Which HEADS (missing bolts)

[Mangie]

Engine was becoming a little tired so a fresh 3.5 (RR 1981) build is almost complete until it was time to fit the fully reconditioned heads (valves, seals, the works). The new heads were chosen out of a set of 3 that I had laying around and they were selected because of the best hardness test results.
So I went to mount my shmick heads last night and found that my shmick heads were missing a few bolt holes, in particular 4 bolts on the exhaust side. WHAT HAVE I DONE ???
I found the donor engine and it doesn’t have these holes but my new engine does, DO I HAVE A PROBLEM HERE ? Summary: my engine has 14 bolt locations but my heads only have 10.

[PLR]

G`day ,

What are the cast numbers in the heads of both heads , maybe in the centre of the rocker side ( top ) inbetween the posts ?

Or on the outside ends

What is the engine number prefix from the engine the heads came from ?

If it`s a Rover the number will be on a pad near where the dip stick is located on the block .

If the numbers not there have a look on the left side , standing behind it , near where the head and block meet .

There are 2 options either the heads came from a Rover 3.9/4.0/4.6 or they`re off a 4.4 leyland .

If they`re off a rover won`t be a great problem , just a matter of the right gaskets but there are two 10 bolt 3.9s .

So it will depend what ratio pistons it has and which 10 bolt heads it has to determine which gasket to use to achieve whatever compression ratio that is suitable .

If they`re off a Leyland , it will be a problem because the Leyland lubricates through the push rods and the Rover through the heads .
The Leyland also has smaller diameter valves than 10 bolt and later 14 bolt Rover heads .


Cheers

[Lucus]

Ten bolts heads ae later model heads. The last 4 bolts where deleted as its believed they where causing uneven pressure on the heads and leading to head gasket leaks.

I have 14 bolt heads on my 4.6 and only use 10 as the block only has provisions for 10 bolt heads. If had no problems with this set up. Companies like RPI Engineering recommend leaving the 4 bolts out or installing them and torquing them to a minimal torque to prevent dirt buile up in the open bolt holes.

cheers
Luke

[p38arover]

As Peter says, if they are Rover heads, no problem. Rover finally dropped those 4 bolts which caused the head to warp and the head gaskets to fail. The combustion chambers are smaller (28cc) to allow for the loss of CR with the composite head gaskets.

See also RPi Engineering - V8 Engines (http://www.rpiv8.com/engine-4.htm#gaskets)

[PLR]

Thinking on it more ,
if they were Leyland heads it would be fairly obvious because the over head gear attaches like a holden and if you tried to sit the rover rocker shafts on it wouldn`t be very pretty .

Cheers

[Mangie]

Thanks for all your input/help. I have identified the heads as range rover not Leyland which is a good start. I also think they were of an EFI setup too as the inlet ports appear to have a small cut out to fit the injector. Never noticed till now.

Does anyone know what year the 10 bolt (only) engine arrive ?

[p38arover]

Does anyone know what year the 10 bolt (only) engine arrive ?

About 1994/1995. My 1995 4.6 litre cross-bolted block is a 14 bolt block but the heads are 10 bolt.

In theory no cross-bolted blocks have 14 holes but mine does.