65sixbanger
Full Access Member
Did the machine re cut the seats in the head? Maybe this seat wasnt cut properly. I would get that sandpapery grease (For valves) and that suction cup to see exactly where its hitting on the valve.
Brown Truck Under the Knife Project - Engine
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6 Nebraska IDIs
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^^^ You're talking about lapping compound, I have it and have everything to do it but am not sure if I want to. The valve is obviously stuck in the guide for whatever reason, whether that be after it hit the piston or it stuck and that's why it hit the piston I do not know yet and I'm not sure if I'm competent enough to take the valve out and actually be able to see what happened.
Fishin76
Full Access Member
Taking a valve out is not that hard. Compress the valve spring, remove the valve keepers with a magnet, release the spring and gently pull the valve out. You will be able to note any binding while your pulling it out.
65sixbanger
Full Access Member
Take a rubber mallet or you can even do it with your palm, and just tap on the valve to try to get it to open up, maybe this will free it up. And the lapping compound would be able to tell you where the valve is seating and what your problem is....Good Luck
I think the guy may have taken too much off the head. Possibly more from one side than the other. You should consider replacing both heads but not surface them. Since they are made from cast iron they are not prone to warpage. No use putting it back together and have the same problem happen on the other side.
sle2115
NRA LIFE MEMBER
Hey bud, I'm sure you know this, but DO NOT just take that head to this guy and leave it! I know you don't want to tear it down and have him say you did something wrong, but make him disasseble while you are there.
If it galled to the guide and hung open, there should be signs of it on the valve and guide when it's disassembled. I'm guessing on something like that. If he tears it apart, that valve and guide are going to dissappear!
If it galled to the guide and hung open, there should be signs of it on the valve and guide when it's disassembled. I'm guessing on something like that. If he tears it apart, that valve and guide are going to dissappear!
trackspeeder
Stone crusher.
X-2 on this.
icanfixall
Official GMM hand model
Sean.... Where are the exhaust valve seals positioned on the head... Are the in the top of the spring holders or pushed down on the guides on the head... If they are on the head and not up in the spring holder then the machinst did it all wrong and the valve ran out of oil and gaulded somewhat...
Hybrid455
Full Access Member
The tell tale will be if the valves show gauling. If they are cherry there may be a deck clearance problem. The exhaust valves need to come out of that head. In either case I would worry about the other head as well. Easier and cheaper to pull it now then later. I am not sure that you need to replace the heads however. You could find out what the crush thickness is on the gaskets that you used and then do some research to see if there are any gaskets with a thicker crush thickness. If there are I would use the thickessed ones you can find. I know that on some engines you can gain as much as .010 deck clearance using thicker gaskets. This might be a good idea no matter what heads you go back together with. Even if the clearance is OK it couldn't hurt to lose some compression. You can get an idea of how much has been taken off the heads by cc ing the combustion chambers on that head and then comparing the measurements to a stock head. Anyone know what the stock chamber volume is?
Hybrid455
Full Access Member
Sorry for double post but I thought of something else. When you go back together with this engine clearance the valves to pistons before final assembly. In my opinion this is imperative on any high compression tight clearance engine when the heads, gaskets, block deck or rotating assembly has been changed through the course of a rebuild.
icanfixall
Official GMM hand model
These motors don't have a combustion chamber that can be CC measured. They have a Richardo chamber in the pistons and a precup chamber in the heads. Plus... The pistons raise upout of the block as much as 31 thousands and the heads are flat... The head gasket keeps the pistons from contacting the heads. The Felpro head gasket is the thickest gasket on the market. Its around 75 to 78 thousands thick and compresses down to around 72 or 73 thous... Now take 31 from 72 and that is 41 thous clearance from the pistons to heads. This wont change even if you milled the heads down 250 thous... The gasket is still the clearance determining factor. What hapens when you mill the heads is the valves get that much closer to the pistons if the valves are not machined deeper into the heads... And if they are set deeper into the heads then the springs wont hold them closed without spring shims. Now lets talk about how much gets ground off the end of the valves so the rockers have the correct geometry... It gets really deep into knowing what your doing now. A deep set valve means the spring is loose and the stem is too high.. One action creates another reaction.. And it just goes on and on like this.....
sle2115
NRA LIFE MEMBER
What he said! The only cure is removing material from the end of the valve, as well as shimming the valve spring if necessary. Compressed spring pressure must be measured, standing height must be known, etc., etc., etc.
