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MG MGA - Cylinder head
|My MGA started life as a 1961 1600 Mk 1. |
My cylinder head is type 15, part no 1H967. Valve sizes 1.5 and 1.25 (approx) The block is 1622 (Austin A60 swap by PO). My guess is he kept the same head
I'm trying to rebuild it as a 1622 MkII (new cam, pistons etc.) Is this the correct head for the job?
|Probably no. If you use the "15" head on a 1622 engine with standard flat top pistons you may have too high compression ratio. If you can get dished pistons the CR could be okay, but the intake valves on the "15" head are sub-standard (one size to small) for the MGA 1600-MK-II (1622cc) engine.|
The "15" head has 38cc chamber volume and is correct mate to 1500/1600 engines with dished pistons. The "16" head has 43cc chamber volume (and larger intake valves) and is correct mate for the 1622 engine with (standard) flat top pistons. The early "18" head is nearly identical the "16" head and makes a good substitute.
|Thanks Barney. The old pistons were dished. So, it would work with new dished pistons, but down in power? And with a 16 or 18 head (early) and flat pistons would be normal?|
|There is no problem using the early smaller displacement chamber with flat top 1622 pistons - it doesn't boost the compression too much, and in fact can be beneficial.|
What you do want to do is use the larger valves, bring the ports up to late spec and clean up the chambers. Or just put an early MGB head on (same as the 1622 used, althopugh different casting #)
This thread was discussed between 26/11/2008 and 27/11/2008
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