Military Tithonus 110 , swapping engine to 300 TDi probs

Hi
after the clutch failing ,i decided to pull my X military Tithonus apart to fit a 300 Tdi so im not holding up lorrys on the road.
My Truck has the R380 stubby box and on offering the engine up , ive noticed some of the bellhousing to gearbox housing studs and bolt holes do not line up, mostly around the bottom section .
How do i resolve this ? is there another gearbox or engine bell housing that will work ?
Berst wishs
Richy

Am i the first person to attempt this conversion ?
I guess i will reconfigure the stud and threaded hole poisitions , im a dab hand at ally tig welding so i will give it a go.

RicardoRich said:

Am i the first person to attempt this conversion ?
I guess i will reconfigure the stud and threaded hole poisitions , im a dab hand at ally tig welding so i will give it a go.

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i prefer to swap the box and fit the 300 as lr did ie up against the rad ,but if your butting your 300 up to the short box just leave out the studs that dont line up theres more than enough that do

cheers for your reply
I have a new R380 box in the truck , i like the way it sets engine right at back .
I have heard of bellhousings cracking due to the missing bolts ? there will be approx 4 that dont dont line up

RicardoRich said:

cheers for your reply
I have a new R380 box in the truck , i like the way it sets engine right at back .
I have heard of bellhousings cracking due to the missing bolts ? there will be approx 4 that dont dont line up

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have you? i havent, v8 one dont have any on the lower 1/3 of the bell housing

Really ? then it sounds like it should be fine
maybe i will risk it for a biscuit
i guess there is no matched housings , or people would have done it by now
cheers James

Iirc you just tap the bottom hole which gives you another stud and remove the ones that don't line up.

I have a 300tdi in my tith but with the lt77

See this guy's site, Glencoyne Engineering, he has loads of valuable advice http://www.glencoyne.co.uk/tdi300.htm
You can also save yourself a bit of effort if you use Steve Parker 300tdi to LT77 engine mounts. (Should be the same as a R380 on a stumpy bellhousing.)
In answer to your original question, you have to add an extra stud to the 6 o'clock position on the 300tdi bellhousing and leave a few of the misaligned studs out. I did this, I have had no problems and I have not heard of any horror stories re breakages.

When you get to the exhaust, this is my suggestion. If it doesn't make complete sense, it's because I have cut and pasted it from another post.

There are three issues with the 300tdi LT77 combination:
1. The engine is 6" further back than a standard 300tdi.
2. The front of the engine is slightly lower than the standard 300, as it doesn't have to avoid the front axle.
3. The space around the engine mount / clutch slave cylinder and starter motor is very restricted.

If you have a spare £125 you can buy a custom front pipe from Steve Parker Land Rovers, now my limited experience of Steve Parker's products (TDi engine mounts) suggests that his stuff is very good quality, but being a tight ar5e I couldn't bring myself to part with £125 for a bit of pipe.

I started with a £20 Britpart front pipe intended for a 300 Defender and took 6" out of the length. 6" seems the obvious length as the engine is 6" further back, but as the front of the engine is lower, it may have benefited with another 1/2" or so removing.
I used a full 300tdi exhaust system, but the over axle bend comes very close to the crossmember in front of the fuel tank (110), so on reflection I would have been better fitting the rear of the exhaust system before the front pipe.

As the front of the engine is lower I also had to cut, rotate and re-weld the rear section of the front pipe to put the joint in the correct position.

I also had to cut a lump out of the large engine crossmember (held on with four bolts) to allow room for the front pipe, this is because the factory 300 Defenders and Discoveys don't have this crossmember, they have a tiny thing near the gearbox.
At first this seems to be a bit of a rough-arse modification, but later Defenders use a much slimmer version of the bolt in crossmember and as I said above, the 300's have a poxy thin thing around the gear box, so there is no significant compromise to the rigidity of the chassis as a result.

I will attach some images which hopefully make my explanation more clear. The third image shows a TD5 crossmember and my modified crossmember, I suspect there is still more strength in mine with a lump taken out that there is in the standard TD5 version.

And another thing..............................
You WILL need to change the transfer box ratio, unless you have monster truck tyres fitted. (Assuming that you still have the 1.6 : 1 ratio fitted)
I fitted a 300 to a military 110 and it screamed its nuts off at 60mph. I replaced my transfer box with one from a Discovery as it came with the engine. This is 1.2 : 1, and is a bit tall for 750 tyres when towing, but it's OK for day to day driving.
While you are at it, fit power steering, another game changer.

To get back to your original question, the clutch housing from earlier engines will bolt onto the rear of 300tdi blocks (with the addition of two dowels in existing holes), but some do not have the facility for the flywheel locking pin at the base (I am told) and none of them have the two ears that allow the 300tdi engine mounts to bolt and triangulate with the bellhousing.
I have only noticed that you are a whiz with a TIG welder, you may be able to weld these "ears" from a 300tdi clutch housing onto your 2.5 N/A housing to make something 100% sound.

