What's happened to the Griff 4.0 / GKN open or limited slip?
Discussion
Ok, the question comes at the end of this post. First I thought I'd give people a run down of what's happened to my Griff over the last month or so, so here's the story.....
IT all started with a MOT failure on the front bushes. I figured if they were shot I might as well change front and rear, so all the suspension came off and polybushes fitted all round. Front lower wishbones had seen better days so I replaced them with new tubular types. All new joints on the front, new steering gaitors and the front was almost done. I added some rose jointed anti-roll bar links as welll for good measure.
On the rear, I swapped the lower wishbones for later ones, and added a rear anti-roll bar with polybushes and rose jointed links.
I'd recently fitted a big front brake kit to my car courtesy of Hans (contactable through piston heads). So I thought I'd upgrade to Griff 500 spec rear brakes. For anyone doing this conversion, to make it fit you need the later type rear bearing carriers which I think are still 2wd Cossie, just later. New rear bearings in the carriers, new discs, new calipers and the rear suspension was back together.
Then I came to fit new driveshafts as the old ones were getting a bit clonky and with the car in gear as I tightened the driveshaft bolts, to my surprise the driveshaft turned. So it seems that either the diff isn't an LSD or it's a little more complex than just "a clutch pack". It's a GKN type. Does anyone know anything about this? Seems a little strange to me.
Anyway, suspension and brakes are all but done now.
On the engine side, I took the exhaust manaifolds off which had been blowing for ages, poured water in them to test for leaks and found a leak right in the middle of the run of four which I couldn't get to. I replaced with much nicer stainless ones from ACT. To complement this I added some ACT carbon trupets and put everything back. A chance check of the distributor alarmed me to realise that the vaccum advance was touching the top water outlet. Whilst I placed my hand on this the distributor turned which isn't ideal. A quick test of the vaccum advance showed that that was ruptured so I replaced that. After some cleaning of the crank damper and spots of white paint I've set the timing up at about 6 degrees BTDC for now which is a good 10 degrees out from where it was. I wonder if the manifold crack wasn't helped by the retarded ignition and hotter temp in the manifolds - not good for my exhaust valves either :-(
I also had the injectors cleaned by Austech just in case whilst I had the bits apart.
As a note, examining the original "merge section" where the two manifolds join it was horrendous. Neither "collector" really points the gas down and the single smaller pipe actually protruded in to the two larger ones making the flow even worse!
After eventually tracking down why the ECU didn't want to play ball (there's a post on this) I fitted a second hand Optimax chip and the car started up and immediately idled at 3000rpm. After replacing the idle valve (which I must have damaged somehow - there's a post on this too). I re-started the car and it sounded like a different machine, so much crisper than before!
So for anyone with a 4.0, my two finds were that Griff 500 rear brakes need just a change of bearing carrier and that Griff 500 rear anti-roll bar fits with later wishbones.
If anyone has any info on the GKN diff I'd be very interested to hear it. Could it have been changed for an open type? Could the clutch packs have just failed?
I'd like to say just how great it is to drive....But I'm still one driveshalf re-fit away from taking it off the stands and trying it - I certainly hope the work's been worth it!
Cheers,
Neil
PS if anyone's interested in any of this I could post some pics.
IT all started with a MOT failure on the front bushes. I figured if they were shot I might as well change front and rear, so all the suspension came off and polybushes fitted all round. Front lower wishbones had seen better days so I replaced them with new tubular types. All new joints on the front, new steering gaitors and the front was almost done. I added some rose jointed anti-roll bar links as welll for good measure.
On the rear, I swapped the lower wishbones for later ones, and added a rear anti-roll bar with polybushes and rose jointed links.
I'd recently fitted a big front brake kit to my car courtesy of Hans (contactable through piston heads). So I thought I'd upgrade to Griff 500 spec rear brakes. For anyone doing this conversion, to make it fit you need the later type rear bearing carriers which I think are still 2wd Cossie, just later. New rear bearings in the carriers, new discs, new calipers and the rear suspension was back together.
