Rover 75 2.5 V6 tuning

Aikie · 8th February 2019, 11:36

Dear all,

Being new on this forum I hope to be to get familiar with the forum, get acquainted and make progress to bring my newly acquired rover in good condition again.

Recently I managed to buy a Rover 75 2.5 V6 manual in Spectre

, pretty rare being no. 8 out of 9 in this disguise. Already my 7th Rover.
It was difficult to judge the car, battery was flat and it was parked pretty tight. It probably needs a new fuel pump and the head gaskets are blown.

My garage will make a first judgement of the car and than we will talk it over. He probably has a used V6 that can be used for the first overhaul. This will be the main focus for now.

Here also appears the first question. I am considering a limited tuning and are wondering which technical changes are feasible without changing originality too much (remapping via Kmaps? , adding MG inlet? etc.)

. Hope the forum can be of help.
Later I am thinking of adding the handbrake compensator change (if still available), upgrading the High line navigation and turn the interior in good shape.

Warm regards, Rob

trikey · 8th February 2019, 12:03

If I were you I’d get the engine sorted to factory spec (get a second opinion on the head gaskets, they rarely fail on a kv6) And enjoy it for what it is, the v6 was never a fast motor, enjoy its smoothness and exhaust note.

If you try and tune it too much you compromise the reliability.

FLYING BANANA · 8th February 2019, 12:16

Welcome to the fountain of knowledge on anything 75/ZT related.

Lord of Hog · 8th February 2019, 13:01

As the Dark Lords Of The V6 have already said, the KV6 isn't an Alfa or a BMW lump, although it is (known issues aside) a reasonably reliable, easily fixed and nice-sounding one. Think about a K&N panel filter or cold-air induction kit (depending on how much under-bonnet sucking you like the sound of) and a stainless-steel cat back exhaust. The system can afford to lose the middle silencer box and stay legal and a custom build can do something about that ridiculous bend where the rear box joins. Again it depends what sort of sound you're looking for. Once past that you're spending a lot of money for not very much change.

SD1too · 8th February 2019, 15:32

Hi Rob and

to the club.

Trikey is right on the button with his advice to you. In addition:

Quote:

Originally Posted by Aikie

It probably needs a new fuel pump and the head gaskets are blown.

I disagree with you on both those points. The fuel pump on the petrol engines is extremely reliable. Why do you think it is faulty?

I doubt very much that the head gaskets have failed. Did the garage tell you that? If so, what are the fault symptoms leading them to that conclusion?

Quote:

He probably has a used V6 that can be used for the first overhaul. This will be the main focus for now.

Eh?

My advice to you on engine tuning is don't!

If you're that way inclined, forget the 75 and buy a ZT instead.

Simon

Aikie · 8th February 2019, 18:23

Thank you all for the reactions. I realise that I didn't mention the whole story, sorry for that. I am totally not familiair with forum discussions.
As I am more on the cruising and confort side, I think I accept the general opinion. I was just looking for a small touch of extra respons and maybe fuel economy, the K&N seems pretty simple. I rather not change the exhaust.

The car has run appr. 125.000 Miles. My experience with my former 75 CDTI was that the endurance of the fuel pump was between 100 - 125 Miles, so that fits the picture. Also the garage of the former owner diagnoses fuel pump failure. The car had to be towed away. By the way, I drove and maintained the Diesel up to 310.000 Miles, and it needed a fuelpump change if I remember it right 3 times.

Furthermore, the car was diagnosed for overheating. The reason for overheating was not found yet, probably further investigation was blocked by the fuel pump failure. When I checked the cooling fluid level, from above it was empty. So further investigation seems necessary before making next steps. As relialibilty is important to me, I want to be at the safe side and that is the reason that I am considering a new HG, of course after diagnosing the course of overheating first...

Main focus for now is bring the car mechanically in good running order and see what other issues must be adressed. The leather interior is for sure one of the issues.

