Diesel conversion (TD42 from TB42)

Thought it was about time I should start a thread seeing as I have just plunged into doing a conversion on my GQ. Obiously the first step is to source a motor preferably off a donor vehicle so you can get the neccessary parts aswell. Fortunatly I managed to find one out of a rolled GQ which already had a Safari turbo and intercooler kit on it.

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The next step is to pull out the old motor and strip the engine bay which I am in the process of doing now. Next will be to get the fuel sorted, get rid of the gas and hook up the standard tank as well as the long range belly tank. . . Hopefully this weekend if all goes well. . . and bloody family social events don't get in the way - I know what i'd rather be doing!

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Anyways this thread is a work in progress so I'll post plenty more pics to come, and probably have a few queries along the way too!

Hi quick question are the bellhousings the same for this converstion or do you have to change them ?

nice work, looking forward to following this project. 20 years ago a work colleague converted a petrol Tojo to diesel - obviously not a common rail or anything back then, but for some reason he replaced the fuel tank and fuel lines as he thought there was some issue with tanks and metal lines that had been used for Petrol. I now wish I had asked him why :-)

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Originally Posted by nissan-nut

Hi quick question are the bellhousings the same for this converstion or do you have to change them ?

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Have to change them mate...

Rossco just dropped the TD42 into his patrol today and It's all coming together.

Except for the last bolt on the engine mount wouldn't go in and a lot of swearing and cursing got him home.

He has taken a few photos of the progress so far but as always we keep forgetting to take happy snaps but I hope he can put up some great info once It's all done.

Can't wait to start this up and see it in action. Massive learning curve doing something like this and you really do learn a lot!

Good to hear its coming along nicley Rossco, Ill have to come have a look next time im down haha

O.K., sorry for the lack of updates but I will get some more pics and info up soon. Unfortunately holidays and work have kind of been getting in the way of things a little! However it is starting to come together now, espacially now the new engine is in. Sorry for the late reply but the bell housing is different- just a standard td42 which bolts straight up to the gearbox. Stay tuned and I'll get some pics up soon.

O.K. , many apologies agiain, but now the conversion is complete I figured I should finish the thread!

Unfortunately I didn't get any pics of the gas system removal (always the way when you get a bit exited!), however it is fairly straitforward as long as you make SURE the gas is turned off at the bottle and I also kept the filler assembly intact Also care is needed removing the tank as they are bloody heavy, especially if there is still gas in the tank, ideally try to empty the tank first. Once the tank is out it is just a case of removing all the lines, wiring and other parts like the converter.

Once the tank is out the new tank (I used a standard diesel tank) will bolt straight in, however the rear bolts are very tight beteen the tow bar (if you have one) and I just got away without removing it. I hooked up both the new tank and the old belly tank using a Pollak fuel swithing valve, however I haven't got it fully wired up and working as yet, so hopefully when it's working I will do a separate thread on the duel tanks.

Now it's simpy a case of stripping everything off the engine ready to be removed. This just takes time and plenty of zip-ties(and a few beers)!. I also labeled every wire that was disconnected to help with re-wiring with the new motor, which was very very helpfull.

Attachment 8687
Engine ready to be removed.

Once the engine is ready to be taken out, it needs to be supported with the engine crane to remove the engine mounts, then lowered slightly to get to the top engine to bellhousing bolts as well as the botom bolts. Once they are removed it's ready to be prised apart from the bell housing and pulled forward and then out. Originally we tried to pull it out with the fan still on but found there was not enough clearance so it needs to come off.

Attachment 8688
Removing the old motor.

Once the engine is out the bell housings can be eisily swapped over with the td42 bellhousing bolting straight up to the original gearbox! Too easy! Then the original clutch shift fork can be installed with new thrust bearing and it's worthwile putting on a new fork boot aswell and siliconing it at the same time. I found the old boot had been siliconed by me a while ago, however it had perished leaving a big split in it and allowing LOTS of water straight into the clutch resulting in the old clutch looking like something off the bottom of the ocean! Probalbly as a result of the last big Toolangi boghole I suspect.

Attachment 8689
Old bellhousing to be swapped with td42 bellhousing

Now the new clutch can be installed onto the back of the new motor, however beforehand I decided to replace the rear main seal, seeing as it was apart and hopefully it won't have to be apart for a while to come. Once the rear main seal was replaced it was just a case of instaling the flywheel again making sure that the bolts are all correctly torqued. Then the clutch can be installed with a new spiggot bush, and it's ready to go in!

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New clutch on motor ready to go in.

For some reason (Can't remember why), I had to use the engine mounts off the old motor. They are slightly different and I think the diesel ones didn't clear something somewhere! Umm my memory must be fading, anyway, once that was done the engine slid in very eisily and everything lined up apart from the last hole as AB mentioned, however after looseng the mounts from the block it was enough to jiggle it in. Also before I put the engine in I gave everything a good coat of UltraCopper to keep everything nice and water tight.

