I think you should be the guinea pig. 2.9 and 4.0 share the same block and I know Copykat discovered the exhaust mounts are the same. Haven't heard anything on internals though.
Uhhh... No, they are NOT the same block.
The 4.0 block is wider across the pan rails to clear the crankshaft counterweights and the block decks are taller (relative to the crankshaft centerline) by 20mm (about 8/10th of an inch) to accomodate the greater STROKE of the 4.0.
The engines share the bellhousing pattern and crankshaft bolt flange (up to mid 1997 anyway) but thats about as far as it goes.
Many posts about or asking questions about modifying a 2.9 engine share a common theme... people trying to avoid the relatively easier path of simply swapping in a 4.0,
Some of the engine mods suggested could theoretically could be done,
but it wouldn't be too out of line for some of the more complex ones
to pack the specially modified parts in crumpled $20 bills to ship them
back to the customer...
Frankly i Think if you REALLY want a roller cam in your 2.9 you should swap the 4.0 BLOCK "into" your 2.9 at the same time.
I think you should be the guinea pig. 2.9 and 4.0 share the same block and I know Copykat discovered the exhaust mounts are the same. Haven't heard anything on internals though.
No he didn't "discover" the fact that the 2.9 Y-pipe will bolt directly to a 4.0
or that a 4.0 from a TTB truck (either 1990-97 Ranger or 1991-94 Explorer)
uses the same mounts because I've personally said exactly that
Oh... probably 250times in the last five or six years.
So "Re-discovered" is a far better word.
Swapping to a 4.0 from a 2.9 isn't rocket science.
what is difficult about it is all the subtle variations in BOTH the engine donors and the (formerly) 2.9 engine receipients make explaing the swap in a single post all but impossible.
And the fact that some swaps (like any swap into a Gen1) is far more electrically intensive than a swap into a Gen2 or Gen3.
My personal truck, an '87 was about as difficult as a 4.0swap gets
on a receipient that atleast already has an EFI fuel system
On a Gen2 you just need to get the COMPLETE engine bay wiring harness
from a RANGER. Sure a 1991-92 Explorer harness CAN be made to work, but
you need to have the EVTM for BOTH vehicles to figuire it out...
"dash swaps" are NOT an easy way out on a Gen1, it just changes which tribe of gremlins you are gonna do battle with...
Personally I think the 4.0 is the engine that should have been in Rangers from the very beginning. The 4.0SOHC was "an improvement too far" as it created a piggish monster with serious longevity and maintainance issues (That "Rube Goldberg" timing chain system)
Switching to a 4.0 myself for a daily driver has made me realize in just how
many ways I really wasn't happy with the 2.9.
AD