Then I came to fit new driveshafts as the old ones were getting a bit clonky and with the car in gear as I tightened the driveshaft bolts, to my surprise the driveshaft turned. So it seems that either the diff isn't an LSD or it's a little more complex than just "a clutch pack". It's a GKN type. Does anyone know anything about this? Seems a little strange to me.
Anyway, suspension and brakes are all but done now.
On the engine side, I took the exhaust manaifolds off which had been blowing for ages, poured water in them to test for leaks and found a leak right in the middle of the run of four which I couldn't get to. I replaced with much nicer stainless ones from ACT. To complement this I added some ACT carbon trupets and put everything back. A chance check of the distributor alarmed me to realise that the vaccum advance was touching the top water outlet. Whilst I placed my hand on this the distributor turned which isn't ideal. A quick test of the vaccum advance showed that that was ruptured so I replaced that. After some cleaning of the crank damper and spots of white paint I've set the timing up at about 6 degrees BTDC for now which is a good 10 degrees out from where it was. I wonder if the manifold crack wasn't helped by the retarded ignition and hotter temp in the manifolds - not good for my exhaust valves either :-(
I also had the injectors cleaned by Austech just in case whilst I had the bits apart.
As a note, examining the original "merge section" where the two manifolds join it was horrendous. Neither "collector" really points the gas down and the single smaller pipe actually protruded in to the two larger ones making the flow even worse!
After eventually tracking down why the ECU didn't want to play ball (there's a post on this) I fitted a second hand Optimax chip and the car started up and immediately idled at 3000rpm. After replacing the idle valve (which I must have damaged somehow - there's a post on this too). I re-started the car and it sounded like a different machine, so much crisper than before!
So for anyone with a 4.0, my two finds were that Griff 500 rear brakes need just a change of bearing carrier and that Griff 500 rear anti-roll bar fits with later wishbones.
If anyone has any info on the GKN diff I'd be very interested to hear it. Could it have been changed for an open type? Could the clutch packs have just failed?
I'd like to say just how great it is to drive....But I'm still one driveshalf re-fit away from taking it off the stands and trying it - I certainly hope the work's been worth it!
Cheers,
Neil
PS if anyone's interested in any of this I could post some pics.
Send me an email and I'll pass on his email address. He was an "RS" breaker. I think that some of the V6 other cars use them too. Anyway all I needed to tell him was "273mm vented discs" and he sent me the right carriers.
I'm currently away so it will take a week or so until I can access and reply to email.
Cheers,
N
I'm currently away so it will take a week or so until I can access and reply to email.
Cheers,
N
kabaman said:
Send me an email and I'll pass on his email address. He was an "RS" breaker. I think that some of the V6 other cars use them too. Anyway all I needed to tell him was "273mm vented discs" and he sent me the right carriers.
I'm currently away so it will take a week or so until I can access and reply to email.
Cheers,
N
YHM,thank you I'm currently away so it will take a week or so until I can access and reply to email.
Cheers,
N
Quinny said:
My Diff sounds to be in a similar state to yours. (Same Diff)
I'm guessing is due a rebuild, and I'd love to find someone who can do it without taking the piss.
Let me know if you come up with anything
Let me know if you do Quinny,i have one at work that needs bearings and seals only would like to have one on the ready for my car,not got worse since ownership but am sure it could be quieter I'm guessing is due a rebuild, and I'd love to find someone who can do it without taking the piss.
Let me know if you come up with anything
currently stripped down on the back of the bench.
Pasco said:
spend said:
To the point of your original posting, AFIK being able to turn one driveshaft when the other is locked is normal & you should only be worried if you cant do it.
O/T Did you see Mikey buddy ? and i hope you have unpacked 
My GKN diff also has the same traits in that there is only slight resistance / small locking levels when you turn it by hand, however I've had it on a loose surface before with some lock on and both wheels spin up.
My feeling is that its probably a bit worn on the clutch pack but it still provides some limited slip
My feeling is that its probably a bit worn on the clutch pack but it still provides some limited slip
Gassing Station | Griffith | Top of Page | What's New | My Stuff