F16 F20 Combination

[ant]

F16 F20 combination idea for a guy.

I noticed that the F20 and the F16CR boxes have the same gear ratios 1st to 5th but different final drive.

I have a F16 with a 3.94 DIff but wide gear set.

So can I just use the F16 mainshaft and final drive and slide on the F20 gears.

I would be using the F16 case as I need the top gearbox mount same as the Cavaliers.

Any traps in this idea I need to think about?

[RallyMarshal]

Re: F16 F20 Combination

Why dont you just use the F16CR complete in that case? I dont think theres a huge difference in the gears themselves - but there is a bearing difference. Maybe it also depends if the F16 is single baulk ring or double? The F18s and F20s are double but some F16s are single and some are double.

Quaife sell their output shaft and CWP as a complete unit for F18/F20 but Ive got one in an F16 casing and an F18 casing with a Quiafe SCCR gearkit and Harvey had one in an F20 casing with standard gears.

Some of the F18CR boxes (Astra Sport etc) have the same mounts as the F16 too. I use them for the cable change bracket rather than an F20 casing.

Paul..

[RallyMarshal]

Re: F16 F20 Combination

Why dont you just use the F16CR complete in that case? I dont think theres a huge difference in the gears themselves - but there is a bearing difference. Maybe it also depends if the F16 is single baulk ring or double? The F18s and F20s are double but some F16s are single and some are double.

Quaife sell their output shaft and CWP as a complete unit for F18/F20 but Ive got one in an F16 casing and an F18 casing with a Quiafe SCCR gearkit and Harvey had one in an F20 casing with standard gears.

Some of the F18CR boxes (Astra Sport etc) have the same mounts as the F16 too. I use them for the cable change bracket rather than an F20 casing.

Paul..

[DarrenH]

Re: F16 F20 Combination

So can I just use the F16 mainshaft and final drive and slide on the F20 gears.

simple answer is yes, however the F20 diff is much stronger chalice and favourable to use but i *think* there is some clearance issues using this diff in F16 housing.

Why dont you just use the F16CR complete in that case?

its a good point but i read it as he only has F20 and a wide F16, so wants to get the 3.94 from wide F16 with close gears from F20.

[ant]

Re: F16 F20 Combination

Paul good points... its just a road car and this is what the guy wants... no don't ask... lol.

Yes Darren I only have a F20 STD and a F16 which is wide ratio but with a 3.94 diff. Just wanting the same or similar as a F16CR.

This is one of the small issues of living in Australia... this is all I can easily get my hands on. I just wanted to make sure I wasn't missing something obvious.

[BenH]

Re: F16 F20 Combination

Yes I did it on my trackcar, but I used a f18W final drive from a mk4 2.0 ecotec astra in a f20 case with the f20 1-5. The diff carrier is more beefy on the F20, just has less cutout's think I might have a picture somwhere.

[ant]

Re: F16 F20 Combination

Thanks Ben, I am stuck with using the F16 Case though... it is going into a Vauxhall Cavalier so it has the gearbox mount on the top of the gearbox... the F20 box I have doesn't have this and although I though of making an elaborate bracket picking up on all the bolts on that side of the box... nah too hard and it's a road car.

[BenH]

Re: F16 F20 Combination

I dont think there is much in the case anyhow, just a bit more webbing on the F20. My Gripper LSD is quite big and fit in a f16 or a f20 case fine, with the exception of the speedo drive but thats a Gripper issue. When I say diff carrier I should of said diff casting really, that has more metal around the planet gears.

[ant]

Re: F16 F20 Combination

Hey I have a question about mechanical speedo drives.

Here are 2 I have



One is 13 teeth and the other 15 teeth.

The 15 tooth Green one is from a Camira (Cavalier) F16 box (3.94 diff) and the other from a Deawoo D16 (3.72 diff) but is also the same in the Calibra F20 I have here.

So are the rings on the Diff different? the gear other than tooth number are the same length and the outer diam the same.

Can I mix and match the tooth number to change the speedo out put?

The Dash I am using is in a Deawoo so it would normally use the white 13 tooth drive... if I put the 15 tooth drive in would it speed up or slow down the speedo output?

[ant]

Re: F16 F20 Combination

Bugger I was hoping someone would know about these mechanical drives.... might just have to do a drive with the ol' gps and try each one and see what the difference.

One very good reason to run the Digi dash... I have a spare I should just sell it to him.

[BenH]

Re: F16 F20 Combination

I'm really not sure as I ran a programmable speedo on mine, are the gears on the diff the same as they might be matched?

[Vinci]

Re: F16 F20 Combination

The green one looks identical to F28 speedo gear, which is definitely different. More teeth would (should) make it show less on the speedo.

As for diffs, you can iirc swap ringgears separately from the diff castings, so any combination there is provided. I have five gearboxes here, with cardridges out packed in plastic containers. I did that to study a bit on them and the differences, and to try a few things out. As Benh said I can only confirm you can swap casings between them with no gear clearance issues.

The boxes I have are F18WR+3.74, F18CR+3.42, F20CR3.55, F16WR3.72 and F28 LZ...

[Vinci]

Re: F16 F20 Combination

P.S. mechanical speedo can be somewhat calibrated running the car with GPS and by pulling the needle and moving it's position on the spindle you can raise/lower spring tension. Best first mark the original position at the back on the spindle to some frame reference point and go from there, and don't pull the needle without holding the spindle tightly, it's not catastrophic, but you will have much more hassle getting even the base position back because the spring will make it go several turns. You can however then keep a reference point by looking at when the needle is pulled back to the zero mph pin...

Good luck anyways!

[ant]

Re: F16 F20 Combination

Yeah thanks for that guys... Ben yeah I have not enough info and idea they are that different at all. The gears measure very similar but 2 tooth different so I suspect they are ment to be the interchanged or can be interchanged without too much of an issue and being Nylon/plastic helps too I guess.

Vinci are yes I have thought maybe this was possible... I think I have a spare Daewoo dash in another shell I'll pull it out and have a play with it befoe I touch this one.

[DarrenH]

Re: F16 F20 Combination

been through all the kadett astra gearboxes, the speedo drive gear on the diff are all 26 teeth, thats F10 through F20. different part number for small and big block gearboxes, but assume that's packaging reasons