Stx550 engine swap options

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Billyburnout

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Not surprising to anyone on here most likely, I have a low km navara d40 with run bearings. Don't want to put another v9x in there as too expensive and just too much of a gamble. Does anyone know of a common or easy swap utilizing the existing running gear? Would consider V8 Nissan petrol or LS if not. Live in Dunedin, New Zealand
 

Old.Tony

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The V9X engine bolts onto an RE7 gearbox which is used in the 370Z if memory serves. Is that a possibility?

If $ weren't an issue, grab a V8 from a Nissan Titan. Chris Forsberg wouldn't argue. You'll need to carry spare rear tyres.
 

Billyburnout

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The V9X engine bolts onto an RE7 gearbox which is used in the 370Z if memory serves. Is that a possibility?

If $ weren't an issue, grab a V8 from a Nissan Titan. Chris Forsberg wouldn't argue. You'll need to carry spare rear tyres.
Hi Old.Tony, I have thought about the 3,5/3.7 petrol. Does anyone have any advice on the ease of transplant? Finding an engine that can mate to the existing auto/transfer case sounds easier/cheaper, but thoughts that the auto box/diffs etc will not suit the hi revving/lower torque petrol engine? Will using the 370z ECU sort the auto characteristics, diffs aside? Still open to V8 options that may or may not be able to use the Re7r01b trans. Also any experience from anyone who has rebuilt the v9x (successfully). I have romantic thoughts of building a fire breathing V8 but should a more practical and less expensive option present itself, I'll take it.
 

Billyburnout

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This is going to be interesting
good luck Billy and welcome to the forum :)
Hi thanks and no offense meant against the V9X if you're a fan, but having seen the bottom end with my own eyes, not keen to give Renault any more money down that rabbit hole.
 

Old.Tony

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Hi Old.Tony, I have thought about the 3,5/3.7 petrol. Does anyone have any advice on the ease of transplant? Finding an engine that can mate to the existing auto/transfer case sounds easier/cheaper, but thoughts that the auto box/diffs etc will not suit the hi revving/lower torque petrol engine? Will using the 370z ECU sort the auto characteristics, diffs aside? Still open to V8 options that may or may not be able to use the Re7r01b trans. Also any experience from anyone who has rebuilt the v9x (successfully). I have romantic thoughts of building a fire breathing V8 but should a more practical and less expensive option present itself, I'll take it.
The reason for mentioning the 370Z motor is the gearbox in your Nav is the same gearbox used in the 370Z, so not only will it bolt on, but the box will handle what you throw at it.

You might have an issue with 4WD though. The 370Z understandably doesn't have 4WD and we already know there's a programming issue in the RE7 box where something uses the same code as the STX550's 4LO signal which causes (in the STX550) to upshift only in 4LO even when manual mode is selected. I couldn't predict what putting a 370Z ECU into a STX550 is going to do when you hit 4LO (to the TCM in the gearbox) - I am fairly certain that the 370Z's ECU won't know about the transfer case!

This means you might have to employ @raptorthumper 's solution for changing transfer case modes, but otherwise there's only the engine bay size to consider, plus a change in fuel tank. The rear diff will probably cope with the extra power (it's a fair size diff, but consider the possible need to grab a Titan diff) but the front may not, Nissan opted for a fairly light diff up front but as long as you don't lift a front wheel and spin it, you ought to be okay there.

Other issues like air conditioning, power steering etc should be solvable with some imaginative plumbing. The radiator ought to provide more than enough cooling.

I have no information about engine mounts from the 370Z and certainly don't know if NZ regs allow you to modify the mounts in the Navara engine bay if needed to accommodate the 370Z powerplant.
 

Adhaul

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Hi thanks and no offense meant against the V9X if you're a fan, but having seen the bottom end with my own eyes, not keen to give Renault any more money down that rabbit hole.
Hey "Billyburnout" what's your opinion of the V9X bottom end, mine for the record is that the crank mains are too narrow and don't seem to handle the load, it also seems that 220k is the limit when they quit.
 

Billyburnout

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Hey "Billyburnout" what's your opinion of the V9X bottom end, mine for the record is that the crank mains are too narrow and don't seem to handle the load, it also seems that 220k is the limit when they quit.
Hi Adhaul, I am not an expert by any means, but the mains are an odd design and too small imho. A couple of local reputable engine rebuilders have said that grinding the crank and rebuilding is a low success fix on these. It's a lot of work to do for a gamble, but would love to hear any stories of success from the audience.
 

Billyburnout

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Hi Adhaul, I am not an expert by any means, but the mains are an odd design and too small imho. A couple of local reputable engine rebuilders have said that grinding the crank and rebuilding is a low success fix on these. It's a lot of work to do for a gamble, but would love to hear any stories of success from the audience.
Mine has 78000 KMS but was fubar'd through incorrect oil - long, sad story.
 

Adhaul

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Hi Adhaul, I am not an expert by any means, but the mains are an odd design and too small imho. A couple of local reputable engine rebuilders have said that grinding the crank and rebuilding is a low success fix on these. It's a lot of work to do for a gamble, but would love to hear any stories of success from the audience.
I’ve rebuilt mine and it’s running well, however I believe that the main bearings are too small, I chipped mine and 50,000 km later- failure, many reports of longevity with no chip , but love the extra power
 

Billyburnout

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I have found a good VK45VE petrolV8. Can anyone tell me if this will mate to the 7 speed RE7 trans from the stx550? I'm sure the Titan VK56 does.
 

Cowboy550

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Hello Billy wonder how the motors will go ? they has a lot more KW but less NM, how about the length of a V8 compared to the V6 ?
 

Cowboy550

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Great video GMG, answers the my question about length even thow they removed the pump or injectors to get it to fit nice, he says the DD is 400NM dosnt look like a 550
 

GunMentalGrey

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Was just the first thing I found when I googled d40 v8. No idea if they have more info on other videos or anything. Given the OP is in NZ,may be able to get in touch with the video channel and get more info too.
 
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