Valve in new engine not seating

I made a valve removal tool out of a pry bar and was able to get the retainers and spring out.  Next, I spun the valve with a drill, and then reassembled the spring and retainers.  I then pressure tested and vacuum tested the intake runner and found that both values improved.  This is an indicator to me that the valve will likely seat once the engine is running because of the explosions pressing against it.

It looks like I will be moving forward with final engine assembly and installation into the car.

Here is a photo of the tool that I made.

Glad to hear that it seems like the valves will seat 👍

If I had the engine out I sure would pull the head, that is a No Brain-er as compared to pulling a head when everything is assembled

Risky business…

I agree with Adam!!!

AND : there are hopefully no explosions in the engine ! … it’s a burn 🔥!

there is also the possibility that the “dirt” , if it’s that , stays in the same position and just gets pounded into the seat on the head or on the valve and it will not get better! Then, you have multiple possibilities of failure!

your problem may even be a not proper installed valve seat… If that’s the case, you are actually lucky that you discovered it before you fired it up!

I would bite the bullet and open it up!

There can only be two answers:

the valve seats proper

or

it doesn’t!

there is no… almost good!

I am wondering how common this problem is.  It is likely that most of us have sent cylinder heads to a shop for a valve job, installed them upon receiving them, and run the engine that way.  On the contrary, I think few of us have pressure or vacuum tested the cylinder heads after the work was done.  The only reason I did so was to test the plumbing for the EFI's MAP and IAC (Idle Air Control).  While testing that plumbing, I found leakage in the manifold gaskets and fixed such with thick gaskets and sealant.  While continuing the testing I found the leak in one valve seat.  Throughout this testing there have not been any leaks in the plumbing for the MAP and IAC.  I am somewhat reluctant to tear down a sealed manifold and cylinder head just in case one valve might not seat once the engine is running.  I am now setup to test the valve's sealing ability at any point in time.  I am inclined to run it as is, and test the valve's seal after break-in.  Over the years I have become somewhat accomplished at removing Pantera cylinder heads in the car and have a special adapter for my engine crane that handles cylinder heads nicely.  I think I will roll the dice and hope that the valve seals.  If it does not then I will pull the head in the car and lap the valve.

Thank you for your input on this.

Here are photos of the plumbing that I was testing.  It is the black tubing and push to connect fittings.

Whenever I got heads back I put the spark plugs in, flip the head upside down and fill the chamber with gas … that tells the story pretty quick…

I spoke with Wilkinson about this and I am going to try lapping the valve in place.  I can reach the valve through the intake runner and apply a small amount of lapping compound and spin it with the drill again.  Then try to remove the compound with a paper towel.  The photo is fuzzy but the valve seat is visible and somewhat accessible through the runner.

Lapping compound is a great idea, if you have any crap on or already into the seat just put that compound on and oh heck attach your drill to the valve and spin it.

@adam posted:

Lapping compound is a great idea, if you have any crap on or already into the seat just put that compound on and oh heck attach your drill to the valve and spin it.

Low speed, changing rotation, With a 4 inch hose connection between so you can not apply side loads!!

@stevebuchanan I’m glad you to attempt to fix the issue!!! I was surprised that you would let it go…

after you detected and fixed the intake leak so meticulously and then you would let a much worse situation slide…..

👍👍👍👍

Not sure how you keep the lapping compound out of the cylinder..😳

I’ll be using very little lapping compound. I’ll try to get it off with a paper towel afterwards. The combustion chamber is packed with rope to hold the valve in place. Maybe it’ll catch any compound that comes off the valve and seat.

If by chance there is some type of debris under the valve and you are able to knock it loose, where does it go?

Hopefully not between the piston and the cylinder wall but hope should not be a plan.

I don't understand the apprehension in pulling the head?

@panteradoug posted:

If by chance there is some type of debris under the valve and you are able to knock it loose, where does it go?

Hopefully not between the piston and the cylinder wall but hope should not be a plan.

I don't understand the apprehension in pulling the head?

