All:
Haven't been able to work on the car for a while until this past weekend. I want to get the timing right and have a question about the valve positioning. I've pulled the valve cover and wanted to make sure that all the valves look like they are moving and operating smoothly. I had my son turn the engine over several times via the crank and everything appears to be working as far as I can tell in the valve train, so I am assuming there are no sticking valves.
My question is regarding valve positioning and TDC. I want to make sure that when I static time the car (finger in the #1 spark plug hole method) to find TDC, the valves are positioned in the correct manner. I know that #1 valves should both be closed (bottomed out on these motors), but what should #4 valves look like? Should they too be closed as well? Just want to make sure to see if this matches what I think it should be with the "finger in the hole" method. Once I get this right, I want to mark the crank and another reference point for future reference.
Also I also plan to rebuild the carb since the last time out it flooded so bad the car stalled.
Thanks for your help...
I'm thinking that #4 exhaust valve should be open and intake closed, since #4 piston should be going up on the exhaust stroke. Is this correct?
hope this will help.
TO SET TIMING:
The breaker points should be adjusted to .020" opening and the manual spark control lever set in the fully advanced position. The crankshaft should be rotated until No. 4 piston is going up on exhaust stroke and stopped when the piston is .050" before top dead center. The bolt which clamps the distributor timing lever to the distributor should be loosened and the distributor cap removed to see that the rotor brush is at No. 1 spark plug cable terminal. The distributor should next be rotated in an anti-clockwise direction, as viewed from above, until No. 1 cam begins to separate the breaker points. When doing this the distributor rotor should be pressed against the direction of rotation to be certain that all backlash is removed. The clamp screw should then be tightened and the distributor cap reinstalled as well as the spark plug cables connected to the proper spark plugs and terminals on the distributor cap. The spark control button on the instrument panel should be checked for full advance and retard.
Tdc on cyl 1 firing
Cyl 4 valves should be rocking between exhaust closing and inlet opening.
Thanks for the replies...those instructions 29plycoop looks like they're straight out of the instruction book, which I have. I see it says "#4 piston going up on the exhaust stroke...". I'm trying to make sure I know what this looks like when looking at the valves. Does this mean that the #4 intake valve is closed and the exhaust valve is open? That's what I'm visualizing. Is that correct?
Imoore - what you describe seems to be the opposite, #4 closed/closing and intake open
You are correct. the #4 cyl. will be in the exhaust stroke with the exhaust valve open. As a note you may know the #1 and #4 pistons are both at top dead center at the same time. #1 piston will be at the compression stroke and #4 cyl. will be at the exhaust stroke. The instruction manual says to use a piston travel indicator in #1 spark plug hole to set timing. The pistons are not easily accessible as they are not directly under the spark plug. There is a small pipe plug over the #4 piston that makes setting piston travel with an indicator very accurate. Also the tune-up chart states that inlet valves open 5 deg.(.010 of piston travel) after top dead center. Good luck - Rich
Thanks Rich. I've tried to get that plug out in the past and had no luck. Your last sentence regarding the inlet valves opening at 5 deg. after TDC, are you referring to #1?
It is a common problem getting the threaded plug out the first time.
It does have a tapered thread. The best way is to get it out when the head is off with an easy out. With the head on and you have a small size acetylene torch you can use a small tip and concentreat the heat on the screw, then try to remove it. When you do get it out put it back in with anti-sieze compound.
- Rich[lsize]
I'll be working on the car this weekend, but here are a couple photos of the valve positioning and where they ended up after doing the "finger method" finding TDC on #1. Although I've done this before, the last couple times the car wouldn't start. That's why I started this thread on what position the valves should be in. I also wanted to observe to make sure everything appeared to be working properly with the valve cover off.
Here's the #1 valves, although they look slightly uneven to me, this is what they look like after finding TDC. I may need to make sure they're even (?):
(http://i947.photobucket.com/albums/ad320/racertb/Car%20Stuff/IMAG1643_zps6cjuy2gv.jpg) (http://s947.photobucket.com/user/racertb/media/Car%20Stuff/IMAG1643_zps6cjuy2gv.jpg.html)
Here's what #4 looks like with the exhaust valve opening/open:
(http://i947.photobucket.com/albums/ad320/racertb/Car%20Stuff/IMAG1644_zpswe6vqwf7.jpg) (http://s947.photobucket.com/user/racertb/media/Car%20Stuff/IMAG1644_zpswe6vqwf7.jpg.html)
Does this look correct? Wrong? Hard to say?
