Technical cylinder heads

[cibbo]

Hi
Can anyone advise My mk2 1.2 8v 1999 elx punto has a blown headgasket ,
I also have a 2004 mk2b 1.2 8v dynamic as a donor car, are the heads interchangeable,
if they are then i can skip the headengineering expense for the elx which would help
The mk2b engine was fine before being taken of the road. and as im asking
are there other parts that are also interchangable

 

[bugsymike]

Hi
Can anyone advise My mk2 1.2 8v 1999 elx punto has a blown headgasket ,
I also have a 2004 mk2b 1.2 8v dynamic as a donor car, are the heads interchangeable,
if they are then i can skip the headengineering expense for the elx which would help
The mk2b engine was fine before being taken of the road. and as im asking
are there other parts that are also interchangable

If it was me and if you know apart from the head gasket it is all good , personally I would have the head machined flat and the valves checked at the same time, check the cylinder block is true as well and refit with new gaskets and bolts etc. correctly tightened and one final thing, find out the cause of the overheating that blew the original gasket.
Others can advise better on interchangeability.

 

[cibbo]

Thanks Bugsy RE finding out why gasket failure
The car sometimes died during the normal startup procedure then reached normal operating temp very quickly from a cold start.
Oil levels and coolant levels were fine but noticed heater is cold even though engine has been runnng for some time. Whilst on M4 red light came on and temp dail was at its limit. coasted to services for about 4 miles to let car cool down which it did quite quickly put about 500 ml water in but notice froth in oil cap So after about 2 hrs started up & things were fine then started to overheat again although running fine so back to services and arranged rescue before anymore damage was done. apart from compression test wouldnt know what else to check thought about just swapping top end of donor car but supose it aint that easy but thanks again

 

[z rider]

Have there been bleed screws on the hoses, especialy to the heater. As far as I know you can only top up completely at the filler neck with bleed open. As the heater was cold there must have been more water missing than 500 ml.
Other questions are: Does the fan kick in as the car gets hot? Thermostat working correctly?
Just another thought is, if engine of donor car is really fine, to swap the whole unit and just do the tear and wear basics like cambelt, oil and filter etc..

 

[bugsymike]

Yes, it very common for people to fix the problem, but not the cause , from what you say it sounds like the issue has been coming on for a while. Is it possible you had a slow water leak or it needing coolant topping up often? When heater stops working but all else seems good that can be an early warning that there is air in the heater matrix/radiator and if allowed to continue the lose of coolant water around the cylinder is next. After that failure is imminent.
Even if you have a slow leak , as long as it is kept topped up then not much damage occurs as water cooling works, once the water level drops and what water there becomes gas/steam it can quickly reach way above the boiling point of water 100 degrees C and becomes super heated steam, so the head warps and the gasket blows etc.
The dying on start up could have been the early stages of the head gasket failure letting water get to spark plug causing a small misfire which soon clears with a quick rev up.
In fairness belting along the M4 by the time you were able to stop a fair bit of damage can have occurred, so if you do decide to do the work , once the head is off before anything else I would have a good look at the cylinder bores for any scoring etc. and then turn engine so all four pistons are at the same height and put an equal amount of oil on top of each piston, if it disappears fairly quickly or not at an even rate across all four cylinders you may have caused major engine damage beyond a head gasket job. Assuming that test is all good then it is wise to clean the surface of the cylinder block and check that for flatness using a steel straight edge and a feeler gauge, only after that start spending on head work and gaskets etc.
Sorry if I am going into too much detail, but I have seen people spend money doing the head gasket only to find the engine underneath it is knackered.

 

[cibbo]

Have there been bleed screws on the hoses, especialy to the heater. As far as I know you can only top up completely at the filler neck with bleed open. As the heater was cold there must have been more water missing than 500 ml.
Other questions are: Does the fan kick in as the car gets hot? Thermostat working correctly?
Just another thought is, if engine of donor car is really fine, to swap the whole unit and just do the tear and wear basics like cambelt, oil and filter etc..

thanks z rider I havnt opened bleed screws on heater hoses ( wish I had remembered that) thinking of trying some liquid seal that you pour into expansion tank, fan does kick in when hot so no prob there not sure re thermostat- Can I just swap engines- that would be good cheers

 

[cibbo]

Yes, it very common for people to fix the problem, but not the cause , from what you say it sounds like the issue has been coming on for a while. Is it possible you had a slow water leak or it needing coolant topping up often? When heater stops working but all else seems good that can be an early warning that there is air in the heater matrix/radiator and if allowed to continue the lose of coolant water around the cylinder is next. After that failure is imminent.
Even if you have a slow leak , as long as it is kept topped up then not much damage occurs as water cooling works, once the water level drops and what water there becomes gas/steam it can quickly reach way above the boiling point of water 100 degrees C and becomes super heated steam, so the head warps and the gasket blows etc.
The dying on start up could have been the early stages of the head gasket failure letting water get to spark plug causing a small misfire which soon clears with a quick rev up.
In fairness belting along the M4 by the time you were able to stop a fair bit of damage can have occurred, so if you do decide to do the work , once the head is off before anything else I would have a good look at the cylinder bores for any scoring etc. and then turn engine so all four pistons are at the same height and put an equal amount of oil on top of each piston, if it disappears fairly quickly or not at an even rate across all four cylinders you may have caused major engine damage beyond a head gasket job. Assuming that test is all good then it is wise to clean the surface of the cylinder block and check that for flatness using a steel straight edge and a feeler gauge, only after that start spending on head work and gaskets etc.
Sorry if I am going into too much detail, but I have seen people spend money doing the head gasket only to find the engine underneath it is knackered.

Great advice many thanks going to try a liquid sealant 1st then if/when that fails I will follow your recommendations before looking into donor car to save the day thanks again Bugsy

 

[bugsymike]

Great advice many thanks going to try a liquid sealant 1st then if/when that fails I will follow your recommendations before looking into donor car to save the day thanks again Bugsy

Not a great fan of sealants, but at this stage not much to lose and you mentioned you have a spare engine as back up.

 

[jonik]

Cylinder head is the same if the engines have same valve cover

 

[cibbo]

Cylinder head is the same if the engines have same valve cover

Hi everyone re my head probs thanks for all of your invaluable advice it really helped to point me in the right direction. It just down to testing now so fingers crossed its job done- so if all works out i will hopefully be able to post the final update soon