Valve Adjustment TDC Uncertainty

[whatwrenchwhere]

Hi,

Background:

Doing a valve adjustment on 1985 Vanagon 1.9 WBX that was rebuild in last 5000 miles, as I think been having sticky lifters that don't go away, sounds like a typewriter. Did the MMO oil to help, but did not, so now valve adjustment.

Question:

I have uncertainty that I am at TDC. When I rotate the engine to cylinder #1 based off the rotor, I find TDC using the tiny metal mark (#1) on the distributor under the dust cover. However, when I look at the main pully, the notches (#3) on that do not align. (For some reason I have two. A thin one on first rim, and a second wider on second rim).

So am I correct on #2, being TDC based off rotor? Or do the notches #3 not aligning mean I am off?

#1 - Mark on Rotor I thought points TDC to Cylinder #1
#2 - My TDC mark I've been using.
#3. - The two notches that don't line up.

P.S. I've thought about doing the sparkplug screwdriver trick to find TDC, but it seems sparkplugs frozen, so trying to avoid that.

[DanHoug]

[Xevin]

When you say you have a “Rebuilt 1.9” with 5000 miles. Do you mean a complete rebuild with all new parts?
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[MarkWard]

You can’t really count on the distributor for valve adjustment. You only need to use the crank pulley. With the valve covers off and the crank pulley at TDC, look at the valve springs for r/f cylinder. If they are compressed or valves are open, you are at TDC for cylinder 3, l/f valve springs will be depressed instead.

To stay organized, turn crank one full revolution to find TDC for cylinder 1 compression. If you were at TDC for cylinder one, you can skip this step. At TDC for cylinder one, you can adjust 4 valves. 1 intake and exhaust, 2 intake and on the other side 4 exhaust. Now turn the engine 1 revolution to TDC and you can adjust # 3 intake and exhaust, number 4 intake and on the opposite side exhaust valve cylinder 2. You are now done.

For adjusting, back the adjuster off so the rocker is loose. Now turn the adjuster with your fingers, you should feel zero clearance. Now take your screw driver and turn in 1.5 to 2 turns in and lock it down. Many beginners miss the zero lash because they can’t feel it with the added leverage of the screw driver. Using your fingers, you won’t or shouldn’t pass that point.

You probably won’t find this method of valve adjustment documented many places, but it is repeatable and works. Good luck.

[Wildthings]

The larger "U" mark is TDC and the small "v" is your timing mark. Mark's idea is fine, but many may find it confusing. What it does demonstrate is that you really don't need to have the crank super close to TDC to accurately adjust the valves.

If the engine was running and you remove the cap and turn the rotor to where the #1 plug wire connects you have found TDC for #1, easy peasy.

A note on timing, you can only use the book timing specs if every part of the ignition functions properly, like it did when it left the factory. If any part of the ignition is non or only marginally functional, there are better ways to time your engine.

[whatwrenchwhere]

[whatwrenchwhere]

@Xevin @MarkWard @Wildthings @DanHoug

Could use your input on this video I uploaded of how I found the valves adjusted when I took off the covers. As you can see from the video, cylinder #3 exhaust and cylinder #4 intake, are rocking alot. I believe this is where my ticking would be coming from, as that is alot of movement.

https://jumpshare.com/s/oaFgC5wM45dYwu3JAV5e

The issue is, after adjusting,I have to turn the screw way out, to stop the initial rocking before the 1.5 turns. The feel on these is much different then the other cylinders, as hard to find where they 'just touch' Here is a picture of my final screw adjustment. You can see the variance in the screw depth.

Question: Any input whats going on? And is it okay to have the screw that far in?

[Wildthings]

About all I can say to do is to set the engine at TDC compression for the cylinder you are working on and then back the screws out five'ish turns and the turn them back in slowly using only your fingers until you find the point of initial contact, which is going to be very subtle. The turn the screw BACK OUT about 1/8 turn and tighten the nut down. Do only one head at a time. Now run the engine and see if the lifters will pump up. Once the engine has gotten nice and hot, shut it down and let it cool and go back in and see what the results are as far as rocker movement. Any of the rockers that feel hard can be rechecked for point of contact, which should NOT have changed, though it may feel very different and then set the preload.

Once you are happy with one side, do the same procedure on the other.

I am not sure at all that this is going to fix anything though.

[crazyvwvanman]

Viewing the photo enlarged, something is wrong with how those adjuster screws look.
There should be more of the threads showing, sticking out past the locknuts.
I wonder if someone reused some worn/damaged ones by grinding away the tips that contact the valves, making them too short?
New adjuster screws may be in order.

I always do a compression test BEFORE hand and write it down.
Then adjust one head and check the compression again on that side to make sure it isn't worse.

Mark

[whatwrenchwhere]

@Wildthings

Good idea, I'll try that. In general, once the lifters are pumped, and valves adjusted correctly, should there be any movement allowed with the rocker arms?

@crazyvwvanman

I was adjusting the screws to remove all rocker movement, which I think was way past the initial point of contact. So I think that the error, and why so little threads showing.

[Cobra88]

from the video neither cylinder is anywhere near TDC for the 2 you show
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[Wildthings]

[MarkWard]

This is why I suggest using your fingers to turn the adjuster in if you haven’t mastered the feel. Using the method I describe, if you are having problems, skip the preload leaving the adjusters at zero lash. Get the engine running and the lifters full pumped up, then go back and preload.

From the thumbnail above, as mentioned the adjusters are physically in too far. If they need to be in that far, something else is amiss. Replacement valves too short, seats not allowing the valves to close properly, or the rocker shafts aren’t fully seating.

[E1]