Compression test 01 Navigator

[Fordgirl01]

TDC on compression stroke. Cam lobes for that cylinder will be pointing away from the head.

Ok-so the pointy side of the teardrop shape needs to be on top-did I interpret that correctly (I’ll learn the correct terms for stuff eventually)?! If that is so, that is where I have it right now so I should be good.

Thanks!!


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[stamp11127]

Yes, pointy thingies away from head.

 

[TobyU]

Yes but you also have to make sure the Piston is physically up or at least near the top within a half an inch or so. The Piston moves a whole lot more in relation to the camshaft turning the lobes. I posted another post earlier but it seems like it did not go through. I was saying that it doesn't make much difference when you add air to the cylinder where it's at top dead center or not but anytime you remove a spring from a valve you want to make sure the piston is at top dead center or no more than a half an inch down. If the valve were to actually slip down hopefully the piston would stop it and you can pull it back up by the stem. If a valve were to fall down and a piston were to be lower you would have to remove the head and just to get it out back into place. That would be bad.

 

[Fordgirl01]

Finally got some air into the cylinder.....it leaked out. From what I found from google, I think my valve that has the roller off of it is an exhaust valve. I read on the drivers side, the exhaust valves are the on the most forward side of each cylinder.

So when I put air in I couldn’t really tell where it was leaking out, but it did sound like it was below. I assume if it was intake I would hear the air coming from the top where I have the upper intake off?

Does this mean that valve and spring need to be replaced?

I did order the valve spring tool assuming I was going to need it. It won’t be here until Tuesday, but I am borrowing one for the weekend that I hope will work (handy deal-I work in a shop that is right next to our big maintenance shop with several great mechanics that have become accustomed to me picking their brains and bumming tools once in a while).

So-feel free to tell me what’s next and I’ll get to it!


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[TobyU]

That was my guess that it would be an exhaust valve. Since you said it looks like it's not coming up as high it seems to be stuck slightly open or actually a lot open. You're going to have to get the piston to top dead center by checking with a long wooden dowel or long screwdriver or something. So in case the valve fallls it won't fall all the way down.
There's a good likelihood that the valve seat has come out of the head and that's what's keeping the valve from shutting. If this is the case that had has to come off. There's also a chance that the valve stem is just stuck in the guide and with some good PB Blaster and Lucas spray chain lube and working it back and forth you can get it to move freely and maybe it won't stick again. These are ifs though.
A valve has to have a straight stem and has to be free enough to move in the guy that when you push down on it with the palm of your hand and press the spring down that the spring has more than enough tension to lift it back up and close it tightly. It also has to have the proper seat angle and everything so it closes off airtight.

 

[rjdelp7]

Intech 5.4l on Buffalo craigslist $1000, asking price.

 

[Fordgirl01]

That was my guess that it would be an exhaust valve. Since you said it looks like it's not coming up as high it seems to be stuck slightly open or actually a lot open. You're going to have to get the piston to top dead center by checking with a long wooden dowel or long screwdriver or something. So in case the valve fallls it won't fall all the way down.
There's a good likelihood that the valve seat has come out of the head and that's what's keeping the valve from shutting. If this is the case that had has to come off. There's also a chance that the valve stem is just stuck in the guide and with some good PB Blaster and Lucas spray chain lube and working it back and forth you can get it to move freely and maybe it won't stick again. These are ifs though.
A valve has to have a straight stem and has to be free enough to move in the guy that when you push down on it with the palm of your hand and press the spring down that the spring has more than enough tension to lift it back up and close it tightly. It also has to have the proper seat angle and everything so it closes off airtight.

Since I need to get into the valve spring, valve and everything related-should I just replace everything in there? It looks like I would need the spring, retainer keys, retainer, valve stem and valve seal. Would that be all I need (along with the special tools of course and a new lash adjuster and roller follower too)? I can’t see going through all of this work to put old parts that failed back in since they are not terribly expensive parts.

Should I also air test the other 3 cylinders for the heck of it? I think originally (before I got it) the dealer claimed a misfire on 3 of the 4 cylinders on that same side. Plugs and coils fixed all misfires but the one on this cylinder I am working at now.

