1936 Chrysler Airstream C-8 Convertible Restoration

[Professor]

March 26  2022 Update:

 

I was able to remove all of the nuts and the one bolt that someone used at some point to replace a stud and nut.  All of the nuts came off easily with two exceptions:

 

One nut needed more tapping and lubricant to remove.

 

One nut needed heat, lubricant, and tapping to remove.  At the start of the sequence of removing this nut, the stud started backing out of the block and then, later in the process, the nut came off.  I will need to figure out what to do with this stud… later.  🙂

 

Let’s start with some images.  The images of the valves start with cylinder 1 and end end with cylinder 8 (closest to the firewall).  The image of cylinder 5 is some sort of reflection.  The valve looks good.

 

 

Edited March 26, 2022 by Professor (see edit history)

[Professor]

More images starting at cylinder 1 and ending at cylinder 8.  After I post these, I will wipe down the cylinders and measure the ring ridge.

 

 

[Professor]

Combustion chambers in the head, cylinder 1 through cylinder 8.

 

 

[VW4X4]

Still need to remove all the valves and a good cleaning before any decision can be made.  What I find interesting is the surface of the valve that is bad.  IT almost looks like the metal fell apart.  One of the valves in Cyl. #5 looks the same... I would take a careful look at that one also.   Modern day valves, when they "burn", typical has a "V" cut in the side from the hot exhaust gases.

This valve  looks like it melted.  Cross your finger that the valve guides and seats are still good.

     One other thing..... This motor does not have a lot of mileage on it since the last time it was apart. You can tell by the amount of build up on the parts.  Note that most pistons you can see the machining on top.    One piston looks like it has some previous damage.  A good cleaning will tell .....

 

ERIC

[Professor]

After lightly scraping off the carbon at the top of the cylinders, there appears to be no measurable ring ridge.  The tops of the pistons on cylinders two and three show what appears to be foreign material impingement.  I will upload some images of the tops of these pistons shortly. 

[F&J]

I type slow, several comments added above before I finished:

 

Well now, if that engine could talk.. 

I see that 2 and perhaps 3 cylinders/pistons "ate something".   That is very odd being more than just one, as sometimes a screw goes down through the carb, and that would be damage marks on just one.  But 2 or 3 showing hits is very unusual.

 

Everything is soaked with oil or antifreeze, but looking at other hints,  this engine was using "some" oil.  But did it smoke or have blow-by through the breather?

 

Many here seem to have baskets of cash on hand and will say go full rebuild.  Depends maybe on your age and what driving will you do.  I think you drove it a lot and were OK with the engine, so if you don't want to see this car tied up for many months at the typical engine builder, then maybe you'd be Ok with just a total vavle job?

 

Some of us have our own valve and seat grinders.  I doubt you do?  You have 8 new exhaust valves, that's good because some are "crystalized".  That is seen on vintage valves at times. You need the seats ground, and the intake valves reground.

 

You don't normally need new intake valves, and slight wear on valve guides is acceptable, especially as it is not overhead valves.  You normally don't need new seats if the burned valve did not burn that seat. That seat looks ok so far.  If you wanted new seats, the shop wants the motor removed, and you start going down a long road at that point. IMO

 

If you wanted to just do valves, I would not want to pull the engine just to be able to bring to a shop to have the all the seats ground and have the intake valves ground.  Would your local shop cut the seats "in the car", if you got it all clean, removed all valves to make it easier for them?  IDK

 

I think best to remove manifolds to make the valve removal easier, by looking at the lack of room to get at the keepers.

 

 

 

 

 

[Professor]

Head Gasket appears to be OEM:

 

 

[Professor]

Based on what I see at this point, I am going to replace all of the exhaust valves and any intake valves that actually need it, assuming I can find any intake valves.  No luck at this point.  

 

I plan to have the head vatted and checked for flatness.  If it is not flat, I will have it surfaced (unless there is some reason I should not).  The valve seat on the burned exhaust valve appears to be good, but I will know more after I remove the valve train tomorrow.  I am going to check the valve guides now to check for axial movement just to get a ballpark estimation of valve guide wear.

 

I want to violate this engine as little as possible.  Until I see something that makes me think a total rebuild is necessary, I am going to move forward with fixing what needs to be fixed properly and not fixing anything that isn’t necessary (or convenient).

