Intake Valve not seating

I have looked at the lifter pretty close but have not pulled it. All of my lifters have that line on them in that location and I even see it in pictures of new ones on the internet.

Looking at my picture I posted I can see where it looks cracked, but it doesn't really look like that with the valve removed. I'll get a picture of the bare lifter and post it later today.

I'm not opposed to pulling it, although I've never done it and don't know how yet to do it. I didn't know how to pull the valve either until a few days ago. :)

I really appreciate all of the input and I am by no means arguing with you all. I'm just trying to learn as much as I can.

Here is a picture of a new one from the internet that has the same line I see on mine.
 

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bmwillia said:
I have looked at the lifter pretty close but have not pulled it. All of my lifters have that line on them in that location and I even see it in pictures of new ones on the internet.

Looking at my picture I posted I can see where it looks cracked, but it doesn't really look like that with the valve removed. I'll get a picture of the bare lifter and post it later today.

I'm not opposed to pulling it, although I've never done it and don't know how yet to do it. I didn't know how to pull the valve either until a few days ago. :)

I really appreciate all of the input and I am by no means arguing with you all. I'm just trying to learn as much as I can.

If you have the valve assembly out, it literally will lift out of the bore. You can use a magnet to pull it out.

Here is a picture of a new one from the internet that has the same line I see on mine.
Click to expand...


Ah, I hope Cam Grinder Pete joins in on this. He's said many times that the reason why Ford changed to the solid sided hollow lifter is because that style of lifter was prone to cracking or the top caving in.
 
I may have missed this idea in the thread, but...
Using a compression tester that is too long,
The valve may hit the end of the tester, and bend the valve.
I've a vague memory of someone bending all of them...
NOT me

Karl
 
I just went back a re-read the post. So swapping out the valve fixed the problem, correct?
 
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I pulled the intake valve on #7 and inserted it with both the #8 and #7 guides and it appeared to seat and lined up with much better clearance than the original #8 valve (that appears to be bent) using either guide.

I was not able to perform a compression test obviously since the head is off so I won't really know how well it seals until I'm able to do that. I can only say that I do not see a gap between the valve and block as I did with the original valve.

As info, I ordered a new valve and guide from Vanpelt this morning.

Brad
 
bmwillia said:
I pulled the intake valve on #7 and inserted it with both the #8 and #7 guides and it appeared to seat and lined up with much better clearance than the original #8 valve (that appears to be bent) using either guide.

I was not able to perform a compression test obviously since the head is off so I won't really know how well it seals until I'm able to do that. I can only say that I do not see a gap between the valve and block as I did with the original valve.

As info, I ordered a new valve and guide from Vanpelt this morning.

Brad
Click to expand...

Pour a little fuel around the valve to seat area. It will give you an idea how good a seal you may have with the exchanged valve to seat tightness.
Phil NZ
 
Thanks Phil.

For the bad valve I put a light in the intake hole behind the valve and could see light around the edges. With the straight valve I don't see light. I suppose liquid would be a better test.
 
he bent valve story. Back in history I ran a rebuilt ¾ race flathead in a ’40. I bought the short block from a friend who had it in his barn for storage. Put it together and installed if. It ran good, but a friend could beat the ’40 in his father’s Chrysler station wagon. That would never do, so I took to very experienced mechanic to check it out. He found one bent valve, and checked the rest of valve train. We figured the valve got bent moving the engine around in the barn. Put it back together and stayed up most of the night getting the valves adjusted. The clearance kept changing as we adjusted one valve and moved on to another. Reground cam flex. Around daylight we pulled out of the gas station and that ’40 pulled like train of mules. The station wagon was no match for it now. We used Jenny Royal gas at the time as it was high octane. and smelled great when it burned.
 
Terry said:
Could lap the valve and see the contact area.
Click to expand...

That is what I'd do.

Also, the chances that a new valve is going to magically have the correct length are kind of slim. On these engines, the valve stems have to be ground to set the valve lash - you can't just drop in a new one.

Sometimes you need to shorten the valve (grind the stem tip), other times you need to lengthen the valve by welding material on the end and then grinding it back to set the clearance. This takes a valve machine and the ability to determine the valve length requirements (a special mic).

Make sure you understand all of this - and measure the lash with the lifter on the heel of the cam. The lash should be somewhere close to .016 or so.
 
If it is too long, then it needs to have the stem shortened on a valve grinding machine. If you have a good depth mic, you should be able to determine how much needs to be ground off the stem - such that you have about .015 clearance.

You'll need to pull the lifter out and put the valve and guide in - then measure the height of the valve to the deck surface. Then, put the lifter back in and measure how much the valve sticks up (from the deck surface). Then subtract the lower number from the higher number, then subtract another .015 and that is the amount that needs to be ground off the stem. You'll need a machine shop to do the work - and make sure you take a pair of dial calipers to measure the total length of the valve and give them the NEW length they need to grind too.

Note: You must FIRST ensure that the lifter is on the HEAL of the cam!

Hopefully I'm making some sense here . . .
 
I first with the lifter removed I installed the valve and guide and lapped the valve. Be sure to absolutely clean any lapping compound without washing any down into the engine.
Next I installed the lifter, valve and guide, and measured clearance with a feeler. I had .006" on my new valve so I knew I needed to shorten the valve .010.
For me the nearest valve grinding machine is 75 miles away so I went for a drive. I had the machinist grind .010 off the stem. Reinstalled the assembly and checked again.
Mines running great again.
 
An alternate backwoods method of setting valve lash; I am not suggesting it is a good idea but it does work. I did my 8BA's this way, a real long day to do a complete engine; ton of time and patience. The set-up uses a valve guide to square up to the face of the grinder, takes seconds to take couple thou off the stem with the grinder running. Stop at 2-3 thou short of planned cut and the rest is done by hand. Hold emery paper against the stone and rock the stone back and forth by hand while rotating the valve with the other hand. Use progressively finer papers and lubricants; the last I used was about 800 and wd40 as a lube. Do at least the last couple thou entirely by hand, slow but it is too easy to take too much off with the grinder turned on. Not perfect but within a thou when installed. The stem has a decent polish when done as 2nd pic shows.
 

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I have the new valve inserted and lapped. I have .011 of clearance and according to Mac VanPelt's chart referenced above, I should be safe to grind the 8N valve being that 5x and 2N are open at the moment.

I'll try to find a machine shop near by that can grind the valve but I may have to resort to Don T's method to get it up to .015 of clearance.

Brad
 
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