I used the na flywheel housing to fit my 300 to LT77. Didn’t worry about the flywheel locking pin and had no issues when I did the timing belt without locking the flywheel.
I made an engine mount adapter so my chassis remains unchanged. Fabricated an exhaust down pipe from some 2.5” stainless tube. eBay flexi and straight through silencer. I used a standard 300tdi rear section for over the axle as I ran out of stainless tube!!
Extended oil cooler, inter cooler and Coolant pipes as required.
Not ran a fan on it since I fitted it 2 years ago.
Currently on 1.4 transfer box but will go with the 1.2 from a disco if I ever get round to it....

Oh yeah, deffo fit pas while you’re at it! Makes a world of difference!!
Rich

Rougharse Racing said:

And another thing..............................
You WILL need to change the transfer box ratio, unless you have monster truck tyres fitted. (Assuming that you still have the 1.6 : 1 ratio fitted)
I fitted a 300 to a military 110 and it screamed its nuts off at 60mph. I replaced my transfer box with one from a Discovery as it came with the engine. This is 1.2 : 1, and is a bit tall for 750 tyres when towing, but it's OK for day to day driving.
While you are at it, fit power steering, another game changer.

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Ohh i didnt expect that , ive just had a full gearbox and transfer box revuild too ? bugger

Rougharse Racing said:

To get back to your original question, the clutch housing from earlier engines will bolt onto the rear of 300tdi blocks (with the addition of two dowels in existing holes), but some do not have the facility for the flywheel locking pin at the base (I am told) and none of them have the two ears that allow the 300tdi engine mounts to bolt and triangulate with the bellhousing.
I have only noticed that you are a whiz with a TIG welder, you may be able to weld these "ears" from a 300tdi clutch housing onto your 2.5 N/A housing to make something 100% sound.

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Unfortuntely ive only got the 300 TDI bell housing , all the NA stuff was sold .

As far as transfer-box ratios are concerned, the 1.4:1 ratio is probably the best all round ratio for 750 tyres, which is probably why Land Rover chose it for the 300tdi.
I have a 1.2:1 Discovery transfer-box on mine and first can be a bit tall when doing hill starts with a horse trailer on the back.
When I first did the conversion I had the original 1.6:1 box fitted and when it was on a motorway or duel carriageway I was constantly holding back so I didn't over rev the engine, a bit like a V8 in a Series 3 if you have ever driven one, although it did accelerate well.
You would be wise to confirm which ratio you currently have, but as it is a 110, I would be very surprised if it wasn't a 1.6:1 as I doubt that the 65bhp of raw power from the 2.5 N/A would have coped with a higher ratio. The first three of the serial number will identify the ratio.
On a positive note, if you decide to keep your current ratio and change later, the transfer box will come out, up through the seat box, leaving the main gear box fitted to the vehicle.
Either way the 300tdi will transform your vehicle.

Yes thanks for info Rougharse
I found the NA embarassing on the road , and quite tedious
I spoke to my gearbox specialist and he replied , Quote
Hi Richard ,
I’m sure the transfer box ratio was a 1:667.
This ratio was the lowest that Land Rover produced.
Regards Andrew
I wont really know what its like until i drive it i guess , my current situation is now locating the engine mounts in the correct place , i did get to cut off the chassis brackets off the donor 300 disco , its just they sit so far back in my defender i may have to fabricate my own ? also getting the engine height right is a bit of a unknown , if anyone could shed light on poisitioning engine please ?

The simplest way to sort the engine mounts is to buy the ones Steve Parker does, they are not cheap, but they are absolutely spot on in accuracy.
They locate on two existing bolts before you weld them on, so there is no measuring or messing and you weld them on before the engine goes in, so it only has to be fitted once.
The Steve Parker weld on mounts use the standard 300tdi engine mounts, he does do bolt on mounts that replicate the 2.5 N/A mounts, but these cause other issues with the exhaust routing.
The Steve Parker weld on mounts cost £60, which is not cheap, but I'm a tight arse and I would use them again.

Hi
I have had to try and guess the poisition of the engine as steve parker does not do mounts for the R380 conversion sadly
i have tack welded them into poisition but i dont like the way the gearbox mounts look twisted and stressed ?
Is there any sure way of getting the mounts in the exact spot ?
cheers

The Steve Parker LT77 300tdi mounts should be the same as a R380 with a stumpy bell-housing.
The whole point of the stumpy bell-housing was to keep the engine and transfer box in the same place when a LT77 was replaced with a R380.
On the positive side, you have saved £65.