Extra thick head gasket for Mondeo Ecoboost?
Discussion
I had the cylinder head for my Mondeo Ecoboost 2.0l turbo engine skimmed today and the engineer said he had to take off 24 thou/0.6mm to get it flat which seems quite a lot. So I've been looking at extra thick head gaskets to avoid problems with valve to piston clearance and raised compression.
The standard gasket is 1.25mm thick so I'd be looking at one around 1.8mm. Sounds simple enough but I'm wondering what the downsides are if any? Is it going to be more likely to blow? Do I need to torque the head down more? So far I've only found one manufacturer - Cometic - who appear to make them in loads of different thicknesses. I've heard of Cometic but no idea how well they're regarded. Should I be looking for a replacement head instead?
The standard gasket is 1.25mm thick so I'd be looking at one around 1.8mm. Sounds simple enough but I'm wondering what the downsides are if any? Is it going to be more likely to blow? Do I need to torque the head down more? So far I've only found one manufacturer - Cometic - who appear to make them in loads of different thicknesses. I've heard of Cometic but no idea how well they're regarded. Should I be looking for a replacement head instead?
Edited by kerplunk on Wednesday 10th October 21:20
stevieturbo said:
Cometic are fine.
What are manufacturers instructions regarding head gasket thickness after head machining like that ?
Do you mean Ford? I enquired at a Ford dealer, who enquired to Ford, if there was a service limit on skimming these heads - they sent back an engine spec sheet which had only one possibly relevent bit:What are manufacturers instructions regarding head gasket thickness after head machining like that ?
Cylinder Head
Maximum mating face distortion (crosswise) - 0.1mm
But I don't know how to interpret that.
Edited by kerplunk on Wednesday 10th October 21:22
Sardonicus said:
Are you sure Ford dont offer a selection of head gasket thickness's to allow for differing piston protrusion across production runs and in service head machining etc ? like as been the way with diesel engines for years 
not familiar with working on this engine so am only surmising
I've no idea I'll have to ask. Someone at a company who do performance stuff for Focus STs (same engine) told me it was 1.25mm standard and that seems to be borne out by looking at suppliers of head gaskets who list my engine. not familiar with working on this engine so am only surmising The engineer is an idiot. As soon as he saw it was that badly warped he should have straightened it first as much as possible before the final skim to get it true. However he probably doesn't know how to straighten alloy heads. In fact I wonder if anyone at all does.
The gasket face might now be flat but the chamber volumes will be massively different and the top of the head where the cams go is still bent by 0.6 mm.
The gasket face might now be flat but the chamber volumes will be massively different and the top of the head where the cams go is still bent by 0.6 mm.
Can't say I've ever heard of anyone trying to straighten a head, so not sure if that comment is in jest or not ?
But I do know that some old ( s
tty diesel usually ) engines when taken apart for work...the likes of cams etc wont turn properly until the head is torqued up. Clearly not ideal but they will run for hundreds of thousands of mile despite this.
But with this "Ecoboost" Engine presumably being direct injection, one would assume that gasket thickness is more important than a more traditional engine.
But I do know that some old ( s
tty diesel usually ) engines when taken apart for work...the likes of cams etc wont turn properly until the head is torqued up. Clearly not ideal but they will run for hundreds of thousands of mile despite this.But with this "Ecoboost" Engine presumably being direct injection, one would assume that gasket thickness is more important than a more traditional engine.
kerplunk said:
The standard gasket is 1.25mm thick so I'd be looking at one around 1.8mm. Sounds simple enough
It's obviously not simple enough for you to have worked it out properly. I suggest you sit and think a bit more about how much has actually been skimmed off your head, or to be more precise what has really happened to the combustion chamber volumes. If you can work that out you'll know how much thicker the gasket actually needs to be.Thanks for the face-slap Mignon - this is what I came here for because whilst a rank amateur like me trying to limit my losses might HOPE things are simple I'm at least savvy enough to know that's often not the case and getting good advice is imperative if I'm to avoid throwing good money after bad (and that's the absolute imperative here).
I've had a lot to learn - when the recovery truck delivered the car to my house the first thing I did was take the plastic engine cover off and that was the first time I'd laid eyes on my engine since I bought the thing nearly 5 years ago. Over the last 5 weeks I've taken the head off to assess the damage (1 x piston chipped and a scored bore, and coolant in the other 3 cylinders) and the weekend before last I took the block out. My roadmap going foward was to get the head sorted first (in case there's anything wrong with it!) and then either go for new pistons and rebore, or buy a new short block from Ford (my favoured option). And that brings me to this point.
So anyway - calculating head gasket thickness seems like an interesting new thing to learn about but is there any point if the top of the head is bent by 0.6?
Is it not fubar? (I think I know the answer to that already)
I've had a lot to learn - when the recovery truck delivered the car to my house the first thing I did was take the plastic engine cover off and that was the first time I'd laid eyes on my engine since I bought the thing nearly 5 years ago. Over the last 5 weeks I've taken the head off to assess the damage (1 x piston chipped and a scored bore, and coolant in the other 3 cylinders) and the weekend before last I took the block out. My roadmap going foward was to get the head sorted first (in case there's anything wrong with it!) and then either go for new pistons and rebore, or buy a new short block from Ford (my favoured option). And that brings me to this point.
