-down test results

[Jack Shaft]

Originally Posted by alexiskai

PB Blaster OK for the penetrant?

yep,as long as its flammable..you can actually see the valve work too.80/20 against it fixing your issue but its worth a try

[alexiskai]

This is worth exploring – when someone says "sticky valve" does that mean the valve is stuck closed, or open, or both? The problem here is the valve is remaining open during the compression stroke.

[Jack Shaft]

#2 cylinder? before you spray take flashlight,shine down on valves and turn engine over ,key off, with starter and you can watch the valve work.

[alexiskai]

Yeah, I think that's why 30CCPU was recommending a borescope, same idea. OK, I'll see what I can do to inspect the valve visually without removing the head. That seems like a good next step.

[katy]

when someone says "sticky valve" does that mean the valve is stuck closed, or open, or both?

Usually means that the valve is slow in seating because the stem and/or guide are carboned up or rusty, also may be caused by a weak or broken spring. The valve may close fully during cranking but when running it doesn't close fast enough.

[30 Closed Cab PU]

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Originally Posted by alexiskai

Yeah, I think that's why 30CCPU was recommending a borescope, same idea. OK, I'll see what I can do to inspect the valve visually without removing the head. That seems like a good next step.

As an FYI instead of shining a flashlight and looking through the spark plug hole I recommended using a borescope - personally my with my eyesight can not focus/and see fine detail well enough. The Borescope gets close and magnifies what you see. It also has a light for Illumination.


Looking through the hole is worth a try if you have good eyesight.


Either way with the ignition off you can use the starter/starter rod, or if you have a helper can hand crank. Easiest is to pull all the spark plugs making it easy with no compression to crank over the motor. And while you are at it inspect the other cylinders.


Just make sure that if you still have penetrant in the cylinders to cover the spark plugs holes with a towel or something. If not you may end up with penetrant blowing all over the place. Do not ask me how I know.

[alexiskai]

I've ordered one of those snazzy scopes that uses your phone as the display, so I'll post an update with pictures from the #2 cylinder and we can see whether a diagnosis is indicated.

[Jim Brierley]

Quit fooling around, the #2 exh. valve is burnt, and the seat probably burnt a little too. Keep running the car and it could do major damage to that seat and block. Changing the valve only is not a good idea, the seat will need to be ground too. You might get some shop to do a house call and grind the seats?

[Patrick L.]

Originally Posted by alexiskai

This is worth exploring – when someone says "sticky valve" does that mean the valve is stuck closed, or open, or both? The problem here is the valve is remaining open during the compression stroke.

Its hard for a valve to stick closed, things have to get 'bent' for that to happen.
They stick open. So, what is the lash, once again ? Is the valve working freely in the guide ? To me, these have to be answered before taking anything apart. But, the sooner this is fixed the better.

[katy]

the sooner this is fixed the better.

Ditto

[alexiskai]

Message received folks, fixing this valve is my top priority. I have no idea how I'm gonna do it but we'll take it one step at a time.

Edit: First step is to get in there with the borescope, see if the problem is visible. Second step is pull the valve cover and check the movement and lash measurements that way.

[40 Deluxe]

Originally Posted by alexiskai

PB Blaster OK for the penetrant?

Spray carburetor cleaner works much better. In my experience valve stems get a coating of a varnish-like substance that penetrating oil doesn't cut very well. A solvent like carb cleaner is better.

[40 Deluxe]

Originally Posted by Jim Brierley

Quit fooling around, the #2 exh. valve is burnt, and the seat probably burnt a little too. Keep running the car and it could do major damage to that seat and block. Changing the valve only is not a good idea, the seat will need to be ground too. You might get some shop to do a house call and grind the seats?

Jim, how about going back to the suction cup stick like you used when you were a pup? My uncle had a fancy one. It looked like one of those old hand cranked drills but had a suction cup on the end and the shaft oscillated back and forth. Was faster than rubbing your hands together!

[alexiskai]

Originally Posted by 40 Deluxe

Jim, how about going back to the suction cup stick like you used when you were a pup? My uncle had a fancy one. It looked like one of those old hand cranked drills but had a suction cup on the end and the shaft oscillated back and forth. Was faster than rubbing your hands together!

I think it'll all depend on how damaged the valve seat turns out to be. Those sticks were for polishing a seat that was basically intact.

[Jack Shaft]

Originally Posted by Jim Brierley

Quit fooling around, the #2 exh. valve is burnt, and the seat probably burnt a little too. Keep running the car and it could do major damage to that seat and block. Changing the valve only is not a good idea, the seat will need to be ground too. You might get some shop to do a house call and grind the seats?

the minute the wet/dry compression test showed 40/40..

[40 Deluxe]

Originally Posted by alexiskai

I think it'll all depend on how damaged the valve seat turns out to be. Those sticks were for polishing a seat that was basically intact.

I agree, but was just thinking how it was often done back in the Model A's heyday when few people had the money for a first rate valve job.