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Daimler V8 250 ZF4 HP-22 conversion

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lomh 13
Posts: 62
Joined: Thu Jan 12, 2017 11:48 am
Location: France

Daimler V8 250 ZF4 HP-22 conversion

Post by lomh 13 »

Hello everyone,
A lot of people in England ask me how I adapted a ZF gearbox in my Daimler V8 250. I will explain everything here.
This adaptation was made two years ago and a few thousand miles have been covered since.
First of all I would like to thank the people from other forums who allowed me to carry out this project.
I know other boxes can be used, but I will share my experience here, and sorry for my english...

The goal is to replace the old BW35 gearbox, slow, with a torque converter that skates constantly, but especially that has only three gears.
The choice is focused on the ZF because it offers 4 gears including an overdrive, very fast passages like a modern box, and a lock-up on the converter that saves fuel.
In the ZF range, the 4 HP-22 is ideal because it takes the necessary power, has no electronics and above all has a removable bell, which is no longer the case with the following models.
Because the goal is to keep the original bell with the starter in its place and the Daimler flexiplate.
This conversion is reversible in the case you want to return to original.
The ZF 4 HP-22 as been used by many makes. Prefer one from a Jaguar (XJ40 or 300) because the output flange is the same as the BW 35 one.

You need :
The gearbox
The dipstick
The rear mounting

1 bell adaptation
The two boxes with their bells and their torque converters:
Image
It is found that the ZF is shorter
Image
7 cm shorter in total length, but the bell of the BW is 2 cm longer. With the thickness of the coupling plate, it will always be shorter. So an extension of the existing shaft propeler will be necessary.
The two bells are deposited.
Image
Attention, on the ZF, the hydraulic pump is maintained by the screws of the bell. At the drop and for the rest of the work, it must be secured. Here we see three screws with washers to compensate for the thickness of the bottom of the bell.
Both boxes have bells positioned by concentric circular shoulders, which facilitates the realization of the adapter plate.
This plate is a crown whose outside diameter corresponds to that of the BW bell
Image
and the small diameter to that of the pump body of the ZF pump.
Image
It is cut in a sheet of 6 millimeters thick by a cut, with water in my case.
The external diameter is 240mm abd the inner 146mm. This is 1mm wider than the final dimensions. The ribs are adjusted precisely to the bell and pump with a lathe.
Here is a PVC test spacer. On the picture, the centering holes have been allready drilled
Image
The screw holes are located directly on the bells. A line materializes the top of the bell BW on the spacer, it will help orient it on the ZF.
Image
The spacer is held in place by a vise clamp to drill the first holes before it can be secured with screws and nuts on the bell.
Drilling is done from the bell side with a system to center the drill.
Here with the means of the edge for the prototypes :
Image
Image
Or with centering devices made on the lathe.
Image
The holes on the BW bell spotted may pass to those of the ZF bell.
For this I used a PVC centerer that I had cut at the same time as the spacer. It simulates the shoulder of the oil pump of the ZF.
Image
This makes it possible to center the spacer on the bell of the ZF. In the photo the final holes had already been drilled.
Be careful when positioning the spacer to respect the BW and ZF side. Otherwise the holes will be reversed.
Bell side BW holes are countersunk and new TF screws are used. Be careful, they must not protrude inside the bell.
Image
If we look at the inside of the bell BW with the spacer in place, we see that some screws of the ZF are no longer accessible.
Do not panic, there is a solution.
Image
As you can see, only 6 screws are accessible. And you have to grind a little the BW bell to allow the socket of the ratchet to be able to pass around the heads of the screws.
Some other minor grinding is needed at this level. The goal is to have the same thicknes of the ZF bell.
For the other screws, no problem. New, shorter TF screws will be used.
The body of the pump is a little modified.
Image
The holes of his screws are countersunk and the new screws will tighten the pump directly on the body of the box, whereas before it was sandwiched between the bell and the body of the box.

