4.2 engine - internal mods?

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m1980k

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Been Googling around for build threads or other info from people who've made internal mods to the 4.2 engine (boring out to 4.7 etc.) but can't find much. Seems there's a German outfit called Leo Nardo who do/did this. Anyone got any knowledge of this type of mod? Cost?

Don't think I'll do this with the GS due to it's... ahem, investment grade status, but I can see a 500bhp n/a, manual '05 facelift 4200 as being a permanent keeper in a future where a stick and lack of turbos will be a distant memory... This would be a long term project for me, but need to start my research so I can keep and eye out for the right car, possibly a Cat car.
 
Zep

Zep

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Not been done yet to my knowledge.

Theoretically the liners and therefore the pistons from the 4.7 will fit in a 4.2 block. I believe the 4.7 crank also has a different throw so would also be needed. That leaves crank journal sizes plus clearances for the rods to the block and clearance to windage plates in the crankcase to worry about and engine management recalibration. Not beyond the wit of man but certainly an expensive exercise.

If you do it I will certainly read with interest..
 
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m1980k

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CatmanV2

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Zep said:
Not been done yet to my knowledge.

Theoretically the liners and therefore the pistons from the 4.7 will fit in a 4.2 block. I believe the 4.7 crank also has a different throw so would also be needed. That leaves crank journal sizes plus clearances for the rods to the block and clearance to windage plates in the crankcase to worry about and engine management recalibration. Not beyond the wit of man but certainly an expensive exercise.

If you do it I will certainly read with interest..
Click to expand...

Aren't all the 4.7s wet sump as well? Will that matter?

C
 
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MAF260

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I've looked into this in a fair amount of detail and although the basic block is the same, there are too many unknown variables to be certain you could just throw 4.7 crank, liners and pistons in with no issues. As Zep says, the electronics may also throw up some problems due to the internal changes. I've been on the lookout for a 4.7 engine as the gathered wisdom suggests this would likely deliver the highest chance of success. The main issue is that I haven't yet found one for less than £5k and for just 40bhp more I don't think it's worth it. I'm also concerned about variator issues with one of these engines (which could be the reason it's become available!) as I think all 4.7s are wet sump?

I now need to find some time to investigate superchargers properly....
 
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m1980k

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Looks like I'm going to have to have a chat with the guys in Germany. This seems to be a standard job for them and includes ECU etc, but I suspect it will be expensive.

I'm way out of my depth here, but I don't believe that the process would be a simple case of turning the 4.2 into a copy of the 4.7 - it would be more of a custom mod of the 4.2. Can't see why dry sump would be a problem and I think dry sump might be 'better' anyway.

Really don't want to go down the forced induction route. Much as I love the looks of the 42/GS, the thing that brought me to these cars was the N/A engine. Want to keep that.
 
Zep

Zep

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CatmanV2 said:
Aren't all the 4.7s wet sump as well? Will that matter?

C
Click to expand...

Yes, but only because the crank might not clear the "sump" as it will be a lot shallower than a wet sump. I expect you would have to retain the 4.2 block to suit the alternate oil system.
 
Zep

Zep

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MAF260 said:
I've looked into this in a fair amount of detail and although the basic block is the same, there are too many unknown variables to be certain you could just throw 4.7 crank, liners and pistons in with no issues. As Zep says, the electronics may also throw up some problems due to the internal changes. I've been on the lookout for a 4.7 engine as the gathered wisdom suggests this would likely deliver the highest chance of success. The main issue is that I haven't yet found one for less than £5k and for just 40bhp more I don't think it's worth it. I'm also concerned about variator issues with one of these engines (which could be the reason it's become available!) as I think all 4.7s are wet sump?

I now need to find some time to investigate superchargers properly....
Click to expand...

I agree completely, supercharging is the route of least resistance.

I imagine a wet sump would stick out of the bottom of the car, so I reckon you would have to strip both engines, measure everything and if it fits do a dummy build to find the wrinkles, probably a bunch of machining and then put it together. The benefit of keeping the 4.2 block and heads would be the lack of variation issues but even then the combustion chambers would need relieving to match the volume of the 4.7 (if different). Every word here has an huge potential cost associated with it. All for 40 bhp and a bit more torque.

