Ignition Timing

[MontanaWDX]

I have a question about setting up the distributor and ignition timing. I have a general shop manual for the early PW's but it does not specifically include a '47 WDX.

Do you set up the distributor to fire the #1 plug when the pointer is on the alternator pulley marks?

Where is TDC? The marks on the pulley are worn and not clear. Looks like there are about five large marks with five small marks between them.

In the manual they talk about using #6 to set up the distributor, but my distributor looks like it is firing #1 when the pointer is nearer the marks on the pulley. However when I set the timing light on #1 plug wire, the strobe doesn't show up pulley marks anywhere near the pointer!

How do you determine when a cylinder is at TDC. The usual dial indicator through a spark plug hole method doesn't work on the WDX's 230

Aside from this, my truck starts right up, idles nice and smooth and drives off strong...but get to the first climb and try to power up, the engine feels flat, looses power and starts making a soft fluttering-popping noise. Pressures and temps are fine. Spark plugs look too lean.


Any advice will be much appreciated...

Thanks!

MontanaWDX

[sixtyninegmc]

Well, normally timing is set off of #6 on the flatheads because that cylinder has a pipe plug in the head you can remove to determine TDC. The marks on my engine were similarly vague, so I made a stop out of a pipe bushing, rolled the motor over until it stopped, made a mark on the balancer, rolled it the opposite direction until it stopped, made another mark, and then halfway between those marks is TDC.

On a side note, I was able to adjust my timing by ear under a heavy load by riding on the fender while a buddy drove up a steep hill in low range with a load of firewood on. Worked like a charm, not one I would put in the shop manual, though.

[MontanaWDX]

TDC on #6

Thank you very much for the helpful reply! I also liked your fresh air tune up method.

MTWDX

Well, normally timing is set off of #6 on the flatheads because that cylinder has a pipe plug in the head you can remove to determine TDC. The marks on my engine were similarly vague, so I made a stop out of a pipe bushing, rolled the motor over until it stopped, made a mark on the balancer, rolled it the opposite direction until it stopped, made another mark, and then halfway between those marks is TDC.

On a side note, I was able to adjust my timing by ear under a heavy load by riding on the fender while a buddy drove up a steep hill in low range with a load of firewood on. Worked like a charm, not one I would put in the shop manual, though.

[Charles Talbert]

Timing procedure

The timing is not set off of #6 unless someone has installed the distributor 180* out of time. I have seen this in more than 1 case on the other hand however.

It should be like this; assuming the oil pump is installed correctly, and the distributor is installed correctly; it is timed off of #1 cylinder being at TDC on the compression stroke. To get there is simple, the crank pulley markings work for #1 and #6; these 2 pistons will always be at the top at the same time. One will be up on compression while the other is up on exhaust stroke. The TDC mark or middle mark on the pulley scale is TDC. This mark will align with the pointer every time these 2 pistons are up, regardless of which stoke its on. A little explanation of how it all comes together is simple. With #1 at TDC on compression, the pointer is aligned with the exact middle mark on the scale, turn the crank clockwise by hand until the middle mark reaches the 4 o'clock position or 1/3 of a turn. #5 is now at TDC on compression. Turn it to 8 o'clock or another 1/3 of a turn, #3 is now at TDC. Turn another 1/3 turn until the pointer aligns with the center mark again, # 6 is now at TDC. Continue clockwise to 4 o'clock again, #2 is now at TDC. On to 8 o'clock once again, #4 is now at TDC. Back to the top into alignment with the pointer again puts it back at #1 and the cycle of 6 cylinders firing starts over once again.

To determine when #1 is on the compression stroke; remove the #1 spark plug, place your finger over the hole. Bar the engine over until you feel pressure trying to push your finger off the hole while watching the timing scale on the pulley. When the middle or TDC mark aligns with the pointer and the pressure stops pushing your finger, you are there. Reinstall the spark plug. Point the distributor rotor at the #1 tower on the distributor cap and install the distributor. It should fall right in with very slight or no shaft rotation. If your unit has points, set it where the points are just beginning to open on #1, should fall in effortlessly.

