Best valves clearance adjustment method - Skoda or Haynes?

[RicardoM]

I bring to your attention the subject of setting the valves clearance for Skoda Felicia. There are two methods available: one described in Skoda workshop manual and another described in Haynes manual. They are not equivalent, meaning they produce different results.

 

So my question is: what method you find more accurate? Why?

 

Skoda method

 

Haynes method

[daverapid]

The Skoda method...that way the clearances are set correctly at the point the relevant cylinder is firing.

[RicardoM]

Is the firing point of the relevant cylinder a good reference for setting the valve clearances?

Or is it the lowest point of the relevant lobe of the camshaft?

[raedalbandak]

Can't decide, I used the Haynes method for many years but just out of interest, what does valve overlap mean and how can one reach it by turning the front wheels? Thanks in advance 

[RicardoM]

Valves overlap: at the end of exhaust stroke, intake valve opens slightly before TDC, exhaust valve closes slightly after TDC. When both valves are open around TDC, we say that valves overlap. For 1.3 l Felicia engines, valves overlap on 20 - 39 degrees of crankshaft rotation angle.

 

 ...how can one reach it by turning the front wheels?

Instead of taking right front wheel out to access the crankshaft pulley nut and use a wrench to rotate the crankshaft, we can just jack up the right front side of the car till the wheel is up in the air, engage 5th speed and rotate the wheel by hand to rotate the crankshaft. So it's not a method to 'reach the overlap', it's an easier method to rotate the crankshaft.

http://imgur.com/p4j2mUw

Edited 25 February, 2015 by RicardoM

[ehabmobarak]

The skoda manual method is available and correct for all 4 stroke engines but the 2nd method is called rule of 9 and can works for old engines and not working for all engines. For me I prefer the skoda method in addition I adjust individual cylebder one by one using the tdc point I'm using a screwdriver for each cylinder.

The overlap means as i know that the ex valve start to colse and the in valve start to open.

The firing point will indicate that the cylinder reached the tdc point and the cylinder will begin to be down and in the same time the lobe of the camshaft relevant to the cylinder is in lowest point they all happen in the same time. That what I know

[ehabmobarak]

will my method using the screwdriver maybe wrong one because it working on the tdc so the overlap method is the wright one.

[ninhan]

I have used the rule of nine on my Felicia. Will this affect it in any way?

[RicardoM]

I decided to make a diagram of timing for a 4 cylinder, 4 stroke engine, in particular for a 135-type engine, but the principle I am about to describe applies to any engine. The diagram helped me decide which valve clearance adjust method is more accurate.

 

In my understanding, and I have to admit I was wrong initially, both methods are good. They are equivalent. In particular, the Haynes method is less prone to errors and easier to do, given the fact the valve clearance is adjusted exactly when the corresponding cam on the camshaft is on its middle lowest point. The Skoda method sees proper to adjust the valve clearance when the piston is at Top Dead Center on compression stroke although both intake and exhaust valves are not on their middle lowest point. That is because the intake valve opens 12 deg. before TDC and the exhaust valve closes 8 deg. after TDC on exhaust stroke. But given the cam profiles (see second illustration) which is circular for 240 deg. (intake) and 230 deg. (exhaust) the clearance is adjusted when the cam is still in one of its lowest points, except not exactly in the middle.

 

It is much easier to use the Haynes method because you don't have to check if you're on TDC exhaust or compression stroke and also you have to rotate the crankshaft only once to adjust all valve clearances.

 

 

[ehabmobarak]

sorry I couldn't understand the first illustration 

[RicardoM]

The diagram is showing the succession of strokes unfolded over 2 rotations of the crankshaft (720 deg. rotation on horizontal axis) corresponding to a 4-stroke 4-cylinder engine with firing order 1-3-4-2. Nothing unusual. On the vertical axis we have the 4 cylinders, each one with 2 valves as they are laid out in a Felicia engine. Imagine it as a top view of the engine, where on top side of the diagram is the crankshaft pulley and on bottom side is the flywheel. I superimposed the position of the corresponding cam lobes for the fully-open and fully-closed valve. That is to see better the reference points for Haynes method.

