- New posts
- Search forums

# ZF 4HP22 step by step.

- Thread starter WarrenL
- Start date May 25, 2013

P

#### PeterZRH

##### Well-Known Member

Jan 18, 2017
#81
Jan 18, 2017
#81
I'm now officially ZF powered! Easily as refined as a 1990s car which is not surprising given that you have effectively a late 90s Range Rover drivetrain with a useful 800kg less to move around. In fact I had a V8 before with this gearbox. However that was a BMW 530i in which BMW seemed to drain all the V8 charisma and sound out of it. The Later 528i 6 was far better.
Now all I need is for it to be warmer than -5 degree and the salt washed off the road.... Pictures to follow...
S

#### smokin1942

##### Member

Jan 18, 2017
#82
Jan 18, 2017
#82
PeterZRH said:
I'm now officially ZF powered! Easily as refined as a 1990s car which is not surprising given that you have effectively a late 90s Range Rover drivetrain with a useful 800kg less to move around. ...
Click to expand...
Nice work! Looking forward to full Pics'n'Words report!
P

#### PeterZRH

##### Well-Known Member

Jan 18, 2017
#83
Jan 18, 2017
#83
Well, here're the pics.
Impressions. Well firstly, with the new box and new UJs, there simply is no slop at all in the drivetrain, no clunking whatsoever. The shifter feels super tight and very much more notchy and positive than the BW35.
Driving the pickup is super smooth and there is no whining at all. It seems to pull away cleaner and more quickly but that might be a function of the state of the old box The clutch engagement/disengagement is so much gentler than the BW35. Even with a V8, 4th gear feels awful tall when locked up! My V8 is a bit down on power at the moment so perhaps I can't fully test it. The kickdown feels more ooperative than the BW but that might be because it's simply well adjusted. Unlike its driver.
As for the installation, you need a surprising beefy bracket for the shifter to pull against. The exhaust is easy. Simply cut it short ahead of the bend, and long behind the bend. Then flip the cut piece 180 degrees. The bend is then moved 10cm or so backwards as necessary. It's a little tight on the Bowden cable so there's a little heatshield on the exhaust just in case. I had to fit a somewhat smaller cooler than Andy supplied, you can see it next to my electric fan which as it is now moved off-centre it needed a cut to the valance which I'd previously avoided.... Hopefully it'll be enough, cooling isn't a likely to be an issue right now but 35 degrees through the Alps.... What are the signs of an overheating box, preferably before it's terminal?
All I can say is Andy (eightofthem) did a top job on the box, it's just flawless, looks new, drives new, operates as new. I can't even described the joy of not having red transmission fluid over the floor!
Last edited: Jan 20, 2017
P

#### PeterZRH

##### Well-Known Member

Jan 24, 2017
#84
Jan 24, 2017
#84
Another effect is that starting the car is much quieter as in almost inaudible and the car doesn't seem to rock so violently, very unexpected. Strange, perhaps the starter ring was worn on my old flywheel and the new flexplate much better..
R

#### roverp5Bcoupe

##### Active Member

Jan 24, 2017
#85
Jan 24, 2017
#85
Peter,
Nice it all works well! I am also very pleased with the ZF box on my P5B. It drives much more comfortable.
I see that on your car there are hoses used to connect the box with the cooler. I used 4 hydraulic pipes with 4 hoses as i was afraid the hoses would rub against engie or bodywork. I assume they used an XJ40 cable between shifter and trans. Just curious how they connected it to the shifter. Do you have a picture of that and are the 1,2 and 3 position also working?
Here's a picture of my set up
Regards
Peter
P

#### PeterZRH

##### Well-Known Member

Jan 24, 2017
#86
Jan 24, 2017
#86
Hi,
1,2,3 and D all work with the modified BW35 shifter, the secret is having the right lever arm on the box (mine came from Andy). Even so it was quite difficult to get this to work properly. At first I could pull it back to "1" and the push it forward and I couldn't quite get "D" without operating the selector button, although it was OK on the way down. There's a very fine adjustment between getting this and being able to reach "1". "1" is very tight but they are all there. Not that you really use "1" really but it's good that the job is done properly.
It might be a good idea to very lightly file the selector gate to get a tiny fraction more throw.
I didn't get any pics of the arrangement. It's quite a long way forward of the shifter compared to your setup.
The hose are secured in several places. I'm not worried about these rubbing, but yours is probably a better solution, most OEM installations are like yours.
Do you have the Jaguar box with the thermo valve? That largish cooler might overcool on some conditions. I couldnt fit one that size and had to go one smaller (I think yours is 13 row, mine 9).
R