No. You are to far past tdc. Cyl 4 valve must be rocking between exh closed and inlet just about to open. This will give to tdc on both cyl 4 and 1. But cyl 1 will be on fireing stroke. Now once this position is found you can then turn engine back 5-10deg. This would be a good start.
Forget what manual says.
Ian
If u set the ign timing to advanced and it kicks back u can always us the timing control to find the right position. Then just hold distributor and push control to full advance position.
Thanks Ian! The last few times I tried to start the car (last weekend and prior) I know it was too advanced because it was cranking slow and I was getting the kickback as you describe. No matter how many times I tried and followed the manual, I couldn't get her going and was driving myself crazy. I'll be playing with this more tomorrow.
So, I assume #1 valves are to be closed similar to my photo (compression) and #4 should look like you describe?
I can tell you that I'm going to leave the valve cover off until I get it right and then I'll be making some markings to save me time in the future!
Ted, wish you well with this. I'd provide 2 cents, but am bankrupt with absolute knowledge of valve position at any given time. Believe you're getting good advice. frank
Hey mate
Just wondering how u r going with it. Did u get her running.
Another thing to note is that u have the correct firing order at distributor.
1-3-4-2
To advance the timing u turn the distributor anti clock and retard is clock wise.
U might also have to remove the distributor and replace to obtain the correct position
If only chrysler put timing marks for a timing light (if they were around then?) on the front pulley. Would make this process a lot easier.
Ian
This video in YOUTUBE may help understand the valve positioning in your engine. Search "blenderguy2008" and look at his video of "4 stroke engine how it works" the video has duel cams but the valve positions will be the same in your 4 cylinder.- Rich
Hey guys:
Not running yet, still playing with it but I think I'm close. Plugs clean and gapped, points clean and set to .20 and valves appear to be in correct position. Firing order 1342, distributor turns clockwise. She was kicking back a little (too advanced) so was using Ian's suggestion of using dash control to retard until it got close. By that time, battery was done, so plugged in charger. Haven't tried today, but possibly tomorrow.
I may have to re-position the distributor as well. Will keep you posted. If you think of anything else I should try, please let me know.
If the battery is a little weak it may cause it to back fire. due to slow cranking. I know with my engine in cold weather I do need to retard the timing a little otherwise she backfires. but once running I put back to full advance
A fully charged battery is important especially in this weather. Just to be safe you might check the spark at the spark plug. Pull one wire off at the spark plug and hold about 1/8 in. from a good ground while turning engine over and see if the spark is strong bright blue or a week flash. You might also check to see if the + wire at the coil is getting full 6 volts when you turn on the ignition switch. Happy Motoring! - Rich
How is everything going. I hope you have succeeded and she is now running.
Ian
Hi Ian,
I took a break from the car for a while until this week and next to work on it. Been busy at work and now with the holidays, I'll have more time to play with it.
I'll keep you posted. Thanks for asking.
Ted
Ok, got her running yesterday for about 5 minutes then cut her off...had to go finish Christmas shopping!
I celebrated that minor victory and have a lot more to do. I only rechecked TDC on #1 and looked at the valve positioning, especially on #4. She fired up and without doing anything else, she ran real rough and I had to pull the throttle lever down to keep her running. There was a steady "popping" from the exhaust. I just wanted to listen and observe (again, a minor victory!)
I'm off for the next week, so I plan on getting back out there and putting the vacuum gauge back on it. I believe at this point it the timing needs to be advanced. I also think I still have a carb issue, but I'm going to hold off on that for now.
One interesting note that may not have anything to do with anything... I put the "old" distributor cap on (after checking for spark earlier at the coil wire) just for grins. I noticed the old cap fits a little tighter than the newer one I have been using because I can feel the old cap pushing down on the rotor button. Don't know if this is significant or not... more to come.
Ted
Update... Got the distributor advanced and car sounds better, but still not great. With vacuum gauge, needle fluctuating around 17hg. Carb mixture screw backed out just about one turn. This is the best I can do at the moment with just playing with the distributor and carb adjustment. Still a miss out of the tailpipe.
Since the car is on jack stands (I wanted to keep it off the tires since its been down a while), I ran it through the gears up to about 30-40 mph. It sounded better at the higher speeds, but still coughed through the carb occasionally at lower speed acceleration.
I will post a video soon hoping for some feedback...
http://vid947.photobucket.com/albums/ad320/racertb/Car%20Stuff/VIDEO0025-1-0_zps1sncmg76.mp4
Hi Ted,
I haven't put a vacuum gauge on my 29 but I did use it on my 1948 Flathead six when I first fired it up after a valve job and new timing chain. At slow idle the Vacuum was at 21 inches of mercury and rock steady. See picture below.
(http://www.1948plymouth.info/1948p15/images/Motor_02262005.jpg)
Thanks Chet, let me know if you ever put on the '29. I had it around 18-19hg max, but purposely backed it down a little. After adjusting the mixture and idle on the carb, I called it a day. This is about the same as it was before when it quit on me. I would think that if my cam gear was bad, the car wouldn't be running.
I need to figure out the fluctuation issue, whether it's valves or something else.
Ted,
Maybe a poor valve seat or a weak valve spring or possiably a sticking valve. Wasn't your motor recently rebuilt. If so was the cam shaft reground or replaced? Slop in the timing chain can give you that needle shake. You have been all over the normal timing stuff.
Chet...
The motor was rebuilt in the mid-80's when my Dad had the car, so I don't know exactly what was done to the motor. I just know it was rebuilt. I think the receipts are somewhere in a box so I could see what was done or not done to it.
I was also wanting to look at my spark plug gap as well to see if it might help he miss...I heard some Model A folks like a slightly bigger gap for a smoother idle. Any thoughts on this? I realize this won't help any possible valve issue, but just trying to see what else I can do with what I have to work with.
I also can work on the carb since I have a new kit and float for it, but might hold off on that for now.
Check this out from the Plymouth Bulletin regarding 4cyl Spark Plug Gap and Timing:
http://plymouthbulletin.com/smf/index.php?topic=327.0
Quote from: racertb on December 23, 2014, 10:31:01 AM
Check this out from the Plymouth Bulletin regarding 4cyl Spark Plug Gap and Timing:
http://plymouthbulletin.com/smf/index.php?topic=327.0
It's worth a try.
BTW I always set timing advanced as far as possible without pinging. If it pings retard it until it stops (pinging). This might require a test drive. Since your engine has no timing marks I thought you were already doing this by ear ? Full advance should be with the spark control cable all the way in. Pulling on the spark control cable will then retard the engine for starting. Much easier to start the engine while the timing is retarded. Once started, your timing should be advanced to the run position, (Cable pushed all the way in).
Chet...
I've got the plugs gapped at .030 and advanced the timing up to 20hg on the gauge. Turned the motor off and re-started. I could tell it was a little too advanced because she cranked a tad slower and the starter kicked back a little. I backed the timing down slightly to 19hg and she started up fine. I suppose I could advance kit to 20-21hg and use the dash control to retard when starting as you suggest. I believe that Model A owners do it that way as well.
Ted,
The spark control was originally designed to retard the timing to just after TDC to allow the operator to crank the motor easier but more importantly to prevent kick back that could injure the person cranking the motor. Of course all the early cars of the period worked similar so the Model A guys have it correct. A modern engine like my 1948 Plymouth uses centrifugal and vacuum advance technology to eliminate the need for the spark control cable.
BTW... Never try to crank start your car by hand with the motor timing advanced. Could be very painful.
Cheers Chet...
I got it! :)
I have always left the dash knob in and would only pull it out to retard if I ever had to hand crank just for that reason... I hope I never have to use the crank for starting!
I think I will be tackling the carb in the next few days. While watching the motor run for a while, it started to idle a little rougher and the vacuum gauge needle dropped a little and was not steady. The carb looked real wet, especially near the top, and looked to be flooding. I revved it up some until things got smoother and needle on the gauge went back to where it was. I think the float is sticking and/or it's dirty inside. If you recall, when the car left me stranded the last time, the carb flooded bad and there was gas everywhere.
It's probably due to be taken apart since the last time I rebuilt it and repaired the float was 12 years ago.