960 Rally Car

Spac

Starting this thread early for a couple of reasons - the main ones are to use it as a planning thread and to see how close the finished reality is to the plans...

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Having not quite finished the BMW, I shouldn’t be starting a new project yet, but there’s a few things motivating me to do so:

First is a couple of good mates had a BIG crash at the Alpine rally late last year, and one of them suffered life threatening and life changing injuries. The short version is that a bunch of weird events put them into the scenery at full noise and were unlucky enough that they hit a “perfectly” sized tree in the gap between the chassis rail and the engine block, negating most of the crumple zones built into their 1970s Japanese car.

This has lead me to wanting a more substantial car and (particularly) more substantial rollcage. Specifically, I want a bar between the front legs and bars out to the strut towers.

The second main reason is that I have been watching too much Swedish Rally on YouTube (https://m.youtube.com/user/SwedishRally). This video has been notably unhelpful:

https://m.youtube.com/watch?v=8QZlQ91Ri6o

Here’s a screenshot from the video...

Combined with the ever-present need to build or fix something (aka my mental health plan) and having some cash sitting around, meant that I went from “idly kicking an idea around” to committing to the project.

After some discussion and much hand-wringing, I decided to start with a live-axle 940 bodyshell, rather than one of the IRS 960 shells.

I have two white 940s in stock (ie: sitting in the back yard). The obvious choice was the 91 GL because it is the rougher car and doesn’t run.

And also because it has manual windows.

Here’s the plan:

91 940 bodyshell.B6304 motor.BMW 6-speed gearbox bia adaptor plate (KL Racing or DIY).Toyota HiLux diff, 4.55 ratio. LSD if I can find a cheap one, locker otherwise.Hotbits front struts, with MCA valving.Offroad Bilstein rear shocks, with MCA valving. Two sets of Triumph triple throttle bodies.Autronic SM4 ECU.Proper bias adjustable pedal box.Comprehensive weld- in rollcage.Falcon 15x7 Snowflake wheels.Plus all the usual rally gear.

I have already accumulated most of this stuff - the main bits I don’t have are the rollcage, rear shocks and ECU.

While my shitty gall bladder and consequent health issues has been limiting my ability to actually get on and do things, I have been buying stuff!

Spac

Some of the bits were already accumulated, some have been purchased specifically for this project.

The BMW gearboxes are $1200 from Aussie wreckers ?, or about $700 inc freight from the UK. I bought a complete, drivable stat write off E87 for $800. I can fit one on my spare BMW 5-speeds and either use it as a khana car or sell it off again.

That’s were it all stands. With the Mirage out of the garage, the next step is to get the 940 up into the driveway and start stripping the interior.

turvolvo_kid

Very nice, most of the 940 Rally cars on YT look soft and slightly slow, or maybe I'm just used to WRC, but this guy is good.

Spac

turvolvo_kid
Very nice, most of the 940 Rally cars on YT look soft and slightly slow, or maybe I'm just used to WRC, but this guy is good.

Everything is slow compared to WRC!

The Swedes are proper fast for old school 2WDs - I can run comfortably mid pack at most Aussie club/state level stuff, but reckon I would be slaughtered over there.

Roinik

This site might be of interest: http://www.kohlerracing.se/

PaddlerEd

4.55 Hilux diff out of what sort of era? There might be cross over to the Prado, 4Runner/Surf depending on era. The benefit of the Prado is disc brake, the others are all drums.

Spac

PaddlerEd
4.55 Hilux diff out of what sort of era? There might be cross over to the Prado, 4Runner/Surf depending on era. The benefit of the Prado is disc brake, the others are all drums.

I bought a housing from a mate and it came with a bunch of ratios from 4.55 to 5.7, so it is all a bit of a guess. There's a 2WD housing, a pair of 2WD axles and a spare set of 4WD axles.

I am planning on using S13 turbo front brakes on the rear, with R33 front brakes on the front.

Major Ledfoot

What class will the completed unit end up in?

Spac

PRC.

Basically going to call it a 1992 960. They’ve relaxed a lot on the details compared to the old days - stuff like people being denied a start because they have 808 tail-lights in their RX-3 is long gone. And not before time!

Spac

Fairly productive day...