#### roverp5Bcoupe

##### Active Member

Jan 25, 2017
#87
Jan 25, 2017
#87
Peter,
I fitted the XJ40 arm which i also got from Andy and changed the "tooth" section in the shifter to get precise shifts and it works very well although the stroke is very short. I have another P5B which i am restoring and got another LDV box some years ago and with this box came the original LDV shifter so i could copy the tooth pattern on the Rover shifter
Above you see the modified one for the ZF box and underneath you see the original BW35 tooth pattern.
I don't have the Jaguar box so i don't have a thermostat fitted. I thought about installing a universal thermostat but didn't do it as very few cars have this. The Range Rover didn't have this thermostat either. I can understand that the workshop didn't fit the hydraulic pipes as it is a lot of work figuring out the routing, making the pipes ect. In general these conversion take a lot of time due to unexpected issue's. But as you say it makes the car so much more comfortable to drive so in the end it is worth it..
Another question: my speedo is working but shows a lower speed then the actual speed. Does your speedo show the right speed?
Regards
Peter

#### WarrenL

##### Active Member

Jan 25, 2017
#88
Jan 25, 2017
#88
Congratulations Peter! Welcome to the club.
P

#### PeterZRH

##### Well-Known Member

Jan 25, 2017
#89
Jan 25, 2017
#89
Hi Peter, I have an identical set-up to Warren's with the Dakota Digital box, the speedo reading is simply a question of calibration. Surprisingly out of the box it wasn't very far off. What a great piece of kit this box is. You simply make up a long wire with a button on the end and go for a drive with your GPS. You can then choose whether to have a really accurate speedo or "go long" by a few percent, I went with 3% but I tend to use the GPS speedo anyway.
The cooler is more of a concern for me because it is regularly minus 10 here and the box would otherwise operate for extended periods too cool. I'm thinking if you are commuting at all then this is going to help warm-up quite a bit.
Your selector gate is very interesting, you've added stops between the lower gears? Can you describe how this works? Perhaps you'd be prepared to supply a copy for a suitable sum? Or at least a PDF so I can print and stick to some metal to Dremel myself one.
Really if someone can produce a reasonable, complete kit and come in between £1500-£2000 then frankly I think for a car that's really used in modern traffic, you'd be out of your mind to put back a BW35 or BW65. These were only just about adequate when new anyway. The way I see it as a practical car the P6 only has two real flaws today, the gearing and wind noise at speed. Let's face it roads have changed a lot since then as well, not simply motorways but bypasses, trunk roads all require higher cruising speeds, which is where many classics fall down badly. I know the originality thing but unnecessary engine noise is just tiring and annoying. It's also out of character with a large V8, so if anything I think of it as therapy to fix a character flaw....
I'm trying to forget the actual cost. Shall we say really very decent P6 money? At the end of the day I still have a very average but solid car but this and the engine upgrades are about making a fun drivable car, it doesn't need to have perfect paintwork.
I just sourced the components and did very little of the work myself as I don't have a garage. This is unavoidable currently and had the box decided to fail at another time, I would have loved the satisfaction of DIYing more of this. However that would mean mothballing the car for this year at least and I don't know when I'll have so much time to drive as I will soon. Also the guy I contracted to do this is an absolute perfectionist and I now have what I can only describe as the Roll Royce of brackets merely to locate my radiator expansion tank when a simple strap would have done. Seriously, when the bill came back I probably would not have done this, at least in this country and the costs implied. My fault, I should have agreed stricter terms when starting the project. I thought providing the major components and the write-up on AROnline would be enough to come in with a realistic estimate. Err, no. I think buying Andy's box and the crossmember then the rest is well within the ability of anyone who can change a gearbox but boy, does making-up custom brackets and general fettling eat up time.
Last edited: Jan 25, 2017
P

#### PeterZRH

##### Well-Known Member

Jan 25, 2017
#90
Jan 25, 2017
#90
Thanks Warren, literally couldn't have done it without you.
R

#### roverp5Bcoupe

##### Active Member

Jan 25, 2017
#91
Jan 25, 2017
#91
Peter,
Beneath you find the toothed part from the LDV shifter which also had the seperate stops for the 1,2, and 3 alrhough there is a lot more room as the LDV shifter was much bigger
This how the shifter works
I welded up the original toothed sectioons like in the photo above and then fitted it to the shifter and connected the shifter to the box with the cable and then shifted threw the gears while marking where the depth should be
I don't have toothed plates anymore but could post a PDF with a scale of the modified toothed pieces.
Peter

#### WarrenL

##### Active Member

Jan 25, 2017
#92
Jan 25, 2017
#92
Oh, I don't know. It was a solution just begging to be implemented. If I hadn't done it somebody else would have, sooner or later. But thank you. It's like night and day, the comparison between BW and ZF, isn't it?
Interesting, your adventures with the shifter. I had less hassle than you getting all positions to select with the original selector. It took me about 10 minutes of adjustment before it worked absolutely beautifully. I guess it comes down to variation in componentry, or something.
P

#### PeterZRH

##### Well-Known Member

Jan 25, 2017
#93
Jan 25, 2017
#93
WarrenL said:
It's like night and day, the comparison between BW and ZF, isn't it?
.
Click to expand...
To me, it would be utterly wrong to say it "transforms the car" or that "it feels like a completely different car". To me, it makes the car how it should naturally be. With the BW35 it simply seemed to run out of gears; it's just unnatural to cruise a V8 over 3000rpm. And really just wastefully pointless. Your write-up is spot on on AROnline, in that a big V8 and an auto are natural companions. In the US currently there is a big scene retrofitting modern GM 4 speed automatic transmissions to 1960s cars, this is very much in the spirit of this.
Another reassurance is overhead for some mild tuning. I'm shooting for 180-190bhp with hopefully the best part of 140-150 at the wheels. Not hot rod territory but enough to make the P6 a match for the likes of a current BMW 320i and still faster than most family cars. Now I know quite a few run tuned motors with the BW35 but it really is perhaps pushing it a bit. Rover seemed happy to move to the GM180 with the SD1.
Finally if I choose to run tyres with a slightly smaller rolling radius, I'm not really going to miss it with that massive overdrive gear whereas with the old transmission it just makes a bad situation worse.
Now to repeat myself - if only someone can put together a totally complete kit.....

#### WarrenL

##### Active Member

Jan 26, 2017
#94
Jan 26, 2017
#94
I'd like to rephrase that. The night and day difference (more a figure of speech than a technical description!) is between the two gearboxes, rather than the car. In changing to the ZF the fundamental character of the car remains exactly the same, but the whole experience is greatly enhanced, which is exactly what I was hoping to achieve. Does that make any sense at all?
M

#### mikecoombs

##### Active Member

Jan 26, 2017
#95
Jan 26, 2017
#95
From memory the box in my '76 P6B was originally a GM180. I have a manual with the service details in it somewhere...Current engine is a blueprinted and mildly modified (roller rockers big bore exhaust, worked heads with standard valves and matched inlet manifold and stage 2 cam) and it produces some 240 ft lb at 3000 rpm at the wheels through a BW35 with '65 drive train (by BW themselves, I think it was the taxi pack). but it isn't much good down below 1500 and really you have to wait till about 2200 before you start moving, then kickdown at 100kms sends you into the back seat. Hence I'm changing the diff down to 3.54:1. I figure when I get the ZF together and installed the overdrive will give me my cruise back! In the mean time getting the engine into the power band and off idle faster should improve both take off and fuel economy.

#### corazon

##### Well-Known Member

Jan 26, 2017
#96
Jan 26, 2017
#96
Mike that will be similar to my 4.6 project with zf and 3.54 jag diff, which when I did the calculations looked on paper to result in a very nice cruise rpm and great acceleration. It will be interesting to compare when they are both finished!
Jim
P

#### PeterZRH

##### Well-Known Member

Jan 27, 2017
#97
Jan 27, 2017
#97
For reconditioning is a complete 3500 BW35 box, flexplate, housing, converter and speedo angle drive worth anything?
H

#### harveyp6

##### Well-Known Member

Jan 27, 2017
#98
Jan 27, 2017
#98
PeterZRH said:
For reconditioning is a complete 3500 BW35 box, flexplate, housing, converter and speedo angle drive worth anything?
Click to expand...
Everything has a value.....
The angle drive particularly, and the rest will make money from the various parts.
P

#### PeterZRH

##### Well-Known Member

Apr 3, 2017
#99
Apr 3, 2017
#99
Anyone finding the overall gearing a little too tall with the 0.73:1 overdrive gear? Top gear locked gives you 32.8mph/1000rpm which is more than my diesel with 50% more torque...
I'm thinking 195/70 tyres which will drop about 4%... Or more? Opinions please.

#### ghce

##### Well-Known Member

Apr 4, 2017
#100
Apr 4, 2017
#100
Hi Peter, the ZF gives you a 1:1 in 3rd so if you just use the stick for locking into 4th for high speed cruising I would be thinking it would be ok.
My beleif is that the RV8 is torquy enough any way for the highe ratio, certainly seemed very acceptable in Warrens car
You must log in or register to reply here.
Share: Facebook Twitter Google+ Reddit Pinterest Tumblr WhatsApp Email Link
Top