A centrifugal supercharger would probably be a reversible mod too.
 
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m1980k

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Zep said:
I agree completely, supercharging is the route of least resistance.

I imagine a wet sump would stick out of the bottom of the car, so I reckon you would have to strip both engines, measure everything and if it fits do a dummy build to find the wrinkles, probably a bunch of machining and then put it together. The benefit of keeping the 4.2 block and heads would be the lack of variation issues but even then the combustion chambers would need relieving to match the volume of the 4.7 (if different). Every word here has an huge potential cost associated with it. All for 40 bhp and a bit more torque.

A centrifugal supercharger would probably be a reversible mod too.
Click to expand...

Leo Nardo quote 520PS for the 4.7 conversion (which includes other internal mods - camshafts, valves, crank), ECU, fuel cooling, sports exhaust, air filter etc. So 120bhp over the stock engine! And this would be more of a track/fast road car so happy to sacrifice some drivability for top end craziness.
 
rossyl

rossyl

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m1980k said:
Been Googling around for build threads or other info from people who've made internal mods to the 4.2 engine (boring out to 4.7 etc.) but can't find much. Seems there's a German outfit called Leo Nardo who do/did this. Anyone got any knowledge of this type of mod? Cost?

Don't think I'll do this with the GS due to it's... ahem, investment grade status, but I can see a 500bhp n/a, manual '05 facelift 4200 as being a permanent keeper in a future where a stick and lack of turbos will be a distant memory... This would be a long term project for me, but need to start my research so I can keep and eye out for the right car, possibly a Cat car.
Click to expand...

Everything by Leonardo costs a LOT.
 
2b1ask1

2b1ask1

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Fuel cooling????

You atomise it as it is injected, how much cooling could it have?
 
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m1980k

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rossyl said:
Everything by Leonardo costs a LOT.
Click to expand...

£5k? £10k? £15k? more....? Gonna email them anyway... But there's got to be someone else out there who's worked on these engines, even if the cars are rare.

Seems like they're more into modding in the US, but more likely to just whack turbos or superchargers on.
 
2b1ask1

2b1ask1

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Personally I find the power very usable on these, much more and you will find it difficult and hard going on the road. Ok it may not out drag everything and there are those track days but it is a Grand Tourer. Also it think if I was looking at a major power gain I would seriously upgrade the brakes first, starting with the master cylinder/servo...
 
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m1980k

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2b1ask1 said:
Personally I find the power very usable on these, much more and you will find it difficult and hard going on the road. Ok it may not out drag everything and there are those track days but it is a Grand Tourer. Also it think if I was looking at a major power gain I would seriously upgrade the brakes first, starting with the master cylinder/servo...
Click to expand...

Yes, just trying to figure out total cost of Cat car + exhaust with sports cats + brakes + coilovers + lightweight wheels + sports seats + the engine mods + sticky tyres + lightweight bonnet. 500bhp and a bit less weight has a lot of appeal for me!

I think I come at these cars from a different angle to most - I see it as an engine with an attractive body and reasonable handling. Not interested in wafting. I reckon turning the engine up to 11 and then doing everything else to keep it on the road would be a good formula...
 
2b1ask1

2b1ask1

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I knew someone who did 'improvements' to a succession of Scoobies and Evo's every time he bought one to the point they became undrivable then he'd sell them and start again... Bonkers.
 
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m1980k

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2b1ask1 said:
I knew someone who did 'improvements' to a succession of Scoobies and Evo's every time he bought one to the point they became undrivable then he'd sell them and start again... Bonkers.
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So Newton, you're not gonna buy this car from me when I'm done with it?! Maybe MAF would...

But seriously, I think there's something to be said about building the ultimate n/a, manual, hydraulic steering sports GT. Ferraris have turbos now. Porsche have resurrected the n/a manual car, but it's pricy and likely to get pricier as the numbers are limited. And it has EPAS.

I'm not talking about a laggy, overpowered dragster here. Bit more power, better suspension and brakes. What's not to like?
 
2b1ask1

2b1ask1

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No I'm happy with mine, stock handling just liberated breathing... One day I may invest in a track day car but that would be trailered to the track I think and 'very' tracked out!
 
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