Warm regards,
Rob

chris75 · 8th February 2019, 18:46

Quote:

Originally Posted by Aikie

My experience with my former 75 CDTI was that the endurance of the fuel pump was between 100 - 125 Miles, so that fits the picture. Also the garage of the former owner diagnoses fuel pump failure. The car had to be towed away. By the way, I drove and maintained the Diesel up to 310.000 Miles, and it needed a fuelpump change if I remember it right 3 times...….

………….the car was diagnosed for overheating. The reason for overheating was not found yet, probably further investigation was blocked by the fuel pump failure. When I checked the cooling fluid level, from above it was emptyRob

The kv6 is a very different engine to the CDT

Rather than the fuel pump , the fuel filter in the tank may have come detached . I see your car is a 2003 , and this is a common enough fault which is often confused with a fuel pump problem !
The also common problem for coolant loss is leakage from the plastic thermostat assembly in the vee of the engine ; look for coolant stains in the vee .
I really wouldn't touch the head gaskets if they are ok .

Aikie · 8th February 2019, 18:55

Thnx, that is very usefull Information!

CivilSteve · 8th February 2019, 21:16

The tuning level depends on your budget, non turbo engines will not see the same results as turbo engines BUT you can still improve them. The last ZS180 I did found about 12bhp & 15lbft from the remap.

Best results on the KV6 though come from getting the VIS motors working right, they make a serious torque improvement to the low/mid range.

The below shows a ZS180 with some VIS motor/wiring issues so the owner wanted some improvement to keep him going until his new engine etc is ready.

SD1too · 9th February 2019, 07:57

Quote:

Originally Posted by Aikie

... the car was diagnosed for overheating.

When you get the engine running again you should check that the radiator fan is working properly. It's very likely that it isn't and, coupled with possible loss of coolant in the 'V' as Chris has explained, will lead to overheating and the inevitable incorrect diagnosis that a head gasket is responsible. Here's how to check the fan's operation:

Start the engine from cold.
On the air con./heater control panel, press the windscreen demist button.
Get out of the car and walk to the radiator grille.
Is the radiator fan running continuously (not pulsing on and off)?

Regarding the fuel filter, there's lots of information available about this common problem by searching for 'orange clip' or 'FFS' (Fuel Filter Syndrome). You'll read that the filter does not need replacing, simply tightening and securing.

Regarding engine response and fuel consumption, check your VIS actuators (Variable Intake System). There are two and the 'balance' actuator, if unresponsive or if the flap valve is sticky, makes the engine feel as if it has lost a litre of capacity! Even when running at peak efficiency, the KV6 will not sip fuel.

Simon

8th February 2019, 11:36	#1
Aikie Newbie Rover 75 2.5 V6 Saloon Spectre Join Date: Feb 2019 Location: Holten Posts: 18 Thanks: 5 Thanked 2 Times in 2 Posts	Rover 75 2.5 V6 tuning Dear all, Being new on this forum I hope to be to get familiar with the forum, get acquainted and make progress to bring my newly acquired rover in good condition again. Recently I managed to buy a Rover 75 2.5 V6 manual in Spectre, pretty rare being no. 8 out of 9 in this disguise. Already my 7th Rover. It was difficult to judge the car, battery was flat and it was parked pretty tight. It probably needs a new fuel pump and the head gaskets are blown. My garage will make a first judgement of the car and than we will talk it over. He probably has a used V6 that can be used for the first overhaul. This will be the main focus for now. Here also appears the first question. I am considering a limited tuning and are wondering which technical changes are feasible without changing originality too much (remapping via Kmaps? , adding MG inlet? etc.). Hope the forum can be of help. Later I am thinking of adding the handbrake compensator change (if still available), upgrading the High line navigation and turn the interior in good shape. Warm regards, Rob

8th February 2019, 12:03	#2
trikey Premium Trader Rover 75 Join Date: Nov 2010 Location: Devon Posts: 33,772 Thanks: 8,837 Thanked 14,831 Times in 8,030 Posts	If I were you I’d get the engine sorted to factory spec (get a second opinion on the head gaskets, they rarely fail on a kv6) And enjoy it for what it is, the v6 was never a fast motor, enjoy its smoothness and exhaust note. If you try and tune it too much you compromise the reliability. __________________ Lest we forget..

