VK56 crankshaft into VH45?

[David Steele]

Is this even possible?

I like to do this but I have no idea if it would fit.

[maxnix]

The bore centers and journal sizes are different, but with enough money.....

Don't know why one would want to turn the VH45DE into a low revving truck. Even with the Impul stroker kit to 5.1L, the top end drops to 5600 rpm.

[David Steele]

The bore centers and journal sizes are different, but with enough money.....

Don't know why one would want to turn the VH45DE into a low revving truck. Even with the Impul stroker kit to 5.1L, the top end drops to 5600 rpm.

The sooner the power comes on the better, I rather stroke and bore.

I didnt know the bore spacing was different.

In that case.... I'll just have my cranktshaft modified professionally.

[elwesso]

The sooner the power comes on the better, I rather stroke and bore.

[sijoko]

The bore centers and journal sizes are different...

Where did this info come from?

The main journals are the same size as the VH45. The rod journals are bigger at 2.1247-2.1250 inches.

The bore centers should be the same as the VK45DE. The main difference between the VK56 and VK45 are increased deck height (maybe?) and the larger bores, along with the elimination of variable cam timing and the titanium valves.

Here's an excerpt from an article on the VK56DE:

"One of those objectives--a 9,400-pound towing capacity--was especially ambitious. Fortunately, Nissan had a V-8 engine and 5-speed automatic in production for Infiniti Q45 and M45 luxury sedans to serve as a suitable starting point.

The initial plan was to convert the block material from aluminum (with cast-iron cylinder liners) to iron as a cost-savings measure. That idea was scrapped when weight and fuel economy became an issue, so the final VK56DE V-8 keeps the light-alloy block and head from the parent Infiniti VK45DE design.

In the interests of durability, the forged steel crankshaft supported by cross-bolted main bearings also made the leap. Two features that did not were the exotic titanium valves used to sustain the vehicle's 6,700 rpm redlines and variable valve timing.

To meet torque and power requirements, Nissan engineers stretched bore and stroke dimensions to their practical limits. Boosting the bore from 93 to 98 mm and stroke from 82.7 to 92 mm bumped piston displacement from 4.5 to a more meaty 5.6 liters.

Topping the reconfigured V-8 is an ultra-long-runner composite-plastic intake manifold, the second measure aimed at plumping up the torque curve at the low end where pickup truck owners live and work.

Lowering the compression ratio from 10.5 to 9.8:1 dropped the fuel requirement from premium to regular unleaded."

[David Steele]

I knew I should've asked for some proof.

Hmm I need some much more definite info I dont want to buy a VK to find this out, guess I'll stick to the plan.

[elwesso]

I would think that it would be about the same price to have your crank modified than it would be to buy a VK crank

[defrag010]

what article is that from? I've never seen any production engine come with titanium valves, and I won't belive that until proven wrong.

[irax]

no it did not come from factory with ti valves

[sijoko]

The article is old. It came out just before they released the Titan.

In regards to the titanium valves on the VK45: All the literature shows that to be true.

I also found some weights for the VK45 valves:

- Intake = 31.5g - Exhaust = 28.9g

Don't know how accurate they are. I got them from here:

http://forums.maxima.org/showthread.php?t=362910

[CRACKD]

If the VK45 does have titanium valves are they suited to turbo applications? As I thought stainless or super alloy was the preferred material due to heat

[elwesso]

I would think the VH's sodiumfilled valves would be better than titanium?

[CRACKD]

Well only the exhaust would be sodium filled, but the weight of the titanium will lend itself to higher rpm for turbo applications

[sijoko]

I was checking out the prices for intake & exhaust valves for the VK45DE.

Infiniti of Scottsdale has them at ~ $22 for the intake and ~ $34 for the exhaust.

Does that price sound good for titanium valves? I am assuming that they are titanium.

[maxnix]

The sooner the power comes on the better, I rather stroke and bore.

Then get electric, steam or diesel. All better at low rpm for torque delivery.

Data is from memory of some other discussions, but I will check VK45DE specifications as VK56DE is mostly a stroker version.

[David Steele]

Then get electric, steam or diesel. All better at low rpm for torque delivery.

I'll do whatever the hell I want to do you'r re no longer contributing.

[mtcookson]

Well only the exhaust would be sodium filled, but the weight of the titanium will lend itself to higher rpm for turbo applications

Not only that, but quicker revs as well. A Maxima guy modded his head and such quite a bit to fit those valves in and he mentioned the difference in how fast it revs alone was a huge improvement.

[elwesso]

did he do mods to juts fit those valves, or a bunch of other stuff including the valves.

