- Joined
- Jun 2, 2012
- Messages
- 25,363
- Reaction score
- 8,369
- Points
- 113
- Location
- canada
- Vehicle Year
- 1994
- Make / Model
- Ford
- Transmission
- Manual
No to the aluminum head, whole new set of problems when running a bi-metal engine(aluminum heads and cast iron block).
You would need to run a MLS head gasket(multi-layer steel) and they don't seal very well unless head AND block are surfaced.
The benefit of aluminum heads are less weight, the draw backs are that aluminum heats up faster than iron so expands faster.
When car makers tried to do aluminum heads on iron blocks originally they had head gasket failures by the truck load, lol, the aluminum heads were "rubbing" through the composite head gaskets every time engine was warmed up and then cooled off, so 20k-30k of driving could see leaking head gaskets, 60k was consider the lifetime.
They switched to MLS gaskets so aluminum head would "slide" as it warmed up and cooled off, this worked but .........they had a lot of issues with cold sealing, MLS gasket would leak when cold and then reseal when warm, the cylinder didn't leak but coolant did leak out the edges or into the oil,
They fixed this by better machining of the heads and blocks, tighter tolerances.
DIY replacing of an MLS gasket can be fine, but can also go badly depending on the condition of the block surface.
They do make graphite coated composite gaskets, these enable "sliding" more than "rubbing", but "rubbing" can still be an issue, these gaskets are better for DIY because they seal better on an un-resurfaced block, they are more forgiving.
So you could go with aluminum and use a graphite gasket but I wouldn't.
The head cracking is a know issue, maybe common was the wrong word.
A failed head gasket is more likely when you have a cylinder leak, but I would have the heads pressure checked, for a crack.
You would need to run a MLS head gasket(multi-layer steel) and they don't seal very well unless head AND block are surfaced.
The benefit of aluminum heads are less weight, the draw backs are that aluminum heats up faster than iron so expands faster.
When car makers tried to do aluminum heads on iron blocks originally they had head gasket failures by the truck load, lol, the aluminum heads were "rubbing" through the composite head gaskets every time engine was warmed up and then cooled off, so 20k-30k of driving could see leaking head gaskets, 60k was consider the lifetime.
They switched to MLS gaskets so aluminum head would "slide" as it warmed up and cooled off, this worked but .........they had a lot of issues with cold sealing, MLS gasket would leak when cold and then reseal when warm, the cylinder didn't leak but coolant did leak out the edges or into the oil,
They fixed this by better machining of the heads and blocks, tighter tolerances.
DIY replacing of an MLS gasket can be fine, but can also go badly depending on the condition of the block surface.
They do make graphite coated composite gaskets, these enable "sliding" more than "rubbing", but "rubbing" can still be an issue, these gaskets are better for DIY because they seal better on an un-resurfaced block, they are more forgiving.
So you could go with aluminum and use a graphite gasket but I wouldn't.
The head cracking is a know issue, maybe common was the wrong word.
A failed head gasket is more likely when you have a cylinder leak, but I would have the heads pressure checked, for a crack.
Last edited: