Thread: Isuzu Engine Swops for Dummies

Well despite Damien's best efforts to describe me as the laziest sod on earth, the reason for the lack of updates have been long days and 4am finishes, and no energy to post the results afterwards. But I will keep the updates coming, albeit a bit delayed.

Waiting for the defender to arrive, I decided to stip down and clean most of the engine bolt ons and spinny bits, and give them a once over before they went into their new home. That included, in no particular order, injectors and glow plugs, starter motor, alternator, water pump etc. The great thing about these engines is that so many normally throwaway itens such as the water pump can actually be broken down to component parts and refurbished, definitely a step up from the 300tdi.

Water pump was in pretty good condition, all things considered.





Injectors and glow plugs given a cleanup and bolted back on. While most people don't bother hooking up the glow plugs here, they are necessary for cold starts in Europe, and seeing as the relay and wiring from the 300tdi is just sitting there, it's an easy job to get them running.






Time to cut down the winged sump to allow for easier routing of the exhaust. I did price a wingless truck sump from Isuzu, but at over $400 I couldn't justify the expense for what is basically a mild steel can.





I followed pretty much the same template that SteveG did when he cut down his sump. Or at least I thought I did. Sump all marked up and ready to go.



Wing cut off and ready to be shortened up.



....and this is why you shouldn't use angle grinders after four or five beers. Apparently for all my measuring, I still managed to come up short, and the cutout section fo the wing didn't line up. Cue some more butchery with the grinder, and tacked up an inch wide strip from the offcut to fill the gap. Spot welded for now, but once it's all TIG'd up, it'll be perfect.







Seeing as I'm running a new turbo setup, it would be a shame not to intercool it, and seeing as one came up for a good price (I don't want it, get it out of my shed and it's yours), I jumped at it. At 300 x 610 x 85mm, there should be no issues with restriction.



However, the only issue is the location of the inlet and outlet are in the wrong locations. So either abandon the idea, or....



A quick bit of work with the right sized hole saws...





Two circular cutouts from some 5mm aluminium plate (which I forgot to photograph) to fill the voids, and she's ready for welding up at the weekend.





The new bits have started to arrive, first in the door was the radiator. I'd shopped around for an Isuzu County radiator, but anything I found was in such bad shape that it needed a prohibitively expensive recore, so I went with a County V8 radiator from Gary at Classic Land Rover in NSW, and I'll swap out the radiator inlets and outlets later.




Air cleaner has also been ordered. Gave Donaldson a call, only to find out that they won't sell directly to the customer, and that to buy the Donaldosn filter housing with filters directly from Land Rover wouldn't leave me much change from $500, which is a whole lot of money for a tin can. So I went with the Fleetguard option as many before me have done, same primary and secondary filter setup as the Donaldson, but $318 for filter housing, filters and brackets.

The choice came down to the AH19066...




...or the AH19268...



Same physical size, roughly the same flow rate (≈300CFM). After seeing the filter setup in SteveG's County, I went with the AH19066 - the inlet will be blanked off and the 3" dust ejection valve can be retasked as the air inlet, and in my opinion, for what it's worth, the top hat arrangement of the filter cover makes it easier to (a) change the filters, and (b) orientate the inlet to whatever position most suitable to the snorkel setup in the Defender.

Woohoo! She's finally here!! After a long and convoluted route from Alice Springs to Melbourne via Darwin, where along the way the transport company managed to lose my keys and immobiliser fob, and the tandem trailer nearly did cartwheels on the final leg of the journey to Vern's shed, she's finally here.



While I was in the city picking up the defender, I also picked up the LT85 gearbox that JC sent up from Tassie. The gearbox itself apparently won't select a gear, but should have salvageable parts that will get mine running again. I realise that this gearbox could well have come out of a forum member's vehicle at some stage, so hopefully take solace in the fact that parts of it get to live to fight another day.



Twins!



Now that I have the two gearboxes side by side, it looks like a few "modifications were made along the way, the most obvious being the shortening of the bias spring turrets, assumedly to fit it into the Range Rover transmission tunnel.



Extension housing off, and 5th gear exposed. Apparently I'm not the kind of person who can just follow the RAVE manual instructions of "Do not displace selector fork slipper pads when removing fork" without thinking "why not???", and tapping said gear with a hammer, and after hearing springs and ball bearings pinging off the roof of the shed, spent half an hour on my hands and knees trying to relocate them... :/



All of the components of the 5th gear synchro back in one place. Just as well, considering that 5th gear is one of the many things that need replacing in my LT85.



Gearbox top cover off the donor gearbox. Now to see what exactly has gone wrong.



Selector rails and forks taken out, to get a better look at the main gear assembly. Thought at first that the problem might have been a broken main shaft, but everything is looking good. 1st/2nd and 3rd/4th synchros both select their respective gears, though 1st/2nd synchro was jammed pretty tight.



As it turns out, the selector forks were the problem 1st/2nd selector fork in particular had both tongues worn almost clean off. In addition, compared to the selector forks from my LT85, they seemed a lot more lightweight, not sure why, but it certainly contributed to their failure.





Gearbox going back together, this time with functioning selector forks.





All done, and ready to go in. Gear changes seem decidedly more gated than when the transmission was in the Rangie, no doubt due in large part to the now functioning bias springs. Gear changes all seem solid, though the gearbox does feel a bit more "agricultural" than the R380 in the Defender. We'll see how she flls later full of syntrans oil before I'll make any conclusions.



Finally, she's in the shed. The 300tdi, who will forever be known as "the bastard", ready to be taken out. Engine is pretty much toast, some of the spinny bits shall be making their way to a new home, and unless someone out there wants a 300tdi for a rebuild project or something, she'll make a good anchor, and not much else.










Time to reassemble the Isuzu drivetrain for the Defender transplant. 300tdi and Isuzu bellhousings side by side - there's a noticeable difference in size. Clutch cylinder is also over on the passenger side, so more plumbing. It's also slightly longer, which presumably would mean a new main gearbox shaft for an r380 conversion.



The hits start coming early it seems. Clutch fork pivot sheared upon tightening up. Wasn't applying much force at the time, so I'm suspecting that it was fatigued from before.







Either way, time to machine up a replacement. Drilled and tapped the remains of the pivot, and threaded up a new bolt section.





Just like a bought one!





Damien using his favourite workshop tool to cut off the 300tdi mounts and clean up the chassis.



LT85 bolted up... LT230 to follow.



I've decided to go with the 1.222 RRC transfer case. Ideally I'd be matching the engine up with a 1.003 TC, but considering that I'll be running laden most of the time, I could probably do with a lower first gear anyways. Crunched the numbers on both TC's, and running 265/75 tyres, the results are as follows.

LT85 gearbox with 1:1.003 TC






LT85 gearbox with 1:1.222 TC





1st gear is noticeably lower with the 1.222 TC, and 100kph highway speeds will put me at 2216 RPM, which is only 150 RPM removed from 4th gear with the 1.003 TC. Will try it for now, and if I decide that few less revs at highway speeds would be more beneficial, especially with the turbo, I can swap it out later.

Just after reading about the works in progress, I had to smack my right hand, it started groping about for a shifter.
.

Hi Mike, great work there!

Yes it is a good thing to see that trans being 'recycled'. Strangely before it jammed up and lost drive it was shifting pretty well, even with those forks.

It was certainly going to be a non event down here, the vehicle it came out of is now extensively modified/ changed, so good to see it get a new life (and free up some space on the floor, too...)

I guess it is a good thing I don't like to throw too much out....


JC

Originally Posted by justinc

Hi Mike, great work there!

Yes it is a good thing to see that trans being 'recycled'. Strangely before it jammed up and lost drive it was shifting pretty well, even with those forks.

It was certainly going to be a non event down here, the vehicle it came out of is now extensively modified/ changed, so good to see it get a new life (and free up some space on the floor, too...)

I guess it is a good thing I don't like to throw too much out....


JC

Yep, it's a good thing for me at least Well as you can see, the selector fork on the right which came out of your gearbox, was almost worn through!! 3rd/4th selector fork was on its way out too. The used ones that I've put in are a bit polished, but they'll get me to where I want to go. Have two new forks and a bearing kit ordered at home, as I'll be pulling the drivetrain out anyways to galv the chassis once I get back.

Actually, do you have any idea if there are different "grades" of selector forks? The one from your gearbox were decidedly lighter and less beefy all round, particularly 3rd/4th?? I should have gotten some better photos at the time, but they were thinner in cross section, with big cutouts, to, I assume, save on the amount of metal used in manufacture? It certainly played a part in their failure, that's for sure.....

Well, D-day has arrived, and the Defender is going to be receiving its new engine. Front of the shed cleared, beer in the fridge, and Steve and Hugh (SteveG and HPLP), as well as Damien, volunteered their time to give me a hand. Steve thankfully, brought along the TIG welder, more to prevent me from melting fist sized holes in important bits of metal, than anything else.

Steve gets set up to TIG weld the intercooler and sump....





...while myself and Damien get the engine and drivetrain set up to be dropped in.



With four sets of hands, getting the engine in was a lot more straightforward than getting out the tdi was.





With any Defender engine swap, the gearbox/Tcase mounts are used as a point of reference, as they are common across the board, the bolt holes being slotted to allow about 25mm of play for the entire drivetrain fore and aft. However, try as we might, we couldn't get the engine to move forward far enough, and after much head scratching as to why, we took a look inside the Defender...



For some reason I had gotten it into my head that the R380 and LT85 transmission tunnels were compatible, which clearly they are not. A little research tells me that the R380 tranny tunnel (not a phrase you want to google btw ) sits about 38mm nearer to the seatbox than the V8/ LT85 one. A quick measure shows that the R380 and Lt85 heights are more or less the same, so in theory it should be possible to relocate the transmission hole in the tunnel and all should be good. I initially thought that I could cut and shut it, but it turns out that the R380 tranny tunnel is made from fibreglass for God-knows-what reason, so for now I've just pulled it out, and will figure out how to fix it later.

Almost in.....



I'd taken measurements from a couple of Isuzu Countys, including Steve's who had driven his down, so here are a few landmarks for locating the Isuzu engine in the engine bay. I used the crankcase pulley as a point of reference. Pulley centre is 278mm from the LHS chassis rail, and if you throw a straight edge across the top of the chassis rails, the bottom of the crankshaft pulley sits 58mm below it. Set it up at about 53mm and weld the mounts at that, as the engine will settle about 5mm or so into the rubbers.



Longitudinally, if you eyeball the engine from above, the timing case cover sits about 14mm forward of the 4 bolt steering box bleed screw.



The tolerances for these measurements are reasonably tight, as the engine and attachments sit pretty snugly in the engine bay. In particular, keep an eye on the starter motor lug, and make sure that it's far enough away from the LHS chassis rail. Mine is about 25mm away, which is fine.



Once the engine is in its final position, it's time to get welding. I decided to reuse the Range Rover engine mounts, for simplicitys sake.

Mounts as they were on the Rangie....





... and now on the Defender, waiting for the welder...





She's in!!!

As straightforward as the post makes it seem, it's still a days work just getting everything set up okay and fettling everything into position, then checking and double checking everything before the final welds are made. Engine sits well in the bay, is level (thermostat housing is a good place to eyeball this from the front, and of course, thanks to Damien, Steve and Hugh for their help all day.

Now the hard work begins....

Originally Posted by mike_ie

...I initially thought that I could cut and shut it, but it turns out that the R380 tranny tunnel is made from fibreglass for God-knows-what reason, so for now I've just pulled it out, and will figure out how to fix it later.
...

So is the LT85 tunnel.