V6 Conversion For Vb To Vk

[vk3800]

Due to the number of people wanting to know about V6 conversion to VB to VK's I creared the below.
Anyone with additional things, bits i've missed or better ways of doing this, let me know and i'll adjust the thread.


Below is a step by step process to converting a VB>VK from original motor to a VN>VS V6.
Note: This is based on a VK conversion and there are other ways of doing the coversion. Some of which are better than what is out line below and some are not. This is to be used as a guide only and individuals should always check with their local/ state authorities before comencing any work.



Step 1 – Research and parts
• Consult an engineer that will do the job. It always better to take to them first, then to do the job and have to change it afterwards.
• Buy a complete VN/VS Commodore. This will give you most if not all of the part that will be required form the job and works out cheaper in the long run and what you don’t use you can sell to the wreckers or call the scrap metal man.
• Get a wiring loom adaptor. This will allow you to basically plug the VN engine loom into the VK car loom. You can get this from V6 Conversion in Moore http://www.v6conversions.com.au/ . Alternatively you can do the wiring your self or get a similar adaptor from other similar outlets eg Castlemain Rod Shop.
• Get a new gear box cross member. You will need one for both the auto and manual gearboxes. You could make your own or you can get this from V6 Conversions as well.
• Get a new radiator. I use a V8 VH/VK one as it bolts in and the hoses line up. You can use the one from the donor car but modifications to the supports of the VB>VK will be required as the bottom outlet hose on the radiator is to low.
• If you car is a carbie, which it probably is, you will need to change the fuel tank and add a fuel line. The VN fits in, but to me the VL tank is easier, as I know that it won’t be a problem to fit. The fuel line you may be able to take from the VN car if not get one from a VB/VK.

Step 2 – Starting the project
• Remove VK engine and gear box. This includes the radiator, tail shaft etc
• Remove the VK engine frame and front suspension, will need to provide support to car at this point by means of car stand or similar.
• Remove EST computer. Found behind passengers kick panel

This will leave you with an empty engine bay.

At this point you should decide if you are going to want your VK engine bay look like a VN. If yes you’ll need to move, or provide a new, battery bay on the other side of the car. If you don’t move the battery, you will need to extend the power wire to the battery. The VN battery is located on the right not the left side of the car.
As most engineers these day a very strict on what they will past, it’s probably a good idea to shift the battery to the other side.

Now would also be the time to paint the engine bay if you want to.

Step 3 – the donor car.
• Remove engine, gear box and engine frame, including the front suspension from VN car
• Remove radiator bottles, fuse box, etc
• Keep donor car around until conversion is complete. You come back to the car for other parts later on.

Step 4 – the transfer.
• Bolt engine frame from VN into VB>VK. This bolts up exactly the same as the VK one did. Do your best to get it as straight as possible, eg no twist in it, as any twist will put your wheel alignment and tracking out, eg car will put to one side.

If you leave the engine frame and front suspension bolted together then you should be able to bolt the whole assemble into the VK in one go.
Edit 1: As discussed below, the VS suspension can be fitted to the VB>VK. But for practicality and cost of the conversion, it would be easier to use the VN suspension or use the VB>VK as they bolt up to the VN K-frame.

Step 5 – installation
• Fit VN computer and wiring
• Drop motor and gear box into the VK and bolt up.
• Modify your VN tail shaft to suite. On mine I had the end shortened and the VK end fitted so it would bolt up to the diff. The rest of the tail shaft will bolt into place.
• Change your fuel tank over to the VN or VL which ever way you go about it.
• Add the extra fuel line. Just open the clips that hold you current fuel line in and add the extra line and close the clips back up. This is needed as fuel injection has a return line to the tank for the fuel that doesn’t get used.
• Wire into VK electrics. This could be part of the wiring loom adaptor from V6 conversions, not sure as I had an auto elect’ do mine.
• Connect water hoses up. If you go with the VH/VK V8 radiator the VN V6 hose should fit. Don’t forget your heater hoses.
• Air intake. If you’ve move the battery to the other side, then the standard VN air box and pipes should fit in nicely. May need to drill some holes in the location of the old battery to fix the air box in. Engineers don’t like pods unless it’s enclosed.
• If you use an auto box, make sure you connect the speed sensor. If you don’t the car will shut down at about 45km/h as the computer thinks you doing 245km/p
• Connect speedo up. This can be down a couple of ways. They way that I did mine was to change the gearing on the end of it one from a Falcon. This only works as mine has the manual gear box. V6 conversions should be able to help if your using an auto.
• Connect your exhaust up. This is up to you. I use the VN one and had it modified to fit under the VK. You might want a complete custom exhaust.



I can’t remember much more, as it was a couple of year ago that I did mine. But there’s all the tiding up bits to do and get it engineered and blue slipped.
hope this is of help to thise that are concidering the conversion.

[immortality]

you can't use the VR/VS suspension as it has a wider track then the VN/NP and also the top strut mount is different

[blakestone01]

Thanks for the info mate its very helpfull! I was just wondering if have you got a rough figure of how much you spent on everything all up?