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New motor finding it's new home

Now that the new motor is in the fun can begin, and not dissimialr to the removal, takes time, zip ties and more beer. The fuel filter assembly and vaccum resevior both mount in the same place as on a standard diesel GQ and already have the holes with captive nuts - too easy! However I lashed out and bought some genuine Nissan clips for the firewall for the fuel and vaccum lines at $11.00 each. A bit pricey for a plasitc clip but it makes it look original.

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Fuel filter and vaccum resevior and their lines

Mounting the intercooler was pretty straight forward once I figured out how it all went together. The brace that runs up and down below the bonnet catch needs to be removed, as well as the thermo fans, and I also had to move the can for the air-con. Once that was done the Safari Intercooler just has top and bottom brackes then a hole needs too be cut for the top hose. Also because I have a body lift the bottom hose was hitting the air-con pump, so I had to cut the bottom tube and use some rubber turbo ducting hose.

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Installing the IntercoolerAttachment 8698Attachment 8699

Also the back of the grille has to be shaved down with a gringer to clear the intercooler, however I didn't get any photos. (Must of been getting exited again).

Once the intercooler was installed I was able to connect all the turbo pluming and airbox. Because I had to be different and locate my snorkel in a different place to everyone, I had to get the air box modified to rotate the inlet around to face the snorkel. Luckily however the hose just managed to squeze through, as you can see in the earlier photo. I also found that the hose between the airbox and turbo was hitting the dual battery tray (ARB), so I had to trim the corner to allow enough clearance.

Next was the wiring whch was pretty simple really, at least just to get it running anyway. The stater motor wiring is the same and hooks straight up, however the alternator is located on the other side so the wiring just needs to be extended which is pretty simple. Power on and off for the injector punp can be used from the fuel cut solenoid on the back of the carby which is the brown wire from memory and swithches with the ignition. All other wiring to the distirbutor, coil etc can just be cut and taped up being carefull to insulate all of the individual cut wires. Initially to get it going I just put the glow plug wire straight on the battery for 5ish seconds when it was cold which worked fine. I have now installed a momentary on type push swithch wired up to a glow plug relay. The only other thing needed to be wired up is the tacho which requires the diesel tacho gauge and has to be re wired form the gauge. Unfortuantly I'm not exactly sure how it's done as I am getting it done at Patrolapart.

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Glow plug relay.

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Glow plug switch

Finished product:
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Now all there is to do is get out and enjoy it! I have to say that I have no regrets whatsoever in doing this conversion and leaving unreliable old gas behind and enjoying a huge increace in power compared to the tb42 (especially on gas). You just gotta love that trusty sound of a diesel ticking away, especially a td42.

Well done Rossco. I have seen this engine in action and it runs like a dream!

Can't wait to get it out in the bush mate!!!

I have been so tempted a number of times to do this conversion myself with the Mav to tell you the truth. The only regret I've ever had with this rig is it wasn't a TD42 other then that I can't part with it so this inspires me to keep my eye out for a donor rig for a future conversion project.

Cheers Rossco for the thread, its mades for some interesting reading.

We did this conversion on a mates patrol last w/end.
Drove it into the shed friday arvo as a tb42 petrol/auto an drove it out sunday arvo as a deisel manual.
Used his old patrol for all the donor parts ,
We had to remove all the dash an swap the wiring looms mount the pedal box for clutch an change brake pedal.
Used engine crane to lower old auto an then lift manual box back in by dropping chain through floor where the shifters normally sit (if you wrap 1 chain around box in front of cross member an one directly behind crossmember the box will lift dead level).
We ran all the deisel loom an fuel lines etc while there was no motor or box in car so we could get to everthing easy.
When you change over looms the fuse box has to be pushed through fire wall from the outside an then all the interior wiring fed through after it. It also helps to trim off all the excess dags an corners on the fuse box as its a real neat fit through the firewall.
Once we had motor box an wiring etc all fitted up we drained an flushed tank flushed lines an then primed her to the filter ,changed the filter ,primed up again up an kicked it in the guts .

I've thought about changing my 4.5L dual fuel to 4.2L Turbo Diesel. What sort of cost would you think it would cost? ball park!

If you can do the swap yourself around $10,000, double that if you're paying someone to do it. That's to fit a factory TD42T with new clutch, water pump, hoses, belts, radiator etc.

Tony

Thanks for the info Tony. In terms of the running gear diffs, box etc. do these need any modification or is it all the same for petrol and diesel?

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Originally Posted by Jamie

Thanks for the info Tony. In terms of the running gear diffs, box etc. do these need any modification or is it all the same for petrol and diesel?

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The gearboxes are the same between 4.5 manual and 4.2 diesel, just a different bell housing.
Front diffs are the same but if you have a manual 4.5 then you will have a bigger rear diff, which is no real problem.
As for diff ratio's I think your 4.5 will have 3.9:1 ratio which is the same as was fitted to TD42 turbo Patrols, naturally aspirated TD42 got 4.1:1 - so close it doesn't matter unless you fit bigger tyres.

