valve adjustment question Options

[stecz]

I've only adjust the valves on my '73 2.0 a couple of times (2 to be exact). Both times I've had this trouble... I am following the Pelican parts procedure. I have the flywheel scribed so I can stay underneath and rotate a tire to line up the valves. The problem is that I'll rotate the engine to get setup for #1 and #3, adjust them, rotate the engine 1 rotation and the adjustment is WAY off as in MMs

What would cause the lack of consistency? I was very careful to always creap up on the line in the same direction to eliminate any valve train slop, but there shouldn't be much of that... Any ideas?

What I ended up doing was rotating the engine so the valve I was adjusting was fully closed and adjusting the lash at that point, I just wasn't at TDC for that cylinder.

The car now runs strong and sounds correct (some valve ticking).

Any ideas?

[Bruce Allert]

I have 2 marks. I begin with #1 @ TDC. Get under the car & make a mark thru that hole in the tranny right smack dab in the center. I put it where the casing halves come together. After I adjust #1 valves I rotate the tire counter clock wise (as if you were backing up) a half turn for #2 so the notch is seen thru the hole in the tranny, dead center where the halves come together again. For #3 it's a half turn again and the mark you made will be seen... adjust, then the same for #4. Hope this helps.......

......b

EDIT: I left out the #2 after adjusting #1... Sorry for any confusion. (IMG:style_emoticons/default/wacko.gif)

[ArtechnikA]

...I'll rotate the engine to get setup for #1 and #3, adjust them, rotate the engine 1 rotation and the adjustment is WAY off as in MMs ...

you cannot adjust #1 and #3 at the same time ! (similarly, #2 and #4)

(please point me to a technical article that suggests otherwise...)*

yes - the pistons for #1 and #3 are at TDC at the same point relative to the crankshaft (flywheel) and a fixed reference. but they are at different points in the firing cycle and TDC power stroke #1 means #3 is on overlap - between exhaust and intake - and both valves will be open. the pistons move together but the cam rotates at half crankshaft speed.

each cylinder is at TDC on its power stroke (both valves closed) exactly once in two engine rotations. any method that attempts to turn the engine less than two complete rotations is doomed to failure...

* (okay - i re-read what you wrote and thought about it some more... anywhere late in the intake stroke, a cylinder's exhaust valve will be as closed as it's going to get. anywhere early in the exhaust stroke, the intake valve is as closed as it's going to get. anywhere late in the compression stroke and early in the power stroke, both valves are as closed as they're going to get. so i suppose it's possible that you could do it in one rotation by finding the valves [<--note multiple] that are closed and adjust those. that could get it done in less than two rotations, i suppose -- i'd have to look at a crank and cam and convince myself... but my original statement stands - you can't adjust all 4 valves on the same head at the same time. you can probably adjust 4 valves at the same time, but it'll be both on one cylinder, another cylinder's intake, and yet another cylinder's exhaust. one rev later, i bet you can adjust the other 4. now that i think on it, i seem torecal that's the beauty of this method. but not all 4 on the same head at the same time.)

(the same 'trick' works on boxer 6's too, and the guys who adjust valves all the time are comfortable with it. i'm not, and i use the old-fashioned two-rotation check TDC method every time. perhaps i'm too easily confused, but i'm more comfortable when i can easily follow what's going on...)

[ChrisReale]

(IMG:style_emoticons/default/agree.gif)
I thought I was reading the original query wrong...

[stecz]

Ok, I'm going to have to read the instructions again...

I thought when my scribed mark 180 degrees off on the flywheel is showing underneath, then I adjust both the #1 and #3 (both rear cylinders), then rotate 180 degrees (notch showing) and adjust #2 and #4. That sounds different than what is being said above.

My point was.... I line up the scribed mark, adjust #1 and #3 and then rotate the engine around until the mark shows again and the valve adjustment is way off. Same happens with the notch for #2 and #4.

[ArtechnikA]

My point was.... I line up the scribed mark, adjust #1 and #3 and then rotate the engine around until the mark shows again and the valve adjustment is way off.

i understand.

my point is - it can't work that way ...

[TheCabinetmaker]

my point is - it can't work that way ...

exactly! It won't work that way. You cannot adjust the valves on the same head at the same time. If you do, your headed for big time valve problems. I too have used the PP method, and that is NOT what it says to do. Better go read it again.

[Bruce Allert]

When I first read Waynes article I thought the same thing and did the valve adjustment as Stecz did but something told me this wasn't right so I re-read it a couple more times. Once I figured it out it made sence but that was after the little hand on the clock went around twice! (IMG:style_emoticons/default/rolleyes.gif) When I bought the teener I had no automotive mechanical experience what so ever. Interpretation is everything. Here is the part of Waynes article that thru me into thinking the same as stecz....

In this manner, the crankshaft position for TDC on cylinder #1 is the same as it is for cylinder #3. Likewise, crankshaft position for TDC on cylinder #2 is the same as it is for #4. Because of this, you only need to know when the crankshaft is at TDC for #1 and #3, and when it is rotated 180°, for #2 and #4.

......b

[Joe.D]

So, FWIW, here's how I think this through.

Keep in mind that each piston has to go through two "strokes"- one where the gas/air mixture in the cylinder is compressed and one where the burnt gasses are pushed out the exhaust valve.

You adjust the valves for ONE cylinder, when the piston is at TDC of the *compression* stroke, where the valves are both closed. Then you must turn the crankshaft 180 degrees to position another cylinder to the top of a compression stoke, and then adjust the valve lash for that one cylinder.

