The V8 Owners Forum -

hello there guys just got joined today, great website.

my motor is a range rover classic 3.9v8, currently she is showing signs of headgsket failure.

ive been given another engine by a friend, the plan being to remove the heads off my spare engine to prepare to fit straight onto my rangie to save time of the vehicle being off the road.

problem being i dont know whether or not they will fit, i have no idea what the engine is from ??

First thing to check is how many bolt holes on the heads, to see if they are early or late model heads. In my experience so far, all Rover V8 heads will fit any Rover V8. I have a pair of late 10n bolt heads in use on an old pre SD1 engine.
You shouild have no trouble using different heads, but they do have different sized combustion chambers from the early to later models. And you should take care to check the tappet pre load when you re fit the top end.
Check out Tonys info on cylinder head identification in the heads section. Top of the list.

as above but if they are 10 bolt heads I would advise using the thicker composite gaskets. If they aren't then use the tin gaskets or you will loose a fair bit compression.

ill count the number of bolts later.

what i do remember is, there are 5 bolts under the rocker cover and two rows of bolts on the outside of the heads near the plugs ??

is there any numbers that i can identify the engine with.

Ill have to get the heads steam cleaned to identify what they are.

seams like 4.0/4.6 heads are best

would 4.6 heads fit my rangie then. (3.9 1990)

What would this do to the compression ratio.

what gaskets would i need.

there is no benefit or loss to 4.6 heads. If they are then use composite gaskets and the comp ratio will stay the same and yes all rover heads fit all rovers.

I understand that tin gaskets are prone to failiure

Should i use composite gaskets with a slight head skim to retain compression ratio

I use comp gaskets now as I was told they were better, but mine did over 90k with tin gaskets without failing.

wayno wrote:I understand that tin gaskets are prone to failiure

Should i use composite gaskets with a slight head skim to retain compression ratio

Like I already said if they are 4.6 heads (you seem to think they are)use comp gaskets there is no need to skim them. if they aren't then use tin gaskets. They are no more prone to failing when they are installed properly.

Sure it's head gasket, not cracked block?

Chris.

Are the blocks prone to cracking then.

i thought that was mainly the later p38 range rovers

All the 'large bore' engines are prone to cracking, so that means anything with a 3.7 inch bore, or anything over 3.5 litres!
Supposedly the 4.6 are worse because of the increased power / stresses on the block.

It's worth checking before doing loads of work to no avail. Softdash3.9 has been down this road, I'm sure he'll have some advice.

Chris.

any ideas how i can check if the block is cracked ?

Im gonna get the heads off and pressure checked. Its only just started using a little water

Get the block pressure tested. You cant see the cracks as they form behind the liners unfortunately.