Tony

Thanks Tony,
I was aware of the Bell housing but not sure on the other issues. Boy do you know you Patrols!

infoormation above so helpfull thanks mate

haha i was thinking quite opposite... remove td 42 and put tb 42 carburetor gas.... now its make me think again :(

hi cani i ask why did you change your petrol 1 for diesel plz..

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Originally Posted by red92gq

We did this conversion on a mates patrol last w/end.
Drove it into the shed friday arvo as a tb42 petrol/auto an drove it out sunday arvo as a deisel manual.
Used his old patrol for all the donor parts ,
We had to remove all the dash an swap the wiring looms mount the pedal box for clutch an change brake pedal.
Used engine crane to lower old auto an then lift manual box back in by dropping chain through floor where the shifters normally sit (if you wrap 1 chain around box in front of cross member an one directly behind crossmember the box will lift dead level).
We ran all the deisel loom an fuel lines etc while there was no motor or box in car so we could get to everthing easy.
When you change over looms the fuse box has to be pushed through fire wall from the outside an then all the interior wiring fed through after it. It also helps to trim off all the excess dags an corners on the fuse box as its a real neat fit through the firewall.
Once we had motor box an wiring etc all fitted up we drained an flushed tank flushed lines an then primed her to the filter ,changed the filter ,primed up again up an kicked it in the guts .

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Originally Posted by Toha

hi cani i ask why did you change your petrol 1 for diesel plz..

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Most people do it for low down torque fuel economy and reliability

hello macca how are ya ? sorry asking too much, low down torque means for less power and if had gas system then it must more economy then diesel right ?your previous engine tb42 wasn't reliable is that u mean to say .. thanks

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Originally Posted by macca86

Most people do it for low down torque fuel economy and reliability

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Quote:

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Originally Posted by Toha

hello macca how are ya ? sorry asking too much, low down torque means for less power and if had gas system then it must more economy then diesel right ?your previous engine tb42 wasn't reliable is that u mean to say .. thanks

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I have never had either engine just going on what people say here. petrol or gas you won't get the miliage from it litre to litre compared to a diesel. Diesel is easier to get out bush compared to petrol or gas especially gas. diesels do make power with the right mods sure your petrol will be faster but not really needed off road reliability well 4.2 diesels get 500 000km plus before a tear down. you should drive in both motors before deciding the swap to what ever suits your needs and preferences.

You get high mileage out if the TB42 as well. Both TB42 and TD42 have the same tough as nails bottom end. My TB42 has over 420 000 kms on it. The head has been replaced in 2007.

Tap, crackle, pop

hi rossco it sounds like everything went really well for you. i have just done the same to my dual cab maverick, eberything went good except for now the wiring situation.for some reason my alternator seems to be a different type to the original because the plug is different so i cant use my original plug,and how did you go with hooking up the vacuum to your brakes?
For some reason it feels like there is not enough vacuum to the brakes and at the same time my clutch is vacuum assisted and that feels fine , im kinda scratching my head at the moment?

I'm planning to do the same in the next few months so might be picking your brains soonish

troy

Yeah no probs yort I'm happy to help with any questions

hey rossco, im goint to do a tb - TD conversion soon, did you get a 24v td42? as TB is 12v if i find a TD from a 24v truck i know ill need a 12v starter and alternator for the TD, but will the injector pump need to be 12v aswell? or can i run the original off 24v truck on 12v system? i got a TB42 carby aswell, and getting 250k's out of a full tank :( so wanting to get more torque and economy. Cheers,

Mike

bump......

Rossco doesn't get on here much. His was 12 volt.

ive done the same thing mate, and i say to any budding diy mechanic out there, give it a go. as much as i created a few new swear words and used them often, it was a great learning curve, and not insanely hard to do either. and with the help of a few mates essentially had it done and dusted in a weekend....
good work rossco

Hi there
My names Russ, I'm from brisvegas, I'm 25 and I'm a diesel fitter. I am a pretty keen Toyota fan but just brought my first serious forbie and got a patrol. Its a Nissan gq 90 model with a td42 manual has done 555000 ks and iv done a compression test all at 430 psi loving it! But it wasn't the real deal has a bit of cancer and couple of big dints. So soon browsing eBay I picked up gq 1992 Ti with an auto tb42 with gas. So ill be doing some work to get 1 on the road. :biggrin: I would just like to know if I need to keep cluster and computer to keep auto has anyone done this? Or am I better of just going manual? Preference is auto but am not fussed if I have to drive a manual. Ill post some pics too of build thanks for the help in the last pages now that I'm a member te to throw some thanks around haha.

Also some issues with where to get flex plate?

Parts specialist can generally source one or remove it from the other motor and it could be a straight swap


Just tap it in just tappy tappy tappy

Thanks for advice going to start a thread on my build this weekend long weekend WOOHOO!!! And ill upload some pics of the trucks to try and find some history on them. Just like to say also this forum is awesome!

if you buy a 24volt motor you will need to change the injector pump shut of solenoid to a 12volt system , youll also need to change the alternator to a 12v type. iv just had my 24v pump rebuild and needed to get a 12v solenoid fitted as im using a 12v gq

well done .You made it look easy

well done looks sweet from the pics.