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Engine Timing and Valve Positioning

Started by racertb, November 11, 2014, 06:23:44 PM

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racertb

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...





racertb

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?

29plycoop

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.
Plymouth and inovation go hand in hand.

imoore

Tdc on cyl 1 firing
Cyl 4 valves should be rocking between exhaust closing and inlet opening.

1928 Q tourer (Holden bodied)
Several vintage stationary engine

racertb

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

29plycoop

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
Plymouth and inovation go hand in hand.

racertb

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?

29plycoop

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]
Plymouth and inovation go hand in hand.

racertb

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 (?):





Here's what #4 looks like with the exhaust valve opening/open:






Does this look correct?  Wrong?  Hard to say?




imoore

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
1928 Q tourer (Holden bodied)
Several vintage stationary engine

imoore

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.
1928 Q tourer (Holden bodied)
Several vintage stationary engine

racertb

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!

frankp

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
frank p

imoore

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
1928 Q tourer (Holden bodied)
Several vintage stationary engine

29plycoop

#14
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
Plymouth and inovation go hand in hand.