944 Turbo Engine Block Bore Options
07-30-2016, 01:35 PM
#1
944 Turbo Engine Block Bore Options
Like many of you I'm at the stage where I need to decide on what I want to do with my engine block, having scored cylinders. The options I've come up with from researching are:
1. Boring the block over with the special techniques due to the alusil block material
2. Nikasil the bores and bore to a chosen size.
3. Steel sleeve the block.
From what I've read, nikasil is a great option but it is expensive and seems silly when the block is alusil which has the same purpose. Also nikasil is corrosive.
Boring the block seems fine and well but in my experience and many others the bores are easily damaged. The 2 motors that I took apart both were scored . I think more times then not these engines are scored to some degree when a tear down takes place.
So this leads me to sleeving. This would put a stronger wall in the cylinder and expands ring options. This seems like a great option but I worry about how sleeves may effect how the head gasket seals as I'll be using a commetic one and the risk of a sleeve moving in a block over time, wear , and thermal expansion.
What are your opinions? For those of you that rebuilt scored blocks what did you do? How did it hold up over time? Thanks in advance.
1. Boring the block over with the special techniques due to the alusil block material
2. Nikasil the bores and bore to a chosen size.
3. Steel sleeve the block.
From what I've read, nikasil is a great option but it is expensive and seems silly when the block is alusil which has the same purpose. Also nikasil is corrosive.
Boring the block seems fine and well but in my experience and many others the bores are easily damaged. The 2 motors that I took apart both were scored . I think more times then not these engines are scored to some degree when a tear down takes place.
So this leads me to sleeving. This would put a stronger wall in the cylinder and expands ring options. This seems like a great option but I worry about how sleeves may effect how the head gasket seals as I'll be using a commetic one and the risk of a sleeve moving in a block over time, wear , and thermal expansion.
What are your opinions? For those of you that rebuilt scored blocks what did you do? How did it hold up over time? Thanks in advance.
07-30-2016, 03:28 PM
#3
Drifting
I've got an 89 2.7 block that hasn't got a mark on the bores, though I read something that Chris White wrote on here that any ridge near the top of the bores means the bores have ovality. AFAIK Porsche Nikasil plate the cylinders in the 911 Turbo/GT engines.
07-30-2016, 11:01 PM
#4