[Mickey Maj]

you can't use the VR/VS suspension as it has a wider track then the VN/NP and also the top strut mount is different

It can be done with a bit of modification. Tyres still fit inside the guards as i have pumped them out a tad. I also fitted the VR diff an fits nicely with slightly pumped guards.

[vk3800]

blakestone01 Thanks for the info mate its very helpfull! I was just wondering if have you got a rough figure of how much you spent on everything all up?

Can't remember how much it was now. But it can be done pretty cheaply these days.
Buy a wrecked car, preferably with no front damage. Should be able to pick one up for under $500.
Engineers certificate, think mine was $350.
Depending on how you go with wiring loom and gear box mount etc, you should be able to do the conversion for around $1000 to $1500 back on the road. Could even be less.
PM some of the members that have done it recently to find out how much it cost them.

[vk3800]

Mickey Maj Quote:

Originally Posted by immortality
you can't use the VR/VS suspension as it has a wider track then the VN/NP and also the top strut mount is different

It can be done with a bit of modification. Tyres still fit inside the guards as i have pumped them out a tad. I also fitted the VR diff an fits nicely with slightly pumped guards.

As your fitted the VR/VS suspension can you provide some more details on how you did it

[Mickey Maj]

I had a little help form my brother as he works for a tyre shop an does wheel alignments so he knows how to set the castor rite with the offset of the top plate. But is all that was needed was the modification of the VR/VS top plate cut down to the same size as the VB-VP top plate and 3 new holes drilling in the appropriate places for the rite amount of castor how ever if the castor is incorrect u can always shim up the radius rod bushes to correct it. Then i just used the VR/VS sway bar lower control arms an brakes etc. and rolled the guards dead flat and pulled them out a little and did the same to the rear guards and the VR/VS diff bolted straight up with the addition of an adjustable pan-hard rod.
My brother bought a wrecked VR for the engine an thought it would be a nice idea to see if it could be dun and it had new shocks and king springs so didnt cost me anything lol.
And also u will need to use VR/VS tie rods and tie rod ends which will go straight on the end of a VN rack if thats wot you've got...

[immortality]

It can be done with a bit of modification. Tyres still fit inside the guards as i have pumped them out a tad. I also fitted the VR diff an fits nicely with slightly pumped guards.

yeah, i guess pumping hte gaurds would work if you wanted to go that far with the mods, the VN/VP would fit without having to pump the gaurds though

I had a little help form my brother as he works for a tyre shop an does wheel alignments so he knows how to set the castor rite with the offset of the top plate. But is all that was needed was the modification of the VR/VS top plate cut down to the same size as the VB-VP top plate and 3 new holes drilling in the appropriate places for the rite amount of castor :

if you are keen on the VR/VS suspension setup then i might possibly suggest using the aftermarket adjustable top strut mounts as were used in the build up of VU for U (ute)by street machine magazine. in the later model commoderes they did away with the strut mount like the VS where it's bolted in with 7 or 8 bolts and they spot welded the strut mounting cup directly onto the strut tower. in the later model commodores they drill out the spot welds, drill 3 holes to suit the adjustable strut mount and he presto the job is done. i bleieve the 3 mounting bolts are the same as the VB-VP strut towers etc so should go straight in.

[vk3800]

Ok, so VR/VS suspension can be fitted, but for practicality and cost it would be easier to use the VN/VP suspension or retain the VB-VK.

Will edit post to that effect.

[immortality]

Ok, so VR/VS suspension can be fitted, but for practicality and cost it would be easier to use the VN/VP suspension or retain the VB-VK.

Will edit post to that effect.

anythings possible with enough time/money. VN/VP is a direct fit bolt on job etc. VR/VS is more work etc. using the adjustable aftermarket strut mounts would probably help with engineering cert also + having to pump the gaurds to fit the wider track and also having to change the rear diff to the wider VR also which means you have to pump the rear gaurds also etc. the benefits of going tothe VR/VS setup would probably be worth the hassle in the long run as the hubs have bigger bearings/brake setup and would be easier/cheaper to convert to the later VT model setup also. more options avail also interms of adjustable suspension conversions for the later model setup too. i've been trying to figure out a way that i can keep the original track but use the VS setup without having to pump the gaurds as i likethe original look and don't wanna modify the body in that way etc. haven't got it right yet though

[Mickey Maj]

if you are keen on the VR/VS suspension setup then i might possibly suggest using the aftermarket adjustable top strut mounts as were used in the build up of VU for U (ute)by street machine magazine. in the later model commoderes they did away with the strut mount like the VS where it's bolted in with 7 or 8 bolts and they spot welded the strut mounting cup directly onto the strut tower. in the later model commodores they drill out the spot welds, drill 3 holes to suit the adjustable strut mount and he presto the job is done. i bleieve the 3 mounting bolts are the same as the VB-VP strut towers etc so should go straight in.

The adjustable strut tops you hav mentioned sounds like a good idea, i shall look into that.

[STEALTHY™]

I'd like to add, i did this conversion in my VK. The tailshaft was just a case of using the front half of the VN tailshaft (out of the gearbox) with the rear half of the VK tailshaft.

The car was a wagon, but i didn't think they were different until VN


Also, this should be made a sticky, if it isn't already.

[vk3800]

I'd like to add, i did this conversion in my VK. The tailshaft was just a case of using the front half of the VN tailshaft (out of the gearbox) with the rear half of the VK tailshaft.

The car was a wagon, but i didn't think they were different until VN


Also, this should be made a sticky, if it isn't already.

I've a few peole say that you can split the tail shaft and use one half from each. But when doing mine the two shafts where different diameter and bolt holes didn't line up.
Mine was one of the earlier VK's, so maybe the tail shaft's where changed to simliar to what was used in the VN.

[STEALTHY™]

I forgot to say, my diff is a disk rear, so that might have something to do with it, aswell as the car being a V8 (before the transplant) and a late 85 model

[DANNY8]

I've a few peole say that you can split the tail shaft and use one half from each. But when doing mine the two shafts where different diameter and bolt holes didn't line up.
Mine was one of the earlier VK's, so maybe the tail shaft's where changed to simliar to what was used in the VN.

That's a good point. I'm not sure bout the VN's, but the VL used a slightly larger in diameter tailshaft, coz when I put the VL diff under my VH, I couldn't bolt the rear section of the VL tailshaft up to the front of my VH tailshaft, so I had to use the rear section of a VK tailshaft which was running a Borgy diff.

Next time I see my bro I might get under his VN with my digital veneer caliper and measure it up, then measure my VH and VK tailshafts and I'll post up the results.

[Mickey Maj]

Yeah you need to use the rear section of a VK V8 tail shaft as it has the bigger uni's and cv joint and will bolt up to the vn shaft where as the 6 cylinders are a smaller cv joint and uni's...

[Mickey Maj]

• If you use an auto box, make sure you connect the speed sensor. If you don’t the car will shut down at about 45km/h as the computer thinks you doing 245km/p

I used the auto box in mine and comlpletely snipped the speedo out of the wiring harness and it has no worries wot so eva doing over 100 km/h, wasnt game to go any faster coz it got no doors or windscreen lol

[vk3800]

OK so the tailshaft.

1. if the car is an earlier model it will most likely have the smaller diameter tail shaft and it would be easier to fit the VN shaft after being shortened.
2. if the car is a later model, it would probably have a similar tail shaft to the VL & VN. This being the case you could change the front half to the VN.
3. if the car is a V8, you could probably change the front half to the VN

[immortality]

early VK's had the salisbury diff and the later VK's had the borg warner diffs. different driveshafts to suit from memory. better using the borgwarner diffs. that way you can get the 4 spider LSD units from later model cars that fit straight in etc. the salisbury diffs only ever came with a 2 spider LSD from memory. also, there is a much larger range of gearing options for the borgwarner diff also

[yobbo88]

Does the Aussie 4 speed gearbox found in the earlier commodores bolt up to the v6 engine? i dont want to change my car to an auto and vn etc manuals are pretty rare and on top of that i could keep my current driveline? Im gettin a bit itchy to do a conversion ive been reading for months and the most affordable for me is the v6 conversion. 5L are so darn expensive...

Edit: Also my car being a VH what is involved in the wiring side of things? does the ecu of the VN control anything other than the engine? theres obviously no existing wiring to adapt into. ie would any wires go through the firewall or would it all be in the engine bay?

[vk3800]

I don't believe that the Aussie 4 would bolt up or be strong enough.
You best bet is to find a complete manual car to use as parts.

Yes there is wires that come through the fire wall. The best place for the computer is behind the passengers kickplate in front of the door. There should already be a hole there that existing wireing goes through.

[dreamcatchu]

out of curiosity has anyone done this conversion but used a V8 instead, if so was there any dramas in regards to the engineering certs e.t.c, thinking about doing this as i now have an extra vc shell to play with, also how hard would it be to fit the later model dash e.t.c aswell, i remember seeing some pics a while ago of a vh that had from memory a vs interior put in but there wasn't much info of what was involved in doing this

[Satanic]

hi there i just got my donor car for $150 just wondering if there is anyone that has done this conversion that could do up a wireing diagram for me so i dont have to spend more on the plug? Also can you use the back half of the vk tailshaft and the front half of the vn together so you dont have to get it shortened?

[vk3800]

Mate it would be easier to spend the money on the plug. When i got mine done it took an auto elec 2 full days to wire it up with a VN sitting along side.

Refer above for the tail shaft. It depends on what year model your car is.

[Satanic]

Motor is in!!!! just got to do the wiring now and fix up the tailshaft still thinking about doing the wiring myself as the plug ( wire kit ) is $375 by itself. as this car is only to take to the track and race i cant see the sence in paying thay just so things like the A/C works. So if anyone has some diagrams that may help me out would be good thanks.