Do I need new head bolts?
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3,225 Posts
It depends largely on which head gaskets you're going to use, but I would suggest the new, composite gaskets rather than the old, waffle steel one.
However, if you are using steel headgaskets, use the conventional head bolts. If you do use the composite gaskets, deffinately use torsional head bolts. They are an made in an alloy whose yield strength is just greater than the amount of torque you'll end up with so continue to add tension as the gasket compresses. You may want to consider planning the heads slighly more than cleanup. Generally when heads are reconditioned, they are only planed to flat, but because the composite gaskets are slightly thicker, a few extra thousands (.008 to .010 if you're using 93 octane, .005 to .006 if you're using 89 or less)) will make up for this so no loss of compression ratio will be had.
I would never reuse even conventional head bolts, just cheap insurance, but, as Sven says, never reuse tortional stretch bolts.
However, if you are using steel headgaskets, use the conventional head bolts. If you do use the composite gaskets, deffinately use torsional head bolts. They are an made in an alloy whose yield strength is just greater than the amount of torque you'll end up with so continue to add tension as the gasket compresses. You may want to consider planning the heads slighly more than cleanup. Generally when heads are reconditioned, they are only planed to flat, but because the composite gaskets are slightly thicker, a few extra thousands (.008 to .010 if you're using 93 octane, .005 to .006 if you're using 89 or less)) will make up for this so no loss of compression ratio will be had.
I would never reuse even conventional head bolts, just cheap insurance, but, as Sven says, never reuse tortional stretch bolts.
Sven, Terry, thanks for the advice.....new bolts on the way.
The new stretch type bolts come as a pack of 20 but my car uses 28. I was intending anyhow to follow the advice of RPI of only torquing the lower 4 bolts to 25lb/ft. Do I need new bolts here as well or should my old standard bolts be ok for 'filling the holes'?
I've gone for a 0.10 plane and will be using the composite gaskets.
Thanks
The new stretch type bolts come as a pack of 20 but my car uses 28. I was intending anyhow to follow the advice of RPI of only torquing the lower 4 bolts to 25lb/ft. Do I need new bolts here as well or should my old standard bolts be ok for 'filling the holes'?
I've gone for a 0.10 plane and will be using the composite gaskets.
Thanks
Joined
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388 Posts
No, dont do that! The composite gasket has no provision for the last row of 4 bolts, this is done on purpose to reduce leaks. Follow the torque values here: http://www.roverparts.com/INS_Headbolt Torque_9224_40_46.html
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