Stuck valves

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Model T Ford Forum: Forum 2016: Stuck valves
Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Warren- Huntington, VT on Wednesday, August 24, 2016 - 08:31 pm:

I have two stuck valves that I am not sure how to free up. I have removed the head, and the exhaust/intake manifold. I have been spraying PB Blaster on the valves for the last two days but no change. I am afraid to hit/pull/push on them as I don't want to damage the valve at all. I am hoping to free it up, clean the carbon/rust off from it and put it back together without doing a complete valve job.

Two questions:
Any ideas on how to free the stuck valve without damaging it?

Is it difficult to do a valve job? I am somewhat mechanical, not afraid to try, but never done much car engine work. Have rebuilt snowmobiles and motorcycle engines in the past...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan McEachern on Wednesday, August 24, 2016 - 08:44 pm:

take off the side cover and turn the engine over until the lifter is all the way down and put a stack of washers or discs (pennies or dimes would work) and them crank the engine over and let the cam push the valve up. Keep doing this and you can jack the valve all the way to spring bind if necessary. the valve should pop loose at some point.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Wednesday, August 24, 2016 - 08:46 pm:

Be sure the cam lobe is point down, then take a dowel and place right in the center of the valve head directly over the stem and tap lightly with a hammer. The valve should go down. Once it is loosened up, you can then bring it back up by rotating the camshaft. Remove the keeper and spring. Grab the head of the valve and try turning it from side to side. It should eventually loosen up.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Eviston on Wednesday, August 24, 2016 - 08:51 pm:

If it was mine, I would gently tap it down with a rubber mallet or bock of wood. Then, I would crank it till it came back up again and repeat. I would also take the valve cover off and put needle nose vice grips on stem above tapper and twist. Good news, that is a good looking valve, and the guides can't be worn much. Brace yourself. You willikely be deluged with opinions advising to hoist up the radiator cap and drive a restored car under it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Tomaso - Longbranch,WA on Wednesday, August 24, 2016 - 08:54 pm:

I'm with Dan but I wouldn't be scared of giving her a little "luv tap" with a small brass hammer with the cam lobe down !


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Eviston on Wednesday, August 24, 2016 - 08:54 pm:

My post presupposed you would tap the valve down only when the other unstuck one was up. Slow Tyler.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Eviston on Wednesday, August 24, 2016 - 08:57 pm:

Typer. sPELLCheck.....


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Warren- Huntington, VT on Wednesday, August 24, 2016 - 09:33 pm:

Thanks Guys! I'll give it another day with PB Blaster then I'll use a block of wood on top of the valve and give it a few light hits to see if I can get it to move down at all. All the valves look the same. They are in great condition and the pistons and cylinders look great too.

I'll let you know how I make out.

Mike


Top of pagePrevious messageNext messageBottom of page Link to this message  By Corey Walker, Brownsboro TX on Wednesday, August 24, 2016 - 11:01 pm:

I know you don't want to but since you've got it torn down that far anyway, grinding or lapping whatever you call it is pretty simple and easy. All you have to do is put some valve grinding compound on the valve seat and rotate the valve back and forth then raise it up turn it a little then do it again and so forth. Take the valve out occasionally and wipe the surfaces clean and see if the valve and seat are making full contact all the way around. You can get a marker and color the seat put the valve in and see if the marker comes off all the way around the valve, you can use Prussian blue or just see if both surfaces are shiny all the way around. Check the clearances you may have to grind the valve stem a bit but make sure it's the clearance to where the valve actually hits the lifter because they get cupped with wear. You may need the suction cup tool,or if they are 2 price valves I stick needle nose pliers in the 2 holes. I smashed a light bulb to bits in a rag before and mixed the bits with oil and made some compound. I've even grabbed a valve stem and twisted it while pushing down on the head to grind it since I didn't have the suction cup,well I've never had one and mine run fine. Shade tree I guess but poor people have poor ways. Good luck.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Thursday, August 25, 2016 - 10:32 am:

Check the block for cracks in or near the valve seat. Sometimes they crack around the exhaust valves. A small amount of water leaking at that point can cause rust. If the car isn't used regularly, the rust can build up and cause the valve to stick. Usually it is carbon buildup, especially carbon on intake valves.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Thursday, August 25, 2016 - 11:08 am:

Switch to a 50/50 mixture of automatic transmission fluid & acetone. Try damming up the port, at least partially, with some clay to retain a good puddle of the ATF/Acetone mix around the valve stem.

You could try lightly twisting the valve also. The twist you induce in the stem may get things to open up a bit, especially near the top, where your 50/50 mix is.


Top of pagePrevious messageNext messageBottom of page Link to this message  By keith g barrier Savannah Tn. on Thursday, August 25, 2016 - 03:39 pm:

Michael, you didn't say if they are the original two piece valves. If they are then I wouldn't worry about damage as they need to be replaced anyway. A valve job is not that much more trouble as you already have the head and intake and exhaust off.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Corey Walker, Brownsboro TX on Thursday, August 25, 2016 - 04:13 pm:

I had a 2 piece valve break. #4 exhaust valve, pieces went out and into the muffler, if it had been an intake they would have got smashed around in my combustion chamber. Has made a good key chain since 94 or 95.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Thursday, August 25, 2016 - 04:29 pm:

You've got to get it moving one way or the other. I think I'd try to grip the head with water pump pliers and see if it'll spin. Any movement is a good thing. The exposed bit of the shaft that will sink back into the guide looks like hell too. Perhaps going up as suggested and trying to clean that shaft up a bit is a good idea. What's showing is probably worse that what's in the guide.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Warren- Huntington, VT on Thursday, August 25, 2016 - 10:26 pm:

I used Dan's method and I placed a small aluminum rod between the valve and the lifter and then I very slowly cranked the motor over which pushed the valve up and out very smoothly. The valves have some pitting where it was built up with carbon and a bit of rust. I cleaned it up with a Scotch Brite pad and it seems pretty clean now.

I believe that the valves have been replaced previously as these are not two piece valves.

I think that I am just going to lap the valves and put the head back on and try to get the motor running. I am afraid that the more I tear into the motor the more of a mess I'm going to make. I am starting to get low on funds for the project and I'd rather get the rest of the car put together and maybe in a year or two I'll pull the motor again to do a complete rebuild. For now, I just want to get it running and be able to drive it around town here a bit. We don't plan to travel more than 10-15 miles from the house in any one direction.

Thanks for everyone's help and ideas on getting the valves freed up.
Mike


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan McEachern on Thursday, August 25, 2016 - 11:45 pm:

You will get a much better lap job if you take the valves to a local shop and have the faces ground. If the stems are worn badly, don't bother. Glad you got them out.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ralph Fitz-Gerald on Friday, August 26, 2016 - 06:31 am:

Mike I have valve reamers and grinding compound if you need any thing.
Fitz


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