rappy1

rappy1

Active Member
Anyone know if the 4.6 p38 inlet and plenum manifold is a bolt up to the 3.5 engine? I am rather interested in what options you can use.
The engine is a 3.5 carb but currently looking into the options of injecting it and running megasquirt. In the country i live the 3.9 and p38 engines are in large numbers so getting second hand parts much more simple than the injected 3.5.
Also my plan was to fit a 4.4 p76 engine which basically the same engine as the 3.5 so the 4.6 woulds have large enough injectors to match.
 
they will bolt straight on but efi heads have notches in inlet ports ,easy enough to mod using die grinder
 
I might be wrong, (I'm sure someone will correct me) but I seem to recall that the P76 block is a touch taller than all the other rover variants, therefore the heads are a little further apart, and has its own inlet manifold to suit. However, its not impossible to machine some 'spacers' to suit.

I also think that the injectors are the same on both the 3.9 and the 'GEMS' 4.6, Same part No ERR722.

I would go for the 4.6 set up as I think the throttle body is a shade bigger than the 3.9/4.2 ones.

Hope that helps, Dave.
 
crazydave said:
I might be wrong, (I'm sure someone will correct me) but I seem to recall that the P76 block is a touch taller than all the other rover variants, therefore the heads are a little further apart, and has its own inlet manifold to suit. However, its not impossible to machine some 'spacers' to suit.

I also think that the injectors are the same on both the 3.9 and the 'GEMS' 4.6, Same part No ERR722.

I would go for the 4.6 set up as I think the throttle body is a shade bigger than the 3.9/4.2 ones.

Hope that helps, Dave.
Click to expand...
I have been reading that most seem to make a spacer for them to fit. Apparantly the rover heads and inlet are better to use on the p76 than the standard ones. even the 3.5 carb inlet.
p38 parts are worth sweet **** all and more common than other rover engines (at least round here) . I think the 4.6 inlet woulld be a closer size match to the 4.4 than the 3.9
Always fancyed the idea of forced induction at some point too. But thats for another time. Seems like the biggest problem with fitting the p76 is keeping it cool enough. My current radiator is in a rather poor state so me thinks i would have to have a custom one made with more cooling. Don't cost much more than having a replacement made for my current one.
I am going to check out this engine sometime this week and probably pick it up over christmas time so i can get rebuilding it. Should only cost me 100pound mates rates:cool:
 
ok so the 3.5 carb heads and inlets are better than the standard 4.4 p76 ones?

wow, thats a shock- the early 3.5 heads arnt supposed to be much good at all?

you could make a mean motor with a 4.4 block and one of out old rover v8s then!
 
The gems injection system will need to be cracked to use it or a modified 14cux to allow the idle control and throttle poistion to work also the base of the gems manifold is the same as the 3.9
 
I think he means that you will need to get past the robust immobilisation fitted into Gems ecu's. Better off staying with 14Cux really - alot easier to set up and will happily run the bigger engine with a couple of mods.
 
I got the impression that the idea was just to find a suitable injection manifold and then use an aftermarket system (was megasquirt mentioned) to run it. I'm running a 4.6 on 14cux (chipped) and its sweet.
 
crazydave said:
I got the impression that the idea was just to find a suitable injection manifold and then use an aftermarket system (was megasquirt mentioned) to run it. I'm running a 4.6 on 14cux (chipped) and its sweet.
Click to expand...

Correct,
I am not bothered to much on the electric side of things as have pretty good knowledge when it comes to that. I wouldn't bother with factory ecu as it would cost me the same for the loom and ecu as it would for a megasquirt (sounds like porn) system.
Would still retain injectors tps and isc. I was reading the p38 exhaust manifolds bolt up to the head and seem like a better option than the 3.5 manifold. its just if they will fit between the chassis and bulkhead. The proper extractors cost a small fortune
 
P38a manifolds don't fit without major moody destroying the great flow they have when fitted in the p38a
As for the injection system 14cux is the simplest and is almost plug and play mega squirt is clockwork and needs a lot of rolling road time to produce a good map to run from
The best system that is standard is the Thor system it is land rover best flowing inlet track system and the ecu is the best at acting to change I am currently having a system cracked to offer a plug and play Thor system for any model classic
 
"I am currently having a system cracked to offer a plug and play Thor system for any model classic"

Sounds interesting! Keep us up to date.
 
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