Philia_Bear

If your doing full cage, the crash bars (tubes) in the doors are a high boron manganese steel and weigh several kg each

On front and rear edge of door you should see the 3 spot welds that hold the strapping that hold the bar in place

Drill the spot welds and it should be easy to remove the bar

Philia_Bear

Also

Since manual, 940na radiator is shorter (on the bottom) than a 960 radiator

I'd run the 940na radiator for less risk, with the factory efan there is still more cooling than you will ever need

Tentacle wagon experience is that even while towing 1.8tons up steep grades in the usa the fan never kicked on when doing more than 70kph

Under 70kph it was cycling occasionally

It never got warm enough (89c on return water) to switch onto high

I had it set to cycle fan onto low when return water above 75c was entering the engine (measures at lower radiator hose)

ramrod

@Philia_Bear

Yeah but being that it's a 1991 940 it will have the small 240 size radiator

You can upgrade to 1992- radiator and thermo fan if you prefer thermo, or keep the clutch fan but put in the bigger 1992- radiator

Spac

Ah... so what are the options for radiator sizes?

This car is an early one with the small radiator.

I also have a 93 940 with the larger radiator. All factory automatics.

I had been assuming that the 95 960 donor car’s radiator was the same as the 93 940’s?

Will the 960 radiator fit into the 91 940’s slot?

Philia_Bear

Spac
Ah... so what are the options for radiator sizes?
This car is an early one with the small radiator.
I also have a 93 940 with the larger radiator. All factory automatics.
I had been assuming that the 95 960 donor car’s radiator was the same as the 93 940’s?
Will the 960 radiator fit into the 91 940’s slot?

Yes, the core support is same part number for 940/960, the later 960 swapped from the removable fiberglass top center bit to a non removable one but the slot on the bottom is the same, 98 s90 radiator will drop into a 91 940na by using the mounting hardware from the s90

ramrod

Yes you might be able to fit a 960 radiator and fan in your 940, test to be sure

Spac

Roof vent was today’s effort.

Had been building this in my head for a while, wasn’t sure how it would work out in practice.

Missing lots of photos, as usual - because I usually don’t have time to take them.

I made a cardboard template that I thought looked about right. Then roughed out two sides from 2mm aluminium.

Bolted them together to get the shape right/same. On the linisher at first, then with a hand file.

Then taught myself how to use the shrinker-stretcher. Fun tool, that one.

Made the top of the vent from 0.9mm aluminium. Partly because it is easy to work with, partly because it is light weight and partly because I actually don’t want the vent to be too strong - I want it to be damaged more than the roof if it takes a hit.

I worked out that putting graduations on it makes it far easier. If you need to tighten the bend, you have a reference - “it needs be be tighter at 7”.

Didn’t get the very front quite right (second photo up). Basically, I shouldn’t have had the front lip folded on the side, because the shrinker couldn’t grab it properly.

OMG, it actually looks pretty good!

I am half thinking that it is too tall and needs the sides cut down. Will deliberately not look at/think about it for a while and see what I think in a few days time.

The actual vents themselves are $6 each from epay. Designed to be Suzuki SX4 dash vents.

Third and fourth items from the left are one vent disassembled. If I leave the black tube out, it is neater and simpler, but I then have to choose between having the vent point in only one direction, or leaking when it rains.

I mean, the gaps here show that they're going to leak... But the tubes pointing up into the space under the aluminium cover will mean that water won't just flow along the roof skin and in through the holes.

If I include the tube, then it won’t leak and can be rotated to point wherever I want. Final decision will have to wait until the rollcage is in.

Oh, and it is booked in at Lochleigh Enterprises to get the rollcage bent up. Not sure exactly when though - they have a government contract to finish first.

Spac

Small progress today - stupid paid employment getting in the way...Plates to replace the bonnet catches and be mounting points for the bonnet pins. 5mm aluminium.

And removed part of the factory seat mounts because they get in the way of the race seat mounts. Kind of a turd of a job, because Volvo’s spot welding machine appeared to have a drinking problem - welds on top of each other, some good welds that are easy to see and some poor welds that are invisible until they stuff you up.

Lumps in the floor will need to be bashed down. Left hand one has the fuel pump under it, right hand one has the catalytic converter. Probably ought to move them before the bashing begins...

Philia_Bear

If you want pics of cross cuts of the chassis let me know and I can post them up

Philia_Bear

Removing the sound deadening is most easily done with dry ice and a sds+ wide chisel in a sds+ rotary hammer (in hammer mode)

Sound deadening is worth 15-20kg over the whole car