To be continued

Robert
Last edited by lomh 13 on Thu Sep 09, 2021 8:53 pm, edited 1 time in total.
Robert
What looks right is right

DaveM
Posts: 57
Joined: Thu Oct 27, 2016 3:36 pm
Location: Haslemere, UK

Re: Daimler V8 250 ZF4 HP-22 conversion

Post by DaveM »

Beautiful work, well done indeed

Cheers Dave

Stevesv8250
Posts: 38
Joined: Tue Mar 02, 2021 10:07 am
Location: Hullbridge Essex. Uk

Re: Daimler V8 250 ZF4 HP-22 conversion

Post by Stevesv8250 »

Great post.

lomh 13
Posts: 62
Joined: Thu Jan 12, 2017 11:48 am
Location: France

Re: Daimler V8 250 ZF4 HP-22 conversion

Post by lomh 13 »

The following

The main thing is that the screws do not exceed the support plane between bell and pump.
Image
Image
The pump is now secured to the body of the box.
Image
The steel spacer is ready to take place
Image
The BW bell can be installed on the ZF box.
Image
The ZF torque converter must be modified with a lathe because the fitting on the crankshaft is different.
Image
Similarly, the flexiplate must be drilled because the ZF converter has only three screws.
Moreover the circle on which are these three holes is smaller.
Image
This requires to enlarge a little the hole of the coupling plate between the engine and the bell to allow the passage of the socket of the ratchet.
Image
The modified ZF torque converter can take place.
Image
Setting up a torque converter is pretty tricky. The easiest way is to position the box vertically and to hang a strap or other to be able to handle it.
Be careful that the splines of the main shaft and the notches of the pump shaft engage properly.
If the converter is empty, before setting it up, fill it with 2 liters of Dexron 3 hydraulic oil.
Even if the opening is facing down during installation, the oil will not come out or at least not much.
The converter with the device to maneuver it.
Image
If the converter is in place, the tip of its centering pin in the crankshaft should be 2 or 3 mm away from the joint plane.
The adaptation of the bell is complete, the box is ready to be coupled to the engine.
Image
Image
Image
Assembly done
Image

Next step, install all this in the car after the tests on the bench

To be continued

Robert
Robert
What looks right is right

lomh 13
Posts: 62
Joined: Thu Jan 12, 2017 11:48 am
Location: France

Re: Daimler V8 250 ZF4 HP-22 conversion

Post by lomh 13 »

The following

The oil dipstick of the box is on the left side of the engine. It will be a little bent to adjust properly. A flange on the exhaust manifold immobilizes it.
Image
Be careful, for a left-hand drive car, when installing the group in the car, the gauge should not be in place because of the steering column.
The cooling hoses of the box are made to measure.
Image
They are in two parts with a central holding flange at the bell.
Image
The front part connects directly to the radiator
Image

2 Changes on the car
The back of the box ZF is wider than the BW.
On my car, witch has been the first done, I have modified the tunnel.
Image
Cutting at the tunnel and bending the sheet. Desoldering the old box supports.
Image
To create new reinforcements adapted to the support of the ZF box, I used a stainless steel profile of 4 mm thick.
Image
The holes were made from below with the support placed temporarily.
Image
The height adjustment of the back of the box is obtained with rylsan spacers.
The goal is to find exactly the same position of the flange as originally.
Image
The hole in the tunnel is capped with a resin cover.
Image
An old plant container will serve as a mold.
Image
If you need to make a boss like me, you can use a petanque ball and a heat gun.
Image
The set is then strated with polyester resin and glass fabric, but will be removable.


Like I said, this is for my car. For the second carried out later, the gearbox support was modified, the rear of the gearbox lowered, which made it possible not to modify the bodywork.

To be continued
Robert
What looks right is right

tjt77
Wise Man
Wise Man
Posts: 525
Joined: Wed Mar 23, 2016 7:01 pm

Re: Daimler V8 250 ZF4 HP-22 conversion

Post by tjt77 »

Given the ZF 4HP22 has no provision for speedometer drive ... what to do about the speedo ?
I have conversion to take a GM 200R4 or 700R4.. I have not installed it yet..but will try and post some images..

lomh 13
Posts: 62
Joined: Thu Jan 12, 2017 11:48 am
Location: France

Re: Daimler V8 250 ZF4 HP-22 conversion

Post by lomh 13 »

The next chapiter will cover shaft, speedometer, gear selection, kickdown and many more.
I am not at home for now and I have no picture with me.
Robert
What looks right is right

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