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LT77 & LT230 into 88"


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I thought I'd start a thread on this as I've read a lot of threads about doing the conversion and yet have still ended up hitting a few snags along the way so here goes.

This is in a Series 3 SWB with a Disco 200tdi mated to a Series 3 suffix D box, running a Fairey overdrive, 3.54 diffs and 235/85R16 tyres. I was quite happy with the gearing both on and off road, it would happily cruise on the motor way at 70mph but I have decided to bite the bullet and fit a 5 speed.

The new box is a 56A suffix H LT77S from a 200tdi Defender,

Transfer box is a 36D suffix G 1.211 ratio LT230 - I believe this is a late 300tdi Discovery box - the one with the 38 spline cross drilled input gear - early version of the D2 Q case?

I have already converted the centre diff to selectable 4wd using the kit from Ashcrofts, I know lots of people are running them in 4wd but it's just personal preference as I've always liked the rear wheel drive.

According to Ashcrofts ratio calculator the new setup should give me a similar high ratio to my old drivetrain only with a lower 1st gear which will be nice and of course it will put the low ratio back down to standard.

So here we go, out with the old box:

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With the old gear boxes out, the LT77 was dropped into place so we could mark for the mountings, I'm using standard Defender mounts that came with the box.

The bracket for the Series handbrake assembly have had to be cut off to make way for the right hand mount. The brake pipe has also had to move to make way for the mount too.

Drilled through the chassis rails and welded in crush tubes.

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As the front drive flange on the LT230 is much further back than on the Series transferbox so I also marked the propshaft line on the crossmember ready to insert a channel for the prop to sit in much like the 109 combat chassis.

The channel is formed by a section cut from a Discovery crossmember.

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New defender / Discovery clutch fitted. I've also had to move one stud and also remove one stud from the flywheel housing to suit the LT77 rather than the series bellhousing.

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I am reusing the series clutch slave cylinder but while fitting it the pipe split so will pick up a new pipe tomorrow - on that note the bolts holding the slave cylinder on the Series and Defender bellhousings are different, the Defender are M8.

Now comes the first difficulty; having read lots of threads about this conversion and lots of them recomending using an x-brake because of the space issue getting the standard drum on and off I went ahead and ordered one, when I came to fit it I found that the caliper is too large to fit in front of the crossmember :huh: and there is no way the original drum would go back on at all :angry2: presumably the people recomending this in the other forums haven't actually done the conversion themselves or have moved something forward.

Only solution I could come up with is to rotate it:

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Having tried it at various angles I've decided the best option is to have the caliper hanging right at the bottom, yes I loose a bit of ground clearance, or rather; ramp breakover angle but not much and I will make up a skid plate to protect it.

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So tomorrows job is to re-drill the plate to allow it to bolt up in this position.

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And this is how it currently sits

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Next job is to get props altered, again having read various threads they mostly suggested that the rear prop would end up rediculously short quoting about 10-12" (again presumably those people haven't actually done the conversion themselves) having now measured the rear prop will need to be 425mm which looking through the tech archive is the same length as an 80" Series 1, the front prop will need to be 785mm. Those measurements are flange to flange with the 200tdi engine mounted on the standard series mounts and the gearbox mounted where it sits when bolted up to that engine.

Off to the prop shaft suppliers in the morning, current plan is for the rear to be the standard Series prop shortened, and for the front I have removed the rear prop from my spare Discovery which again I will have shortened to fit.

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What perfect timing with your thread Pollywog and informative.

I have 2 offroad dates for July, my MOT at the end of July then in Aug I will be installing a LT77/LT230 combo in my Series 3 Hybrid. I'm just finishing up with rebuilding the same 1.211 transfer case, on my hybrid I plan to keep the 4.70 ratio but nothing is stopping me from maybe changing to 4.50's down the road.

I see how tight it is for you with the original frame, my Designa Chassis frame doesn't have that cross member therefore I'm keeping the Defender handbrake. Also I've never seen anyone chop so much out of the front cross member as you did. The reading I've come across state that scalloping the cross member is enough. BUT as you said (and I agree) you just can't take some of the info found on the internet for gospel. I've have though seen where one inventive person used a spacer at the drive flange.

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If I may suggest for propshafts, that you get yourself 2 early RR rear propshafts then get them cut down. The reason for this suggestion is that the early RR (70's) propshafts had the square shape flanges that are wide angle compared to later Defender/Disco/RR and also the series. Also it uses the same larger u-joints as found on series vehicles. Search this forum for wide angle propshafts for more information on them. ;)

What are your plans for the tunnel? Can you post pictures of your mounts that you have bolted trough the frame, just wondering how low they hang.

..........more questions once more progress is made. :P

Cheers,

Todd.

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HiTuko,

I'd read your comment about the RRC props before but alas haven't been able to find any at a reasonable price and I'm now in the position of needing it back on the road as soon as possible as it's my daily driver, so for now I will have to make do.

I had considered a spacer but didn't think there would be much difference in price between having a spacer machined or the props shortened, also having the part time kit the front prop isn't so much of a concern as it won't be spinning most of the time.

I chose to cut a little extra from the crossmember just to be on the safe side, I'd hate to have cut out too little and have to re-do it, also having left all the other crossmembers in place I've no concerns over strength.

