Trued an engine head

deakin said:
if it's overhead cam and the head is warped so is the cam journals the method is heat straightening instead of surfacing
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This. I have a Geo Tracker with a 1.6l 8v. The motor just stopped, after going through progressive checks I found the cam had broke in half due to the head warping. The head has to be heated and brought back inline otherwise it will keep breaking cams.
 
Looks nice. You haven't mentioned any specific checking method used to ensure flatness after. Usually after workholding is released a straight edge is used with feeler shims. It's good to have very thin shims for that (under a thou).

Also, I'm not sure about this car, but with mine I had to buy a different thickness gasket after resurfacing (they have 3 thicknesses, it is supposed to start with the thinnest from factory).

I've done surfacing on my VW TDI 2.0L (turbo diesel) from 2005, 16V overhead cams. I made a special bolt on steel plate to hold the aluminium head on my mag chuck on a surface grinder and I surface ground it. It looked and measured beautiful.... But it still leaked coolant into the same cylinder. Anyone who dealt with vw heads made around 2005 knows their castings were crappy (porous). The pores require a microscope to be seen sometimes. So eventually I used chemical methods to "fix it". (a head sealer containing sodium silicate). This was a tiniest of leaks so I'm not claiming this is a good idea for anything else, but it has been working for me.
 
Flynth said:
Looks nice. You haven't mentioned any specific checking method used to ensure flatness after. Usually after workholding is released a straight edge is used with feeler shims. It's good to have very thin shims for that (under a thou).

Also, I'm not sure about this car, but with mine I had to buy a different thickness gasket after resurfacing (they have 3 thicknesses, it is supposed to start with the thinnest from factory).

I've done surfacing on my VW TDI 2.0L (turbo diesel) from 2005, 16V overhead cams. I made a special bolt on steel plate to hold the aluminium head on my mag chuck on a surface grinder and I surface ground it. It looked and measured beautiful.... But it still leaked coolant into the same cylinder. Anyone who dealt with vw heads made around 2005 knows their castings were crappy (porous). The pores require a microscope to be seen sometimes. So eventually I used chemical methods to "fix it". (a head sealer containing sodium silicate). This was a tiniest of leaks so I'm not claiming this is a good idea for anything else, but it has been working for me.
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I used an 18" rule and a light in multiple spots. Zero light where there were no passages.

I used a 3 point fixture with 123 blocks. No rocking and to torqueing.
 
Gnpenning said:
This. I have a Geo Tracker with a 1.6l 8v. The motor just stopped, after going through progressive checks I found the cam had broke in half due to the head warping. The head has to be heated and brought back inline otherwise it will keep breaking cams.
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I'm no engine guy. Just a machinist. The engine was running when he pulled the head gasket. I don't assume anything at this point.
 
Batmanacw said:
I used an 18" rule and a light in multiple spots. Zero light where there were no passages.

I used a 3 point fixture with 123 blocks. No rocking and to torqueing.
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Sounds good
Batmanacw said:
I'm no engine guy. Just a machinist. The engine was running when he pulled the head gasket. I don't assume anything at this point.
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That's the best way :)

Working on one's own car (when one isn't a mechanic) is a completely different matter. Having said that I never heard about a head so warped as to break cams.... But I know stuff about one brand (the type and vintage) of cars only.
 
Batmanacw said:
I'm no engine guy. Just a machinist. The engine was running when he pulled the head gasket. I don't assume anything at this point.
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the cam journals were straight when running because the bolts held it that way. when removed it warped. after surfacing the deck is straight but the journals are in the warped position. assuming you have a good straight edge check the cam journals. if the deck showed warpage and you surfaced it the cam journals should be warped at this point. this most likely can be salvaged. the head would need to be heat straightened until the journals were straight then carefully resurfaced. at this point should only be removing material from the center of the head
 
deakin said:
the cam journals were straight when running because the bolts held it that way. when removed it warped. after surfacing the deck is straight but the journals are in the warped position. assuming you have a good straight edge check the cam journals. if the deck showed warpage and you surfaced it the cam journals should be warped at this point. this most likely can be salvaged. the head would need to be heat straightened until the journals were straight then carefully resurfaced. at this point should only be removing material from the center of the head
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I let him know it could be an issue and left the decision with him.
 
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