HELP! Valves won't seat

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Model T Ford Forum: Forum 2015: HELP! Valves won't seat
Top of pagePrevious messageNext messageBottom of page Link to this message  By John Eaton on Thursday, January 22, 2015 - 08:29 pm:

Valve guides have been reamed oversize, valve seats have been ground 45 degrees. New SS valves will not seat. Ground new valve and still will not seat. Used compound and will not seat( light in port shows around back edge of valve). I welcome any and all constructive criticism. Something is definitely wrong. ( All work was done with B&D valve grinder and seat grinder, new and freshly dressed stones.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan McEachern on Thursday, January 22, 2015 - 08:37 pm:

Bent grinder pilot?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Glen Chaffin on Thursday, January 22, 2015 - 08:37 pm:

John, Are you using a new cam? If so the base circle of the cam is larger and requires that you make the valve stem shorter. This is a common problem.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Bender Tulsa Oklahoma on Thursday, January 22, 2015 - 08:41 pm:

Assuming the valves are not touching the lifters, pilot was not the proper size for the reamed guides???. Not sure as I use a Kwikway seat cutters. Be interesting to hear what the problem/solution was.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Frank van Ekeren (Australia) on Thursday, January 22, 2015 - 08:42 pm:

Is your seat grinder using a lock in shaft in the guide? or the guide pin on the stone tooling? it is very easy to be out of alignment using the vendors reams if using them free hand, the seats can take some cutting to get them right again but must use the guide locking pin to get all square again.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Bender Tulsa Oklahoma on Thursday, January 22, 2015 - 08:43 pm:

What Dan and Glen said, they type faster than me. LOL


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Thursday, January 22, 2015 - 09:07 pm:

I put new valves in an engine with a new camshaft and adjustable lifters. This was 2 summers ago. New valve seats and all ground to fit. However we could not get the valves to seat with the lifters adjusted all the way down. We had to take about 60 thousandths off the valve stems. You see those new valves were made to fit a different car so you need grind the stems to fit. Once we ground off the stems we did the fine adjustments with the lifters and the car runs like a cat purring. Don't grind off 60 thousandths just because I did. Make your measurement and grind off enough that you will be able to use the adjustable lifters to fine tune. Your clearance on your engine might be different than the one I worked on. So measure first before you grind.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Eaton on Thursday, January 22, 2015 - 09:35 pm:

Glen, I have not installed the cam or lifters yet. Frank, the seat grinder uses a guide that locks in the guide. Mike, the pilot is very snug in the guide and then tightens to solid so it is self aligning.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Eaton on Thursday, January 22, 2015 - 09:44 pm:

Dan I have put the pilot in on several occasions so if bent the light should show through in a different spot each time. The valve guides were done by a machinist friend of mine. I believe they are all the same. I have tried different angles on separate valves and none made any difference ( 44, 45, 46)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Thursday, January 22, 2015 - 09:59 pm:

Maybe the guides are not true to the seats,ie, at angle slightly off.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Clayton Swanson on Thursday, January 22, 2015 - 10:00 pm:

i bought an old black and decker valve grinder thinking it was a good deal, and all three of the handles that the stone screws onto were worn out so bad that it made egg shape holes. the pilots were snug, freshly reamed holes, but loose handles. they are about 40 bucks each on ebay, and you should have one for each stone, or retrue every time you switch stones for different angles


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Redelman on Thursday, January 22, 2015 - 10:00 pm:

The secret is to ream the guides with a fixture that guarantees that the guides are cut perpendicular to the block surface and not freehand. If they aren't square with the world you will have all kinds of trouble to get the valve seat symmetrical with the valve guide. I recommend to take the block to a shop and have new guides installed before proceeding to install new seats and do the valve job. I have fixed many heads and blocks that people thought they could just buy a reamer and do it by hand.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Eaton on Thursday, January 22, 2015 - 10:05 pm:

Clayton, I will check the handles for wear. Steve the guides may indeed be off square.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Thursday, January 22, 2015 - 10:24 pm:

John,

When you try to lap the valves in, what are you finding?

