Ay up gents!
probably been done to death
The old P38 has a worn out old 4.6 - infrequent oil changes from its previous owners, and a life of towing have taken their toll on the motor, and it is quite slow, it seems to fall on its face above 2800rpm
No misfires or lumpiness it just doesn't pull like it should..
What kind of build would be ideal for an heavy old 4x4 which will be towing a fair bit?
Stock HP is 218hp and 300 lb-ft according to the original specs
Is it possible to get 400 lb'ft out of a 4.6?
H
V8 Engine Build for a P38
Moderator: phpBB2 - Administrators
Re: V8 Engine Build for a P38
The 4.6 in my P38 is in good order. I rebuilt it 80,000 miles ago and the only change I made was a mild cam update to take it from 225BHP to 248BHP.
I have to say that seems pretty adequate to me - given how shocking the handling is.
Chris.
I have to say that seems pretty adequate to me - given how shocking the handling is.
Chris.
--
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8
Re: V8 Engine Build for a P38
Sounds typical of a worn out cam - that tends to suffer first with poor servicing. To get a big increase in torque, you either need a larger engine or forced induction.
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
Re: V8 Engine Build for a P38
Well I narrowed my apparent lack of power down to a defective MAF
she picks up quite well now...
Apparently stock the motor has 218hp and 300 lb'ft
Mark Adams offer's a chip to improve performance, i'm guessing they're strangled for emissions reasons the the map "opens them up" anyone had the map?
And finally is camshaft wear guaranteed for the RV8 at around 130k she has had LPG since 2003 however the Oil changes weren't that frequent, however being that LPG doesn't have the impurities that petrol does, would that make any difference to internal wear/conditions?
H
she picks up quite well now...
Apparently stock the motor has 218hp and 300 lb'ft
Mark Adams offer's a chip to improve performance, i'm guessing they're strangled for emissions reasons the the map "opens them up" anyone had the map?
And finally is camshaft wear guaranteed for the RV8 at around 130k she has had LPG since 2003 however the Oil changes weren't that frequent, however being that LPG doesn't have the impurities that petrol does, would that make any difference to internal wear/conditions?
H
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Re: V8 Engine Build for a P38
Cam wear is almost always the number 1 thing to look for, assuming the engine has been neglected with oil changes, but if it has been flogged hard AND neglected, then you will be in for the rest of the engine, too.Henry-b wrote: ↑Thu Feb 04, 2021 8:58 pmAnd finally is camshaft wear guaranteed for the RV8 at around 130k she has had LPG since 2003 however the Oil changes weren't that frequent, however being that LPG doesn't have the impurities that petrol does, would that make any difference to internal wear/conditions?
H
Cheers,
John
John
Re: V8 Engine Build for a P38
By those figures it is a late P38 with the Thor engine? BMW spent quite a bit of time optimising the RV8 for 4x4 use. The power is reduced over previous versions, but torque improved, due to the longer inlet tract. Before chipping it, I'd make sure it is good health - perhaps check the power output etc on a decent rolling road?Henry-b wrote: ↑Thu Feb 04, 2021 8:58 pmWell I narrowed my apparent lack of power down to a defective MAF
she picks up quite well now...
Apparently stock the motor has 218hp and 300 lb'ft
Mark Adams offer's a chip to improve performance, i'm guessing they're strangled for emissions reasons the the map "opens them up" anyone had the map?
And finally is camshaft wear guaranteed for the RV8 at around 130k she has had LPG since 2003 however the Oil changes weren't that frequent, however being that LPG doesn't have the impurities that petrol does, would that make any difference to internal wear/conditions?
H
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
Re: V8 Engine Build for a P38
I would think that all the map can do is to richen the mixture up through the mid range as it is highly optimised for economy and emissions rather than outright power.
There is no way that a remap can get any more air into the engine, so all it can do is adjust the mixture a little.
I fitted a different cam to mine (+25BHP) with no other changes, and no remap, and it works fine.
As an side, I also built a 4.6 with ported heads, very high lift cam, high compression pistons, but it is too far outside 'spec' for the Thor system so it does not idle properly at all, and throws a fault code. So I would shy away from going too mad with Thor.
Chris.
There is no way that a remap can get any more air into the engine, so all it can do is adjust the mixture a little.
I fitted a different cam to mine (+25BHP) with no other changes, and no remap, and it works fine.
As an side, I also built a 4.6 with ported heads, very high lift cam, high compression pistons, but it is too far outside 'spec' for the Thor system so it does not idle properly at all, and throws a fault code. So I would shy away from going too mad with Thor.
Chris.
--
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8