Yep… My thinking as well…

Reading about sealing the intake manifold it probably takes  one day to just clean the  sealant off.. Still wouldn’t stop me pulling the head..

And lapping compound is like fine sand in a paste.. and absorbs the metal ground  off…. Rotating will sling the paste… and it will dry and fall in…

lapping the valve worked.  With a screw driver, I applied a small amount of lapping compound, about half the size of a pea.  I ran the drill at low speed in both directions as Roland suggested.  Then I put a series of paper towels soaked with WD40 between the valve and the seat in an effort to collect debris.  I ran the drill between some of the cleaning cycles.  The valve spun smoothly in its seat at the end.  The combustion chamber is packed with rope through the spark plug hole to hold the valve up and it may have contained some of the debris.  There could not have been much that was causing the problem.  With the spring reinstalled, it now holds a vacuum like the other intake runners.

That sounds very good… !!

were you able to see the lapping mark on the valve? Sufficient?

I hope you don’t get me wrong. I’m rooting for you….

I am just allergic to shortcuts because my car was made out of shortcuts ….

i sure you know all the things I did and the 💩 I went through… opening can of worms seems to be my main job since last November when I bought my Pantera…

From pedal box to brakes and brake lines to cooling system to heater and A/c core and fan  to dash and center console with all the electrical problems including headlight motor , window regulators to gas filler to wheels and rusted through heater tubes to brake discs and wheel bearings, headlight switch ordeal and on and on …

I thought it’s a 4 month thing I’m doing here BUT I’m looking a whole year right in the face 😳

I drove my car today for the first since I bought it… 12 miles I did…

I came back with a few things… and the fighting continues…

Thanks and it’s great that you got your car going. I think that’s the most important thing with Panteras is to have them driving. I love working on them, but it’s most important that they are drivable. Good work.

@stevebuchanan posted:

Thanks and it’s great that you got your car going. I think that’s the most important thing with Panteras is to have them driving. I love working on them, but it’s most important that they are drivable. Good work.

Thank you 🙏

my car got killed by 1000 shortcuts (I assume as sales prep )and then sitting in a museum for many years..

It will be my daily driver… I will beat it into submission!!!

I began leak down tests on all eight cylinders and found that #1 intake still leaks.  Also found that #4 exhaust leaks as well.  All of the others worked well but I will retest all eight cylinders again.  For now it looks like I will be pulling the passenger side cylinder head and getting those two valves fixed.

The cylinder head is off and will be going to the machine shop this morning to fix the #1 intake valve and the #4 exhaust valve.  I did another leak down test this morning and the other valves are sealing properly.

This is a high compression engine.  It has 1970 D0AE closed chamber heads and flat top piston making it higher compression than the 1971 Panteras.  The 1971 D1AE closed chamber heads have a higher volume chamber.  Hmmm, maybe I should reduce its compression with the thick head gaskets intended for such?  Or just run 100 octane?

Do you know what compression ratio your set up has? I would try to be able to use 93 pump gas.. ) -10.2 ish- just for ease of operation and if you ever want to sell it you would have limited customers for 100 octane only and it’s a pain in the ass to live with that! …. couple posts ago you said yourself “The most important part is that they  are Drivable” 100 octane only puts a limit on it…

I’m glad you took the head off and fix it properly..

When you get it back put the spark plugs in, flip it over and fill the chambers with gasoline… Just for the fun of it (and “trust but verify”)

I used Summit's calculator and it came in at 9.64.  I don't know if I am doing this correctly.  If 9.64 is correct then 93 octane will work fine.

Inputs to Summit's calculator:  Bore 4.030, Stroke 3.5, Volume 62.8 cc,  Piston Dome/Dish 0.0, Deck Clearance .072, Compressed Gasket .033, Cylinders 8

It could be the deck clearance (.072) that is reducing this engine's compression ratio.

@stevebuchanan posted:

I used Summit's calculator and it came in at 9.64.  I don't know if I am doing this correctly.  If 9.64 is correct then 93 octane will work fine.

