Jim Martin's 1939 Imperial, with a straight 8, gets a valve job

by Jim Martin

Imperial Home Page -> Repair -> Engine -> Valvetrain -> Jim Martin

In the spring of 2001, long-time member, Jim Martin, decided to do a valve job on his 1939 C-24 limo.  Jim was kind enough to let us come along for the repair and share much of his valuable knowledge and experience.  Below is a detailed account, including photos, of Jim's repair.  If you would like to see a more detailed photo, please click on the picture for a higher resolution, greater detailed shot.

Even though I didn't hear any noise from my valves, I realized I needed to do a valve job on my flathead engine.  The car was getting a little under powered, although it moved the car at highway speeds (70 mph or more, if I chose).   I adjusted the valves cold two thousandths over hot specs- 10 intake and 12 exhaust.  It's pretty much standard procedure for all the old mechanics I know.  Reason being, it's a pain working under the right fender and around a hot exhaust manifold and exhaust pipe to adjust the valves at operating temps. This allows for the valves seating in and still operate with adequate clearance.

My reason for changing the guides was, on removal of the head, I could move the valves more than I liked, side to side, indicating excessive clearance.  I could have had the guides knurled but I don't baby  the car and I like it running well.  I decided to take a compression check and it indicated a valve job was also necessary.  The vacuum reading was also lower than average.  And so I began...


With the right front wheel off and two pieces of tin (splash pans) removed from my engine bay, this is the view of valve adjustment area.  Most mechanics adjust valves cold, two thousandths over hot specs - this picture shows why!!  Working around the exhaust manifold, juggling two valve adjusting tools and a feeler gauge can result in a hot time on a running engine at operating temps.  Also note, some of the valve guides I was unable to remove, causing me to remove the engine and eventually deliver it to a shop.  IMPORTANT:  When doing only a valve job, stuff rags in every oil drain hole, to prevent valve keepers from dropping into the pan.  When you think you've plugged them all, check again to save yourself future problems. 



My first step was to remove the starter.  Over the years, I have learned a trick when removing these starters: create a "safety sling" to hang the starter from, over the engine for easier reinstallment.  This photo is looking down upon the engine compartment from above.






Here is another view of the starter removal and use of the safety sling.  Above and to the rear of my left hand is a bellhousing to engine bolt, difficult but necessary, to reach to separate the engine from the bell housing.  The plastic bottle on the firewall is a remote brake fluid reservoir to eliminate removing carpet to access the master cylinder. 





My two sons, Patrick and Tim, helped me with this project.  Here is a photo of Patrick taking a break.  We needed a lot of breaks!!  Notice (orange) lifting sling.  We installed it backwards...a mistake!!  The hoist interfered with the crank on the sling.  Marvel Mystery Oil container on the fire wall, below a red shop rag, was an earlier unsuccessful repair remedy.  (Note vacuum feed to plate between carburetor and intake manifold--tube removed and not visible).  I also removed the coil for added clearance. 




 And here is a picture of both of my helpers and the engine ready to be removed.





Here is a picture of me, the bewildered "chief mechanic", wondering, "How in he!! did I ever get in this predicament!" 






Here is a view of engine with the water pump, fan, heads and all engine compartment accessories removed prior to engine removal.   I have taped over the cylinders to protect pistons from debris.  Coil on firewall had to be removed to provide clearance for engine removal. The vacuum line on the manifold is used for the vacuum-assist power brake unit (left-side of picture, indicated by the arrows).  





Another view of the '39's engine compartment, from the passenger side.  The arrows show: 1) Quick disconnect for easy access to jumping and/or charging battery which is located under the driver's seat.  Other half of "disconnect" is on jumper cables.  This eliminates the need to remove the front seat and battery cover in times of need.  2) Remote starter connection for underhood work.   3) Headlight relay to furnish power from battery directly to headlight bulbs. 



Crankshaft separated from Fluid Drive unit.  When removing the Fluid Drive, I have found it helpful to mark the crank shaft AND the FD unit as the studs on the FD unit are offset and it will ease the re-installation. Without Fluid drive, I believe the fly wheel may not have this problem.  Facing forward, there is one bolt (bell housing to engine) on the driver's side at about the 11 O'clock position that can be a problem. I solved this by torching and bending a 9/16 box/open wrench to get the best result for removing that bolt.  At this point, it is important to have protection for the radiator.  I also removed the fan and pulley.  Notice valve guides are still in engine...RATS!!



At this point, twisting, tilting and turning come into play.  Getting any engine out of any car is always an adventure.  With the flathead engines, the Chrysler service manuals tell  you to remove the hood and accessories in the engine bay (anything that impedes engine removal).  The engine can be removed with the sheet metal in place.  Without saying, it is necessary to remove all the obvious parts and pieces below the car.  A car hoist was an advantage, as was my pit in the garage. Another useful piece of equipment is a 4-legged sling with the screw jack, so that the engine can be tilted when removed.





Lucky break!!  Freeze (casting) plug was rusty and ready to go south if I hadn't found it.  These are impossible to replace with the engine in the car.  I have now installed a new brass plug.  





Son Tim thinks he did all the work.  The engine is out at last.  Notice the Van Dorne valve refacer to right of the engine.  I was running out of time to make an appearance at the annual Southern California meet, held this year in Solvang, so I had a machine shop replace the valve guides as well as grind the seats and  valves.  The machine shop used a new (to me) three angle seat tool. The total cost for my repair was $360.00.



This page last updated May 23, 2001.  Send us your feedback, and come join the Imperial Mailing List - Online Car Club