Range Rovers Forum banner

Swapping a 4.2 serpentine for a 4.6

1346 Views 2 Replies 3 Participants Last post by  classicjack
I am slowly getting together the bits I need to replace my knackered 4.2 with a remanufactured 4.6. To keep costs down i have bought a 4.6 short engine and plan on re-using all the bits i can from my old engine.
The 4.6 short engine I have bought is already fitted with the cam from a 3.9 but I have a new cam for a 4.2 sitting about. I know they are different but is there any advantage to fitting it? Also as my existing engine is a serpentine and has a "different" oil pump is the cam wrong anyway? Do i need to have the crank pulley machined or will it just fit and work?
I run on LPG so i'm not overly worried about chipping the ECU (i will probably do it after making sure everything else works OK) but is there anything else I should be thinking about? Nobody seems to have much experience with serpentine 3.9/4.2 engines so the "experts" aren't able to help.
Sorry for the long list of questions, I am trying to minimise cockups so i have a nice easy engine swap rather than a swearfest.
1 - 3 of 3 Posts
so its my understanding the the serp front covers will work on a 4.6, I think there are some issue with the bosch block vs gems or it could be the other way around. I think the hard part is going from a vbelt to a serp, as they have different oil pumps, crank vs distributor driven. If your doing a short block you might as well do a hotter cam lifters and timing set. I wish I knew more about the swap, there is a lot to read about this on the discoweb.org
I changed a 4.2 to serp belt drive for install in disco, excuse the language. Crank damper on 4.2 had different pulley so had to be swapped with serp damper pulley, it took some grinding to get to bolts.Serpentine front cover has integral oil pump ( built into cover ) , which explains $450 cost for serp oil pump , compared to 4.2 which is seperate from front cover.
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.