Audi A4 new engine or just cylinder head?

[Burnerman]

The inlet valves will be the smaller ones in a group of 3, the carbon deposits will be darker than the exhaust valves....you can also see whats what from the position of the manifolds.
It will take a while for the hydraulic tappets to fill with oil, and until they do the valves won't be opening fully.
John

 

[iwaters]

Did you leave it for 30 mins after assembly before starting? This is
required to allow the hydraulic elements (tappets and cam chain tensioner) to settle.

Have you checked that the cam chain is installed correctly? There should be 16 rollers between the marks on the inlet and exhaust cam. If there isn't your timing will be out.

 

[iandandav]

A general check is to set No 1 cylinder at TDC and slowly turning the crank...the inlet valve should open immediately and be fully closed on the next up stroke, which is compression. When the piston reaches BDC on the power stroke, the exhaust valve should be open as the piston rises again. Bit rough and ready, but it'll give you some idea.
John

Just confusing myself from what you wrote above and the hayes manual. It says 'No1 piston at TDC is on the compression stroke' so I assume this means at the end of it (if it was the begining the piston would be BDC), and it is now TDC ready for the power stroke. If this is the case then the valves on this piston should all be closed ready for the ignition, however you say the inlet valves should open.

The manual says the firing order is 1 - 3 - 4 - 2. So to try and clear things up I have drawn a diagram to try and predict where each valve should be. When I know this I can check the cams on my head and see if they are in the right place.

Can you guys take a look at the diagran and telll me if it looks correct.
A few explanations
P - begining of power stroke
E - begining of exhaust stroke
C - begining of compression stroke
I - begining of intake stroke

Arrows show the direction the piston is about to move in
closed - all valves on this side closed
3 circles - intake valves open
2 circles - exhaust valves open

 

[Mursal]

Everything is correct on the diagram
But to be honest we would not even look at cylinders 2 or 3.

Only 1 and maybe 4

When No1 is at TDC both valves will be closed and its looking for a spark
to go down on the power stroke. It should get a spark roughly 10
degrees before TDC.

Now No4 will have the Exhaust valves open (because they didn't close
yet) and the inlet valves open (they open a little before TDC). This is
known as "Rocking".

So we say that No4 will be "Rocking" when No1 is firing.

So when you have your timing marks all lined up it tells you No1 is about
to fire (explode) and go down on power. But No4 will be Rocking (both
valves open a little). So if all your marks are lined up as in the manual,
thats it.

Remember the engine travels in a CLOCKWISE direction so always turn
it clockwise when checking timing marks.

Its probably lack of a spark or fuel, all plugs reconnected to all
sensors/solenoids?

Try a little carburettor cleaner in the inlet manifold, it might help her to
fire up.

These temperatures wouldn't encourage anything to start.

 

[iandandav]

So all I should look for at TDC is all valves on cylinder 1 closed and all valves on cylinder 4 in transition ie slightly open. I havent got the cam cover off at the moment so cant look, but should I see the cams (exhaust and inlet) on cylinder one turned away from the tappet and cams (exhaust and inlet) on cylinder 4 partially pressing on them? I remember hearing about rocking and seem to remember working on an old ford many years ago where the rocker was loose at some point. Is this what you mean by rocking? Would this be noticable with hydraulic tappets?

Yes Im praying its just a temp thing as the cars been off the road for some time and I dont think I got the motivation to takre the head of again. the garage is *#**@** freezing.

 

[Mursal]

Yes thats correct.
As a guide all valves open on No 4 (a little) and all valves closed on No1
when crankshaft at TDC.

But this wont be accurate enough you will have to check that the marks on
the cams to head are lined up and the marks crankshaft to engine block are
lined up. If they are out by 1 tooth it wont start properly. Turn in aclockwise
direction to lin the marks up. Are the marks hard to see?

You may not be able to "feel" the clearance in the hydraulic tappets, but if
you have a set of feelers they will fit between cam lobe and valves on No1.
But will not fit on No4 therefore No4 is said to be "Rocking" all valves open a
little.

 

[iandandav]

Rechecked the marks on cam an have attached som pics
Over all pic. Haynes manual states that there should be 16 rollers between the two marks on the cams and the exhaust cam mark (left of pic) should be offset slightly TO the centre of the cylinder head. Now there are definately 16 rollers between the two marks but the pic shows that the exhaust cam mark is offset AWAY from the cylinder head.

This means that the exhaust cam could be one tooth off to the left. However if I move the exhaust cam 1 tooth to the right so that the mark is off set to the centre of the cylinder head as the haynes manual says then there will only be 15 rollers between the two marks. I am cannot see how this can be acheived.
Unless
1) the haynes manual means 16 rollers between the marks on the cam clamps (sorry dont know terminology) and not between the marks at the base of the sprockets.
or
2) There is something wrong with the tensioner. If the tensioner was exherting more force in the upward direction maybe this would cause the cammarks on the sprockets to turn towards each other resulting in the exhaust cam sprocket mark being offset to the centre of the cylinder head when the inlet cam mark was lined up.

Can anyone confirm theory 1 or 2.
Also if it is indeed off by one tooth could this be the cause of the car not starting?


Close up of the inlet cam showing 16th roller (red dot).

Close up ofexhaust cam showing first roller (red dot)

Over all view

 

[Mursal]

I haven't got the 20valve 4cylinder diagram in the manual I have its to old. So I take it that the arrows are the marks and they line up with the slits in the cams?

Have you all the slack out of the chain on the top to make 16 rollers?
Is there slack in the chain on the bottom? The tensioner takes the slack out of the chain and its the bottom of the chain drive that pulls the cams along in time. I mean the chain we cant see underneath the sprockets.
Turn the engine clockwise and see if you get more slack on the top of the chain (that you can use to get 16 rollers and still have the marks lined up).