So anyway - calculating head gasket thickness seems like an interesting new thing to learn about but is there any point if the top of the head is bent by 0.6?
Is it not fubar? (I think I know the answer to that already)
Edited by kerplunk on Thursday 11th October 10:34
Edited by kerplunk on Thursday 11th October 11:36
stevieturbo said:
Can't say I've ever heard of anyone trying to straighten a head, so not sure if that comment is in jest or not ?
Think about it. What causes a head to warp? I'm not talking about just the obvious but at a molecular level what is a "warp" in a piece of metal? In which fields of metalwork do we encounter such things, what is done about it and what is the technical term for that?30 years ago when faced with a really badly warped head (20 thou or so) I worked all this out from first principles and then rather than machine the head true I straightened it first and then skimmed the last thou or two off to get a perfect gasket surface. It has been an invaluable thought exercise in redeeming heads that might otherwise have been past using again.
Mignon said:
stevieturbo said:
Can't say I've ever heard of anyone trying to straighten a head, so not sure if that comment is in jest or not ?
Think about it. What causes a head to warp? I'm not talking about just the obvious but at a molecular level what is a "warp" in a piece of metal? In which fields of metalwork do we encounter such things, what is done about it and what is the technical term for that?30 years ago when faced with a really badly warped head (20 thou or so) I worked all this out from first principles and then rather than machine the head true I straightened it first and then skimmed the last thou or two off to get a perfect gasket surface. It has been an invaluable thought exercise in redeeming heads that might otherwise have been past using again.
Mignon said:
Think about it. What causes a head to warp? I'm not talking about just the obvious but at a molecular level what is a "warp" in a piece of metal? In which fields of metalwork do we encounter such things, what is done about it and what is the technical term for that?
30 years ago when faced with a really badly warped head (20 thou or so) I worked all this out from first principles and then rather than machine the head true I straightened it first and then skimmed the last thou or two off to get a perfect gasket surface. It has been an invaluable thought exercise in redeeming heads that might otherwise have been past using again.
Unequal application of heat, but how are you going to replicate that in the opposite?30 years ago when faced with a really badly warped head (20 thou or so) I worked all this out from first principles and then rather than machine the head true I straightened it first and then skimmed the last thou or two off to get a perfect gasket surface. It has been an invaluable thought exercise in redeeming heads that might otherwise have been past using again.
Off the top of my head (duh) all I can think of initially is putting it in a bloody huge press or attempting to apply heat to certain areas of it to get it to pull back the other way, but neither seem easily viable.
227bhp said:
Unequal application of heat, but how are you going to replicate that in the opposite?
Off the top of my head (duh) all I can think of initially is putting it in a bloody huge press or attempting to apply heat to certain areas of it to get it to pull back the other way, but neither seem easily viable.
Nah. It is blindingly simple really but then all simple things tend to require some complex thought in the first instance Off the top of my head (duh) all I can think of initially is putting it in a bloody huge press or attempting to apply heat to certain areas of it to get it to pull back the other way, but neither seem easily viable.
Mignon said:
227bhp said:
Unequal application of heat, but how are you going to replicate that in the opposite?
Off the top of my head (duh) all I can think of initially is putting it in a bloody huge press or attempting to apply heat to certain areas of it to get it to pull back the other way, but neither seem easily viable.
Nah. It is blindingly simple really but then all simple things tend to require some complex thought in the first instance Off the top of my head (duh) all I can think of initially is putting it in a bloody huge press or attempting to apply heat to certain areas of it to get it to pull back the other way, but neither seem easily viable.
Penelope Stopit said:
Mignon said:
stevieturbo said:
Can't say I've ever heard of anyone trying to straighten a head, so not sure if that comment is in jest or not ?
Think about it. What causes a head to warp? I'm not talking about just the obvious but at a molecular level what is a "warp" in a piece of metal? In which fields of metalwork do we encounter such things, what is done about it and what is the technical term for that?30 years ago when faced with a really badly warped head (20 thou or so) I worked all this out from first principles and then rather than machine the head true I straightened it first and then skimmed the last thou or two off to get a perfect gasket surface. It has been an invaluable thought exercise in redeeming heads that might otherwise have been past using again.
227bhp said:
Mignon said:
Think about it. What causes a head to warp? I'm not talking about just the obvious but at a molecular level what is a "warp" in a piece of metal? In which fields of metalwork do we encounter such things, what is done about it and what is the technical term for that?
30 years ago when faced with a really badly warped head (20 thou or so) I worked all this out from first principles and then rather than machine the head true I straightened it first and then skimmed the last thou or two off to get a perfect gasket surface. It has been an invaluable thought exercise in redeeming heads that might otherwise have been past using again.
Unequal application of heat, but how are you going to replicate that in the opposite?30 years ago when faced with a really badly warped head (20 thou or so) I worked all this out from first principles and then rather than machine the head true I straightened it first and then skimmed the last thou or two off to get a perfect gasket surface. It has been an invaluable thought exercise in redeeming heads that might otherwise have been past using again.
Off the top of my head (duh) all I can think of initially is putting it in a bloody huge press or attempting to apply heat to certain areas of it to get it to pull back the other way, but neither seem easily viable.
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