The engine should crank up at this setting; to set the timing, install a timing light. 4* BEFORE TDC is the optimum setting. 2 different scales were used, on one each mark indicates 1 degree; on the other each mark indicates 2 degrees. Simply look at your scale and determine which yours has. Most I've seen is 1 mark = 1 degree. To achieve 4* BEFORE TDC on this scale, just look at the scale and count 4 marks before the center TDC mark as the pulley rotates clockwise; mark that short mark with chalk or a silver permanent marker. Start the engine, with engine idle set at approximately 600-650 RPM activate the timing light. To advance the timing, rotate the distributor counter clockwise slowly by hand until the 4* mark aligns with the pointer tip. Tighten the bolt that secures the distributor to the block, you are done. In the event the timing was too far advanced, simply rotate the distributor clockwise to retard timing until the 4* mark aligns.

A method we use here to get a very close initial timing set is this. When we build up an engine and before the distributor is installed, align the crank pulley and pointer on the 4* BEFORE TDC MARK and the rotor pointing at the #1 tower. Install the distributor and secure it. We have developed a feel for doing it this way; most times when we check with the timing light, adjustment is correct and good to go. After doing this a few times, it becomes old hat, very easy.

[sixtyninegmc]

Sorry to disagree charles, but both my industrial engines manual and B series service manual instruct to set timing with number 6 on TDC compression stroke, and to set it with a dial indicator on the piston for an accurate setting. I learned a long time ago not to trust balancer marks or timing pointers, too many things can be off kilter. Not to mention it is actually easier to do on my truck (B1-PW) than to try and get a good look at those marks!

[MontanaWDX]

Ignition timing

Thanks Charles and SixtynineGMC for your input.

Another question: Can the oil pump be set at any position other than the two which would point the rotor at #1 or #6 in the distributor, when the pulley is at TDC?

My truck starts right up and idles very smooth but when I strobe the pulley I don't see any marks! It is tough to hold the light just right to pass the belt and fan blades however.

When I first checked, and set the pulley TDC mark at the pointer and took off the distributor cap, the rotor did look as though it was pointing at #1 plug wire (about 8 o:clock).

Seems to me that the truck wouldn't start if wires and the rotor were mixed up...or could it?

MTWDX

[Charles Talbert]

Thanks Charles and SixtynineGMC for your input.

Another question: Can the oil pump be set at any position other than the two which would point the rotor at #1 or #6 in the distributor, when the pulley is at TDC?

My truck starts right up and idles very smooth but when I strobe the pulley I don't see any marks! It is tough to hold the light just right to pass the belt and fan blades however.

When I first checked, and set the pulley TDC mark at the pointer and took off the distributor cap, the rotor did look as though it was pointing at #1 plug wire (about 8 o:clock).

Seems to me that the truck wouldn't start if wires and the rotor were mixed up...or could it?

MTWDX

Regarding your oil pump question, actually yes it can. If no marks line up correctly with any piston at TDC, someone has possibly installed the oil pump out of sync with the cam or in a position so that nothing comes together with marks and the pointer. If your rotor points at 8 o'clock, it sounds like someone has installed the pump a few teeth off of where it should be.

Obviously if it starts well, runs well, who ever set it up did so using some manual method that has the set up very close, really nothing to worry about. However I can tell you think like me and it bugs you because you can't reference things and set it up perfectly so you know exactly what you have.

You are also correct that it will NOT start and run correctly with the plug wires out of sync with the correct firing order. Obviouisly yours are not out of sync. One can make any tower on the cap #1 or #6 by changing the wires around so long as the wires are configured in relation to the 1-5-3-6-2-4 firing order. Let me take a stab at what you may actually have based on the info you have shared with us. Of course I can't be absolutely sure because I'm not there to see your set up, but it sounds like this may be what you have.

You said when you align the TDC mark with the pointer, the rotor points to 8 o'clock. Assuming your pointer is correct, big IF, when the pointer is aligned with the TDC mark, either #1 or #6 piston is at TDC on its compression stroke. NOW THERE IS ONE BIG IF WITH ALL THIS; there are several different timing chain covers that fit the 230. Each different cover has the pointer in a different location; I've seen at least 3 different factory configurations over the years, if someone has installed a different cover on yours, well that will cause the marks and pointer not to align at the correct position, it is high on the list of possibilities this may be what has happened in your case. An example is this; the civilian application 230 uses a smaller diameter pulley than the military application 230 in an M37 truck; the covers interchange perfectly as far as fit goes with the cover itself, however if you install a civy cover on a military spec engine, the crank pulley hits the pointer because of the larger diameter pulley. Engines used as power units for welders, etc use still a different cover because of pointer position. I've seen many with the pointer cut off completely to alter this issue, also seen some with the pointer removed and relocated. Some of these relocations were done precisely and correct, others were strictly shade tree. There are other possibilites I could add here, but this is enough to let you know any # of possibilities could be responsible for your issue, and you will simply have to figure out if any such issue may apply in your case.

