Cylinder Head Options - DVA Power or Scrappy?
Discussion
A mate and I are currently working on repairing the head gasket failure on my K Series VVC engine ...
However upon removing the cylinder head and checking all the usual areas, we noticed some damage, which resulted in a 'WTF?' moment. In fact, we contacted a friend who used to work for a Lotus approved repair specialist, who was just as confused as ourselves!
The head gasket looks a bit sorry for itself - It's burnt on the exhaust side of all four cylinders, although the cylinder on the far right has less soot/residue than the others. It's the damage to the cylinder head that's the mystery!
If you run your finger across the inlet side, nearby to the valves, it's all smooth and flat. However if you run your across the exhaust side, where the liners push up against (within the red circle), there's a noticeable ridge. It's the same for the other three cylinders; smooth on the inlet side, ridged on the exhaust side.
I quickly asked on SELOC and someone said:
1. Would you bother finding somewhere (In Bucks/Berks) to run a hardness test, or would you just opt for a replacement head?
2. If the latter, does anyone know a reputable place to find a good K Series VVC head?
3. Alternatively, I noticed that RimmerBros has a new head for £1K! However DVA Power does a k06a kit for £1050 unfitted, which uses a reconditioned (tested/skimmed) head + some work that will provide 170-175BHP ... Seems like a better option?
Money is tight, what with others bits and pieces in life! However if it's the difference between a doggy head from scrapyard for £200-300, or a decent head with more power for £1K, I could stretch ... just.
What would you do?
However upon removing the cylinder head and checking all the usual areas, we noticed some damage, which resulted in a 'WTF?' moment. In fact, we contacted a friend who used to work for a Lotus approved repair specialist, who was just as confused as ourselves!
The head gasket looks a bit sorry for itself - It's burnt on the exhaust side of all four cylinders, although the cylinder on the far right has less soot/residue than the others. It's the damage to the cylinder head that's the mystery!
If you run your finger across the inlet side, nearby to the valves, it's all smooth and flat. However if you run your across the exhaust side, where the liners push up against (within the red circle), there's a noticeable ridge. It's the same for the other three cylinders; smooth on the inlet side, ridged on the exhaust side.
I quickly asked on SELOC and someone said:
Someone said:
Your head is annealed through overheating, and indented due to softening of the aluminium.
You need to get it hardness tested.
If it's above 90 Brinnell, it's ok, below, it's toast....though theoretically you can get them re-hardened, I'd start looking for another VVC head if I were you.
A new head would be 110 to 115 Brinnell.
You may get away with skimming it, and try using an SAIC (Chinese N series) gasket, as they have a wider fire ring and are allegedly better with annealed heads.
Problem with skimming these heads is that you may find porosity in the fire ring area.
So the questions are ...You need to get it hardness tested.
If it's above 90 Brinnell, it's ok, below, it's toast....though theoretically you can get them re-hardened, I'd start looking for another VVC head if I were you.
A new head would be 110 to 115 Brinnell.
You may get away with skimming it, and try using an SAIC (Chinese N series) gasket, as they have a wider fire ring and are allegedly better with annealed heads.
Problem with skimming these heads is that you may find porosity in the fire ring area.
1. Would you bother finding somewhere (In Bucks/Berks) to run a hardness test, or would you just opt for a replacement head?
2. If the latter, does anyone know a reputable place to find a good K Series VVC head?
3. Alternatively, I noticed that RimmerBros has a new head for £1K! However DVA Power does a k06a kit for £1050 unfitted, which uses a reconditioned (tested/skimmed) head + some work that will provide 170-175BHP ... Seems like a better option?
Money is tight, what with others bits and pieces in life! However if it's the difference between a doggy head from scrapyard for £200-300, or a decent head with more power for £1K, I could stretch ... just.
What would you do?
Rover K heads with groove in the firering area are soft. Safe the money for a hardness test. it is soft. the fire ring has indented the head.
the alloy got hot being exposed to more than 300C for some time and lost its hardness.
Classic HGF from overheating.
if you want to be safe, buy a known good head of Dave Andrews DVA or Roger Fabry. They also sell ported heads. So you gain some power, too :-)
If scrappy, find a unskimmed head that does not have grooves.
Do not buy a skimmed head without hardness data for a unreputable source.
Consider fitting a electric water pump such as a EWP80 plus controller.
My hypothesis is that the main water pump provides little flow at low rpm and idle. After a hard run this flow is insufficient to cool the head and it turns soft.
The electric water pump will maintain a reasonable flow even at idle and continue to cool the head ultimatly preventing the alloy turning soft.
the alloy got hot being exposed to more than 300C for some time and lost its hardness.
Classic HGF from overheating.
if you want to be safe, buy a known good head of Dave Andrews DVA or Roger Fabry. They also sell ported heads. So you gain some power, too :-)
If scrappy, find a unskimmed head that does not have grooves.
Do not buy a skimmed head without hardness data for a unreputable source.
Consider fitting a electric water pump such as a EWP80 plus controller.
My hypothesis is that the main water pump provides little flow at low rpm and idle. After a hard run this flow is insufficient to cool the head and it turns soft.
The electric water pump will maintain a reasonable flow even at idle and continue to cool the head ultimatly preventing the alloy turning soft.
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