That I might address prophylactically?
Like water pump or the like?
What usually wears out first rings or bearings?

PS: Found a nice datapage on this engine:
http://mywikimotors.com/vk56de-vk56vd/

From a longevity standpoint they're just like the VQ's, except for timing chains and guides I've seen lots of them reach a quarter mil and more. The bottom ends are pretty indestructible. The big weakness in the gen1 Titan/Armada is the diff, not the engine.

Thanks for the quick reply.
So no significant threats from bad cats ceramic ingestion like the V6s?
Do they have the same cats?

Do they have a threat form chains and/or guides then like the VH45de?

PS: this one seems pretty tight... It was noticably overfilled when I picked it up and yet after 1100 miles of driving hadnt lost a drop.
I pulled out .75 quarts today thats how far it was overfilled.

PalmerWMD wrote: ↑

Sat Jan 16, 2021 7:08 pm

So no significant threats from bad cats ceramic ingestion like the V6s?
Do they have the same cats?

You're most welcome as always! Any Nissan engine can inhale a cat, that's a function of using Miller cycling to avoid the need for an EGR valve. The ECM basically uses the IVT to induce exaggerated valve overlap, deliberately sucking a bit of exhaust gas back into the cylinder. This reduces the amount of burnable oxygen in the intake charge, reducing cylinder temperature and preventing NOx from forming. It's very slick and works great right up until you ignore codes from the rear HO2S (which is only there to monitor the cat) and your cat disintegrates. Don't ignore it. When the HO2S tells you a cat is shot, listen and replace it.

Like the VQ's, the later model VK guides have much better materials than the older ones (the march of science). However, the VK chains are long and skinny with hydraulic tensioners just like the big chain on a VQ. Eventually they'll go, accompanied by the usual "bumblebee" warning noise. Same deal, don't ignore that either. The noise is from metal-to-metal contact between the chain and a guide or tensioner (usually the latter), so you ignore it at your peril.

PS - The mains are already 4-bolt, there are plenty of guys running 1000+ hp on stock mains. For big power, only the crank, rods and pistons are usually changed out.

VStar650CL wrote: ↑

Sat Jan 16, 2021 7:39 pm

PalmerWMD wrote: ↑

Sat Jan 16, 2021 7:08 pm

So no significant threats from bad cats ceramic ingestion like the V6s?
Do they have the same cats?

1) When the HO2S tells you a cat is shot, listen and replace it.


2) accompanied by the usual "bumblebee" warning noise. l.

1) I am toying with the idea of replacing cats prophylactically. The car does have 160,000 miles on it.
I have no idea if they have ever been changed.
No CELs of any kind.
2) Do we have a audio file of this?

PalmerWMD wrote: ↑

Sat Jan 16, 2021 8:34 pm

1) I am toying with the idea of replacing cats prophylactically. The car does have 160,000 miles on it.
I have no idea if they have ever been changed.
No CELs of any kind.

At 160K, not a bad idea.

PalmerWMD wrote: ↑

Sat Jan 16, 2021 8:34 pm

2) Do we have a audio file of this?

Dunno but it's hard to miss, a distinct buzz that rises with RPM. Usually hard to hear from inside the car when it first starts, but quickly becomes audible all the time.

VStar650CL wrote: ↑

Sat Jan 16, 2021 9:04 pm

PalmerWMD wrote: ↑

Sat Jan 16, 2021 8:34 pm

1) I am toying with the idea of replacing cats prophylactically. The car does have 160,000 miles on it.
I have no idea if they have ever been changed.
No CELs of any kind.

At 160K, not a bad idea.

PalmerWMD wrote: ↑

Sat Jan 16, 2021 8:34 pm

2) Do we have a audio file of this?

Dunno but it's hard to miss, a distinct buzz that rises with RPM. Usually hard to hear from inside the car when it first starts, but quickly becomes audible all the time.

What are some "good enough" cats that dont break the bank?

For aftermarket I'm partial to Bosal and Eastern Catalytic, both very well constructed and we haven't seen "cheap cat" failures with either one.

Wow nearly a grand for each side of front cats by itself.

PalmerWMD wrote: ↑

Sun Jan 17, 2021 7:52 am

Wow nearly a grand for each side of front cats by itself.

Lots cheaper than a new engine. Not much else you can say on that count.

VStar650CL wrote: ↑

Sat Jan 16, 2021 8:10 pm

PS - The mains are already 4-bolt, there are plenty of guys running 1000+ hp on stock mains. For big power, only the crank, rods and pistons are usually changed out.