Compression Ratio :	9.64 : 1
Total Displacement (in.3) :	357.16
Total Displacement cc's :	5855.08

Inputs to Summit's calculator:  Bore 4.030, Stroke 3.5, Volume 62.8 cc,  Piston Dome/Dish 0.0, Deck Clearance .072, Compressed Gasket .033, Cylinders 8

It could be the deck clearance (.072) that is reducing this engine's compression ratio.

And you did not account for the valve relief  either..

You should be fine..

did you meter the 62.8 cc?

I was thinking the same thing about the valve reliefs.  The value of 62.8cc for the combustion chamber is from the Internet.

Your calculation is close enough. You are about the limit of 92-93 octane in the pumps in the US.

The closed chamber head Clevelands are particularly sensitive to octane. You still may need to limit total timing and more likely the rate of advance but you can't know that until you are up and running.

You do not want any more static compression so use standard thickness head gaskets.

Agree… you should be fine running pump gas 93 Octane.. and play with timing once it’s running as Panteradoug suggested!

and if push comes to shove and you get a little pinging going on when it’s extra hot , you can add octane booster… I had to do that on my 1974 911 Carrera (210hp) I brought from Germany… Worked great!
but I doubt it very much being in the 9s..

I removed the spring and inspected the valve and the seat, and it looked perfect.  Next I put a thin layer of blueing paste on the valve, pushed it down in the seat, and removed the valve. The paste that transferred to the seat looked perfect as well.  I then cleaned off the blueing, pushed the valve down and filled the chamber with gasoline.  No leaks.  Only the weight of the valve is holding it down.

And I just tested the exhaust valve on #4, and it is leaking.  Not a lot, but there is gas accumulating in the exhaust port.

@stevebuchanan posted:

And I just tested the exhaust valve on #4, and it is leaking.  Not a lot, but there is gas accumulating in the exhaust port.

No leak is what it should be with springs installed… you can skip all the vacuum testing and blue paste and whatever…

It has to hold gas…

I found the exhaust valve leak when the engine was assembled by doing a leak down test.  The spring was installed during the test.

Are there valve seats installed in these heads?

The valves should seal with no springs installed.

With the head out I'd look at all of the valve seats.

It looks like the intake valve seat is original as you can see in the first photo.  The second photo is the exhaust seat.  I can't tell if it is original or a replacement.

Valve Springs installed or not it wouldn’t make any difference on the seating…

Just saying if you get them installed you wanna check there’s no need to take the springs out…

...Were All the Valves Lapped-In By Hand!!! Before Assembling in the Head??

NO Power Drill! IT Influences the alignment and It Wears the Valve Guides, Oblong! It's simply Too Fast! The Guides are Not there for the Valves to be spun in them, only a slight rotation during operation. It is Not as accurate as Lapping by Hand.

If The Valves are already Installed in the  Head, You Disassemble The Valves. Every one and Lap them In, By Hand ONLY, Slow, Reversing and Accurate.

I Did!!  Just use the FINE Grit. Do Them All and Make sure they get back in their matching Bores

...If a Exhaust Valve doesn't seat, You're Burning a Pathway through the Seat! An Explosion is Not going to seat It!

In My Opinion.

MJ

P.S.  In the Above Photo, is That the Decklid Sitting On The Roof?? NOT a Good Idea, Even with Protection, The Weight of it, over Time, will Leave Marks, that can not be Easily Removed! Glad To see you have some protection at the 'Tail'.

The photo with the deck lid on the roof was from the seller.  I was equally concerned.  I have never done that and never will.  Seems like it could fall off.  Can you imagine bumping into it?

Thanks for the lapping recommendation.  I tried to get the head into a machine shop but they are all backlogged and will take a month.  I am going to lap the valves by hand as you suggest.

@LeMans850i posted:

No leak is what it should be with springs installed… you can skip all the vacuum testing and blue paste and whatever…

It has to hold gas…

Roland and Doug,

The leak down test showed an intake valve and an exhaust valve leaking on that head.  Now that the head is on the bench, the gasoline test shows the intake valve sealing and the exhaust valve leaking.  It appears that a leak down test is a more stringent test than the gasoline test.  Have you come across this before where a valve passes the gasoline test and then leaks once installed?

