First time Valve Adjustment Issues Options

[revhi109]

So I am trying to get my engine back in the car and figured it would make more sense to adjust valves with the engine on the ground. I have never owned a vehicle with a distributor or adjustable valves, So I forgot how this works. I started with TDC on #1 and adjusted valves to .008" which is the smallest gauge I had. turned the crank 90 degrees so the distributor would be firing #4 and adjusted #4's valves and so on. I got to the #2 cylinder and something didnt seem right. the rockers had way too much play and the adjusters wouldnt tighten far enough. I double checked my work on all the cylinders again and they all seemed correct...except the last cylinder. Is it possible that the guy who "rebuilt" my engine put in the wrong rockers or cam? Stumped.

[NORD]

Check the rockers, are they the same as the others? No spacers under the blocks ?

Could be two short pushrods. (IMG:style_emoticons/default/driving.gif)

[stugray]

If the cam was the problem you would have the same issue on the opposite cylinder since both sides use the same lobes.

And when you say " turned the crank 90 degrees" you mean that you turned the crank until the distributor turned 90 degrees right?

You have to rotate the crank 180 degees to get the dist to turn 90

Use the mark on the flywheel to find TDC.
And you cant always trust that the dist is pointing where you think it is after a rebuild.

[revhi109]

Yes Sorry. I meant I turned the crank 180 so that the distributor pointed 90. I made sure to adjust valve in the firing order. I had to pull out the distributer gear and flip it 180. hmm. I had all the pushrods out to redo the tube seals and didnt notice any short ones.

[TheCabinetmaker]

Did you put the pushrods back in exactly like they came out? Are you sure you were tdc #1? Is that valve closed all the way?

[revhi109]

No, I tore the engine apart last fall and mixed them up while cleaning them. They looked all the same length so I didnt think it mattered. The last cylinder is way off like something is missing. There is at least a quarter inch gap when I pull the rocker back. And yes I am pretty sure #1 is at TDC when I start. I have a 50-50 chance that I'm on the compression stroke or the combustion stroke. I made sure the distributor was pointing towards the tick mark.

[Cap'n Krusty]

Might want to adjust 'em the way I've outlined in the thread in the classics forum. Report back after you've done so. Easier, faster, and not at all dependent on outside factors.

The Cap'n

[revhi109]

I think I found your article you are talking about. Not sure where the classics forum is. The only difference is that these adjustment articles are written as if it was in the car. Are you referring to your chart?

#2 Ex & #3 In #4 Ex & #1 In
#1 Ex & #2 In #3 Ex & #4 In
#4 Ex & #1 In #2 Ex & #3 In
#3 Ex & #4 In #1 Ex & #2 In

[Dave_Darling]

Take a quick look at the valve tips. Are they closer to the head than the other cylinders? Hopefully not. If they are, you may have something holding the valves open. In my case, that was a dropped valve seat. It's much less likely to be the case when both valves have that much clearance, but...

--DD

[revhi109]

These heads just got back from an aircooled specific machine shop. I re-installed the valves myself. but the machinist said the valve stuff looked good. When adjusting the valves, Ive been doing them in the firing order. Does it matter if you are on the compression stroke or the combustion stroke? The valves should be fully closed either way. Right?

[Cap'n Krusty]

These heads just got back from an aircooled specific machine shop. I re-installed the valves myself. but the machinist said the valve stuff looked good. When adjusting the valves, Ive been doing them in the firing order. Does it matter if you are on the compression stroke or the combustion stroke? The valves should be fully closed either way. Right?

Wrong. You adjust them ONLY on the compression stroke if you're using the TDC method, which I strongly discourage. You don't need to have the engine in the car. My method works even without an installed distributor. Here's the link:

http://www.914world.com/bbs2/index.php?showtopic=28758

The Cap'n

[brant]

I agree that you need to use the capt'n method to eliminate variables....
you can't go wrong that way


I'm also concerned that we are talking about a freshly assembled motor
are the pushrods stock original... are you sure they are stock length?


it would be very possible that a previous owner had built custom length pushrods in a prior build.... if that did happen, then you are using the wrong length of rods in the wrong positions. The solution for that would be to measure each of them accurately and perhaps use the process to set then correctly by replacing them with the valve train adjustment procedure

which cam is in there now?
a valve train (top end) job on these motors is precise work if its not a stock motor and your not using 100% original OEM, never been rebuilt NOS parts.

[revhi109]

What is stock length? Its a 1.7 case, 1.8 heads, and 2.0 cylinders. No idea where these rockers or rods came from... I am drawing up a diagram know to help me understand this method. Im having a hard time understanding what that table means.

"rotate the engine until the rockers are rocking in accordance with the first entry in the table below"

So, Turn until #2's exhaust valve starts to rock?

[stugray]

IMO it is better to understand the basic method to set the valves before learning the "shortcut" method from the Cap'n.

His method is excellent, but it is kind of like learning a backflip-fulltwist before the backflip.

If you cant get it right using the stock/basic method, then trying the new method will just mess you up.

Getting the engine at true TDC is childs play with the engine out & looking right at the valves.
Use the mark on the flywheel!

It is completely possible to get the cam & crank out of synch when installing the camshaft.
Is the oil pump in yet?

[Dave_Darling]

You can also understand the Cap'n's method by putting it this way:

Look at both rocker boxes. Rotate the engine until one valve is all the way open. Adjust the same valve on the other side of the engine. So if the left-front cylinder's exhaust valve is open, you adjust the right-front cylinder's exhaust valve.

Repeat until all 8 valves are done.


....Or just set each cylinder to TDC (compression stroke) in turn and adjust both valves on it. Which is not the Cap'n's method.

--DD

[revhi109]

Ok. I think I understand the quick method now. I thought I was doing it right until I got to the last Cylinder of the firing order (#2). Now that I know how the cam system works, I will try again.

[r_towle]

You can also understand the Cap'n's method by putting it this way:

Look at both rocker boxes. Rotate the engine until one valve is all the way open. Adjust the same valve on the other side of the engine. So if the left-front cylinder's exhaust valve is open, you adjust the right-front cylinder's exhaust valve.

Repeat until all 8 valves are done.

--DD

The camshaft has 4 lobes on it.
those 4 lobes actuate 8 valves.

Each lobe is shared with the valve on the opposite side of the motor.
When one valve is all the way open, which is easy to see, the valve on the other side of the motor is now on the bottom of the lobe.

Adjust each valve when its on the bottom of the lobe.

Forget about TDC
Forget about what part of the compression stroke you are in.
Forget it all.

Just think about what MUST happen for a valve to open.
The other valve must be closed...period.

rich

[RogerYellow914]

Question, why does it matter if the valves on the cylinder being adjusted are at TDC or BDC?

[Dave_Darling]

Look at how the valves open and close, relative to the position of the cylinders. In particular, look at what is happening at BDC.

--DD

[RogerYellow914]

Both valves are closed. As the crank turns the exhaust valve will begin to open.

But at either TDC or BDC, what difference does it make if they are both totally closed? Not trying to be contrarian. Just trying to understand from a position of ignorance.