6 bolt mains

PalmerWMD wrote: ↑

Sat Jan 16, 2021 10:28 pm

VStar650CL wrote: ↑

Sat Jan 16, 2021 9:04 pm

At 160K, not a bad idea.



Dunno but it's hard to miss, a distinct buzz that rises with RPM. Usually hard to hear from inside the car when it first starts, but quickly becomes audible all the time.

What are some "good enough" cats that dont break the bank?

Why replace cats at all?

kaipo13 wrote: ↑

Thu Apr 01, 2021 2:07 am

Why replace cats at all?

Because 160K is getting up where cats fail, and Nissan engines are all Miller-cycle. Cat failure on a Miller-cycle engine can be a cat-astrophe.

Just replaced the left side manifold (it was leaking) and the cat on that side was of course included.
Was quite satisfied with the price 1050 USD minus a 100 USD cash discount= 950 USD.
This was done at a shop with an excellent reputation and 5 star reviews.

Owner assured me he used quality parts and i believe him due to his rep.

Now the annoying drivers side rasp is gone.

VStar650CL wrote: ↑

Thu Apr 01, 2021 4:39 am

kaipo13 wrote: ↑

Thu Apr 01, 2021 2:07 am

Why replace cats at all?

Because 160K is getting up where cats fail, and Nissan engines are all Miller-cycle. Cat failure on a Miller-cycle engine can be a cat-astrophe.

You misunderstand me, why waste money on cats? Why not just put a straight pipe in? But yes, Titans/Armadas have had their VKs die early deaths due to cats... & fuel pump failures...

PalmerWMD wrote: ↑

Fri Apr 02, 2021 5:45 pm

Just replaced the left side manifold (it was leaking) and the cat on that side was of course included.
Was quite satisfied with the price 1050 USD minus a 100 USD cash discount= 950 USD.
This was done at a shop with an excellent reputation and 5 star reviews.

Owner assured me he used quality parts and i believe him due to his rep.

Now the annoying drivers side rasp is gone.

You are on borrowed time, factory style exhaust manifolds fail regularly (aftermarket or OEM). Buy/make quality headers - this is a known defect/failure point with VK56DEs... JBA makes the cheapest, aftermarket replacements... Cat delete and long tube headers is the common place, accepted fix for these engines in Titans/Armadas. Make sure you tune if you take the leap.

kaipo13 wrote: ↑

Mon Apr 05, 2021 1:30 am

You misunderstand me, why waste money on cats? Why not just put a straight pipe in? But yes, Titans/Armadas have had their VKs die early deaths due to cats... & fuel pump failures...

I dunno where Palmer lives, but straight pipes aren't legal in most states. Maybe he cares about the air, too -- a cat-less engine literally puts out tens-to-hundreds of times the pollutants, depending which pollutant you're talking about.

kaipo13 wrote: ↑

Mon Apr 05, 2021 1:32 am

PalmerWMD wrote: ↑

Fri Apr 02, 2021 5:45 pm

Just replaced the left side manifold (it was leaking) and the cat on that side was of course included.
Was quite satisfied with the price 1050 USD minus a 100 USD cash discount= 950 USD.
This was done at a shop with an excellent reputation and 5 star reviews.

Owner assured me he used quality parts and i believe him due to his rep.

Now the annoying drivers side rasp is gone.

You are on borrowed time, factory style exhaust manifolds fail regularly (aftermarket or OEM). Buy/make quality headers - this is a known defect/failure point with VK56DEs... JBA makes the cheapest, aftermarket replacements... Cat delete and long tube headers is the common place, accepted fix for these engines in Titans/Armadas. Make sure you tune if you take the leap.

Good input,.. if/when the problem reoccurs I will have to strongly consider it.

VStar650CL wrote: ↑

Mon Apr 05, 2021 5:42 am

kaipo13 wrote: ↑

Mon Apr 05, 2021 1:30 am

You misunderstand me, why waste money on cats? Why not just put a straight pipe in? But yes, Titans/Armadas have had their VKs die early deaths due to cats... & fuel pump failures...

I dunno where Palmer lives, but straight pipes aren't legal in most states. Maybe he cares about the air, too -- a cat-less engine literally puts out tens-to-hundreds of times the pollutants, depending which pollutant you're talking about.

I move around a bit, so passing emission is important to me.
I am also not too keen about creating lots of extra ir pollution but it the problem keeps reoccurring then...

Also I was told my vehicle has California emissions.
Would that not mean it is more sensitive to no stock emissions and will throw an SES?

PalmerWMD wrote: ↑

Mon Apr 05, 2021 7:22 am

Also I was told my vehicle has California emissions.
Would that not mean it is more sensitive to no stock emissions and will throw an SES?

Yep.