Getting back on track, most likely whoever did yours has used the 8 o'clock tower on the cap as #1 or #6. You can determine by checking to see whether the plug wire on that tower goes to #1 or #6 spark plug. If my guess is correct and indeed it goes to 1 of these plugs, you have that part of the mystery solved. Looking at the distributor cap and going in a clockwise direction of rotation, the next plug wire will be going to either the #5 or #2 plug, depending on whether #1 or #6 was on the compression stroke when you started. In a word, any tower can be #1 or #6 as long as the installer keeps everything in the proper sequence from his starting point. This kind of off key sequence usually comes into play when someone installs the oil pump a few teeth off and just goes with it rather than pulling the pump back out and installing it correctly. They know what they have done and make everything else work with it. The next person that comes along unaware as you have, you have to figure out what the last person did before you can make their set up work or either you have to start at the beginning and redo things correctly, your choice with that. If you don't want to go to the trouble to change it, you can simply determine exact TDC by using a dowel or similar tool in the 1/8" npt hole over #6 piston to locate exact TDC and the finger over the plug hole method I described in my first post to determine whether #1 or #6 is on the compression stroke. When exact TDC has been determined, mark the pointer position on the crank pulley accordingly. You can draw a degree chart for yourself by drawing a perfect cicle on poster board with a compass the exact diameter of your crank pulley. Cut out the circle and establish a TDC mark on your charts outer edge; using a protractor and working off the exact center point of your chart, mark in 1 degree increments up to 10* on the clockwise side or to the right of the TDC mark on your chart. Once marks are established, go back and cut a plug from the center of the chart large enough so it can be placed directly against the outer edge of the pulley lip with the TDC mark on your chart aligned with the TDC mark you already established on your pulley. Transfer the 1* increment marks from your chart over to your pulley's flange. You now have correct reference marks for exact timing set that is relevant to the way your system is set up. Start you engine and set the timing at 4* BEFORE TDC using an appropriate timing light. This should solve your issue.

[Charles Talbert]

Sorry to disagree charles, but both my industrial engines manual and B series service manual instruct to set timing with number 6 on TDC compression stroke, and to set it with a dial indicator on the piston for an accurate setting. I learned a long time ago not to trust balancer marks or timing pointers, too many things can be off kilter. Not to mention it is actually easier to do on my truck (B1-PW) than to try and get a good look at those marks!

69, I'm not disagreeing with you at all. Your procedure will also get you to the destination perfectly well. This can be done any number of different ways by a person who understands how the system actually works. My intent was to help Montana obtain a better understanding of how the workings go, and a few possibilities that may be in play in his individual situation so he can figure it out and establish the method he needs to get him back on track.

This reminds me of my prior days as a grade foreman for a crew of heavy construction equipment operators. I would explain what we needed to do, sometimes my operators would ask how would you like for me to go about doing that? Obviously a procedure that may work great for 1 operator may be hard for another to follow, that's just our nature as humans. My answer when asked this question was always the same; I don't care how you get there, do it the way it's easiest for you as long as we arrive at the proper destination with the end product. The same applies here.

[sixtyninegmc]

The timing is not set off of #6 unless someone has installed the distributor 180* out of time.

Sorry, I guess I misunderstood.

[MontanaWDX]

Saturday work on the WDX

Thanks Charles for the contributions and to 69GMC also. I did re read my WD manual and they do talk about setting up the ignition at #6 while it's on compression but they do fail to say to check where the rotor is pointing.

Anyway, I found the 1/8" NPT plug, removed it and set up my dial indicator. Sure enough at TDC the middle hash mark on the degree scale on the pulley lined up under the pointer. Good start to the day.

