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MG MGB GT V8 Factory Originals Technical - '96 Disco 4.0L, Trans and F.I. questions

I just aquired a 4.0L FI with all components (incl brainbox)from a '96 Disco. I know there are differences between the 3.9 and the 4.0, but does this include the transmission? Could anyone point me in the right direction or tell me some more about the tranny options (bellhousings, gearbox, etc) available for this engine? Are they the same as the 3.9 (SD1 or Borg Warner T5 w/adapter plate)? Also, any links on the distributorless system and the FI. I have found general info in the archives here, and in Roger's V8 conversions pages on the UK site, but nothing specific to the 4.0. Any help would be greatly appreciated! Thanks!
jim thornburn

oops, this will hopefully be going into my 1976 MGB.
jim thornburn

I imagine that you have the GEMS 8 engine management which will be the system that goes with the innlet castings that are similar to the previous 3.9, but with a squared and flattend plenum top, painted black and sporting '4.0 Litre' machined decoration. If so then there are some possibilities fo fitting the engine as acomplete unit. The fronmt cover and oil pump is a completely different set up with the pump now being driven from the nose of the crankshft. This leads to a different position of oil filter attachemnet which for RHD is really in the way of the steering. For LHD there may be some greater flexibility, but sice I haven't gone this route this needs further comment from one who has.

With the GEMS 8 you have a fully integrated engine managment system with double output coils (wasted spark principles apply) and a sequential injection system. I have no expecience of operating the systems in anything other than fully standard modes, so I can't comment on whether there would be any possibility of using say just the ignition side and not injection. I suspect that it would need some ECU mods to work properly.

By 1996 the manual trans was updated to the R380 series which is a much improved design over the older LT77 series. It does offer the advantage of allowing previous LT77 (SD1 pattern) bellhousing, gear remotes etc to fit. Quite whether the rear end casing from an LT77 would fit an R380 to replace the 4X4 transfer box is another issue and here is expect it would not.

Rog
Roger Parker

Roger,
Thanks for your speedy reply. You are correct in the ID of my model (squared and flattend plenum top, painted black and sporting '4.0 Litre' machined decoration). I was hoping to use everything, especially the fuel injection, in the fully standard mode. If you could provide a source of reading material online, or the title of a good book (even if it's the factory Disco manual), I have an FI savvy person I plan to use, who could use this info.

Also, if you or anyone else has more specific info on using the Borg/Warner T5 (which adapter plates, bellhousings, flywheels, clutchforks, etc. I can use), the SD1 stuff seems to be hard (and more expensive) to come by here in the states.

Thanks again,

jimt
jim thornburn

The GEMS 8 has this sqared polenum which is a real pig for the bonnet (hood) clearance. Fortunately any of the earlier domed Plenums from the Hot Wire set ups can be fitted. What further mods are needed will depend on the actual engine final fitted position and what sort of bonnet line you want.

An RV8 bonnet line can be achieved with the domed earlier plenums with no intake system mods as long as the engine sits in the same place as the factory V8's and uses the slimmer RV8 engine mounting rubbers. If the bonnet line is to be standard then you need to remove an amount of metal from the intake castings but here the different fuel rail and injectors would deamnd you do some specific calculation to ensure that all will fit. Not having done any work on non standard GEMS 8 or the current Bosch systems I can't comment in detail.

There will be some issues on the oil system plumbing due to the oil pump on the nose of the crank and the different front covber design, however several people have used these engines now and so I doubt there is too much of a problem in creatring a new remote oil filter system.

The complete wiring from the Land Rover should be used and this should allow a reasonably simple integration into the MGBs wiring system. For simplicity and reliability create a new separately fed fuse box to feed all the new engine functions and take some of the others away from the MG system. Cooling fans for example. This reduction of loads to the MG system should actually increase that systems reliability.

For further reads you can do no better than go the the V8 conversions section within mgcars.org. Ceratinly all the additional fuel system mods applicable for earlier fuel injection systems apply to your system as well.

Rog

Roger Parker

I have sourced a '97 Range Rover with an R380. Roger stated that he doesn't think the LT77 box rear housing would bolt to the R380 where the transfer case attaches. Has anyone tried this? Is it just a matter of the main shaft? Hmmmmm.... a very stout transmission.

Curtis in Sacramento.
C.J. Hunter

This thread was discussed between 12/12/2000 and 20/12/2009

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