Extra thick head gasket for Mondeo Ecoboost?
Discussion
Just did a quick test using the camshafts. First impression is that nothing has happened - the exhaust camshaft still has an obvious rock to it when you press on the ends - feels the same as it did before the oven treatment to me (the inlet camshaft had no movement beforehand and still doesn't)
Overheated cylinder heads don't just bend uniformly like they were put in a press. The heat comes from the combustion chambers and the bottom of the head tends to distort more than the top. The head changes overall shape more than it bends. If you had a camshaft that was still true in its bearings then by definition the top didn't distort much. Put a straight edge across the gasket face and see what that looks like now.
Mignon said:
Overheated cylinder heads don't just bend uniformly like they were put in a press. The heat comes from the combustion chambers and the bottom of the head tends to distort more than the top. The head changes overall shape more than it bends. If you had a camshaft that was still true in its bearings then by definition the top didn't distort much. Put a straight edge across the gasket face and see what that looks like now.
It's consistent with what the engineer who did the skim said - the warp was deepest on the exhaust side. Could the fact the exhaust side was facing the oven door have made a difference to the temperature do you think? I did it that way because of the protruding pivot rod but I might be able to get it in the other way around with a bit of shoving, and give it another go?
Mignon said:
kerplunk said:
Could the fact the exhaust side was facing the oven door have made a difference to the temperature do you think?
Nope, very much doubt it.With something filling the oven so completely as that head, I'd expect the air circulation to be even more compromised. The results are quite visible when baking a large loaf of bread, with the crust darkening at different rates.
Aluminium conducts heat very well. It would have stabilised in temperature eventually. Until the gasket face is checked there's no point guessing if anything happened. Maybe machining so much off changed the stresses. I can only say it's always worked for me but YMMV. My old house had a free standing cooker and a 4 pot head fitted into that very easily. These built in things up at eye level seem much smaller.
227bhp said:
It's because you didn't baste it 
Seriously though, how did you measure the temp?
I used to have cheap probe connected to a digital read out for doing stuff like that, put probe in oven, read out on worktop, thin connecting 'cable' was simply trapped in the door.
I didn't measure the temp - I turned the knob to midway between the 200 & 220 marks. I'll pick up a thermometer today and have a pizza for me tea (after I've given the oven a good clean).Seriously though, how did you measure the temp?
I used to have cheap probe connected to a digital read out for doing stuff like that, put probe in oven, read out on worktop, thin connecting 'cable' was simply trapped in the door.
kerplunk said:
I didn't measure the temp - I turned the knob to midway between the 200 & 220 marks. I'll pick up a thermometer today and have a pizza for me tea (after I've given the oven a good clean).
Thanks for posting all your findings and images, the pizza may well taste of lube even after cleaning the ovenOk so the gasket face is flat as a flat thing - can't get a rizla in anywhere.
So that's that, but now the oven temperature - I bought a multi-meter with a temp probe today ( here) and it appears that, despite erring on the high side, the oven probably still wasn't heating the cylinder head up to 200C. What I found was that with the oven temperature knob in the same position as the Sunday roasting, the temperature constantly varied +/-5C-ish as the halogen clicked on and off and only hit 200-202C at the peak before sinking back to 190-192C at the low point, so my best guess is the head never got higher than 195-ish.
So unless someone tells me it's a bad idea I plan to have another go tomorrow.
ps. the pizza was fine.
So that's that, but now the oven temperature - I bought a multi-meter with a temp probe today ( here) and it appears that, despite erring on the high side, the oven probably still wasn't heating the cylinder head up to 200C. What I found was that with the oven temperature knob in the same position as the Sunday roasting, the temperature constantly varied +/-5C-ish as the halogen clicked on and off and only hit 200-202C at the peak before sinking back to 190-192C at the low point, so my best guess is the head never got higher than 195-ish.
So unless someone tells me it's a bad idea I plan to have another go tomorrow.
ps. the pizza was fine.
Edited by kerplunk on Tuesday 23 October 23:12
In my experience I have only seem heads successfully straightened under heat combined with pressure as related in the following article.
http://www.enginebuildermag.com/2014/10/head-surfa...
I have seen a lot of heads and cams sit true on blocks once torqued down as Stevie said earlier, especially olde worlde diesel engines. Whilst warpage seems worse on ally heads we have seen warpage on CI heads, especially big old six cylinder Healey and MGC ones.
I must admit I have never tried straightening a head in an oven though. We do heat ally heads on a twin hot plate hob so we can fit valve guides, particularly with V8 SD1 heads.
http://www.enginebuildermag.com/2014/10/head-surfa...
I have seen a lot of heads and cams sit true on blocks once torqued down as Stevie said earlier, especially olde worlde diesel engines. Whilst warpage seems worse on ally heads we have seen warpage on CI heads, especially big old six cylinder Healey and MGC ones.
I must admit I have never tried straightening a head in an oven though. We do heat ally heads on a twin hot plate hob so we can fit valve guides, particularly with V8 SD1 heads.
The result of the 2nd attempt is the same as the first attempt - no perceptable change. For the record the head was in the oven for 3 hours and for 2 of those hours the temperature was maintained at 209-215C (it took the best part of an hour to reach 200).
I think that's probably the end of me trying to get something out of the old engine and I'm now in a waiting game for a 2nd-hand engine.
I think that's probably the end of me trying to get something out of the old engine and I'm now in a waiting game for a 2nd-hand engine.
kerplunk said:
The result of the 2nd attempt is the same as the first attempt - no perceptable change. For the record the head was in the oven for 3 hours and for 2 of those hours the temperature was maintained at 209-215C (it took the best part of an hour to reach 200).
I think that's probably the end of me trying to get something out of the old engine and I'm now in a waiting game for a 2nd-hand engine.
Is this lack of success down to skimming before cooking or are there other possible reasons?I think that's probably the end of me trying to get something out of the old engine and I'm now in a waiting game for a 2nd-hand engine.
There is no way I'm running up a big electric bill in cooking heads
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff