S3 6cyl to 4cyl converstion

[Jimmy]

Hi all,

A question.

What would I have to do to replace a Series 6 cly with a similar vintage 4cly diesel. Civvy vehicle to ex-army. Currently the 6cyl is a holden, but I have all teh bits for the original rover 6 as well.

I'm thinking adaptor plate mods and engine mounts, but maybe some crew has details on how hard this is, what will be required, what is a better option, any other required changes?

Could I replace the engine/gearbox in its entirety or is that just getting harder with engine mounts and connection to diffs etc?

OR maybe its just a waist of time and I should put a 200TD in it, dunno? the rover 4cyl looks like a nice little donk.

My knowledge is limited in this department, so feel free to provide as much detail as possible:D:D.

Thanks in advance

Jim

[Shonky]

First, good luck finding a decent 2.25D. They are definately out there, but there aren't many and most that I have seen needed a bit of work to come good.

Good contacts would be Dave (BlKnight.aus) who has one in his Series III and I think IsuzuRover has one aswell. Edit: As does Dinty in his LRPV Replica...

I don't know much about either the 2.6P (Rover 6) or the 2.25D but I understand that the 2.25s are externally much the same between Petrol and Diesel variants. ie, it is easy to convert a 4cyl Petrol to Diesel.

I am fairly certain that as you say, the mounts are different between 4 and 6 cylinder models (as is the bellhousing and firewall) so you would need to change the mounts and bell I would think... (?) The firewall should be right.

My knowledge is also limited, so I am really just sounding off my understanding in the hope that it might make sense to you, and someone will fill in the gaps so we both can learn something!

:wasntme:

[Blknight.aus]

youll need new mounts, change the adaptor or the bell housing as a minimum..

then its onto rehosing the radiator but thats childs play as is the aircleaner setup.

the throttle linkage will also cause some minor problems but I have 2 sets of the 4 pot linkages one from the zenith and the stromberg setup. so you can borrow one of them to template off of or shell some $$ at it.

how hard it will be will depend on if the rover was originally a 6 or 4 pot.

[Jimmy]

youll need new mounts, change the adaptor or the bell housing as a minimum..

then its onto rehosing the radiator but thats childs play as is the aircleaner setup.

the throttle linkage will also cause some minor problems but I have 2 sets of the 4 pot linkages one from the zenith and the stromberg setup. so you can borrow one of them to template off of or shell some $$ at it.

how hard it will be will depend on if the rover was originally a 6 or 4 pot.


The series was originally a 6cyl, converted to a holden. I've got a donor 4cyl deisel vehicle in mind (with Fairy), so one of the ideas was to do an old switch-a-roo of the engine, box etc etc and just link it up to the diffs. I could be dreaming :D:D I just kinda figured the 4cyl would be smaller and hence need new mounts and linkages (which I could get off the donor vehicle).

THe other option was just a nengine swap, and hence new mounts, adaptor and some wiring/linkages etc etc.

Happy for someone to tell me I am dreaming.

Jim

[Blknight.aus]

nope its not a dream its been done before...

its not exactly hard but will require engineering certs as your going to have to do chassis welding to move the mounts or fab up adaptors to get the engine mounts to suit the chassis.

the petrol 2.25 and the diesel are one for one swaps... everyone at work told me I was nuts for trying it with fozzy but I had it all done in 3 8 hour days and then spent a week doing tidy up for rego.

in the first 3 days I pulled 2 donks, swapped a gearbox, changed the propshafts and fueltanks from one vehicle to another, installed the diesel in fozzy, setup the fuel system and the exhuast and then put all the cab back together and the radiator frame and cooling system. but I was swapping like parts for like parts and I knew that there would be no welding or cutting work required.

if you are still keen on going this route do yourself a BIG favor get yourself a 2.25 anything thats dead and strip it down to just the block, engine mounts, adaptor plate, and starter motor. It makes setting things up a lot easier for when you put the real engine in.

[Davo]

Yes, it could be done, but I wouldn't, being too lazy. The reason is because the six cylinder has a different chassis to the four. The gearbox sits further back by a few inches. They had to do this to get the six to fit with the headlights in the grille. This means that for you the diesel would sit back further than it normally would, and this means all sorts of little troubles with things that don't quite fit. Also the six cylinder bellhousing and input shaft are different to the four, and the four cylinder box is what you want to mate up with the diesel.

Personally, I would stick with the Holden any day. I took out a 202 to put in a Rover 2.25 petrol and have been disappointed with the lack of power ever since. In the olden days, the Rover six was a great candidate for a Holden six because there was easily enough room, unlike the four cylinder where the radiator had to be moved forward.

Dare I mention the K.I.S.S. principle? :D

[Dinty]

G'day All, I knew that the 6cyl bell housing was different to the 4cyl version but on my understanding the input spigot is the same right through the Series range maybe I'm wrong but I don't think so cheers Dennis:angel:
PS maybe not the same as the very early S1??

[Davo]

Gawd 'elp me, you're right, the input shaft is the same. I was thinking about another box. Sorry about that! It's just the bellhousing bolt pattern that's different, and someone might have changed that on yours to a 4-cyl. pattern anyway. :angel: