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Messages - 29UJohn

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I doubt you caused any damage to your car by cleaning and adjusting the oil pressure relief spring.  On a cold start at idle, it should read 35-40 lbs.  As it warms up, your idle oil pressure may drop to as low as 12-15 lbs, but should not be of concern. 

Your oil pump should not be mixing air with teh oil.  The previous owner did the  right thing by plugging the vacume port since it is not being used for the fuel pump vacume.  As for the vacume line - it does not draw much air if it is connected properly to a working vacume fuel pump.  It creates a vacume and should hold that vacume.  If air is introduced into the line in any great quantity, the pump will not draw sufficient oil from the sump. 

As for the releif valve, the problem is, you have no way of knowing if someone else had adjusted the relief valve before you obtained the car (as was the case for my engine).

The relief valve spring should be set to let off excess pressure - above 40 lbs.

However, at some point Plymouth changes where they read the pressure.  On my 29U the gage reading was taken down stream from the pressure relief valve. There is no port on mine at the pump.  When I obtained a pump off a 28Q with a port on the pump (as in yours), I was able to take pressure readings at two points - at the pump and downstream, by adding an extra pressure gage. 

I have noticed that the oil pressure at the pump may read 45lbs, while the gage reading from the downstream port measures about 38 or less.  As the engine warms up on an extended drive, the difference gets greater.  At 40 mph, the pressure at the pump still reads about 40 lbs, but my downstream reading is about 30 lbs (probably because my engine has a worn cam bearing).

These engines are pretty hardy.  A worn engine may run fine on 25-30 lbs of oil pressure hot, and 10 lbs at idle, with no detriment.  Idealy we all want our engines to be "like new", and a completely rebuilt engine should be.  But extreme excess oil pressure is not a good thing.

If I were you, I would plug that oil vacume port,a nd adjust the oil pressure releif spring to about 45 lbs when hot and running about 40 mph.  Obviouisly, this is a trial and erro thing, so make adjustments small - half a turn at a time and test drive hot.

General Discussion / Re: 28 / 29 Interior
« on: June 14, 2008, 05:16:22 AM »
You are very fortunate to have such a good set of door handles.  The pot metal they were made of does not stand the test of time well.  I suspect the driver side handles and windshield crank may have been replaced, as these would experience the most wear.

General Discussion / Re: Any Thoughts.?
« on: June 08, 2008, 05:56:17 AM »

Not sure, but I think your carb may be a Tillotson.  I beleive they were sold as replacement carbs for Ford Model As.  When I purchased my 29U in 73 it had a Tillotson carb on it.

I see it looks like you have an original air filter.  Advise you hand onto that, they are harder to come by than the original Carter brass bowl carbs that came with these cars.

By the way, you are very fortunate to have such good interior handles on your car.  All but one on my car had disintegrated.


General Discussion / Re: 28 / 29 Interior
« on: June 08, 2008, 05:41:03 AM »
Wow.  Looks really nice.

General Discussion / Re: Any Thoughts.?
« on: May 29, 2008, 03:50:58 AM »
Head Torque?  Good question.

There are no official guides for the early Plymouth 4s.  I used to use 55-60 ft-lbs, based on a 36-42 Plymouth Service Manual (I do not have a copy, reference is from Plymouth, the First Decade web site.)  Now I use 60-65 ft-lbs, based on a Head Torgue guide produced by Tom Hannaford of the Antique Auto Cellar.

I scaned the guide, but it is too big to post.  I will email it.

Here is the torque procedure I use, based on Tom's guide:

1) Torque to 1/3 (20 ft lbs)
2) Torque to 2/3 (40 ft lbs)
3) Torque to almost full (55 ft lbs)
4) Torque to 60 ft lbs
5) Start engine and warm it up, then retorque
6) After first drive, retorque while still hot

See Attached PowerPoint for sequence.

General Discussion / Re: Any Thoughts.?
« on: May 28, 2008, 04:16:26 AM »

If it runs and burns oil - that should be OK for now.  These engines are hardy.  As long as the engine is getting oil, it will probably run OK even if the pistons and rings are the wrong size.

When I first got my 29 (at age 16 in 1973) I put in a quart of oil every 40 miles!  After college I had the bearings re-babbitted and the rear main seal replaced.  After that, I only had to put in a quart every 80-100 miles!  Years later when I rebuilt the motor, I realized that the pistons were .030 over sized - it was stamped right on the piston face, and I missed it!  I had put new rings in myself as a kid - standard size rings!  I also learned that the engine shop had installed the rear main seal improperly.  After I installed new correct oversized rings from Hastings and installed the rear main seal correctly, engine oil consumption dropped dramatically.  I change the oil every 500 miles - and now do not have to add any between oil changes!

Having said all that, as a kid I drove my old car a lot, even though the engine had many problems (that I could not afford to fix) - it still kept running! 

Do not be concerned about the valves not having a Chrysler number on them.  There were several companies that made valves.  I doubt you can find an original Plymouth Chrysler valve for the engine today.

Good luck at the Father's Day car show!


General Discussion / Re: Any Thoughts.?
« on: May 27, 2008, 03:46:28 AM »

Wow - I think you fixed a big problem that could have lead to major engine damage.  I had a similar experience with my engine's relief valve after I had the oil pump rebuilt.  The oil pressure was 40 at idle and 55 at 40 mph.  After a short drive the back pressure on the pump striped the pump drive gear and damaged the cam pump drive gear, which lead to a replacement cam shaft. 

After talking with a knowledgable mechanic (something I should have done more of first!) he explained to me that a good oil pump is capable of putting out 100 psi.  He advised me to set the oil pressure relief valve as follows:  At idle, initally set the relief valve to about 20, then drive it at normal operating speed (~40 mph) and check the oil pressure.  It should be between 35-40, and should not exceed 40 psi.  If it exceeds 40 psi, turn the pressure relief screw counter-clockwise one half turn and reinsert the cotter pin, then repeat the test.

As for your question of what else to do, if I were were you, I would pull the valves (numbering each with masking tape) and take them to a machine shop to have the faces reground.  If they are badly worn, you may be advised to replace them.  Then I would grind (or lap) each one in its valve seat.  (Detailed instructions are in the operators manual, or you can consult a Dykes manual.) If you do not want to do all that, as a minimum you should check each valve face visually to see if the faces are worn badly.

Regarding your concern that excess pressure may be blowing oil past the cylinders, that is not possible on this type engine.  The cylinders are lubricated by a spray that comes from a small hole in the rod bearing.  If the engine were burning excessive oil, then the rings may be suspect.  Did you check the cylinder pressure before you pulled the head?  If so, you might have been able to determine if the rings and or the valves were suspect before you pulled the head.

If your engine is not burning the oil, it may very well be leaking from the rear main seal. (The oil will drip out the weep hole vent under the flywheel cover.)  This is not uncommon with these engines.  Did the previous owners have the rear main seal replaced when they rebuilt it?  Note that originally these used a rope seal.  Rope seals work well if installed properly.  However, it may have been replaced by a "modern" split steel and neoprene seal.  But, unless the block was modified properly, this type seal will not seal properly (which was the case with my engine when I bought my car.)   

As for the carbon you found in the cylinders, these engines will build up carbon deposites rapidly.  I would not be concerned about that.  The operators manual advises owners to pull the heads and clean out the carbon occasionally!

Hope this helps a little.


P.S. It looks like your block is missing a stud.  You can have one made, but I saw a new one on sale on ebay.)

General Discussion / Re: u model brakes binding
« on: May 25, 2008, 05:15:18 PM »
I recommend rebuilding the master cylinder.  You can do it yourself.  A new (not NOS) master cylinder kit is fairly inexpensive. (Buy from a brake parts specialty company.) 

I would also replace the brake shoe return springs.  Over time they become weak.  If the spring does not pull the brake shoes in, the front shoe will grab (when going forward.)  I bought some new from Roberts for $7 each.

General Discussion / Re: Under seat storage??
« on: May 23, 2008, 03:37:17 PM »
I have stored my 29U car's tools there under the rear seat for years - air pump, jack, wrenches, etc. 

General Discussion / Re: Oil Pressure
« on: May 18, 2008, 05:01:44 AM »
The pump draws oil from the sump via the long copper pipe that attaches to the top of the pump - this pipe goes thru the engine block just abov ethe oil pand and then to a vertical pipe to the sump filter screen.

The oil pump pushes oil out the smaller forward side U-shaped copper pipe that attaches to an oil galley port in front of the pump. 

Here are a few tips for priming a 1929 Plymouth (I have used them all):

1)  Remove all the spark plugs.
2)  Remove carb.
3)  Remove Oil Pump and put oil in it by either:
     a) Use some 90 weight gear oil that comes in a tube and put oil in the intake port (top of pump), squeezing tube slightly while turning oil pump by hand.  This is messy, but works well, and you can tell right away if the pump works, or,
    b) Remove cover and pour oil in it and replace cover (while cover is removed, check that the vanes and springs are in good shape), or,
    c) Remove cover and pack with vasaline and replace cover.  The theory is that when the oil gets hot, it will wash out all the vasaline.  (This works well, but I was surprised to find vasiline in a "nook and cranny" of the pump when I disassembled it many miles later.)
4)  Using some 90 weight gear oil in a tube, put some oil into the draw tube. (The long upper tube)  Squirt it in under a little pressure.  This way you can also tell if the line is free to the sump.  You may find it helpfull to remove the crankcase vent for easy access.
5) Reinstall pump.
6) Using starter, turn engine over with the spark plugs removed untill you notice oil pressure on the gage.  This may take a few minutes.  If no pressure appears after 60 seconds, stop, let the starter cool a few minutes, and try again.  You should get 10-20 lbs of pressure when it primes.

Now regarding trouble shooting - if no luck on pressure, try:

1) Remove U-shaped copper pipe from front of pump.  With spark plugs removed, one person turn engine over with hand crank while the other watches to see if any oil comes out of the pump.  If oil comes out, pump is OK.

2) Remove oil pressure gage line and check that it is clear (not obstructed). 

3) If the above checks out, and you still cannot get a prime or oil pressure, even with a new gage, then you may need to use a device that will externally pressurize the oil system.  I made one using a new one gallon pressure sprayer from the hardware store.  I removed the spray nozzel and installed a presure gage, shut off valve, a flare fitting.  I put a couple of quarts of oil in the hand pump, then attached the hose to the galley port on the engine (bypassing the engine's oil pump).  I then pressurized the tank (with the attached hand pump).  If the oil galleys are free, oil will flow from the tank through the system and drain into the oil pan.  (It is best to empty the oil from the engine oil pan completely before you start this test.)  Also, this test will tell you if there is an opening to the engine oil gally that is preventing the oil from building up pressure.  If so, you will notice the oil rush out of the tank and quickly fill the engine's oil pan.  If everything is working properly, oil pressure should build up, and the external oil tank should slowing empty into the engine.

If you want, I can take a picture of this test device.

Good luck.

General Discussion / Re: 28 / 29 Interior
« on: May 09, 2008, 03:40:42 AM »
When I bought my 29U 4 Door sedan in 1973 it had the original interior.  It was in very bad shape so I replaced it all.  I remember clearly there was a map pocket on the front passenger door and on the rear driver side door.  My Mom was a good seamstress and made me new map pockets, using the originals as paterns.

General Discussion / Re: Leaded or Unleaded?
« on: April 27, 2008, 05:19:52 PM »
Yes - just run it on regular. 

Even at that, you will find that if you try to set the timing by the owner's manual, it will run rough, if at all.   Reason is, fuel in 1929 had a much lower octane and so ignitied much faster than today's fuel.  There are no timing marks on the 28Q or 29U.  You will have to adjust the timing by ear, advancing it somewhat.  So, if you try and set it by the manual, and it refuses to run, advance the distributor a little and try again.  The simplest method - once you get her running - is to adjust the distributor at idle to obtain the fastest rpm, then turn it back just a hair.  You can also attached an RPM meter (set for a 4 cylinder).  There are other methods, and I am sure you will hear from others.

Good luck.   

General Discussion / Re: Leaded or Unleaded?
« on: April 24, 2008, 04:09:03 AM »
The 28Q and 30U did not have hardened valve seats.  There are many diferent opinions on lead substitute additives.  I use Bardahl Instead O' Lead on my 29U.  However, I do not use the octane boost version - these cars ran on much lower octane than we have today, so you do not need an octane boster.

General Discussion / Re: flywheel repair
« on: April 24, 2008, 03:52:24 AM »
The clutch throwout bearing has it's own return spring that is separate from the clutch pedal return spring.  On my 29U, it attaches to a small knotch on the bottom of the upper access opening to the clutch (i.e., the access opening that you use when putting grease into the bearing.)  This same spring was used for many years.  I recently obtained a new exact replacement from PowerWagens for just a few dollars. 

Rich Rodgers advertises on ebay and claims to have a good supply of both pilot bearings and throwout bearings for old cars.  I have never done business with him, so I cannot vouch for him.  Here is his email address:
Rich Rodgers:

Thanks guys - All is well with the fuel pump!

I took the 29U on several test drives this weekend and the pump is working well, and not overflowing.  I am amazed that the Kingston Vac Pump does not have any check valve to prevent gas from being drawn into the oil pump.  It appears Chet is right - the system is in balance somehow with a well vented gas tank. 

I put new gaskets on the old original gas cap, but ensured that the cap vent was well open.  The gas tank does not appear to be leaking any at the cap or gas gage, so all seems well and good.

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