Whats the belt pulley like on the marks for the belt, that would be more critical to go for a start?

 

[iandandav]

I asume the arrows lign up with the slits as there are no other marks, and looking at the cams they are all in a position that matches my drawing and your description that no4 should be just touching (rocking) and no1 not touching (valves closed) That tensioner was also concerning me. Although it feels tight the chain must have some slack there as you can see that the links are not completely pulled taut. Should that tensioner be sprung up higher? If it was I can see that it would turn the cams a bit lining things up more to as the manual states.

The tensioner must be compressed with a special tool, but looking at it is appears to already be compressed as there is very little of the piston showing. Are these things pneumatic or do they have a spring. Im wondering if it is broken

The crank his lined up and the pistons TDC when the pics were taken so everything seems correct except these marks on the cam are not exactly as the manual states

So you think this would not be enough to prevent the car from starting? If so I will have to look elsewhere for a problem.

 

[iandandav]

heres the cams. difficult to see properly

 

[Mursal]

Can you get the chain to have 16 links between the marks. I mean is there any slack in the chain at the bottom where we cant see it in the picture? If there is your out a tooth? Because as the chain tightens it will move the cams out of time away from the marks on the clamps.

If the book says 16 then have another look, turn the engine using a spanner 2 full revolutions clockwise and see if all the marks lineup again? I they don't your out a tooth.

To explain it another way. The cam on the left turns clockwise pulling the cam on the right along the bottom run of the chain. All the slap will be on the top. After two turns all marks should line up. And I don't think they will as it stands. But check

The chain will be tensioned when the oil pressure rises. It is designed that when it goes out it will not go back in, at least not fully back in.

From your picture I see the camshaft sensor is out front on the right hand cam. A link will make a difference on this sensor. This will control ignition timing and fueling? Is it in place and connected OK? Double check that it didn't move out of position or disconnected.

Do let us know how you get on.

 

[iandandav]

Can you get the chain to have 16 links between the marks. I mean is there any slack in the chain at the bottom where we cant see it in the picture? If there is your out a tooth? Because as the chain tightens it will move the cams out of time away from the marks on the clamps.

There is 16 rollers between the marks. I didnt notice the bottom of the chain. Maybe its not visable with the c/head on the engine.

If the book says 16 then have another look, turn the engine using a spanner 2 full revolutions clockwise and see if all the marks lineup again? I they don't your out a tooth.

I have turned the engine by hand, and even tried to start it. Its been turned many times. The marks always end back in the same position
The only thing that concerned me about the marks is that when the inlet cam marks line up with each other, the exhaust cam marks are slightly offset, with the one on the sprocket to the left of the arrow on the clamp, where as the manual says the cam mark should be offset slightly towards the centre of the c/head. I take this to mean that the mark on the sprocket should be slightly to right of the arrow on the clamp, not the left as it is in the the pic.

The chain will be tensioned when the oil pressure rises. It is designed that when it goes out it will not go back in, at least not fully back in.

Thats good to hear it would explain why the tensioner is not extended more. Meaning that its not broken

From your picture I see the camshaft sensor is out front on the right hand cam. A link will make a difference on this sensor. This will control ignition timing and fueling? Is it in place and connected OK? Double check that it didn't move out of position or disconnected.

I will double check this. However, I have not removed this But the piston place that did the head may have when they did the valves. Do you know how freely the cams should turn (with valves in place). They seem stiff so Im wondering if the clamps havent been put on right. They probably have, they specialise in pistons, heads etc, just grasping at straws as this has got me baffled.

Im thinking the battery might not have the power to turn the crank fast enought to get it to start. It seems weak. Not sure if this is because the battery is clapped out or theres exessive resistance somewhere.

Do let us know how you get on.

I will. Im on the verge of calling it a day and getting a mobile mechanic to visit and take a look.

 

[Mursal]

But the way I'm reading it there is only 15 rollers between the marks?

Yes the battery will go flat as its not just going to burst into life, it will need a few turns. The cams are hard to turn against the valve spring pressure. Jump off another car to have more capacity and or recharge.

Can you place the plugs sitting on the head or block (steel work) to see if you have a spark when cranking? Have a fire extinguisher or at least water on hand at all times.

The head guys would have had the cam sensor off

Don't give up its probably something simple.
Is it coughing or spluttering making any attempt?

 

[iandandav]

But the way I'm reading it there is only 15 rollers between the marks?

Yes the battery will go flat as its not just going to burst into life, it will need a few turns. The cams are hard to turn against the valve spring pressure. Jump off another car to have more capacity and or recharge.

Can you place the plugs sitting on the head or block (steel work) to see if you have a spark when cranking? Have a fire extinguisher or at least water on hand at all times.

The head guys would have had the cam sensor off

Don't give up its probably something simple.
Is it coughing or spluttering making any attempt?

From what I understand they include the rollers inline with the marks too ie including the ones with red dots. The angle of the shot and perspective may be deceiving too, making the marked roller look offset to the arrow.

will try and do the spark plug thing tommorow.

It can get about 5 turns from the battery before it dies. It never seemed to sputter of cough at any point, just the starter motor noise.

I will check the cam sensor too
Thanks

 

[Mursal]

OK so all the marks are lining up when you turn it over 2 turns with the spanner. So timing marks are setup correctly.

It will need more grunt in the battery department to get her up and running. It will need a really good spin from the starter to fire up. Jump leads or boost starter/charger.

If you have a spark and all wires to the injectors out in the inlet manifold are OK, then put an eggcup full of petrol down each plug hole. Put the plugs back in and try her again. You could try a little easy start in the inlet manifold as it is turning, but be careful to much can be harmful.

With the above it should make some attempt to fire up even if it stops again?