8th February 2019, 12:16	#3
FLYING BANANA Moderator/Club Shop MG ZT 1.8t+. No.3 of 4 in Sunspot Yellow & Ford Fiesta in Black. Join Date: Aug 2010 Location: Rattler Farm Posts: 22,568 Thanks: 9,270 Thanked 15,645 Times in 6,806 Posts	Welcome to the fountain of knowledge on anything 75/ZT related. __________________ 233,431. That’s our second meet done, no.3 next weekend. onen hag oll

8th February 2019, 13:01	#4
Lord of Hog Gets stuck in Rover 75 2.5 V6 in Wedgwood Blue Join Date: Dec 2015 Location: Felbridge, East Grinstead Posts: 982 Thanks: 250 Thanked 294 Times in 206 Posts	As the Dark Lords Of The V6 have already said, the KV6 isn't an Alfa or a BMW lump, although it is (known issues aside) a reasonably reliable, easily fixed and nice-sounding one. Think about a K&N panel filter or cold-air induction kit (depending on how much under-bonnet sucking you like the sound of) and a stainless-steel cat back exhaust. The system can afford to lose the middle silencer box and stay legal and a custom build can do something about that ridiculous bend where the rear box joins. Again it depends what sort of sound you're looking for. Once past that you're spending a lot of money for not very much change. __________________ Conformity is not morality. Consensus is not truth.

8th February 2019, 18:23	#6
Aikie Newbie Rover 75 2.5 V6 Saloon Spectre Join Date: Feb 2019 Location: Holten Posts: 18 Thanks: 5 Thanked 2 Times in 2 Posts	Agreed Thank you all for the reactions. I realise that I didn't mention the whole story, sorry for that. I am totally not familiair with forum discussions. As I am more on the cruising and confort side, I think I accept the general opinion. I was just looking for a small touch of extra respons and maybe fuel economy, the K&N seems pretty simple. I rather not change the exhaust. The car has run appr. 125.000 Miles. My experience with my former 75 CDTI was that the endurance of the fuel pump was between 100 - 125 Miles, so that fits the picture. Also the garage of the former owner diagnoses fuel pump failure. The car had to be towed away. By the way, I drove and maintained the Diesel up to 310.000 Miles, and it needed a fuelpump change if I remember it right 3 times. Furthermore, the car was diagnosed for overheating. The reason for overheating was not found yet, probably further investigation was blocked by the fuel pump failure. When I checked the cooling fluid level, from above it was empty. So further investigation seems necessary before making next steps. As relialibilty is important to me, I want to be at the safe side and that is the reason that I am considering a new HG, of course after diagnosing the course of overheating first... Main focus for now is bring the car mechanically in good running order and see what other issues must be adressed. The leather interior is for sure one of the issues. Warm regards, Rob

8th February 2019, 18:55	#8
Aikie Newbie Rover 75 2.5 V6 Saloon Spectre Join Date: Feb 2019 Location: Holten Posts: 18 Thanks: 5 Thanked 2 Times in 2 Posts	Thnx, that is very usefull Information!

8th February 2019, 21:16	#9
CivilSteve Avid contributor MG ZT Join Date: Oct 2017 Location: Manchester Posts: 237 Thanks: 20 Thanked 108 Times in 56 Posts	The tuning level depends on your budget, non turbo engines will not see the same results as turbo engines BUT you can still improve them. The last ZS180 I did found about 12bhp & 15lbft from the remap. Best results on the KV6 though come from getting the VIS motors working right, they make a serious torque improvement to the low/mid range. The below shows a ZS180 with some VIS motor/wiring issues so the owner wanted some improvement to keep him going until his new engine etc is ready.