How to convert to a 5 speed gearbox

[entwistlecymru]

Seeing as I'm in the middle of converting my R4F6 to run a 5 speed box I thought I'd post pics to help anyone else thinking of doing the (hopefully worthwhile!) conversion.

First you need to find a 5 speed box. The cheapest route is to find a HA1 gearbox from a mk1 Renault 5. It's basically a HA0 box (the standard R4 gearbox) with an extra gear bolted on to the front of the casing and a different top cover for floor change (see below)

Because of the slightly longer casing there is some cutting and welding of the front crossmember needed so the bonnet will need to come off. If you can get hold of the donor cars X-member it may make things easier but I'll be making my own which should take up less space than welding on the 5's slightly chunky item.

Doing this conversion is a lot easier with the engine out - the standard box will need to come out anyway which means taking the engine out!

The first job is to convert the HA1 from floor change to dash change. Put both gearboxes into neutral to make rebuilding easier. You need to take the top of your HA0 box off (12 x 11mm bolts) and put to one side. Do the same with the HA1. Notice the 'box top is plastic on the HA1 (below right) and alloy in the HA0 (below left).

The next job is to swap the reverse gear selector arm which is slightly smaller on the HA1 (bottom right in above pic). The HA1 reverse selector is held on with a circlip and bolted on on the HA0. You need to use the HA0 bolt and spacing washers with the HA1 reverse selector lever.

Now comes the tricky bit! I found this bit easier with the gearbox at eye height (I put it on a stool on my worktop). You need to line up the gear lever and both ends of the reverse selector with the right bits in the gearbox. It's quite hard to explain but easy when you get around to it.

With the top of the box placed loosely down on the box, you can just see where the main selector and the reverse selector need to go.
The short fat arm of the reverse selector fits into slot marked 1.
The longer, thinner arm fits into the ring on the reverse cog marked 2.
The main selector needs to fit into the slot between the 3 selectors marked 3. The slots in the 3 selectors should be aligned if you put he box into neutral before starting!

Once all 3 selectors are lined up properly the top of the box can be bolted down. You may find if the top of the box has been off beofre that the gasket is a bit ropey. You can either cut a new one or do as I did and use silicon. Tighten all 12 bolts equally and try selecting all 6 gears.

The next installment will be the dirty job of cutting the old crossmember out and making a new one. Check back soon!

 

[mr-reno-139]

and try selecting all 6 gears

Amazing ,when it left me i am sure it only had 5 !!!!

the standard box will need to come out anyway which means taking the engine out!

not strictly true as box will come out the bottom ( not funny if it lands on you whilst under car though - Ouch!)

only joking with you Chris

 

[angel]

not strictly true as box will come out the bottom ( not funny if it lands on you whilst under car though - Ouch!)

When I didn't have a car lift I used to remove R4 gearboxes by lifting them until they clear the crossmember from above. I slacken the engine mountings so as not to strain them. It is necessary to remove the steering rack but it is a lot easier than the official Renault method.

 

[bantamallan]

Paul, you are not thinking, there are 6 gears, one is for going backwards!

 

[entwistlecymru]

Part 2!
Here's the new front x-member. It's 4 mmplate, bent around the front of the 'box and drilled to fir the 5spd mount. I've braced it along the bottom edge and gusseted between it and the rear edge of the remains of the old x-member.

If you're doing this an engine crane is a must. I had to lift the engine in and out 5 times to get it sitting right.

Here it is as a finished article

It seems modifying the bottom edge of the bonnet is unavoidable. I chopped out the flat section where the number plate screws to (some cars have vents here). Then I made up a panel that fits in place of the bit I chopped out, but instead of it being flat it's bells out along the bottom edge. This way when viewed from the front you can't see the mod, only when you look from above can you see the bonnet has been 'flared'. It's not perfect yet but it will be!

If cutting the bonnet up you must remember to put strength back into it or it'll twist and flop around all over the place. I remade all of the lower front braces to give plenty of clearance for the gearbox. I'll get some pics up soon

 

[mr-reno-139]

thats a nice shiny gearbox rubber mounting

 

[angel]

Your R4 looks nice! Should drive nice with the 5 speed box!
It is not necessary to modify the bonnet that much. Clementine's solution seems to place the gearbox mounting lower. On my Plein Air replica (which came with an already modified crossmember) there is another type of gearbox mounting with 4 holes. Maybe there were two R5 gearbox mountings or did they use one from another Renault?

 

[mr-reno-139]

well done chris

certainly looks strong enough ,gearbox needs to be at correct height for several reasons
1 ex pipe will not clear inner wing hole
2 drive shafts need to run at correct angle
Angel, part i supplied is standard R5 5sp mounting ,very odd design as had to fit in to r5 cross member - which is same on 4 and 5 speed cars

r4 cross member is closer to end of box hence mods needed

of course if you are really silly (like me) and fit gordini box, chassis legs need extending as well and then just bolt in gordini cross member
(un fortunately lost original photos of my mods , will try and take some more when i can get to my car, looking unlikely with rain outside )

ps i have now found 9!!! ha1 5speed boxes for sale at £50 each if anyone interested

paul

 

[malcolm]

I had to modify my bonnet as well - the bit below the number plate fouls the mount itself when the bonnet is open. I just chopped the bottom 10mm off the front skin of the bonnet and bent the front forwards a little. It's hidden by the UK numberplate. Easier job for me though - I used the Renault 4 bellhousing which is 10mm shorter.

Mine should be about the same height as the original - I measured the height of the driveshafts on a 4 speed box.

I'm sure mine came with the type of mount in the finished photos but I lost it on the way home! Had to buy one from Renault which wasn't such a handy shape - same as the one in the first photo.

 

[entwistlecymru]

I've done something similar to you by the sounds of it Malcolm. The bonnet is now the same depth as it should be but I've put a little "flick-out" bit at the bottom so it clears the new gearbox mount, then hidden all my hard work with a number plate! Good trick with the R4 bellhousing - I'll try that next time!

As for the height of the mount, I measured the distance from the back of the head to the bulkhead, height of the driveshafts from the chssis rails and distance frm the box to the chassis rails (sideways). As well as the driveshafts the carb should really be at the right level/angle or you may get running problems.