When you say I should be able to push the valves down-does this mean I should be able to push all of the valves down with my hand? I can’t get this one to move at all but I never tried others. I know one of the videos showed tapping them with a rubber mallet but, the one I am working on is in a spot I could never get a hammer at. It’s a lower one and it’s behind the brake booster. Even if the camshaft was not there I don’t think I could get at it to hit it with anything.


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[Fordgirl01]

Another question I just thought of. If air in the cylinder keeps the valve from falling down, how am I going to achieve this when the cylinder won’t hold air? Do I just keep a constant air flow to it?


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[TobyU]

Another question I just thought of. If air in the cylinder keeps the valve from falling down, how am I going to achieve this when the cylinder won’t hold air? Do I just keep a constant air flow to it?


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That's why I said you have to make sure you put the Piston all the way at top dead center but even then the valve can fall down and it's going to be hard to do but at this point it really doesn't matter. They had has to come off. You can't replace a valve seat attained down out of the head keeping the valve from shutting without removing the head. You don't need to replace valve springs retainers and Keepers that aren't physically broken or damaged. You can't just put a new valve into ahead even if the valve stem was bent without having a valve job done to make the valve match the seat is ceiling on. Regardless, you have to remove the head to even get the valve out. Removing the head and the chassis is a ton of work and that's why I said it's almost easier to just pull the engine in the first place.
If you have a valve stem that's bent or a valve seat that's popped out of the head then you're going to have to remove the head either get one from a junkyard to install or take the head to a machine shop and have them fix it which typically involves of doing a valve job on the whole head. You don't really need to replace the guides but they might recommend that but I wouldn't waste the money on that. You could just fix the one or do all of the valves on the head but this starts to get pricey.

 

[Trainmaster]

Assuming that the valve is stuck or the seat is messed up, the head has to come off. If the spring's just busted, it doesn't. Are you sure the spring is pulling up on the valve? Sometimes a broken spring lets it drop and stay open. That's your best situation, because you can just put a new spring in there.

If the head has to come off, the exhaust manifold has to also. That may be a bit rough on your truck. The nuts retaining the manifold are often rusted gone, so it can be trying.

Removing the head is a job in these truck, but it can be done. After you get it off, take it to a machine shop and for a few hundred dollars they'll give it back all fixed up. A new head gasket and you are on your way...

 

[Fordgirl01]

Got it-to do anything with the valves, the head has to come off. Hopefully I will end up finding the spring is broken down where I couldn’t see it.
On the plus side: I’m pretty sure the manifold bolts would come out-this is a vehicle from Arizona. Also, I know an excellent machinist who would not overcharge me.
Let’s hope it doesn’t come to that. I don’t really want to go that far, but I’m already way deeper into it than I though was possible....so there’s that! I do love a good challenge.

Thanks for the replies!


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[Fordgirl01]

I’m assuming I should not mess with the spring until I have another one to replace it? I’m guessing there is no way to hold the valve from falling other than the air? So i think I couldn’t try to take the spring off tonight to see if it’s broken and somehow hold the valve up and go get a spring-right?


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[stamp11127]

Old school trick is to feed as much twine or thin string into the cylinder as you can through the spark plug hole while the piston is bsfore tdc (btdc). Rotate the crank to tdc, if there is enough in the cylinder it will stop before tdc.
The interference between the string, piston and cylinder head will keep the valve from dropping into the cylinder.

 

[Fordgirl01]

Old school trick is to feed as much twine or thin string into the cylinder as you can through the spark plug hole while the piston is bsfore tdc (btdc). Rotate the crank to tdc, if there is enough in the cylinder it will stop before tdc.
The interference between the string, piston and cylinder head will keep the valve from dropping into the cylinder.

That’s helpful-thank you!! What if some of the string breaks off in there before you get it back out?


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[Fordgirl01]

I just googled your rope trick! I think I’m going to try this as I’m uneasy about the air since it leaks out! It seems like a great idea. Thanks again.
https://www.pistonheads.com/gassing/topic.asp?h=0&f=66&t=156176
https://advrider.com/f/threads/how-to-do-the-ole-rope-trick.951976/

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[TobyU]

Rope is only way in your case since it is not holding air.