Edited 2 March, 2015 by RicardoM

[Thefeliciahacker]

I just feel each rocker arm with my finger when it stops moving I know I am reasonably close to the lowest point of the camshaft lobe. 

And that gives me a quick and easy adjustment of the valves. But I usually follow Haynes. 

[D.FYLAKTOS]

On 27/06/2019 at 07:52, Thefeliciahacker said:

 

And that gives me a quick and easy adjustment of the valves. But I usually follow Haynes. 

 

Some say  0.25mm intake / 0.20mm exhaust

and other post for 0.20mm intake / 0.25mm exhaust

Today i asked one one of the most famous Skoda repair-shop here and told me 0.25mm all around !

 

It's a mess.

[Papez]

2 hours ago, D.FYLAKTOS said:

0.25mm all around !

 

It is 0.20mm for steel pushrods, 0.25mm for aluminium. Old Skoda engines had steel pushrods all around, so it was 0.20 all around. 135-6 engines have aluminium pushrods on intake valves and steel on exhaust, so it's 0.25 intake, 0.20 exhaust.

 

Although, there is some info, that steel pushrods can be set to 0.25 at temperatures beyond 32°C to compensate for different thermal expansion.

Edited 15 April, 2021 by Papez

[RicardoM]

There is no mess at all in anything about Skoda Felicia if you read Skoda Felicia factory repair/maintenance manuals.

Everything is clearly stated and explained. No room for errors, no if's and but's. As for 'famous' garages, I prefer less known but competent ones.

[D.FYLAKTOS]

5 hours ago, Papez said:

 

It is 0.20mm for steel pushrods, 0.25mm for aluminium. Old Skoda engines had steel pushrods all around, so it was 0.20 all around. 135-6 engines have aluminium pushrods on intake valves and steel on exhaust, so it's 0.25 intake, 0.20 exhaust.

 

Although, there is some info, that steel pushrods can be set to 0.25 at temperatures beyond 32°C to compensate for different thermal expansion.

 

Thank you for the infos !

What are the symptoms if a 136 Felicia has 0.25 all around lets say for 10.000 Km?

There will be some consequences?

...............................................

 

When a repair-shop has a good reputation on repairs, runs with Skoda cars in local races and has guys with 30+ years experience on Skoda cars their advice is valuable.

These are the guys which suggest for example to change the Felicia radiator switch with another other ''one click lower'' to prevent overheating or gasket problems or have in mind thet the starter solenoid is frail etc.

 

[Thefeliciahacker]

Look if you drive the car agrssively you could go with 0.25 all round.
But i preffering quiter valves so I stick to 0.25 intake 0.20 exhaust 

[D.FYLAKTOS]

7 minutes ago, Thefeliciahacker said:

Look if you drive the car agrssively you could go with 0.25 all round.

But i preffering quiter valves so I stick to 0.25 intake 0.20 exhaust 

 

The first combination has to do with higher fuel consumption?

[Thefeliciahacker]

20 hours ago, D.FYLAKTOS said:

The first combination has to do with higher fuel consumption?

heating the engine up more but yes i think it will affect fuel consumption

[D.FYLAKTOS]

On 16/04/2021 at 18:04, Thefeliciahacker said:

heating the engine up more but yes i think it will affect fuel consumption

 

From my humble experience the combination of 0.25mm intake and 0.20mm exhaust is a big Winner on the fuel economy sector.

I have replaced my metallic catalyst with a ceramic one and i feel that i ''lost" something in the high rpm but i ''won'' something in the low ones and most of all the fuel consumption was much lower.

With the 0.20mm intake / 0.25mm exhaust and the 0.25mm all around i get something on high rpm but i paid it in the gas station more than it's worthed.

I had the 0.25mm intake and 0.20mm exhaust for many years and after the 2 tests i will return to that combination as long as i can drive my Trusty.