Plan at the moment for the tunnel is to use Defender panels, I might get time to mock it up this afternoon, just off to the prop shop now.....

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When I put the LT77/LT230 in my 109 had had similar problems with the handbrake. My solution was to cut that crossmember in half, then cut out the section from the middle to the drivers side chassis rail. I welded plates to the end of the piece and trimmed the gap so that when I welded a plate to the remains of the crossmember the gap was right. Few brackets top and bottom of the chassis rail and the bit is bolted back in. By removing this piece the drum can be slid on and off, and so can the LT230, although it's tight. A friend of mine did something similar, but he cut out the whole crossmember, then welded some angles vertically up the inside of both chassis rails, and he now bolts that crossmember back in with bolts running fore/aft

I'll see if I can find the photo's later

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001.jpg

I also made my own gearbox mounts, which actually fit the LT230 to the Series gearbox crossmember, rather than drilling and tubing the chassis for the defender mounts. I did this as I didn't want to have to alter a galv chassis on another 109 of mine, and because I wanted to prove I could!

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I have lightweight bodywork so the seatbelts mount to that crossmember and with the shape of it would be difficult to scallop it around the brake lever. The X-brake is now re-drilled and mounted upside down, it's not ideal hanging so low but for now as long as it works I'll be happy. I can always revisit the layout and maybe move the crossmember back an inch at a later date especially if I have to take the tub off for some reason.

New clutch pipe fitted after having to swap the fitting and re-flare the pipe due to the new one having the wrong thread.

Here's the Defender gearbox mounts; at the moment I'm only using the 2 upper holes on each, I will at a later date make up some L brackets to weld to the bottom of the chassis and pick up the lower bolt.

Left hand:

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Right hand:

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Started work on the layout of the tunnel this afternoon:

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The next job is to refit the flat Smiths heater, it is going to need to be moved a couple of inches higher than standard so will have to move the aux fuses & VHF radio mount first.

Props should be ready by Thursday / Friday.

If anyones interested we will be on the Gloucestershire & Worcestershire 4x4 Response stand at the Malvern Land Rover Show next weekend - hopefully I'll have it back on the road by then, if not it'll get towed along...

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Pollywog,

The tunnel cover, can you give us a close up of what you did there please. In the center on my hybrid I have a Defender center seat, I'm wondering with how far back the difflock shifter is, will I be able to still use it or will the shifter have to be altered to allow free movement.

Thanks.

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Can you be so kind to give us the dimensions of the greabox/crossmember mount. Looks to be made of 6mm stock, right?

I can, but I really made it all in situ, cutting and welding as required! It is 6mm plate, had plenty of bits lying around, 4 would probably do.

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This is an awesome read :D

Many thanks guys.

I have a SWB Series Hybrid that will get the 200 Tdi from a Disco I.

This is very interesting as I have a full rolling chassis as a Donor.

The Hybrid's chassis is galvanized though..

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Pollywog,

The tunnel cover, can you give us a close up of what you did there please. In the center on my hybrid I have a Defender center seat, I'm wondering with how far back the difflock shifter is, will I be able to still use it or will the shifter have to be altered to allow free movement.

Thanks.

I don't think you'd get a centre seat in unless it sits a long way back, I've had to cut into the top of the seatbox by an inch to clear the lever:

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Excellent pictures Pollywog,

I just wonder if that shifter can be removed from it's housing? If a bit of heat is applied, it could be shaped into a "z" can we say so that it clears the seatbox. I have an extra so I'll take a closer look today plus look at the position of the middle seat.

Todd.

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Looking at this photo, could you not flip the calliper round so the slim side (with the fixed pad) was facing the rear? Looks like that would give you a fair bit more clearance. Might have to trim the tubes down a little but they're only tubes after all.


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Your's is further back than mine. MY LT230 shift lever sits clear of the seatbox

Perhaps it's a difference in the seatboxes with mine being lightweight? Looking at Grems photo's it would appear that the front edge of his seatbox leans backwards while mine is vertical - could easily account for an inch if that is the case?

Looking at this photo, could you not flip the calliper round so the slim side (with the fixed pad) was facing the rear? Looks like that would give you a fair bit more clearance. Might have to trim the tubes down a little but they're only tubes after all.

I didn't think the gap between the disk and the mounting plate looked wide enough to do that? I'll have a measure.

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Picked up the props this morning; shortened, re-phased, & balanced for £35 each by Proptech Ltd on Hartlebury Trading Estate, Kidderminster. Fantastic service and finished a day earlier than expected.

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Nut plate for the Defender handbrake lever arrived today so got that all mounted up but need to make up a stiffner plate to take the flex out of the seatbox. Also had to click the arm around a notch on the caliper to fit the supplied cable.

Heater re-fitted 70mm higher than original - all hoses were fine with this amount of movement thankfully.

I plan on fitting the speedo assembly from a Discovery in the near future but for now I have connected the Defender cable to my existing speedo (the ends are the same) which is a 1000 tpm Smiths originally from a Triumph Spitfire 1500, this was pretty well spot on with the old drivetrain and looks very similar to the standard Series unit. I don't think it'll read too far out.

Took it for a quick spin up and down the road and all appears to be working fine. I have got a knock from the clutch when sat in neutral but according to Ashcrofts site this is quite common and caused by the new clutch springs, hopefully it'll quieten down with use.

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