Get piston down a good way in bore ( you should only turn engine the correct way by hand and not backwards) and feed 3-4 feet in there (depending on what size you use) then slowly turn the balancer/crankshaft bolt clockwise (correct way again) until the rope is pushing up on the valve.
You leave a foot of so hanging out so you won't loose any in there.
I just did two riding mower engines this way this month.


Let'd HOPE it is just a broken spring.
BTW if you know a machine shop, you can take it by and tell them what it's from and they will probably hand you a good used one for free.

Use a magnetic pick up tool to catch the valve retainer keepers after you push the spring down. The you hope you can pull the valve up by hand, or wrap shop cloth around it and use pliers.
It should move freely and come up just as far as the other ones.

 

[Atman246]

Hey Fordgirl,here's a question. When you put the air to the cylinder and you said you heard the hissing from down below. Where was the down below? I'd try the air again and listen at the tailpipe and also from the dipstick tube. Pull the oil dipstick out and listen. Tailpipe,exhaust valve issue,dipstick,holey piston Batman. I'm still leaning towards the valve spring being the issue. That being said,if it's a broken spring,you should be able to move the spring and valve freely. Not very much mind you,but if there's no spring tension,then it could move. You did say it wouldn't move at all. That leads me to think bent valve. If it comes to that and you end up pulling the head,then you'll need to hold timing chains in place etc etc. I'd be inclined at that point to replace chains,guides and tensioners. That's where I was on my 5.4l 3 valve until i pulled a camshaft bearing and found a pooched cam. New used engine for me,but i'm doing all of the above plus a new oil pump. My two cents again. Good luck.

 

[Atman246]

I just went back and looked at the pics from Aug 23. The one pic looking down on the two cams,with your arrow on it,i see the valve spring and it "looks" like it's up,as in the spring isn't broken and the valve should be closed. I'm hoping i'm wrong and the pic is deceiving. Can you get your hand down there and wiggle that spring from side to side? If so,it's broken. That would be a good thing.

 

[Fordgirl01]

This is getting discouraging. I was busy most of the weekend but planned on making progress today on he Navigator. I got my rope ready, turned the camshaft (clockwise) until cylinder was at the lowest point. I then kept turning until it started to some back up. I wadded maybe 4’ of rope in there and poked it down in until no more would go and left a long piece out. I turned the camshaft again waiting for it to feel like it was binding against the rope. It never did and it was at the high point. I pulled the rope back out to try again-rope was all there. So began to turn the shaft again and it suddenly will not turn anymore. The camshaft stopped turning but the end of the bolt still turned a little so I stopped. I did see if it would move the other way (counterclockwise), but it does the same thing. I then tried the other camshaft and it seems bound up too.

So it appears to be at the highest point. I stuck the camera in there and it looks like the piston is right there at the top and the camshaft lobe is on top.

I got my spring compressor tool so I’m the meantime I am going to see if I can make that work just to push on the spring. I won’t try to take it out obviously. I see I am going to have to unhook the steering arm as that is right where I need to be.


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[Fordgirl01]

Hey Fordgirl,here's a question. When you put the air to the cylinder and you said you heard the hissing from down below. Where was the down below? I'd try the air again and listen at the tailpipe and also from the dipstick tube. Pull the oil dipstick out and listen. Tailpipe,exhaust valve issue,dipstick,holey piston Batman. I'm still leaning towards the valve spring being the issue. That being said,if it's a broken spring,you should be able to move the spring and valve freely. Not very much mind you,but if there's no spring tension,then it could move. You did say it wouldn't move at all. That leads me to think bent valve. If it comes to that and you end up pulling the head,then you'll need to hold timing chains in place etc etc. I'd be inclined at that point to replace chains,guides and tensioners. That's where I was on my 5.4l 3 valve until i pulled a camshaft bearing and found a pooched cam. New used engine for me,but i'm doing all of the above plus a new oil pump. My two cents again. Good luck.

It wasn’t really hissing....more like losing air almost as fast as it was going
In. I don’t have a compressor so I was using an air tank.

The spring doesn’t move so I’m guessing it won’t be that “simple”! I’m still hoping the spring is broken and just somehow wedged tight, but my optimism is starting to wane.


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