A good friend of mine who's a really knowledgable mechanic especially with rover stuff told me that alot of times the head gaskets fail because of the row of lower head bolts in the heads. He was saying that on an older motor when you replace the gaskets and bolt the heads back on you are supposed to leave the bottom row of head bolts out so that when the head heats up and expands it doesnt lift and blow the gasket. He showed me on my 98 disco how my heads are the "newer" style heads that DO NOT have the lower head bolts thus making it less prone to head gasket failures. Sure enough I was looking at my heads and there are no lower headbolts on my 98 but his older RRC has the lower bolts. SO I'm not sure what year rover finally caught on but now I'm curious what year exactly did rover stop putting the lower headbolts in and does this truly LOWER the chances of losing a head gasket.

 

Yea when I did my head gaskets I had to leave those bolts out , its a 94 so they were still using them then

 

It's one of the differences between the 3.9 and the 4.0

 

What year was the 3.9 to 4.0 done?

 

1996. 4.0 is the same engine displacement as the 3.9. They changed the name from 3.9 to 4.0 to differentiate between OBD1 and OBD2 engine management systems.

 

Yeah I just researched it also, same displacement motors but they did have some changes such as GEMS and also OBDII. I guess theres a few other small differences like beefier bearing design, better piston's etc etc