Rover V8 Standard and Performance Cylinder Head Rebuild Kits
Notes - Cylinder Head Identification
There are various types of cylinder heads fitted to the Rover V8, with only subtle differences between them.
Care must be taken in selecting the correct rebuild kit or components to ensure compatibility with your engine.
Early Cylinder Heads
Early cylinder heads - as fitted to Rover P5B, P6, MGB V8 and early Range Rover - are fitted with small (38mm inlet, 33mm exhaust) valves and may not be suitable for use with unleaded fuel. These heads can be identified most easily by removing one of the spark plugs and measuring the length of the threaded section of the plug. If it measures 12.5mm, the cylinder head is an early type. If it measures 19mm, the cylinder head is post-1976 (SD1 or later).
Later Cylinder Heads
Identify later cylinder heads as follows:
1. Count the rows of cylinder head bolts. All cylinder heads have a row of head bolts inside the rocker covers; they also have a second row of 5 head bolts just below the spark plugs. Finally, cylinder heads up to around 1994 have a third row of 4 bolts just below the second row. 3.9, 4.2, 4.0 & 4.6 litre engines after this period have a total of two rows of head bolts.
2. Look at the ends of the cylinder heads, as fitted to the engine. There are tapped holes in the ends of each cylinder head, to which the ancillary component brackets are bolted. The number of holes determines which type you have, as follows:
3/3 bolt (3 bolt holes in each head), 3/4 bolt (3 bolt holes in one head, 4 in the other), 4/4 bolt (4 bolt holes in each head)
Standard Cylinder Head Rebuild Kits
Standard cylinder head rebuild kits contain everything you need to recondition a pair of cylinder heads. We assume you will have any required machining done. Valves in all kits are lead free compatible. Each kit contains: inlet valves, exhaust valves, valve springs, valve guides and valve stem oil seals for two cylinder heads. Additionally, why not add rocker shafts and/or rocker arms when you order your rebuild kit?
Performance Cylinder Head Rebuild Kits
We offer two performance cylinder head rebuild kits, both based around later (i.e. post-’76) type heads, with which you can modify.
COMPRESSION RATIOS - CYLINDER HEADS & SHORT ENGINES
Several Rover V8 cylinder head designs were manufactured during the engine’s production life, with different combustion chamber sizes, giving a variety of compression ratios when fitted to a short engine. Therefore, you will need to know the combustion chamber size of the cylinder heads that you intend to use in order to be able to calculate the engine’s compression ratio.
As a general rule, cylinder heads up to the introduction of Range Rover Series 2 (1995 model year) have approximately 34-36cc combustion chambers. From the introduction of Range Rover Series 2, through Defender EFi and Discovery Series 2 (i.e. 4.0 and 4.6 litre engines), they have approximately 28cc combustion chambers, as have 1995 onwards 3.9 and 4.2 litre engines in Range Rover Classic and Discovery Series 1. If in doubt as to what you have, 1995 onwards cylinder heads have only two rows of cylinder head bolts; earlier engines have three rows.
Following all this, the compression ratio also depends upon whether tin or composite head gaskets are fitted – please refer to note under Head Gaskets.