I had a head gasket leak, so i got the top off and had it milled down, then fit a new head gasket. Simple enuff job, no need to take out either manifold, just pull them aside and get the bolts out, then refit. I had the valve rods out and reinstalled in proper order, also reajusted the valves. tight plus 2 turns on the cylinder opposite the one with both valves moving.

Turn the whole thing with no sparkplugs in it to make sure it runs, then run it with the starter and finally get the plugs in and start it up.

 

Anyways, the engine doesnt fire up on third stroke as my old twin cam engine did and its a little weak when cold and low rpm. Also it has a hint of a saxophone sound when it gets full throttle accelerating. Idle is a little rattely and not perfectly even.

Exaust seems to be mostely tight and i checked the fuel injectors plus changed the fuel and air filter.

 

So atm my bst guess is either the valves are set too tight (thou as specified) or the timing chain tension is wrong or the timnig chain and gears is worn.

 

Car has 160k Km on it and im not the first owner.

 

 

Im considering loosening the valve adjusters a turn or so, to see if thats somehow the issue. Other than that obviusly i could take the whole thing apart and change the chain and gears plus get the tension right. But with no idea if itll help it could be a complete waste.

 

Any input on the matter?

Is this the overhead valve model? If so you could change the chain to stop it rattling so much?

The valves on the MPI are hydraulic and don't need adjusting if only the head gasket has been changed. They only need an initial adjustment if the valve gear has been dismantled. But since you've had the head machined, it was probably a good idea to do it.

 

Did you follow this procedure? http://workshop-manuals.com/skoda/fabia-mk1/drive_unit/1.0/37;_1.4/44;_1.4/50_kw_mpi_engine/engine_cylinder_head_valve_gear/repairing_cylinder_head/basic_setting_of_hydraulic_valve_clearance_compensation/

 

The timing chain has no tensioner and they are notorious for rattling on this engine but they usually still run fine. These ancient engines also tend to have a slightly rough idle as a consequence of being tuned to meet emission standards.

I had the cylinder head machined at work and the operator said it took notably more (this is in 1/10 mm variation area) in some places than other. Also i dont have service history for the car and i know the valve tops get little indentations over time. So i rechecked the valve adjustment just to be sure.

I think some valves was adjusted upto ½ a turn, but its hard to say exactely as i just loosened the screws and set them all right, i dont mess up things like that most of the time so i wasnt worried.

 

It sounds a little like a diesel car when ideling from cold, some ticking or ratteling can be heard. The economy is 6,4L / 100km if i run it around 100kmh so its not terrible economy wise, but the possible loss of power concerns me somewhat. Its just not pulling its weight the same way it used to, but i dont have the equipment to test that acurately and i did install slightly larger wheels for the summer.

 

Pardon my spelling.

There is no way it should sound like a diesel. I'd check the valve adjustment again.

not exactely like a diesel but somehow off timing now and then. Ticking ratteling and that saxophone ish sound when pulling weight at higher revs.

 

I couldnt have messed with the timing since its a pushrod system, but like i said at first either the valves are worn and shouldnt be set so tight or the chain is loose/worn

Oh btw im running it with 0w30 instead of the originally specified 5w30. (well its 5 less but i forget if its originally 10w30). Obviusly thinner oil will enhance ratteling etc, but it was a new recomended castrol synth oil.

According to you car's milage, I'd be going with 10W oil. 

Your right i should, dont know how i forgot about that. Just clicked the suggested oil without thinking.

 

Oil thickness would affect ratteling, But im getting this idea that the valve timeing is off somehow. I dont have good graphs for fuel consumption vs speed. But im getting the impression that this self adjusting hydraulic thing is somehow stuck so the engine runs its best around 2-2500 rpm.

 

How is it supposed to self adjust? just oil pressure working a piston to set the pressure on the valve-rods?

How is it supposed to self adjust? just oil pressure working a piston to set the pressure on the valve-rods?

 

Yep, that's about it.