Outer Limits 4x4 Board

I am looking at stroking a 3.9L engine using the 4.4 crank. I have most of the info on the conversion but I am unsure of what pistons I will need to use. This conversion will take the engine capacity to around 5.0L.

If anyone has done this conversion or has any more info on it I would love to hear from you.

Cheers

Sorry I don't have the info you are seeking, but I will be watching this post with interest. As I have a 3.9 v8 in my Disco that doesn't go as good as it should. It leaks like a sieve (not sure of spelling), is this normal for a rover? I have an auto with the lockable centre diff, how would this handle the increase in power? I have Maxis with axles front and rear (sitting in a box ) for diff strengthening.

luv4bee'n wrote:Sorry I don't have the info you are seeking, but I will be watching this post with interest. As I have a 3.9 v8 in my Disco that doesn't go as good as it should. It leaks like a sieve (not sure of spelling), is this normal for a rover? I have an auto with the lockable centre diff, how would this handle the increase in power? I have Maxis with axles front and rear (sitting in a box ) for diff strengthening.

The auto should handle the power no worries, depending on year it might be the zf 22 or 24 both good boxes. As for leaks no sure.

For a start you will have to grind the 4.4 mains down to the rover size and get the correct length rods as the 4.4 block is roughly 20mm taller, then piston pin height will be critical as well.

Loanrangie wrote:For a start you will have to grind the 4.4 mains down to the rover size and get the correct length rods as the 4.4 block is roughly 20mm taller, then piston pin height will be critical as well.

I already have some one ready to do the grind to suit standard 3.9L main bearings. Also the 4.4 rod I am pretty sure are the one to use from the info I have as the 3.9L one are to short and the piston hit the crank. It is just finding the right piston. I think it is the 4.0L one as it is the same diameter as the 3.9L but I think it is a more shallow piston. I just need to get some dimesions to see if it works. The 4.0l also has the right wrist pin size so no modifing there either.

Cheers for your reply.

I think it will be the 4.6 pistons you need pin height wise although wrong bore size as the 4.6 is a longer stroke than the 3.9/4.0 ltr but in the same size block.

When i said leaking i meant the engine my disco is a 97 model does that help with the zf 22 or 24 thing and which 1 is better

luv4bee'n wrote:When i said leaking i meant the engine my disco is a 97 model does that help with the zf 22 or 24 thing and which 1 is better

Leaking from where ? ZFHP22 is a tough box but like anything needs to be looked after, what sort of power upgrade ?