When #1 is at TDC of the compression stroke, #3 is at TDC of the exhaust stroke, whick means the exhaust vavle is OPEN. One rotation of the crankshaft later, the opposite is true: #1 is TDC of the exhaust stroke, and #3 is TDC of the compression stroke.

I hope this might help explain why it seems you have to turn the engine 180 degress three times (after getting #1 set up at the start), to get all the valves into the correct position to be adjusted.

Joe

[tat2dphreak]

ok, all of this confusion has got me confused now... I thought I understood this before, but now I don't know...

assume we are at TDC for #1... do you adjust both the intake and exhaust valve at this time?

should you do them in the same order as the firing order?

the way I did it, and correct me if I did it wrong(I've only done it 2 times as well)

I sat the engine at TDC according to the peep hole in the fan housing, the rotor was pointing towards the fan (as stated in the pelican article) I did both valves on cylinder 1, rotated 90 deg. to the next mark I could see through the viewhole in the tranny, did both valves on cylinder 2, rotated 90 again, did #3, 90 deg. did #4...

is this correct?

[ArtechnikA]

assume we are at TDC for #1... do you adjust both the intake and exhaust valve at this time?

should you do them in the same order as the firing order?

if we're doing it The Factory Way, yes, you adjust both Intake & Exhaust for the cylinder on TDC Compression. i always do mine in firing order; this is The Factory Way.

90 degrees at the distributor is 90 degrees at the camshaft which is 180 degrees at the crankshaft.

the 'Pelican' method - it goes by a few other names - takes advantage of the fact that there are multiple valves closed at a time. people who've used it a lot and are comfortable with it claim it's faster and it probably is. i still do it The Factory Way tho ...

(yes - your way works just fine ...)

[Bruce Allert]

you rotated 180 degrees... not 90 (I hope!) but to answer your question, yes your progression is right 1,2,3 then 4 by rotating 180 degrees beginning at TDC of #1.

.......b

[tat2dphreak]

assume we are at TDC for #1... do you adjust both the intake and exhaust valve at this time?

should you do them in the same order as the firing order?

if we're doing it The Factory Way, yes, you adjust both Intake & Exhaust for the cylinder on TDC Compression. i always do mine in firing order; this is The Factory Way.

90 degrees at the distributor is 90 degrees at the camshaft which is 180 degrees at the crankshaft.

the 'Pelican' method - it goes by a few other names - takes advantage of the fact that there are multiple valves closed at a time. people who've used it a lot and are comfortable with it claim it's faster and it probably is. i still do it The Factory Way tho ...

(yes - your way works just fine ...)

90 deg. at the distributor is what I meant... sorry.
I just wanted to make sure I was doing it correctly. thanks!


the thing that really threw me was this: when the Fan shows TDC, and the rotor is pointing towards the center of the fan, doesn't that mean that it is #4 cylinder at TDC? that is the one about to fire, correct?

[TheCabinetmaker]

Forget the timing hole. Find tdc for #1 by feeling in the hole at the top of the transmission case for the big notch on the flywheel. Then make a mark on the bottom of the flywheel. You can make sure your on # 1 by looking at what plug wire the rotor is pointing at. Both valves should have a little lash at this point. If not, either the valve is too tight or your on the wrong cylinder. Adjust both valves on #1. If you rotate the flywheel 180 degree (or 90 degrees at the diz), the notch will appear at the bottom hole. If you rotate the engine backwards, you'll do 1,2,3,4. If you rotate the engine the same way as it turns when its running, you'll adjust 1,4,3,2. I start on #4, then do #3, Then I button up that side and move to the other side and do #2, and last, # 1. I put the car on two stands, and remove the wheel on the side I'm working on for easier access, and use a clamp on the rotor and backing plate to hold that side still while I rotate the other wheel by hand to find my two marks on the flywheel.

[need4speed]

Personally, I initially find TDC by removing a spark plug, and sticking a depth-gauge down in there. When the piston's at the top, I *know* it's TDC. (I only do this once - then I compare with the mark on the flywheel) -

Also, I usually go PAST TDC, then crank it back (um, when I'm working opposite of firing order), to take up slop in the valve train. (ensure that the whole thing is moving the same way it would be when it's running).

[bondo]

I just adjusted my valves (man did I get dirty) and I used the alternate method that's at the end of the pelican tech article. It's similar to what I'm used to for adjusting the valves on my MGB, and it worked well for me. It also made sense that if the cam has one valve all the way open, the one on the opposite side (that rides on the same cam lobe) has to be closed.

--Royce

[stecz]

Ok, now I get it...

- put the engine at TDC for #1 (rotor toward notch on distributor). (scribed mark on flywheel lined up underneath)

- Adjust intake and exhaust for #1 (driver side rear)

- Rotate engine so flywheel notch show at bottom
(rotating driver side wheel in forward rotation direction)

- Adjust intake and exhaust for #4 (passenger side front)

- Rotate engine so scribe mark shows

- Adjust #3 intake and exhaust (passenger side rear)

- Rotate engine so notch shows

- Adjust #2 (driver side front)

Sound right?

[Bruce Allert]

.......there ya go Man!

you can also turn the tiar backwards & do 1, 2, 3, 4 so you aren't jumping from one side to the other.

but do it what ever way is understandable & enjoy (IMG:style_emoticons/default/boldblue.gif)

.....b