VH's un-rebuildable after rod knock?

[Dammitboy]

I been reading around for a bit now and have come across several post saying after knocking, or other serious issues, these motors are "past the point." Is this really true, or am i missing something here?

Thanks!

[Q45tech]

You have to balance the cost of a JDM takeout [plus it's rehab] with what you already have.The question is how many years do you want the engine to last after the work is done?

Fairly simple to replace rod bearings from engine bottom selecting the perfect match and securing oversizes can be difficult. All assumes zero crank damage.

[Dammitboy]

Valid points Q45tech. Of course, I'd like it to last forever! But if there is crank damage, can it be serviced?

Thanks!

[carfrk666]

theres nothing in the world that cant be fixed or rebuilt, just depends on how badly you want it done, i spun 2 rods on my crank, ground the crank and resized the rods and put undersized bearings in and presto

[darinz]

I haven't done it yet but apparently there are 4 different size bearings for the VH available in NZ. My plan is to pull the crank and get it ground udersize to open the clearances and allow more oil in. That seems to be the key to getting them to survive when offroad.

[gs14racer]

^^^^^ exactly the stock specs suck for what we do with them, that why they spin rod bearings, they are to tight. They need to be opened up.

[CrazyTrance]

I would tend to agree with them needing to be opened up a bit for abuse. I've got two engine's i've acquired that i haven't taken apart yet, but both have spun bearings from high rpm abuse. Only makes sense, along with the head getting loaded up with oil...

[Bart]

I would tend to agree with them needing to be opened up a bit for abuse. I've got two engine's i've acquired that i haven't taken apart yet, but both have spun bearings from high rpm abuse. Only makes sense, along with the head getting loaded up with oil...

To stop the head loading up with oil you could use a scavenge pump right? Scavenge from the head to the sump?

[Mettler]

Hmmm, getting ideas for a new sticky thread about recommended reliability mods for VH engines to be thrashed.

I'm running standard size big end journals and standard size bearings, I bloody hope I don't end up spinning any, seriously can not be bothered with another rebuild. lol

[Bart]

Hmmm, getting ideas for a new sticky thread about recommended reliability mods for VH engines to be thrashed.

I'm running standard size big end journals and standard size bearings, I bloody hope I don't end up spinning any, seriously can not be bothered with another rebuild. lol

We need someone with cash and balls to take these engines to the limit, Nizpro has done such extreme things but it’s not like they’re going share their R&D

[Dammitboy]

I haven't done it yet but apparently there are 4 different size bearings for the VH available in NZ. My plan is to pull the crank and get it ground udersize to open the clearances and allow more oil in. That seems to be the key to getting them to survive when offroad.

Darinz, any way to get a link for those different size bearings? That would be great!

[Mettler]

We need someone with cash and balls to take these engines to the limit, Nizpro has done such extreme things but it’s not like they’re going share their R&D

A certain jetboat owner here in NZ has... it was previously 830HP NA, and is now twin turbo and putting out around 1500HP.

[Bart]

A certain jetboat owner here in NZ has... it was previously 830HP NA, and is now twin turbo and putting out around 1500HP.

Yesvery good point, i think i know who you mean, he posted here couple of times.What his contact details? He would be good to get in touch with.

[CrazyTrance]

To stop the head loading up with oil you could use a scavenge pump right? Scavenge from the head to the sump?

$$$$ lol.

I'm running standard size big end journals and standard size bearings, I bloody hope I don't end up spinning any, seriously can not be bothered with another rebuild. lol

Be careful lol. On the engine's i have I believe one of them happened after the guy went over some rumble strips on a track and banged up the pan. The other one he said only lasted about 10-15 minutes of abuse...

As with all things i think it's luck of the draw as well. My engine has held up pretty well so far with 170k+ on it *knocks on wood* although i hardly let it bounce off the limiter when drifting.

And just some food for thought. The two engines that blew were 94+ engines with the oval intakes and better injectors. And mine is a 92 i believe with the plastic guides and siamese intake ports. Not sure if that makes any difference but i thought i'd throw it out there. But to my benefit I must mention that the previous owner looks to have taken VERY well care of it. The heads are immaculate and the guides were already replaced with metal backing ones.

I wonder if tolerances changed slightly when Infiniti did their re-design of the VH.

[Bart]

[QUOTE=CrazyTrance]

$$$$ lol.

Not really, I wasn’t taking about a dry sump pump, I meant these guys, they use electric pumps for turbo oil scavenge, and it is a gear type pump not diaphragm so it will last for ages. This could be used to pull the excess oil from the head if you’re using a wet sump. I bought the middle sized one for around $300

http://www.rbracing-rsr.com/oilsystems.htm

[dsagers]

Have you considered an Accusump (sp)?

[Dammitboy]

Correct me if I'm wrong, but is an Accusump only good for start up lubrication only?

Since were talking about bearing clearances also, what would be an "ideal" clearance? Being in the upper looser limits of factory specs, or even past that?

[kingkilburn]

Accusumps can be used to boost oil volume and pressure when for what ever reason you lose either.

[dsagers]

Accusumps can be used to boost oil volume and pressure when for what ever reason you lose either.

Drag racers use them to maintain oil pressure during launch when all the oil is climbing the up the inside walls of the block, autocross guys use them because of the numerous abrupt hard turns, which send the oil away from the oil pump pick up. Circle track guys use them as a poor man's dry sump to save their expensive engines.