Stuck valve?

oldspert

oldspert

Senior Member
Started disassembling the rebuilt engine I purchased and there is one valve (so far) that is stuck in the guide. The guide is moving up and down in the block. Any idea how to get this valve out without destroying the guide. They are guides especially for this engine, the paperwork says they are one piece, cut down. the valves are not regular Model A valves.
Ed
 
oldspert said:
Started disassembling the rebuilt engine I purchased and there is one valve (so far) that is stuck in the guide. The guide is moving up and down in the block. Any idea how to get this valve out without destroying the guide. They are guides especially for this engine, the paperwork says they are one piece, cut down. the valves are not regular Model A valves.
Ed
Click to expand...
do you have the guide tool to knock out guide? Or just knock guide out and redo the guide? Does it really matter if the guides are just for this motor? Try oil/heat!
 

Attachments

  • valve guide tool.jpg
    valve guide tool.jpg
    43.1 KB · Views: 20
  • valve guide tool1.jpg
    valve guide tool1.jpg
    43.3 KB · Views: 16
Last edited:
The one piece types generally have keepers to hold the valve. If you can get a valve spring compressor then you can get the keepers out. A stuck valve will require either pulling it out with the guide attached or finding a way to unstick the valve if it has a flanged guide. It will take some thought on how to back up the guide in order to tap the valve down. I used Marvel Mystery Oil but any solvent that will cut hard carbon will work unless the problem is all corrosion. It's usually a combination of both.

The fact that the guide is loose indicates a fit problem between guide and block. A knurled guide may work or an oversize guide, if available, will be needed to restore the tight drive fit.
 
I will second what Rotorwrench said. Use a good penetrating oil. A combination of automatic transmission oil and kerosene has been reported to work well. Also Coke or white vinegar. After the penetrating oil and removing the spring, try twisting the valve to break it loose.
 
Before we get too much misinformation swirling about, his engine has the guides without a shoulder that are driven in with an air hammer to a predetermined depth in the block. (I live close-by and have been helping oldspert with this engine). We want to be careful not to dislodge the guide from its moorings by getting too rough. I think we should use some heat along with penetrating oil and take our time.
 
mcgarrett said:
Before we get too much misinformation swirling about, his engine has the guides without a shoulder that are driven in with an air hammer to a predetermined depth in the block. (I live close-by and have been helping oldspert with this engine). We want to be careful not to dislodge the guide from its moorings by getting too rough. I think we should use some heat along with penetrating oil and take our time.
Click to expand...

Why do you not want to allow the guide to come out of the block? I would think that would be the easiest way to do it. Remove valves and guide together, then separate them. The guide will have to come out to fix why it is loose anyway or am I missing something?
 
If the guide is moving with the valve it is shot already.
knock the retainer and spring off and push it out with the valve.

After separating the guide from the valve you can assess the situation.
It is not uncommon for some of the guide holes in the block to be loose/oversize.
If the guide is still good ID, you can knurl the OD slightly and loctite it into the block.

I have never had a block with consistent guide holes, always 1 or 2 too tight and 1 or 2 loose requiring the knurling tool.

I am actually impressed for the age how close they are.

John
 
Retainer and spring are already out. Nothing but the valve and the guide left. Tried to turn the valve with tools, tried forcing the valve up but the guide comes up too. I will try heat and more PB Blaster.
Ed
 
Besides knurling the guide, you can use one of the Loctite permanent adhesives. Just make sure that the guide and hole are cleaned with acetone or lacquer thinner to remove all traces of oil before insertion.
 
Need to get an old guide from a machine shop that is the 11/32" or what ever the stem size is. A worn out one might do. Cut it down to fit it up on the stem if possible or clamp one that is slit in two on there so you can back the guide up against the follower and cam. Tap lightly to get it to move. Heat and MMO or penetrant should eventually get it to loosen back up. I just keep tapping as square on the head as I can to keep from bending it. Eventually some combination will work. Patience is a virtue on stuff like this. Going back up with the valve may require a different strategy if the guide is still too sticky but one of those valve guide pusher tools may be set up to either hold the guide or force it down if that is possible.

Non flanged guides can go either way but they are usually driven in from the bottom at overhaul. I'm not a big fan of flangeless guides for this very reason. A flanged guide with flange on the bottom will stay in the hole even if it comes loose due to the valve spring components but a non flanged one can come out the top and limit support for the valve when the engine is trying to run that way. Most of the time, hardened valve seats and guides stay put but every now and then for one reason or another, they can come loose.
 
Last edited:
Got it out by horsing it out by using a puller under the valve head. Guide came out too. Pressed the valve out of the guide in my hydraulic press. It had corrosion on the stem is why it would not come out. Luck was with me because the stem cleaned up and was not bent. I will ream the guide for about .001 or .002 clearance and see if it will knurl if it isn't too hard, reinstall it with green locktite. looked like it might have gotten wet and corroded. Mike came over and helped strip the block down for cleaning.
Ed
 
I would use caution in selecting the Loctite product solely on the fact that it is green colored!

1. There is the Loctite 680 mentioned in post 17 which is green.

2. There is also a green Loctite Part # 290 which wicks into the threads and THEN cures .

If the 290 gets between valve and the valve guide, the valve will seize up!!

Just saying ...

See description below.

Loctite 290 Wicking Grade MIL-SPEC Medium-High Strength Green Threadlocker is a medium-strength wicking threadlocker for pre-assembled bolts up to 1/2". Penetrates threads by capillary action. Secures set screws and other assemblies after settings are completed.
 
Last edited:
The 600 series green Loctites are for cylindrical object locking and have a guide on the back of the package that tells you what they were made to do. It would be wise to use one that is appropriate for the job in holding capability and temperature capability. Otherwise it should be over-sized for correct fit. The temperature capability is likely the least controllable factor in working with cylinder components. Exhaust valves transfer heat to the cylinder block though the guide so they can get very hot at times.

The old two piece guides were not very well suited for use in engines. Ford used them clear up into the early V8 era due to the mushroom tip valve stems. On the model A, a poor fitting two piece guide used in it's history could have damaged the guide bore.
 
Last edited:
You must log in or register to reply here.
Back
Top