 

Standby for more.

 

Joe

[VW4X4]

1 hour ago, F&J said:

I type slow, several comments added above before I finished:

 

Well now, if that engine could talk.. 

I see that 2 and perhaps 3 cylinders/pistons "ate something".   That is very odd being more than just one, as sometimes a screw goes down through the carb, and that would be damage marks on just one.  But 2 or 3 showing hits is very unusual.

 

Everything is soaked with oil or antifreeze, but looking at other hints,  this engine was using "some" oil.  But did it smoke or have blow-by through the breather?

 

Many here seem to have baskets of cash on hand and will say go full rebuild.  Depends maybe on your age and what driving will you do.  I think you drove it a lot and were OK with the engine, so if you don't want to see this car tied up for many months at the typical engine builder, then maybe you'd be Ok with just a total vavle job?

 

Some of us have our own valve and seat grinders.  I doubt you do?  You have 8 new exhaust valves, that's good because some are "crystalized".  That is seen on vintage valves at times. You need the seats ground, and the intake valves reground.

 

You don't normally need new intake valves, and slight wear on valve guides is acceptable, especially as it is not overhead valves.  You normally don't need new seats if the burned valve did not burn that seat. That seat looks ok so far.  If you wanted new seats, the shop wants the motor removed, and you start going down a long road at that point. IMO

 

If you wanted to just do valves, I would not want to pull the engine just to be able to bring to a shop to have the all the seats ground and have the intake valves ground.  Would your local shop cut the seats "in the car", if you got it all clean, removed all valves to make it easier for them?  IDK

 

I think best to remove manifolds to make the valve removal easier, by looking at the lack of room to get at the keepers.

 

 

 

 

 

Some interesting observations, specially about eating a bolt.... How did it get into TWO cyl.?

 

I personally would not touch the intake or exhaust manifolds.  When removed, and reinstalled a lot of people don't understand that these can get very complicated, to reinstall correctly.  If not done right, cracks and leaks will be the result because of the extreme heating and cooling.  Removing these, specially on this particular engine is just another can of worms.

 

ERIC

 

[Professor]

Well… so much for Bernbaum’s quality control.  Of the 7 exhaust valves they shipped me, only one is correct (or at least, I am assuming it is correct until I get the old valves off).  Ugh…. One would have thought that they would have at least looked to see that all the valves were the same size.

 

Back to the drawing board….  I do not want to put this engine back together without replacing the exhaust valves that look near failure.

 

 

[VW4X4]

1 hour ago, Professor said:

Well… so much for Bernbaum’s quality control.  Of the 7 exhaust valves they shipped me, only one is correct (or at least, I am assuming it is correct until I get the old valves off).  Ugh…. One would have thought that they would have at least looked to see that all the valves were the same size.

 

Back to the drawing board….  I do not want to put this engine back together without replacing the exhaust valves that look near failure.

 

 

Andy Bernbaum..... He's well known for this....  He has ever part on earth that doesn't fit.

 

[Piaras]

There is no way those are the same valves! Vendor failures are about 75% or “better” today. Whether it is Andy or a multi billion dollar company. Too bad.

Pierre

 

[Piaras]

Looking at the cylinders, they appear in very good shape. Maybe you can just get the valves done with recut seats and go drive the car. I don’t see any valves that are currently seated with recessed seats.

Pierre

Edited March 26, 2022 by Piaras (see edit history)

[Bloo]

I don't even know what to say about those disintegrating valves. Odd.

 

Normally what determines whether a valve needs replacing is the "margin", in other words the flat area along the edge, measured after the valve is ground. Not every every engine needs new exhaust valves, even if it burned one. It comes down to measurements just like a bearing. Usually margin is the problem, but stem wear could also be an issue.

 

On the other hand, if there is a metallurgy problem or maybe you want to replace everything. Edinmass has spoken of having new valves made out of better materials for some prewar cars, but that was really expensive. If you are using NOS/NORS replacement parts that were made before the war, a new valve is probably no better than an used one, depending on margin.

 

 

[Professor]

Here are a few images of the tops of the cylinders after I wiped them down.

 

 

[Professor]

And the final image of the day.  I will go visit the gentleman who owned this car before me tomorrow, so I am uncertain if I will pull the valves tomorrow.  Since I do not have replacement valves yet, the urgency has decreased a bit.

 

Here are a couple of things I have noticed that need to be replaced (unrelated to the valves):

 

Water pump has a broken tab on the bypass hose connector.

Water temperature sending bulb is broken off where the tube connects to it.

 

8 cylinder water pumps are a bit rare, so I may have to create a workaround if I cannot find a rebuildable replacement.  I found plenty of videos on how to fix the engine coolant sensor bulb.

 

By the way, I noticed that the pistons are standard, and one of the markings made me think that they are the factory pistons.  I would not expect factory standard pistons in an engine this old.  I will spend some time on Google tonight to see what I find.

 

Thanks again for all your guidance everyone.  It looks like I need to go find some parts.

 

Joe

 

[F&J]

1 hour ago, Professor said:

Of the 7 exhaust valves they shipped me, only one is correct

The taller valve in the pic is not even an exhaust valve, the head looks like an intake valve, too thin for exhaust in that era of engines.

 

27 minutes ago, Bloo said:

I don't even know what to say about those disintegrating valves. Odd.

 

Normally what determines whether a valve needs replacing is the "margin", in other words the flat area along the edge, measured after the valve is ground. Not every engine needs new exhaust valves,

 

On the other hand, if there is a metallurgy problem

In my 70 years, I have seen that crystallization of exhaust valves before.  I know I have one prewar engine in my shop that has it on one valve.   Up until this thread, I just assumed it WAS metallurgy of prewar exhaust valves, but you have me rethinking a bit.

 

Ok, you mentioned reground valves that get too thin at the edge which promotes burning, as there is not enough mass at edge and they overheat there.  Same is true if a guy cuts 2 angles on a valve seat but left the contact point way too narrow, and then when the hot valve touches the seat, that narrow contact band can't transfer enough heat to the seat &  block on a flathead.

 

That is what made me rethink...    Heat transfer...  Looking at the need to transfer the heat from the exhaust valve; can we think of this like too tight of point gap on distributors; not enough duration/time to saturate the coil?  What I mean is, if the 2 valves he has that are crystallized, could it be that those 2 damaged valves were way too tight, and then the much shorter duration/time of how long the valve sits on it's seat, is not enough to get rid of heat??  It kinda makes sense?, as if it was only a metallurgy issue, then why are all of the exhaust valves not showing it?

 

I would like to know if those 2 crystallized valves are at almost zero on the lash adjustment, before removing them. I do still think the metals were not as good as well, because I just can't recall ever seeing crystallization on post war cars, or at least 1950s-up cars.

 

6 minutes ago, Professor said:

Here are a few images of the tops of the cylinders

One was a threaded screw. One looks like lock washer getting broken up.  Then one looks like lock washer chunks but it also has a few round hits like the end of a machine screw?

[keiser31]

52 minutes ago, Professor said:

And the final image of the day.  I will go visit the gentleman who owned this car before me tomorrow, so I am uncertain if I will pull the valves tomorrow.  Since I do not have replacement valves yet, the urgency has decreased a bit.

 

Here are a couple of things I have noticed that need to be replaced (unrelated to the valves):

 

Water pump has a broken tab on the bypass hose connector.

Water temperature sending bulb is broken off where the tube connects to it.

 

8 cylinder water pumps are a bit rare, so I may have to create a workaround if I cannot find a rebuildable replacement.  I found plenty of videos on how to fix the engine coolant sensor bulb.

 

By the way, I noticed that the pistons are standard, and one of the markings made me think that they are the factory pistons.  I would not expect factory standard pistons in an engine this old.  I will spend some time on Google tonight to see what I find.

 

Thanks again for all your guidance everyone.  It looks like I need to go find some parts.

 

Joe

 

Can you post a photo or two of the water pump? You never know what one of us like me has lying around.

[VW4X4]

Amazing that those piston lived through all that damage. Even more amazing is that they are stock. Take a good look at the very corner, where the cylinder meets the block.  If you find a very small edge, there is a chance that the engine may have had sleeves put in, therefore allowing stock pistons. 

 

ERIC

[Professor]

Thanks F&J

 

I will measure the valve lash on the exhaust valves to see how they differ.  One thing I noticed; of the valves that are up,  the exhaust valve on cylinder 3 (stuck) has the highest wear on the valve guide.

 

 

Joe

 

[Piaras]

That would make sense that the uneven side loads would off set the valve stem a bit at the final closing.

 

[Professor]

Hi All,

 

I am having trouble finding the valve specifications for my C8.  I checked the factory parts manual and maintenance manual, and cannot find the dimensions for the head diameter, face cut angle, shaft diameter, and length.  Can anyone point me in the right direction?

 

Thanks so much.

 

Joe

[Piaras]

In the manual, there is a section at the back called “Service Standards”. All I found was stem diameter of .340-.341” and .001-.003” stem clearance intake and .003-.005” exhaust stem clearance. Valve seat angle of 45 degrees which is pretty much standard even today.

 

Check in the Plymouth one I sent you. A better explanation on replacing the exhaust seats.

Pierre

[VW4X4]

Joe, 

  Check with these guys.  Be prepared to pay with your first born child...  

 

https://egge.com  

 

https://www.kanter.com/productdetail.aspx?DeptNo=1400&MakeName=Chrysler&MakeYear=1936&CategoryID=96&ProductCode=3485&Router=Gallery

 

 

[Professor]

Here are a couple of images from an old Thompson catalog.  If this catalog is correct, I found a set of 9 exhaust valves on eBay.  I will pick them up.

[Professor]

I will take a picture as soon as I go out.  I think the 8 cylinder water pumps are not as common as the 6 cylinder versions, but it is certainly worth a shot.

 

20 hours ago, keiser31 said:

Can you post a photo or two of the water pump? You never know what one of us like me has lying around.

 

[VW4X4]

1 hour ago, Professor said:

I will take a picture as soon as I go out.  I think the 8 cylinder water pumps are not as common as the 6 cylinder versions, but it is certainly worth a shot.

 

 

Joe

   The six cylinder water pump is still available at your FLAP (Friendly Local Auto Parts).  I'm fairly sure this is because it fits so many other engines for Chrysler over the years.   Don't discount a good old fashion FLAP.   The straight eight from Chrysler was used, in cranes, generators, wood chippers, boats, and a few other applications.     So, shop around...

 

ERIC

 

[Professor]

With respect to the exhaust valves, I found something interesting today.  I measured the head diameter of a couple of the exhaust valves that were not crystallized (or showed no signs of damage) and the head measured 1.510”.  According to the Thompson manual,  the head diameter of the exhaust valves for the C8 (and CZ) is 1.410.  Take a look at the attached images of the closed exhaust valves.  Notice that they sit above the block significantly more than the intake valves?  Based on measurements, this engine has incorrect diameter exhaust valves and correct diameter intake valves.  I would be interested in the thoughts of the experts here.  Could incorrect diameter exhaust valves be the problem?

 

Also, for the record, here are the exhaust valve dimensions for the C8:  Head diameter, 1.41, shaft diameter, .340, length, 5.436.

 

 

[Professor]

Water pump images:

 

 

[Piaras]

A place to start maybe? Gates catalog shows part number 42554.

 

 

https://www.moparpro.com/water-pump-1935-1950-plymouth-dodge/p1494

Edited March 27, 2022 by Piaras
Added Gates info (see edit history)

[VW4X4]

1 hour ago, Professor said:

With respect to the exhaust valves, I found something interesting today.  I measured the head diameter of a couple of the exhaust valves that were not crystallized (or showed no signs of damage) and the head measured 1.510”.  According to the Thompson manual,  the head diameter of the exhaust valves for the C8 (and CZ) is 1.410.  Take a look at the attached images of the closed exhaust valves.  Notice that they sit above the block significantly more than the intake valves?  Based on measurements, this engine has incorrect diameter exhaust valves and correct diameter intake valves.  I would be interested in the thoughts of the experts here.  Could incorrect diameter exhaust valves be the problem?

 

Also, for the record, here are the exhaust valve dimensions for the C8:  Head diameter, 1.41, shaft diameter, .340, length, 5.436.

 

 

Joe,

     What really matters is that the valve properly sits on the valve seat, and seals.  Lots of times a valve job was done on these engines by grinding the edge of the valves, and reinstalling them.  This would make the valve sit lower in the seat. There's specs for how much can be ground off, but few people would look at it, as long as it seals.

 

In the first picture what are we seeing on top of that piston?  Hopefully just dirt...

 

ERIC

[Professor]

Thanks Eric.  The thing you see in the top picture is flakes of carbon coming off the top of the piston.

 

58 minutes ago, VW4X4 said:

Joe,

     What really matters is that the valve properly sits on the valve seat, and seals.  Lots of times a valve job was done on these engines by grinding the edge of the valves, and reinstalling them.  This would make the valve sit lower in the seat. There's specs for how much can be ground off, but few people would look at it, as long as it seals.

 

In the first picture what are we seeing on top of that piston?  Hopefully just dirt...

 

ERIC

 

[Professor]

Eric,

 

I would think that having the wrong valve diameter head would leave excessive valve head material exposed to combustion chamber heat and pressure without having a good heat sink to dissipate the heat.  I think from a thermodynamic perspective, you want as much of the valve head in contact with the valve seat (and in this case, engine block) to help dissipate heat.  Thoughts?

 

Joe

[VW4X4]

2 hours ago, Professor said:

Eric,

 

I would think that having the wrong valve diameter head would leave excessive valve head material exposed to combustion chamber heat and pressure without having a good heat sink to dissipate the heat.  I think from a thermodynamic perspective, you want as much of the valve head in contact with the valve seat (and in this case, engine block) to help dissipate heat.  Thoughts?

 

Joe

Valves back than, have a very wide angled surface. The seat has a very small surface.  This I assume was to ensure there is plenty of pressure to make a seal.  If the valve was slightly to big or to small the seat would (should) move ever so slightly to a different spot on the valve.  Most of the time, when you remove the valve springs you then can see a clean area on the valve seat where to valve comes to rest....  As long as you can get that clean ring, when installing the valves, (new or used) and the valve was not adjusted to tight, you should not have a  heat problem. 

 

ERIc

Edited March 27, 2022 by VW4X4 (see edit history)

[Piaras]

At the power level these engine have and the low compression ratio, the exhaust gases are cooler compared to todays harder working units. 
Pierre

[Bloo]

Typically you want the valve up high, not the wrong size of course, but a little bigger is better. Valves with a lot of margin left and the seats not worn out stick up. Recession is a sign of wear. It also reduces flow.

 

If the seat recession is fairly bad, cutting the seat will make it bigger You might want the valve slightly oversize if things don't fit up quite right. It's better than using inserts because there is less to go wrong.

 

I have never heard that narrow seats are bad, or that they could contribute to burning, in fact that contradicts everything I learned in tech school. The valve and seat are usually ground 1 degree different. This results in a fairly narrow contact area when the engine is new. Sometimes one valve is 30 degrees (and one degree different than the seat) instead of the usual 45.

 

On a 3 angle valve job, the top and bottom of the seat and face are angled away in the interest of better flow, but the valve face and seat at the center still have the expected one degree difference, and a fairly narrow contact area.

 

A wide seat is not necessarily bad though, especially in a lowly stressed engine. If you can lap a new valve to the seat, and you get a nice even gray stripe around the middle of the ground seat, and the stripe is not too close to the top of the valve, you are good to go. It's what they would have done in the 30s.

 

Edited March 27, 2022 by Bloo (see edit history)

[F&J]

1 hour ago, Professor said:

I would think that having the wrong valve diameter head would leave excessive valve head material exposed to combustion chamber heat and pressure without having a good heat sink to dissipate the heat.

You are 100% correct.    If far too much of the outer edge past the lapping pattern exists, that edge will run too hot, and it does not matter if low compression or high, the exhaust is hot enough to start to burn that edge during lugging on hills, trailering, etc . 

 

I have never in my life, ever heard of using a valve with a bigger diameter head than stock ones, on just a stock valve grinding job.  Bigger valves are only used when race heads get bigger diameter seats and then ported flow chambers. Not to further start a sh-t storm, but also, nobody ever grinds the valve head diameter smaller when doing a valve job. 

 

Lapping test below, pic from web.  This looks like a very small diameter valve, as if it was a large diameter valve, that lap pattern would be a bit too wide.

You do not want the widest lap pattern you can get.  Why? because the valves "guarantee" of 100% sealing can suffer.  Heck, some car specs run a one degree difference between the seat angle and valve angle, just to insure a very fail proof 100% seal right from the start-up after grinding.  Then they "pound in" to be the exact same mating angle after the car is driven a bit.  But you still must do a test lap with lapping compound to see what the eventual seating line will be, just like a 45/45  test lap does.

 

One other bad thing about super wide lap pattern is it more prone to carbon particles "embedding" and having a better chance of starting a leak, and this is very especially true with such low valve spring seat pressures on prewar era light duty springs.

 

One more thing to say about the width of the lap line during valve grinding; this width line will definitely get wider as the valves "pound in" over time.

 

More info : You want the lap line basically centered like the pic. A little off is Ok.  During grinding and the first test lap, you likely will see the line is too wide, this is when 2 angle or 3 angle grinding is totally needed to narrow it and move that line outwards or inwards. 

 

I will only refer to a 45 degree angle just for example. I have not looked up this cars proper angle specs.

 

Most times you will be using only 2 angles of stones, grind the 45 first, then use visual inspection or test lap. Then typically, it's too wide, AND the lap line is too close to the outer edge, you then hit the face of the seat with a 15 degree. Very rarely do you ever find the need to use a 60 on typical "non race car" valve jobs. ...Once you grind a few in this car you likely will see that a 60 should not be used.  (The lap line probably will be slightly un-centered, and is already a bit more towards the edge, so a 60 will make it worse).

 

 

37 minutes ago, Bloo said:

I have never heard that narrow seats are bad, or that they could contribute to burning, in fact that contradicts everything I learned in tech school.

Some teachers say stuff or better yet, not say enough...well... I will stop there.   

A very narrow lap line simply cannot transmit enough heat from exhaust valves.  Not enough surface area, just like using too small of a soldering tip on thicker metal.   My text above explained the 45/46 grinding spec on some brands, and why it's done one degree different.   But the 45/46 still needs a lapping compound test to see the "eventual" width (after running/seating) and it's total location, rather that using dye-chem.

[Bloo]

Agreed, but it still results in a comparatively narrow contact pattern. By the way I did not mean to suggest going to the "next size bigger: or something on the valve. Only that if the seat requires too much cutting the valve will wind up too low because the seat is now a little too big. A new valve should take care of that usually. A used one might or might not. Your valve in the picture looks fine to me. I would expect the lapping mark to wind up a little thinner on freshly ground valves, but not by much. This is in my opinion exactly what I would be looking for on a re-lap. If @Professor can get a pattern like that, he's good to go.

 

 

 

[VW4X4]

Hey professor,

    Get any valves out yet?    I stumbled upon this guy.  https://www.ebay.com/sch/i.html?_dmd=2&_dkr=1&iconV2Request=true&_ssn=73revordnal&store_cat=0&store_name=73revordnal&_oac=1&_nkw=chrysler 36

       They seem to have a lot of valves....  They list a lot for the AIR FLOW....  straight 8.  Might want to check with them anyway.

Can you tell us what the differences would be between the eight in the Airflow VS Airstream? Unfortunately I've never had a chance to learn much about such rare birds...

 

 

ERIC

 

 

[Professor]

Hi Eric,

 

Thanks for checking in.

 

I found exhaust valves (the part numbers posted in one of my previous posts) on eBay and am waiting on the valves to arrive.  I do not know all of the differences between the various 1936 Chrysler products, but the C8 uses a unique part number (compared to the airflow 8 cylinder models) for the valve guides, intake valve, and exhaust valve.  This said (thank goodness), the valve springs are shared.  As it stands now:

 

I need intake and exhaust valve guides, but could get by with just exhaust valve guides.

 

I need intake valves, but only because I would rather replace them while I am inside the top (and side, lol) ends.  My intake valves seem fine.

 

One other update:  I took the head in to be vatted and resurfaced (for flatness) yesterday.  The performance shop doing the work said I should have it back today, but I am skeptical, not that it matters since I am not ready for it anyway. 

 

The only thing worrying me right now is that I know I have one exhaust valve guide that is worn more than I would like (the one on the failed exhaust valve).  I am hopeful that I can find valve guides, but so far, no joy at all.  I may have to have guides made... not exactly rocket science, but likely to take some time and be relatively expensive.

 

Joe