Technical Head gasket?

[Semm345]

Hello all,

i have a mk2b sportsound, in wich lays a 1.2 16v engine. the 188A5000. had it overheat on me wich (i thought) blew the head gasket. after replacing the head gasket and having it skimmed, cleaned an put new valve seals in i put it back together only to find out there is somehow still exhaust gasses coming in to the coolant. plus there is a knocking sound from the valvetrain (im thinking something to do withy the hydraulic lifters) wich is new. i am also thinking maybe there is a crack in the engine block somewhere. anyone have any suggestions on how to check for this?

 

[bugsymike]

Hello all,

i have a mk2b sportsound, in wich lays a 1.2 16v engine. the 188A5000. had it overheat on me wich (i thought) blew the head gasket. after replacing the head gasket and having it skimmed, cleaned an put new valve seals in i put it back together only to find out there is somehow still exhaust gasses coming in to the coolant. plus there is a knocking sound from the valvetrain (im thinking something to do withy the hydraulic lifters) wich is new. i am also thinking maybe there is a crack in the engine block somewhere. anyone have any suggestions on how to check for this?

Leak test.
Sounds simple and is if you have a garage air compressor and an adaptor to fit the spark plug holes.
Basically you put the engine on TDC on firing stroke on the cylinder you are testing and lock it up so engine doesn't turn, (Jam flywheel is best) then plug in air pressure with rad cap off, if air bubbles out you know which cylinder is faulty. Repeat on rest of cylinders.
Note this works for checking inlet and exhaust valves and piston wear as well.
The test is meant to be at 90psi but I always use 150 psi.
If engine seriously overheated the block could have warped as well, I always check the cylinder block with a straight edge and feeler gauges when doing a head gasket job as well as having head skimmed.
Re hydraulic tappets/cam followers I leave the new ones soaking in engine oil overnight to "prime " them. If reusing the old ones I do the same for them but also make sure to replace in original positions.

 

[GrandePunto PL]

Who did the "repair" (skim etc.) and how much was trimmed?
Skimmed without checking for cracks?

 

[bugsymike]

So many things can be a problem even if not a cracked block.
Were the threads in block cleaned so bolts torque down correctly etc.
Was the original cause of overheating fixed.
Was air bled fully from system.
Not accusing you of anything, it is just so many things can cause an issue.
I have even had duff quality head gaskets that didn't compress correctly to seal, the machine shop I used wanted to supply the gaskets to increase their profit margin, this was 25 years ago and to this day I will never use Ultra Parts make of gaskets one was a Ford Fiesta and the other a Triumph TR7!

 

[Semm345]

Hi all, thanks for your replies!!

so update: i had the cylinder head checked for cracks and that seems to be good. the guy who did the checks did know what the knocking sound from the valvetrain was. i spimply made the classic mistake of putting the head gasket on the wrong way round so the oil feed to the cylinder head was blocked.... so if you ever plan on changing a head gasket on a FIRE engine, be weary of this.

as for the exhaust gasses in the coolant, there must be something wrong with the engine block itself. are they known for cracking or warping?

 

[bugsymike]

Hi all, thanks for your replies!!

so update: i had the cylinder head checked for cracks and that seems to be good. the guy who did the checks did know what the knocking sound from the valvetrain was. i spimply made the classic mistake of putting the head gasket on the wrong way round so the oil feed to the cylinder head was blocked.... so if you ever plan on changing a head gasket on a FIRE engine, be weary of this.

as for the exhaust gasses in the coolant, there must be something wrong with the engine block itself. are they known for cracking or warping?

No more than any other cast iron block , unless it has been frozen through lack of antifreeze , or boiled to a stand still and refilled with cold water, that can do it .
First though I would check the cylinder block for flatness as I mentioned before using a steel straight edge and a feeler gauge, if a 002. thousands of an inch slides out then to me the block is not flat and will blow head gaskets unless machined flat again.