4 hours ago, SaltySkoda said:

she’s a GLX model

 

That's the way Men here in Greece speaking about their cars (even when they were in the Army), they give them female names.

 

3 hours ago, SaltySkoda said:

Valve clearance is much more critical and I do that annually.

 

Every year there is a gap change? You adjust them all the times?

Or you inspect them ''just as precution"?

49 minutes ago, D.FYLAKTOS said:

That's the way Men here in Greece speaking about their cars (even when they were in the Army), they give them female names.

 

It's not usual around here but I'm a weirdo in many other ways also.

 

49 minutes ago, D.FYLAKTOS said:

Every year there is a gap change? You adjust them all the times?

Or you inspect them ''just as precution"?

 

It's part of regular maintenance.

Valves wear, valve seats wear, lifters wear, pushrods wear, camshaft wears... The valvetrain is one of engine parts that suffer the most abuse, it is critical to engine performance and tolerates no deviation from correct adjustment. You'd be surprised how much just a 0.05 mm difference means. It's not just about valve timing, it also very much controls valve bounce at higher rpms. The camshaft is precisely designed in such a way that upon the moment valve starts to open or finishes closing, the lifter is at constant speed (i.e. its acceleration is zero) thus minimizing valve bounce.

Apart from valve bounce, it also minimizes the valvetrain wear.

 

A nice presentation (in extreme conditions, however, just to clearly show the effect) can be seen on this video:

 

 

 

 

This is a plot from a university textbook (in Croatian):

 

X-axis is the cam angle.

Y-axis is the acceleration.

Red line is the valve deceleration caused by valve springs.

Black line is the acceleration of cam-lifter contact point, and is approximately the ideal valve motion one wants at all engine speeds.

Blue line is the actual valve acceleration.

4000 rpm is quoted as camshaft speed, corresponding to 8000 rpm crankshaft speed, because this effect escalates with engine speed.

You can see the valve is not following the cam and bounces around.

It's mainly the cause of "banging" exhaust sound you hear on redlining.

 

So it's one of crucial things for engine performance and durability.

 

The correct adjustment for 781.135 and 136 engines with all iron pushrods is 0.20 mm on all valves.

135B/136B, the more modern engines that have aluminum pushrods on inlet valves, and they should be set at 0.25mm on inlet and 0.20 mm on exhaust valves.

Edited 20 May, 20242 yr by SaltySkoda

1 hour ago, D.FYLAKTOS said:

Every year there is a gap change? You adjust them all the times?

 

My mechanic had an interesting comment, according to him, he never had to adjust valve clearence on gasoline Felicias until ~2010's. Wonder if it's due to age of the cars, or due to changes in fuel quality.

 

19 minutes ago, SaltySkoda said:

The correct adjustment for 781.135 and 136 engines with all iron pushrods is 0.20 mm on all valves.

135B/136B, the more modern engines that have aluminum pushrods on inlet valves, and they should be set at 0.25mm on inlet and 0.20 mm on exhaust valves.

 

Afaik, even carburettor Favorit 135/136 engines had aluminium pushrods on inlet. Did they roll back to steel all around on Felicia?

3 minutes ago, Papez said:

Afaik, even carburettor Favorit 135/136 engines had aluminium pushrods on inlet. Did they roll back to steel all around on Felicia?

 

Don't know about that, it may be a special Balkan edition 😆

18 minutes ago, Papez said:

My mechanic had an interesting comment, according to him, he never had to adjust valve clearence on gasoline Felicias until ~2010's.

 

Mine says, every 2-3 years, no need for more often because the gap only opens does not close so won't get any worst.

I don't know if he is right or wrong.

 

39 minutes ago, SaltySkoda said:

So it's one of crucial things for engine performance and durability.

 

I have an MPi, so it's 0,25 IN and 0,20 OUT.

Every year valve adjustment no matter the mileage?

New gasket every time?

Edited 20 May, 20242 yr by D.FYLAKTOS

53 minutes ago, D.FYLAKTOS said:

Mine says, every 2-3 years, no need for more often because the gap only opens does not close so won't get any worst.

I don't know if he is right or wrong.

 

Well, that's right if you don't want the clearances too tight.

But as I tried to explain, too loose is also a no-no.

 

54 minutes ago, D.FYLAKTOS said:

Every year valve adjustment no matter the mileage?

New gasket every time?

 

I always do it on a nice day in September. I'm pretty much driving about the same amount of kms every year so it doesn't matter.

 

A new valve cover gasket isn't always needed, and I change it if I think it needs changing.

It seems that the valve cover is rather warped from all the thermal cycles over the years, and it drools oil nevertheless I change the rubber gasket or not.

However it keeps a natural anti-corrosive coating of oil on the front of the engine so I figure she does it on purpose 😁

My mate sets his valve clearances to his setting rather than the book as the engine aren't new and he has so much experience on the engines and having used his "classic" as a "daily" for so long and the engines aren't standard anyway.

 

He now owns my last "classic" that I used as a "daily" and the only car I owned for the previous 16 years (I could also use my wife's car if available but it rarely was).  The others have seen the vid but you might be interested.  My neighbour asked if he could do a video on the car for his YT channel and  his well established comprehensive website on motor car history, this was all done in a bit of a rush on s/h camera just out of Covid lockdown (hence my long "covid-locks" hair) everything one take and edited on free software.

 

His site. - https://motor-car.net/

 

The video, a go car not a show car. -