Redtop onto an F16 Box....

[AndyGee]

A wee while ago, I bought a Redtop Engine complete with the F20 Gearbox still attached, the idea at the time was to swap the Redtop and F20 box in place of the 8V and F16 Box in one piece.
Now, I'm thinking I just want to swap the Engines, and bolt the Redtop to the existing F16 Gearbox. The reason for this is that I know the existing F16 Gearbox is a good yun, and I don't know what condition the F20 is in - maybe it's a clunker....

Tonight, I've just spent a few hours "pulling" the Gearbox Imput Shaft out of the F20 ready for seperating the Gearbox from the Redtop when I had a thought... - will the F16 Gearbox Shaft fit into the Redtop Engine Clutch Plate....

Anybody got any info please...

Oh and, the Redtop has the later "Pot" type Flywheel, not sure if this makes any difference.

[ant]

Re: Redtop onto an F16 Box....

As far as the box is concerned they are the same with fitting to the redtop and drive shafts etc.

The main differences between the F20 and F16 is the strength of the box. The F20 has a larger Input Shaft Bearing to take the extra HP/Load the Clutch Fork is Stronger and the Sump/Oil Pan is Solid/Cast Aluminum to help strengthen the Diff area of the box.

The F16 will take the power of the XE but may fail if the continuously thrash it or drag race it but saying this my F16 with Straight cut gears and diff plus ATB had 150HP@wheels running through it a STD XE has aprox 150Hp at the flywheel so some 120ish HP at the wheels.

If you run the F16 make sure you use a spigot bush/bearing in the end of the Crankshaft for the gearbox pinion shaft to locate. This will help with the Pinion Shaft bearing taking a beating. You should use the pinion bush/bearing for either gearbox anyway... some people don't I have noticed.

I would consider getting the F20box looked at and using it as it will be a better box and may have a CR gear set.

I am going to change my F16 box case to the F20 for the rally car to get the strengths as I mentioned above. but what I'm going to do with my other box is build a spare from a combination of my F16 spare (another spare one) and the leftover F20 internals. The F20 is a 3.5:1 diff with a Close Ratio Gearset and the F16 is a 3.9:1 with Wide Ration Gearset. Im going to use one of the F16 cases and fit the F20 CR gearset to the F16 3.9:1 DIff this will give me the slightly lower diff ratio for excelleration and the CR gearset to keep up the momentum... obviosly I don't care about the fact I might not be able to hit the same topend speed.

As for the clutch I only have ever has flat type clutches but as far as I know it should be ok if you make sure you keep the Throughout Bearing that match the clutch... so if you use the F16 box make sure you get the F20 Throughout Bearing off the clutch fork and fit it onto the F16.

If you got the equal length drive shaft when you got the XE/F20 now is a time to fit it as well. If you didn't get one I would have a hunt for one as it will makes a bit difference in drivability and traction.

[richie00boy]

Re: Redtop onto an F16 Box....

You will need to fit a flat flywheel to the XE to mate with the F16 box and clutch, and the 8v flywheel won't be any use as it's 6 bolts opposed to 8. If you haven't actually loosened the gearbox bolts I would just put the input shaft back in and drop the lot in. It's a pig trying to swap a box with the engine still in.

[ant]

Re: Redtop onto an F16 Box....

For my own interest (as I have one here but never used it)... why wont the Pot Flywheel/Clutch fit with the F16 box?

Just did a google and found a few posts on other forums for you to read.

http://www.migweb.co.uk/forums/engin...f16-c20xe.html

http://www.clubcalibra.com/index.php?topic=8185.10;wap2

So other than the weight there seems to be some people that says it just fits. Unless someone can tell me why it wouldn't.

[richie00boy]

Re: Redtop onto an F16 Box....

I thought the F20 used a different clutch to the F16, the F20 one is a little bigger?

[ant]

Re: Redtop onto an F16 Box....

The flywheels are the same size outside otherwise the starter wouldn't work or fit. The only reason I can think of is if the Clutch Folk is different but then it wouldn't work for swaping with a flat plate either so any difference would be in the length of the Through out Bearing if the there is a difference in the thickness between the Flat flywheel/clutch and the Pot flywheel/clutch.

My previous post has some links to support a "yes it fits"

So sorry for the confusion Andy I am sure some who has done the F16 to XE with Pot Flywheel will let us all know.

[DarrenH]

Re: Redtop onto an F16 Box....

for the original question yes an F16 input shaft will fit to F20 clutch friction plate, same splines and shaft OD.

you are right in saying you just need the correct combination of clutch. i.e all the bits for a pot flywheel, or all the bits for a flat flywheel.

if an F16 bellhousing wont clear a pot flywheel you will soon know about it, i think it will as the boxes are indenticle other than the bearings ant mentions, and the F20 differential is bigger (in terms of phsyical mass of metal its made from, and planet/sun gear size) if it doesnt then we've all learnt something and you have a backup F20 anyway

[AndyGee]

Re: Redtop onto an F16 Box....

Thanks for the info folks, seems like the F16 Box will bolt onto the XE. From the replies, looks like I will have to swap the Clutch Release Bearing and arm to suit the "Pot" type Flywheel, but everything else looks good for the swap.
As for the equal length shafts ANT, unfortunately the scrappies cut the Driveshafts when removing the engine from the Calibra, so it's going tohave to stay with the "prop shaft" length right hand drive shaft...
MOT next up, then the XE is deffo going in, it's been sat on the delivery pallet for 12 months now, and I'm really looking forward to fitting it, getting it running, and comparing the the XE vs the 8V.
I've been driving the 8V for 10 years now, and have never driven a 16V Astra, so I'm really looking forward to seeing what the real difference between the Engines actually is......

I'll post the change on my Resto thread, AND what I think the difference in Power e.t.c actually is.....

[ant]

Re: Redtop onto an F16 Box....

Bugger... yeah chase a equal length drive shaft when you can it's worth the effort.

I'm 99.9% you won't need to change the Clutch Release Bearing Arm just the Clutch Release Bearing itself to match the clutch. Try to get a spigot bush/bearing for the crank if it doesn't have one to give the F16 the best chance with the extra HP.

FYI: I was told many years ago from Harry Hockly the max flywheel HP the F16 box would take with a spigot bearing in place was 190BHP.

[AndyGee]

Re: Redtop onto an F16 Box....

Cheers Ant, keeping the existing Release arm is one less thing to change mate.
As for the equal length Shaft stuff, what does it improve - Torque Steer????

The srappy did leave all the Right hand shaft bearing stuff on the Engine, so maybe I could convert if I can get hold of the shaft....

[DarrenH]

Re: Redtop onto an F16 Box....

never seen a spiggot bearing on a FWD vauxhall engine. but it wouldnt hurt

[screamer69]

Re: Redtop onto an F16 Box....

f16 will bolt stright on

f20 isnt that strong as people make out ive smashed 5 + apart and did 2 in a weekend on mine and i now use a f18 but mine is turbo

[ant]

Re: Redtop onto an F16 Box....

Yeah Andy torque steer and help with traction etc.

Yeah I seem to see that now... all Australian variation running the F16 run a Spigot Bush... but this is an extreme place... Ive had driveways to my houses longer and ruffer than a special stage on the British WRC

The boxes have a fairly long input shaft from front box bearing to clutch and because of this length it doesn't take much to load the bearing and try to flex the case around the bearing. The F20 box was designed to fix this problem as they found with the F16 and 200BHP they often broke the boxes. So increasing the bearing and I'd say the case is stronger around it to help. I never found out what the expected HP the F20 was rated at but I still will run a spigot bush with the rebuild XE/F20 case combination as I intend to give it a workout as you do with a rally car.

Of course I am talking from a Race/Rally perspective here, so I am looking at the extreme and preventative measures.

[Simon]

Re: Redtop onto an F16 Box....

If you need a hand to wire it up give me a shout andy

[AndyGee]

Re: Redtop onto an F16 Box....

Cheers Simon, as I said MOT first, then the XE swap.
Need to sort the Power Steering Pipe before anything else, the 8V Four Branch manifold has managed to "Melt" a hole into the pipe that goes from the pump to the Rack. Spent all morning removing it, off with the Fan, Radiator and the Steering Reservoir, don't fancy my chances trying to get a new one, so i'm taking to a place in Kilmarnock tomorrow that can hopefully fix the hole.
Managed to deposite 1.5 Litres of Steeing fluid onto the Ayrshire Roads limping the car home from work on Friday - oops...