Steve,

Air will pass through a "leak path" whereas liquids won't.

John

@stevebuchanan posted:

Roland and Doug,

The leak down test showed an intake valve and an exhaust valve leaking on that head.  Now that the head is on the bench, the gasoline test shows the intake valve sealing and the exhaust valve leaking.  It appears that a leak down test is a more stringent test than the gasoline test.  Have you come across this before where a valve passes the gasoline test and then leaks once installed?

gasoline is usually a good test substance because of very little surface tension… and it easily administered.. when the engine is apart!

… leak down test is usually implemented if you get low results in a compression check.. this gives you the ability to detect where the leak is..

like head gasket into water jacket or neighboring cylinders , valves, piston rings or bores…

there is a % of acceptable leak down, which makes sense obviously for certain discoveries…

I personally stipulate 5% as still pretty good, 10% says to me  start saving money for a rebuild!
10% can still run pretty good as the high pressure is only lasting for a split second but will “inject “ high temp and deposits into areas where they should not be and will accelerate the deterioration..

I wouldn’t drive myself crazy about that subject.. it’s a car engine and not a submarine….  Some minor leaks are okay.. especially with new parts.. rings not sealed…. And so on..

all of the above is just my opinion… others may think differently!

@jb1490 posted:

Steve,

Air will pass through a "leak path" whereas liquids won't.

John

Thanks John.  Should that intake valve's air leak be of concern?  It seems like the gasoline leak test is a good starting point and that every engine build should include a compressed air leak down test once the heads are installed.  Or is this overkill?

@stevebuchanan posted:

Thanks John.  Should that intake valve's air leak be of concern?  It seems like the gasoline leak test is a good starting point and that every engine build should include a compressed air leak down test once the heads are installed.  Or is this overkill?

See above .. not working anyway and overkill … I think

gasoline leak down is absolutely sufficient!! Lapping the valves provides a surface that seals against gasoline usually and it provides its surface that is not 100% smooth, which is the same idea as the cross hatch on the cylinder wall everything is new and then the wear of the piston rings and the cylinder wall provide a perfect seal! Same holds true with the valve seat and the valve itself!

Steve,

I agree with Roland.  

Once the head is installed, it's kind of "too late".

With the head off, any valve that leaks with the gasoline test needs to be hand lapped.

John

I have never had an issue with valves not seating fresh from the shop.

I did have issue with one shop when I discovered that they were only doing one cut on the valves and seats and I was paying them for a three angle.

After that I bought my own equipment, and do my own. I even do the valve guides as well.

None of it is difficult, but it is time consuming.

I have done leak down tests on fresh rebuild straight from the shop. There I let the shop do all the machining and I do the assembly.

Fresh short blocks always show leakages. That is to be expected.

Your cylinders look good.

I have heard the term, "warped valves" before but I still don't know what that means on fresh seats?

It is a good idea to hand lap the valves as Marlin suggested but I have never had an issue with Sioux equipment.

This isn't necessarily very complicated. I could have high school kids doing "valves" in not much time.

The issue is being conscientious. It helps to be "nerdy". The work is not for "hot dogs" at all.

While the head is out, why don't you "cc" the combustion chambers?

@panteradoug posted:

I have never had an issue with valves not seating fresh from the shop.

I did have issue with one shop when I discovered that they were only doing one cut on the valves and seats and I was paying them for a three angle.

After that I bought my own equipment, and do my own. I even do the valve guides as well.

None of it is difficult, but it is time consuming.

I have done leak down tests on fresh rebuild straight from the shop. There I let the shop do all the machining and I do the assembly.

Fresh short blocks always show leakages. That is to be expected.

Your cylinders look good.

I have heard the term, "warped valves" before but I still don't know what that means on fresh seats?

It is a good idea to hand lap the valves as Marlin suggested but I have never had an issue with Sioux equipment.

This isn't necessarily very complicated. I could have high school kids doing "valves" in not much time.

The issue is being conscientious. It helps to be "nerdy". The work is not for "hot dogs" at all.