Does the seat area of the valve show evidence of being lapped all around the circumference, or just partially?

Or,

Does the seat in the block only look partially lapped, versus lapped all around it's circumference?


If the valve looks fully lapped, and the seat only partially, then the seat is either not concentric to the guide, or it is not perpendicular to the guide.

If the valve looks only partially lapped, (and the seat fully lapped), then the valve grind is either not concentric to the stem, or it is not perpendicular to the stem.

You first have to determine where the error lies before you can troubleshoot the cause.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Eaton on Thursday, January 22, 2015 - 10:43 pm:

Jerry, The valve seems to lap and the seat seems to lap however more on the front than on the rear of the seat and that is when I can see the light.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Thursday, January 22, 2015 - 10:44 pm:

Sounds like the trouble is in the seat then.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Eaton on Thursday, January 22, 2015 - 10:50 pm:

Ill have to try again tomorrow. Thanks for all the help and suggestions


Top of pagePrevious messageNext messageBottom of page Link to this message  By samuel pine on Friday, January 23, 2015 - 03:57 am:

After all said & done, our final check is to use
the shop vac with the hose stuck on each port.
The vac will suck the valve to the seat and check
for leaks and watch your fingers..


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andre Valkenaers on Friday, January 23, 2015 - 04:57 am:

John, I think you will need to cut your valve seats. You can do it your self but there for you need a seat cutter.
After, you need to do what Norman said before.
Good luck

Andre
Belgium


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Eaton on Friday, January 23, 2015 - 07:03 am:

I'll check the seat grinder pilot and handle for wear. The valve guides may not be totally true 90 degrees but they were done on a machine so they will probably be all the same (right or wrong). I've been using a light in the port to check the fit of the valve but I will also check the seat with the shop vac.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Anthonie Boer on Friday, January 23, 2015 - 07:16 am:

John :
For reaming the oversize Valve Quides, I use the following,see pictures.
Toon
284R
286R
289R


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Eaton on Friday, January 23, 2015 - 08:56 am:

Toon, I Will try that next time. Clayton, The pilot and handle seem OK but the pilot on the wheel dresser seems worn. I will replace it and try again.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Semprez-Templeton, CA on Friday, January 23, 2015 - 11:29 am:

John, I prefer using the Nuway cutters for the reasons you have described. The Nuway system allows one to make a very light first cut, which will reveal the ovality of the seat instantly. Since the Nuway is cutting the seat (not grinding), it will gradually cut a new seat perpendicular to the guide if used with a light touch. My experience with stone grinders is that it is easy to use too much pressure which can allow the pilot to deflect slightly allowing the stone to wander or follow an oval (worn) seat, resulting in an elliptical or off centered seat. Ask me how I know this...


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Eaton on Friday, January 23, 2015 - 01:58 pm:

John, Thanks for your post. I am an old dog trying to learn new tricks. I am not a fast learner. These valves are giving me some grief as I hopefully learn. I got a little more frisky with the seat grinder and went a little deeper It looks like I cannot see any light around the valves Now I will lap and hope for the best.. It looks like I may have been more satisfied with the cutters but I didn't know about them. ( refer back to slow learner section)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Craig Anderson, central Wisconsin on Saturday, January 31, 2015 - 09:28 pm:

If the seats get too wide you can lap yourself to hell and back and it will be for nothing.
Regardless how the new valves arrive it they do not have a triple grind take them to a shop to have that done.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Eaton on Monday, February 02, 2015 - 08:03 am:

Thanks everyone, Craig, as I said before I am an old dog trying to learn new tricks. I took some old, but good, valves and did a triple grind and now have them all lapped in. I am timing and setting lash now.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Monday, February 02, 2015 - 08:55 am:

Be aware original T valves has a tendency to break where the two pieces are joined - 90 years of corrosion makes fatigue breaks even more likely today than back in the day. So old but good valves may be fine as long as they aren't the old Ford two piece style seen below:

old valves

valve

(pictures borrowed from older forum threads)


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Eaton on Monday, February 02, 2015 - 12:27 pm:

The valves that I used were oversize one piece from the 1970's They were never used a great amount so looked newish.


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