Ford 5speed into avenger

[hunted]

Cool article I found on how to put a seierra 5 speed into an avenger. doesnt look too hard if you have the skills and tools

http://rootesgroup.proboards.com/index.cgi?board=general&action=display&thread=140

[avenga]

Interesting read. I might have to look at getting that done on my 1975 Hillman.

It really feels like it needs a 5th gear on the motorway, it does 3,500RPM at 100kph.

Thanks heaps for the link.

[hunted]

yeh I think i might look into it at somestage as well. my plan is for 175/50/13s on my new rims so itl be ringing its tits off at highway speeds haha.

[avenga]

haha, maybe we could find somewhere that will give us a group discount.

[avengertiger]

popular conversion in the uk lots of rally cars go for it as there are hundreds of different options of gear sets from the likes of burton power,quaife etc skip browns used to do a bellhousing conversion so it was ajust a case of 4 bolts off with the ford one and one with skips one same splines on the gearbox as the avenger driveshaft to.

[oldschool]

An easier way to fit the Sierra 5 speed is to use an automatic bell housing with a 12mm spacer plate. Also, changing the standard 155/13 tyres to 165/13 or 175/13 will increase the gearing by 2.75% and 5.5%. My 1974 Alpine seems to have higher gearing than a standard Avenger, can anyone confirm that?

[avenga]

In my Manuals it says there are 2 different ratio manual gearboxes for the Avenger. I don't know if we got both in NZ or when they switched but here are the ratio

Gear ratios (to chassis number R4 184358)
4th 1.000:1
3rd 1.366:1
2nd 2.029:1
1st 3.317:1
reverse 3.680:1

Gear ratios (to chassis number RH 184359)
4th 1.000:1
3rd 1.387:1
2nd 2.165:1
1st 3.538:1
reverse 3.680:1


As for the differential. From what I have seen in NZ is most 1600's had a 3.7:1 ratio differential. most 1300's in NZ have a 4.11:1 ratio differential. I have a 3.7:1 in my '75 Avenger.

To tell what differential you have there are a few ways you can do it.

You can jack in up and count how many rotations of the drive shaft and wheels.

Also you can tell by counting the crown wheel and pinion teeth.

Lastly if you still have standard rolling circumference on your tyres then you can tell by engine speed.

Here are some details on the different differential, note not all were available in NZ.

4.37:1 35 crownwheel teeth, 8 pinion, road speed= 25KPH per 1000RPM, 4,000RPM@100KPH
4.11:1 37 crownwheel teeth, 9 pinion, road speed= 26KPH per 1000RPM, 3,846RPM@100KPH
3.89:1 35 crownwheel teeth, 9 pinion, road speed= 27KPH per 1000RPM, 3,704RPM@100KPH
3.70:1 37 crownwheel teeth, 10 pinion, road speed= 28KPH per 1000RPM, 3,571RPM@100KPH
3.54:1 39 crownwheel teeth, 11 pinion, road speed= 30KPH per 1000RPM, 3,333RPM@100KPH

[NZTiger]

Both gearset were used in NZ. Early ratios changed with the intro of the Estate in the UK to give a lower ratio 1st gear...Estates would carry more and therefore needed the lower ratio and the intermediate gears were changed to suite.

Rear axle ratio...
All NZ 1500 had 3.89.
1300 had 4.11 along with the Estate.
1600 had 3.89 until the last mk2's that changed to 3.7, so 3.89 is most common.
4.375 was never fitted to NZ built Avengers, it was standard in UK 1250 and 1300? and also 930cc Sunbeams.
I am sure that 3.54 was never used for NZ Avengers and I am not sure what it was used in.

[avenga]

Thanks for that info. It is really hard to find out any of the production info so your knowledge is greatly appreciate.

I use an Estate 4.11:1 diff in my race car.

It is interesting that I have a 3.7:1 in my '75. It started off life as a 1300 so I know the diff has been replaced by the previous but they told me they got the diff out of a '74 1600, maybe it had it's diff swapped for a later model one also.

Pretty much all the Avengers I used to scrap for my race car were 79-80's and they all had 3.7:1 so I assumed that was standard because it is all I have ever seen in a 1600, But I have never scrapped an early Avenger so that would be why I haven't seen a 3.89:1 before.

Is there any external markings that you can tell what the diff is from? I have had mine apart and have counted the teeth so I know it is a 3.7:1 but I was hoping there was an easier way to check.

Because of the non-standard diff my speedo is well out so I use a GPS speedo to get acurite speed because my standard speedo reads way low. I plan to fix this when I change to the Alpine dashboard.

[avengertiger]

funny talking about diffs when i was tidying up my stuff at home i came across a box i had long forgotten about in it was a 5.1 cwp the guy with me at the time who rallys a sunbeam his eyes lit up and he did a merry dance around the shed.
cant remeber were i picked it up but they were rare even when i got it and that was prob 10 yrs ago.

[NZTiger]

Re speedos, there are 2 different speedo drive gears in the tail-housing of the gearbox, red is for 4.375 and 4.11 diffs and whites is for 3.89 and probably 3.7. Very easy to change, unscrew the speedo cable, then remove 2 small bolts (7/16" AF) and the remove retainer then pull out the gear with pliers..

[avenga]

I have a spare white gear but I haven't changed it over yet. I am going to do it when I swap over to the Alpine dashboard. They use different speedo cables for the super and alpine dashboards so I need to replace the clip on super cable with a screw on alpine cable.

I have both the new cable and gear so I will do that once I get the Alpine dashboard and cluster restored.

[avenga]

NEWS FLASH!!!! Hunted and I have brought the Avenger engine and automatic gearbox that has been on trademe recently.

Hunted will keep the engine but I will be using the Auto bell housing to attempt to do a 5 speed conversion on my '75. I am bidding on a Sierra gearbox on Trademe so once I get all the parts I will start a thread about my adventures.

As an added twist I am going to try using the BW45 from the Avenger engine to replace the BW35 on my Charger making it a 4 speed instead of a 3 speed. So +1 gears to all cars!

[sunbeam]

Hi,5 speed ford boxes are easy to fit , i ve done two on rallycars, Easiest as above is to use the auto housing , turn up a spacer ( start with 15mm alloy plate) turn down three mill of one face to the size of the hole in the bell housing. This gives in put shaft alignment, because you then bore a hole the size of the ford gearbox input shaft coverplate IE the outside diameter. This aligns everything. You then drill holes to take the ford box bolts. Then drill and thread holes to take the old auto gearbox bolts, bolt together. You can use the existing avenger clutch set up by drilling/taping the stand of for the pivot bolt. Then make up rear gearbox mount (not Hard) The slines are all the same, drive is same,You need to get a ford speedo cable. The gearlever hole needs to go back a bit. The quick shift in one of the photos is steeped up a little high. General rule of thum is to raise 13 mm. The ford syncros are not that good on these. The input shaft crank needle roller needs to be changed (Ford od is smaller)just make spacer. Don't use bronze bush. have found these not too good at high rev's and cluch dust

[avenga]

Thanks heaps for that info. Helps heaps for my upcoming 5 Speed conversion. I have the gearbox and I have brought an Auto bellhousing so when I get the bellhousing I will start work on it.