Just doing one angle would likely not provide you with the correct seat width…  the other 2 angles are needed to set the correct height and width to have a proper seat…
a warped valve (anything not true like valve stem or head ) would easily identified by the lapping picture on the valve.. only the high spot of the valve is getting lapping marks…

Great information all.  I will lap the two valves and test with gasoline.  After assembly I will do a leak down test with compressed air since it is already setup.

On the other head (driver side) there is a faint compressed air leak on one exhaust valve.  It is unlikely that gasoline would leak through that valve since the 85 PSI air leak is only barely detectable.

Before assembly I will measure the volume of the combustion chamber.

Thank you all.

@stevebuchanan posted:

Great information all.  I will lap the two valves and test with gasoline.  After assembly I will do a leak down test with compressed air since it is already setup.

On the other head (driver side) there is a faint compressed air leak on one exhaust valve.  It is unlikely that gasoline would leak through that valve since the 85 PSI air leak is only barely detectable.

Before assembly I will measure the volume of the combustion chamber.

Thank you all.

You can give the leaking valve a “gentle “ tap with a hammer while air applied..

hopefully cleaning the seat …

if it’s a dirt issue…

@panteradoug posted:

The issue is being conscientious. It helps to be "nerdy". The work is not for "hot dogs" at all.

Well, I'm no nerd.  Just because I walk around in the garage with the 351C firing order taped onto my sleeve does not mean that I'm a nerd.  My wife saw something taped onto my sleeve and was somewhat amused.

You wish Steve…

but we are still not as nerdy as the guys who have pet dung beetles and share pics of their daily endeavors on their forum and don’t let people join who can’t prove they have one.. makes me so mad!!

...Lapping does Not widen the Seats. It Only deals with the 'One' Angle where the Valve MEETS the Head (Seat). 'That' Single angle is cut on the Valves at 44 Degrees, on the SEAT at 45 Degrees. You can see the two angles meet at a Taper. Lapping Insures the 'Contact Area' is a 100% Custom FIT!

The Bores are Perfectly Round, there should be Hash Marks at 30 Degrees in Both Directions. These Hold 'Oil' from the Oiling Ring to Lubricate the Cylinder Walls, Piston and Compression Rings. Ofcourse the Oiling Ring.

The Pistons are Cut as a OVAL, this is so there is 'Room' for the Piston the Expand when HOT. When Cold these Leak in a 'Leak Down Test'. The Ring Gaps. although 'Staggered' will Leak when COLD. These Gaps are Calculated to come nearly Closed when Hot.

When COLD any Engine will show leaks in a L.D. Test, even though the Valve seats are PERFECT! It would be just about Impossible to Do a L.D. Test on a HOT Engine. But more than likely...Very Successful.

I agree with Doug and All Others who Lap their own Valves. Shops are in a Hurry to be done and get paid. And some just don't Have the Disciplines!

...Some racers will Have Just One ROUNDED Seat Cut, in the Head, with the Valve cut 'Normally'. With an even THINNER Contact Area! and No other angles in the way of the Fuel/Air Flow, within the Head. These Must be 'Drag-Racers'.

Doug Makes Sure of His Valve Seats!! You Dig!! I Applaud You!

All the Best,

Marlin I may not have the terminology that you do because I have not been formally trained.

I do learn proportionally more from my mistakes then anything else and just hope that they weren't expensive mistakes on irreplaceable items.

I have learned much of this through necessity and the failure of others that I relied on and am the better for it as a result.

I ultimately have to fix their mistakes.

Doing my own valves also lets me get the width of the seats where I want them. I find that the thin "drag race" seats offer the most improvement. For me that doesn't matter so much since I don't put many miles on them anyway and can always redo them if necessary.

I was pleasantly surprised how detailing the seats gives so noticeably increased pep to the engine. It adds crispness to the throttle amazingly.

Only cutting the 45 degree angle will widen the seat! Obviously!

@panteradoug wrote:

“I did have issue with one shop when I discovered that they were only doing one cut on the valves and seats and I was paying them for a three angle.”

...ALL of That is Eliminated when I Polished the Sharps and the Valve Bowls!!

This Increases Horsepower.

I was complimenting Doug on his Great Work! Improving and Making the Valves/Seats More Accurate. Don't take it Wrong.

Most Seats are already 'Cut', we are Just Re-Dressing It. Some work is Not even finished.

The Diagram Shows a 'Common' '3 Angle' Valve Job! Some Engine Builders have Modified Those angles.

My Mentor, is Responsible for the Building of No Less than 12 Nascar Championship Winning Engines! Yes, Hard to Believe, Right??

He's the Expert, I'm Going to Listen to and Follow!! I just take the time to Try and Pass his wisdom on this Forum, to Those who will Listen. Seems, some need an Interpreter.

MJ

The one set of heads I was refering to, when I popped some valves to look at the seats, the seats must have been .120" wide! Just a single cut.

It was a "high performance shop" frequented by the local drag racers.

I can tell you that in experimenting on some scrap heads with the 60° bottom cut and "port cutter" that it is pretty easy to hole through. I definitely learned that.

I had come to the conclusion that the casting thicknesses varied from head to head. I would not want to do heads for a living at all.

...All Exhaust Valves and Seats are cut to the .120" For Improved Heat Transfer to the Head. The Intakes are, I believe at .090"? (.070" for the Boss 302)

The Top 30 Degree should Have been Cut. I would think they didn't do the 60 Degree cut, to Be Taken Out during 'Bowl Polishing', anyway. For Improved 'Deep Breathing'. 'Volumetric Efficiency', Race Engines are 85% and More.

Good Job!

MJ

...This is an Example of polishing the Sharp Edge and Turning Radius of the Valve Bowl. I couldn't find a FORD Head this a Chevy. But, the Principle is the Same. Bowl Polishing is always done Before the 'Valve Job', if the Seat should be Marred by the Burr, it may be fixed during the 2 angle job. See in the Before and after pictures, the 60 Degree Angle, and Sharp Edge are Removed and inner Radiused. Intake and Exhaust both done is good for a Increase of 20-40 Horsepower. That helps a 351 Cleveland approach 500 HP with 4V Iron Heads. When Ran with Dual Quads and Higher Compression.

MJ   

...This Bowl Has just Been 'Roughed-Out', it has yet to be finely Polished., and the Guide Boss, also.

The Cleveland iron head has a cast in "restrictor ring". It is intended to increase the velocity through the pockets.

When "performance" prepping the heads, that is commonly cut out with the 60° pocket cut and sometimes the iron valve guide is also and replaced with a pressed in bronze guide like the aluminum heads use.

There is easily 25-30hp to pick up with those modifications but are intended for manual transmissions and performance driving. Not automatic transmission cars used for everyday transportation.

There is a reason a Boss 351 is only 330hp. It was detuned in many ways to make it a dependable street car. The valve pockets is one area.

You also need to narrow the seats by about half from stock but remember that is for racing and those engines get torn down al ot so cleaning the seats isn't that much of a big deal.

If you wanted to put 100,000 miles on the car before you do the valves again, you should stay stock.

The only thing that I would add to that is likely the stock iron valve guides only last about 30,000 miles.

Update:

I hand lapped the two leaking valves and tested them with gas.  They both sealed.  One of them (the exhaust valve) needed a lot more lapping than the other (intake valve).  I reassembled everything and did a compressed air leak down test on the two valves.  The intake valve was completely sealed while the exhaust valve had a very slight leak.  It should seal during break-in.

The valve that prompted this posting was the intake valve and it probably would have sealed during break-in without doing anything.

While doing leak down tests early on, I came across the leaky exhaust valve.  I don't think it would have sealed during break-in.  While everything in this posting has been a bunch of work, it likely eliminated a big hassle later on when the engine is in the car.

Nice job Steve

Perfectly done!!

I know, it was a lot of additional work, especially after you were already so close to the finish line…  But definitely worth it!

” while I’m there, I should… - Opening a can of worms” @stevebuchanan I’m sure you know where that came from…

https://pantera.infopop.cc/top...uld-the-can-of-worms