[sijoko]

Well, I was checking out the valve measurements on the VH45 and the VK45.



Intake Valve head diam:...1.496 - 1.504........1.417 - 1.429 Intake Valvelength: ......4.0039 - 4.0276........3.8020

Intake Valve stem diam...0.2743 - 0.2744......0.2351 - 0.2354

Intake Valveseat angle: ..45.15 - 45.45........45.15 - 45.45


Modified by sijoko at 3:03 PM 7/19/2006

[mtcookson]

did he do mods to juts fit those valves, or a bunch of other stuff including the valves.

He did quite a few other mods... but I don't know if at the same time or not. I know he said for sure that the valves made quite a difference.

[defrag010]

he wouldn't have noticed the higher revving from the valves alone.. the only thing Ti valves allow for is the use of softer valve springs and more heat rejection under heavy duty use. they don't have as big of an affect on reciprocating weight because they don't weigh very much to begin with, and they are spinning at only half of the crank speed.Where you will notice a faster revving engine from using Ti valves is by the use of lighter valve springs (think lighter than stock) for less load on the camshaft as it turns.

For example, brand X steel valve at a given weight would require a 300 lb spring to sustain say 8000 rpm, but a Ti Brand Y valve (which is half the weight), would only need for example a 220 lb spring to sustain 9500 rpm.

[mtcookson]

I believe his car retained the stock valve springs. I'll have to search for it though.

[biohzrd]

http://www.titantalk.com/forum...=9361

this should shed a little light on this subject..... actually what i am working on is the oppisite. i'm putting a vk45 crank into a vk56 block. shorter stroke for higher rpm's, but with better dynamics. this will be due in part to the larger bore( unshrouds the valves) and longer rods which creates more piston dwell at tdc..

[biohzrd]

another link for you guys...

http://www.flzclub.com/vk56de/http://ww ... om/vk56de/

[maxnix]

I'll do whatever the hell I want to do you'r re no longer contributing.

By all means! Fortunately civil personal freedom is not indexed to mental capacity.

[ultrapulse]

So tell me where can I get a VK56 crank for less than the new price I was given of US$3700 from Courtesy Nissan!

I have emailed John Dixon about his crank but not had a reply.

[David Steele]

By all means! Fortunately civil personal freedom is not indexed to mental capacity.

Was I with holding your freedom? You think too hard and this is also outside the subject of this thread. 4 stroke DOHC V8 Nissans's only please.

Recommendations of the non Nissan sort isnt helping / contributing.

[Mettler]

4 stroke DOHC V8 Nissans's only please.

Recommendations of the non Nissan sort isnt helping / contributing.

Kinda like trying to compare Nissan's VTC to Honda's VTEC ?

/stir

Take it easy man, speculating about putting the crankshaft from one motor into a completely different generation motor doesn't seem entirely logical to me. All you'd gain from a significantly increased stroke would be much higher fuel consumption, your redline would drop bigtime... taking away one of the main characteristics that make Nissan V8's so awesome & such a cult engine (the ability to rev like hell), and then you'd lose a lot of efficiency since the cams would be completely wrong for the new engine configuration.

And that's not even taking into account the fact that it might not fit at all, would require considerable custom engineering to get it to fit, totally new rods and pistons, cams, heaps of head work, change the injectors, reprogram the computer, etc.... It would no longer be a sports motor, but a towing motor.

Seems like it would cost up to and beyond $10k to do, for which you could nicely twinturbo 4.5, or supercharge it, or even probably buy a complete VK56... it's a superfluous flight of fancy, and seems like a waste of time even discussing it.

[David Steele]

By the way I was comparing Honda i-vtec Active cam gear not the lift control.

Mettler your giving me advice on my plans, no thanks. I'll be fine in that subject.

High fuel consumption you say. well more air more power, its comprimised, wanna save gas keep your foot off the pedal.

I have a couple things to say.

Rev like hell? No thanks dont need to rev higher with the right stuff. I dont want a peaky engine with a high lift camshaft that makes your low end suffer greatly. Stroke and bore, the basics to kicking the *** of the smaller engine. You have no idea what I was planning to do with this motor. Towing motor? How did you know I wasnt going to modify the rod stroke ratio for less angle and aswell as move the piston pin up in result having a longer rod which basically. Gives me something better than the orginal with more displacement.

Cost? IFthats the problem I would've gotten something with some aftermarket love instead of the ''one off'' custom parts engine.

[biohzrd]

So tell me where can I get a VK56 crank for less than the new price I was given of US$3700 from Courtesy Nissan!

I have emailed John Dixon about his crank but not had a reply.

http://www.car-part.com