stevec
9 posts
Joined: 31/07/2007 20:13:44
Location: Norwich United Kingdom (Excluding channel Islands)
BK450 gastet volume
I'm trying to calculate how much to skim my head to get a 10:1 CR. I need to know the volume of the BK450 gasket. Minispares says 2.8cc. The AFRacing CR spreadsheet says 3.8. I have seen a figure of 3.2cc elsewhere. The gasket I took off (AF270) calculates out at about 3.5cc but Minispares says it's 2.8cc. So I'm a bit confused. Getting it wrong can make a difference of about 0.25 in ratio.
Posted: Jan 17, 2008 03:52 PM
The gasket I took off was AF470 not 270.
Posted: Jan 17, 2008 03:54 PM
John
1948 posts
Joined: 28/05/2006 16:49:46
Location: cambridge United Kingdom (Excluding channel Islands)
if u give me ur email il send u a spreadsheet for calculating it accuratly
Posted: Jan 17, 2008 06:23 PM
Thanks, I have a spreadsheet for calculating CR from all the figures. I have measured the volume in the block and volume in the cylinder head by measuring the amount of thin oil each can hold using a syringe. The one unknown is the compressed volume taken up by the gasket. I have seen various figures for the BK450.
Posted: Jan 17, 2008 07:39 PM
In case anyone accesses this in the archive. I spoke to Simon at Morspeed today. They use BK450's and work on a figure of 3.5cc for the compressed gasket space. I think I'll go with that.
Posted: Jan 18, 2008 06:58 PM
T. Perks
57 posts
Joined: 19/11/2006 09:21:16
Location: Wotton under Edge United Kingdom (Excluding channel Islands)
1275cc Head
Yes you can fit a 1275 head on to a 1000 as long as your valve lift does not exceed the depth of the combustion chamber and is a very good mod not only does the head flow better about 15cfm average than a 100 head but the compression ratio will be up to about 10.5 which will give more torque/power but also help with fuel economy, make sur to use the 1275 head gasket and check alinment of the water ways along the front of the block, and where the fire ring of the gasket sits. If the gasket over lyes the water hole you can fit a threaded bung to stop leakage. Remember the lift to check is the exhaust lift which will be around 318-320thous chambers are generally around 340-350thou and you have you gasket thickness on top too. Oh yes and dont use the aht 188 copper gasket as the fire ring is a little bigger use the payen Bk450, or the rover geg300.
Posted: Feb 22, 2007 08:40 PM
W. Cardwell
3 posts
Joined: 27/06/2007 21:59:28
Location: Holyhead United Kingdom (Excluding channel Islands)
Payen Gasket Number...
James,
BK450 for a head gasket
DK450 for a head set
Both for a 1275 A+ (not A series)
Warren
Posted: Sep 23, 2007 10:38 PM
head gasket help needed
Incidentally - the dark staining that appears on the block and head faces on the rear (push rod side) are not caused by increased heat as many believe - it is meerly water staining/rust caused by a very slight water blled from the three block to head transfer ports. These later black gaskets do not have ring seals around these holes in the gasket like the copper ones do. It is not a problem except where weak/old studs are used, or rockers with aluminium posts. Both of these 'relax' in use/when hot, reducing the clamping pressure set when torqued down. I have considered using a VERY thin smear of sealnat in this area alone to see what happens - but haven'ty really had the need to rty it yet. KC
Posted: Feb 08, 2007 09:57 AM