Next I screwed in my 14mm compression tester hose (less valve) into #1 spark plug hole, but instead of fitting the gauge, I connected my compressor air line and slowly turned up the pressure. I shut her off at 60 psi and went back to the truck for a listen. No air was leaking so I knew we were on compression for #1. Just for fun I did the same thing back on #6 and sure enough, no pressure and lots of noise presumably coming from the exhaust valve. (An earlier compression check, engine cold showed all 6 hit 115 to 120 after 4 compression strokes)

Now I thought the day was going great until I looked at the open distributor. The rotor looked as though it would have passed #1 plug wire post and the points were still closed.

I then put the plugs back in (didn't forget the 1/8" NPT plug over #6) and wired up and as usual she started right up. But when I strobed the pulley...NO timing marks could be seen. I took the light around to the right side of the engine and shot the pulley again, where I saw the timing marks at about the 10 o:clock position (as if you faced the engine from the front).

This seems to indicate I am either way advanced, or that the pointer is way off. But, having checked TDC and seen marks and pointer line up, it had to be the distributor position.

With engine still running, I loosened the distributor plate bolt and turned the distributor clock wise which moved the marks closer to the pointer, but not far enough. I then had to readjust the distributor housing-plate bolt thus reaching max allowable travel to clock wise.

The light proved that the pulley mark moved even closer to the pointer, almost 11 o:clock. I shut down and pulled the distributor cover an found that the rotor was better positioned now to the #1 post.

Realizing that unless I fabricated a new base plate which would allow more rotation of the distributor body, I was a close as I was going to get to lining up where I wanted.

I decided that I had done as much as I could so I took her out on the road. What a difference! On the first test drive the old PW could hardly climb our small hill, even in first. Now I can climb a pretty steep grade in 3rd, no problem. In 4th on the flat I can floor it and the truck really pulls nice.

So what now? Do I cut a new plate and continue to retard the ignition...or leave it? Or, could I move all the plug wires one post to the right, making post#5 the new #1? This way I might have more adjustability, which the distributor seems to lack now.

In regards the oil pump, can I say it does look like it may be off a tooth or two?

I don't like seeing the timing marks way off to the far side of the pointer (when looking in from the left). That would indicate that the timing is still too far advanced.


Thanks again for all the help. I really appreciate the support.

[Charles Talbert]

Your findings surely suggest that the oil pump is installed out of time with the cam. I would suggest that you be certain that you aren't getting a false timing reading since you are checking at an angle. If you are satisfied with the angle of check, the more simple fix is to pull the oil pump and install it correctly. Then you can set it exactly on and right by the book.

[Gordon Maney]

This is a really excellent thread. Thank you, gentlemen.....

[MontanaWDX]

Oil pump set up

Thanks for the reply Charles.

Can the oil pump be taken out then reinstalled correctly while the engine is in the truck?

You are correct that strobing the pulley from an angle would not be as accurate as shooting directly from above the pointer but the water pump pulley gets in the way so a side shot is the only way to illuminate the marks on the main pulley. I did take a look from both the right and the left. To be clear, none of the marks, about four wide grooves with 8 smaller marks between them, showed up anywhere near the timing pointer. The first of the marks is now about 1.5 inches away, (right side of engine) so in my estimation, still too advanced.

Like I said, the truck pulls really well now but I don't want to damage anything. I do note that the plugs look better, somewhat darker than what I saw the first time out. Inside the new exhaust tail pipe has a dry chocolate colored dusting.

Am I correct in thinking that since the 230 does not have a very high compression ratio that having too much advance would not be too critical?

Next time I work on the truck, I'll try either making a new distributor base plate so I can continue to retard the timing, or I'll move all the plug wires and see if the base plate then permits better adjustment.

Thanks again for your input and expertise.

(Here are some photos: First one shows timing marks under the pointer with #1 at TDC on compression stroke. 2nd shot shows the indicator through the access plug over #6. Third photo shows where the distributor rotor lined up, past the #1 plug wire post. Rotating the distributor body clockwise as far as it would go did improve timing but needs to go further.)

[MontanaWDX]

Spark Plugs

Here is a photo of selected plugs after a road test, after all the distributor adjustments described previously. My estimation, a bit too lean looking. What do you think?

MTWDX

[MontanaWDX]

What it's all about

After talking about bits and pieces for so long, sometimes it's good to step back and realize why working on these fine old PWs is so satisfying:

MTWDX