head gasket size
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head gasket size Help please! I'm getting at lot of mixed answers and thought I would turn to the trusted form for some answers...
I'm in the process of building my Whipple charged LS. LQ4 block, bored to 4.030", standard stroke. 12cc dished pistons, so should be around 9.3:1 compression ratio with my 70.5cc head chamber capacity. I have 821 casting heads that have been hand ported.
Cometic have given me mixed advice on what head gasket size to run, one answer I got was to run 0.030'' to 0.060'' bigger than bore size, so lets say a 4.060'' gasket for a 4.030'' bore size according to them. I will be going for a standard 0.051'' compressed thickness.
What will be best for my application? size on size? Or follow what the 0.030'' oversize?
And how does my 821 casting heads effect the equation? If I'm not mistaken the oem head gaskets for original L77 engine which had these 821 casting heads had a 4.100" 'bore' gasket for an actual 4.000'' bore size.
any advice and experience will be appreciated.
thanks,
Rob
I'm in the process of building my Whipple charged LS. LQ4 block, bored to 4.030", standard stroke. 12cc dished pistons, so should be around 9.3:1 compression ratio with my 70.5cc head chamber capacity. I have 821 casting heads that have been hand ported.
Cometic have given me mixed advice on what head gasket size to run, one answer I got was to run 0.030'' to 0.060'' bigger than bore size, so lets say a 4.060'' gasket for a 4.030'' bore size according to them. I will be going for a standard 0.051'' compressed thickness.
What will be best for my application? size on size? Or follow what the 0.030'' oversize?
And how does my 821 casting heads effect the equation? If I'm not mistaken the oem head gaskets for original L77 engine which had these 821 casting heads had a 4.100" 'bore' gasket for an actual 4.000'' bore size.
any advice and experience will be appreciated.
thanks,
Rob
You can’t have any exposed gasket into the chamber. What that means is, which ever is the larger diameter (head or cylinder) you have to get a gasket for that size.
My engine for example a 4.070 cylinder, with a tfs235 head. The 235 chamber is about 4.130 wide… so I need a 4.150 or greater gasket.
measure the chamber width of your head, and you’ll know what you need.
My engine for example a 4.070 cylinder, with a tfs235 head. The 235 chamber is about 4.130 wide… so I need a 4.150 or greater gasket.
measure the chamber width of your head, and you’ll know what you need.
Help please! I'm getting at lot of mixed answers and thought I would turn to the trusted form for some answers...
I'm in the process of building my Whipple charged LS. LQ4 block, bored to 4.030", standard stroke. 12cc dished pistons, so should be around 9.3:1 compression ratio with my 70.5cc head chamber capacity. I have 821 casting heads that have been hand ported.
Cometic have given me mixed advice on what head gasket size to run, one answer I got was to run 0.030'' to 0.060'' bigger than bore size, so lets say a 4.060'' gasket for a 4.030'' bore size according to them. I will be going for a standard 0.051'' compressed thickness.
What will be best for my application? size on size? Or follow what the 0.030'' oversize?
And how does my 821 casting heads effect the equation? If I'm not mistaken the oem head gaskets for original L77 engine which had these 821 casting heads had a 4.100" 'bore' gasket for an actual 4.000'' bore size.
any advice and experience will be appreciated.
thanks,
Rob
I'm in the process of building my Whipple charged LS. LQ4 block, bored to 4.030", standard stroke. 12cc dished pistons, so should be around 9.3:1 compression ratio with my 70.5cc head chamber capacity. I have 821 casting heads that have been hand ported.
Cometic have given me mixed advice on what head gasket size to run, one answer I got was to run 0.030'' to 0.060'' bigger than bore size, so lets say a 4.060'' gasket for a 4.030'' bore size according to them. I will be going for a standard 0.051'' compressed thickness.
What will be best for my application? size on size? Or follow what the 0.030'' oversize?
And how does my 821 casting heads effect the equation? If I'm not mistaken the oem head gaskets for original L77 engine which had these 821 casting heads had a 4.100" 'bore' gasket for an actual 4.000'' bore size.
any advice and experience will be appreciated.
thanks,
Rob
