My first A4 debug: a stuck #4 valve

[lat 64]

While running the engine on 3 cylinders is there any harm I can do by hooking up the plug wire to that cylinder?

No.

Just be careful you don't give your pacemaker a jump

Whiskey-Delta-Four-Zero: Good for hosing down the shaft coupling that is always rusty. Also good to spray on fishing tackle, it attracts halibut I hear.

[gagabriele]

Ran out of time, hoping time will help, now.

Well, we ran the engine yesterday for about ten minutes. It actually ran fairly well on just the 3 cyls so I can't wait to see how we'll it runs on all four. We had what seemed like good water flow out the exhaust. We watched the water temp and it moved up to about 130 but then stayed there. The oil pressure read 80 psi and stayed there. I'm not sure how accurate they are since they look original.

We shut down and this morning I went out and check the compression on number 4 and it was still nothing, so back in the the MMO in all cyls and some Blaster in 4, then I put the plugs back in and packed it up. We had to head back north and I won't be able to get to it until July. Here's hoping that time helps it unstick otherwise I may have to see if I can get the head off when I return. Anyone pull the head in a C27? It looks like it can b done without removing the engine.

I took lots of picture of the motor which I will post sometime soon with other questions I have. Thanks to all for your help. This will be a sweet engine when it's running in all 4.

[gagabriele]

Stuck valve or stuck lifter?

Well, I've finally been able to return to work on this engine and get this valve unstuck. The first thing I did was check to see if the compression was still zero in #4 and it is. As my first step, I decided to remove the valve cover to see what it looked like in there. All the valves look nice and oily but when I turn the crank the #4 exhaust lifter is the only one not moving. I appears to be stuck in the up position. If it was free to move, I would have expected the spring to push it back down. The spring looks good. I have pictures if it's helpful.

So, is this a case of a stuck valve or stuck lifter? I'm hoping not to remove the head, although it looks like it has been recently removed.

Gary

[gagabriele]

It's a sticky lifter!

Ok, sorry for the last post. I got a wrench on the top of the lifter gave it a little twist and the valve popped down. However, it is sticking in the up position when I crank the engine around. In going to keep working it but any suggestions are still appreciated.

[Loki9]

It's unlikely that the lifter is the part that is sticking. Much more likely is that the valve is gummed up and sticking in the guide. The proper fix is to remove the valve and clean it (and all the others while you have the head off). Short of that, you can try removing the manifold and spraying some solvent (carb cleaner, etc.) in there to loosen the crap and then working the valve up and down a bit manually.

[gagabriele]

Jeff,
Thanks for your reply but I'm confused.

As soon as I turn the top of the lifter the smallest amount, it snaps down and I can hear the valve closing. I'm assuming that if the lifter wasn't sticking but the valve was, the valve spring would push the lifter back down but the valve would stay open. Am I wrong?

Thanks,
Gary

[ILikeRust]

Yes, sorry, but you're wrong. The valve spring actually pulls down on the bottom end of the valve stem. The spring does not push the lifter back down - the bottom end of the valve stem pushes the lifter back down, because the spring is pulling the valve stem down. The lifter is trapped between the cam lobe and the bottom end of the valve stem. The cam lobe pushes the lifter up; the bottom end of the valve stem pushes the lifter down.

However, if the lifter is staying up, it might be sticking a little bit - it should drop back down, although the fit is close enough that it might not do so by gravity alone. I'd be surprised if the lifter is sticking enough to stop the valve from coming back down, unless the valve also is sticking - which is more likely.

[gagabriele]

Jeff,
Yes, of course that's how it would have to work. Thanks for the clarification.

Yesterday I was able to work the valve up and down either by pushing from the top with an Allen wrench or from the bottom by twisting the lifter a bit. It's clear that this lifter isn't as free to move as the other lifters and it still concerns me a bit that by twisting it just a little the valve will close. It doesn't take too much effort to push the valve closed from the top either.

What are the chances that this is a sticky lifter and not a sticky valve? Or perhaps a weak valve spring? A sticky valve or weak spring I could fix without major surgery (head off, valve out, etc.); the sticky lifter seems to require a more complete teardown.

Thanks,
Gary

'79 Catalina 27

[Mark Millbauer]

Gary,

I just completed a rebuild on an A4 that had several very sticky lifters that would stick enough to hold their respective valves up. Upon dismantling, there were no broken springs and the valves moved easily. This engine had sat for a long time and I believe had probably overheated shortly before the engine was pulled out. A few of them were so bad I had to hone the lifter bores during the rebuild process.

Given yours is just one lifter and it's on number 4, it's probably just gummed up so you might consider repeated twisting, tapping, and lubrication with MMO of the offending lifter. You may want to thin the MMO a bit with acetone to help it work down into the lifter bore.

Of course you need to make sure the valve stem and spring are in good shape and not contributing to the issue.

[thatch]

"Spring Time"

Having just done a rebuild on A4, I will say that the difference in pressure between original valve springs compared to the replacements is substantial. Going with new springs will go a long way in assuring that the sticking lifter/valve will not happen.
Tom

[Mark Millbauer]

One definitely should strongly consider going with the new, heavier springs when doing a valve job or rebuild. That said, when everything is correct, the lifters should follow the cam lobe down on gravity alone.

[gagabriele]

Update: It's barely stuck

After a few days of treating with MMO and repeately handcranking and pushing the valve back down, it's at a point now where the lifter is still sticking up but it will snap back down with a light tap of the wrench on the side of the lifter. I get a very sharp "snap" as the valve returns. It is clear that this lifter is not as loose in its guide as the others and it is not following the cam, but I can't imagine what's holding it - it doesn't take much of a tap with the wrench to get the valve to return.

I've decided to just continue with this for another couple of days and hopes it finally totally loosens up completely. What are the chances that this will work itself loose if I go ahead and run the engine with it still sticking as it does now?

Gary
79 C27

[Ball Racing]

With the lifter at it's highest point give it a spray of carb cleaner, and then get it to go back down.
Hopefully there will be room enough for some of it to go down the lifter and wash away the gum-varnish that may be sticking the lifter.
Then go back to putting a oil on it.
MMO oil can do alot, but does not cut away gum as fast as carb cleaner.

[gagabriele]

It's running!

Today I put the engine back together have working the MMO into cylinder 4, handcranking and forcing the valve back down repeatedly. Even though it didn't take much to get it back down, it was still sticking. So, I decided short of taking the head off I'd give it a shot and it started and seems to be running quite smoothly. I haven't pulled the plug on number 4 yet by pulling the plug but it seems to be running very smoothly. I'll live with my dream a little before I try that and confirm it's unstuck itself.

Now, I'm concerned about the temperature of the engine. After letting it run for about 10 min the temperature gauge read 200. This appears to be the original gauge and I don't know if it reliable or not. Based on what I've read on this forum, it seems like I should be seeing something closer to 150-160 for my fresh water intake.

The exhaust has a steady "putt-putt" of water coming out the stern exhaust. I don't know if that's the right amount or not. One indication that it was getting water was that I had left the hose on top of the exhaust manifold disconnected by mistake and there was a steady stream of water shooting out of it before I saw that mistake.

In a recent discussion with Moyer I confirmed that the exhaust on the C27 is correct.

Should I be concerned? Is it time for a new impeller or something else?

My installation is a late model A4 on a 79 Cataline 27.

Thanks,
Gary

[gagabriele]

It's running! Correction

I may have misstated my cooling system. I said it was a fresh water system. I believe I should have said it's a raw water system in that it gets its cooling water from a through hull. This was recently cleaned, btw. Sorry.