Hybrid455
Full Access Member
Yes the valve stems have been obviously ground down. That was one of the first things I noticed. I didn't understand why until now though.Intake more than the exhaust for whatever reason but yea he ground them down.
Cutting .009 off the heads makes the valves that much closer to the pistons now. That also increases the comp ratio some. The valves need to be sunk into the heads by a certain amount. It .042 to .054 for the intakes and .051 to .063 for the exhaust... The precups can be + or - .0025... The heads are junk when they are less than 4.795 thick measured from the valve cover gasket rail to the bottom of the head. They have a stock mearsurement from 4.795 to 4.805... If you had heads that were 4.805 to begin with then you now have heads that are 4.796... So you can loose 1 thousands and still be just fine....Now just maybe this guy sunk the valves deeper in the heads the same 9 thousands. Thats fine if he shimed up the springs because if not they wont have the pressure to stay closed. The rocker geometry stays the same but the lifter is now using a 9 thousands differance postition and that just fine too.
Ok obviously I have a lot more experience with gassers then these babies but I am learning and a lot of the principles still apply. Shouldn't you be able to cc the precombustion chambers
? If the shop actually put the heads on a milling machine and watched how much they took off then .009 is good but I've watched guys throw these things on a surface grinder and they don't have a clue how much came off. I went back through the posts out of curiosity and found some interesting stuff. I heard talk about a Federal Mogul gasket set. But didn't see that confirmed. Federal Mogul absorbed Fel Pro and others. The gaskets that were used appeared to be composite fiber. Were the gaskets used Fel Pro's or another design swallowed up by Federal Mogul? I'm used to seeing the old blue hard as nails print-o seal Fel Pro head gaskets. Maybe the ones for this engine are different ? After some quick checking the OE Ford gaskets are supposed to be about .060 compressed. If that is correct then there may be as much as .012 additional piston to valve clearance available for the cost of a set of gaskets. It also concerns me that the exhaust valves have posi lock seals. If the machinist used the posi locks with the retainer seals as well the exhaust valve guides are probably starving for oil. It would also be interesting to lay a straight edge along the valve faces and see if any are above the head surface. After looking at the pictures of the heads when they came back from the machine shop it's hard to tell but the springs do appear to be shimmed.
RacingSTude
Registered User
Just one other consideration, fellas.... It could well have been his own lifter that caused the bent push rod. He used his old hydraulic lifters and it's very possible that it got a piece of crap in it during the work. A hyd lifter is actually a little hyd pump, even a grain of sand can prevent it from pumping, holding the lifter in the "up" position, over-extending the valve train. OR, due to the cut head, the lifter had crap in it to start with and/or the little piston in the lifter was out of it's original "wear zone" or area where it had been pumping, causing it to stick. From what I see, just one valve is bent, an easy fix. Have that one intake valve checked for straightness, put a new exhaust valve in it, put a new or re-man set of lifters in it, (ALWAYS should do that anyway), and run it. It'll be fine...
It's kind of odd that just one push rod was bent and why I think it was the lifter. A properly contoured lifter base, (camshaft end), is convex in shape, NEVER flat or concave. A lifter MUST rotate as it operates. Never a good idea to use old lifters in a new motor.
It's kind of odd that just one push rod was bent and why I think it was the lifter. A properly contoured lifter base, (camshaft end), is convex in shape, NEVER flat or concave. A lifter MUST rotate as it operates. Never a good idea to use old lifters in a new motor.
seawalkersee
It needs a turbo...
Uhhhh...you know some of that does not apply here. They are rollers in these, so there is no convex/concave surface. I understand where you are going though.
SWS
SWS
