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Old 29-11-2019, 01:00 PM   #1
Oz
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Default Watsons frame under a standard front

I've been debating whether to do this post because I didn't complete the conversion but I thought the work I did do might help others with their conversions.

Earlier this year I started trying to get a Watsons frame under a standard round nose. I had gone ahead on the shoulders of others (largely Mivic) who had modified their shell in an attempt to reduce the extended nose. Mivic had managed a 55mm extension.

The reason why the standard Watsons/K series frame doesn't sit in the same way the A series Mini frame sits in a Mini shell is because the K series frame has a flat back and so the subframe cannot be positioned far back enough to allow the suspension towers of the frame to sit back in the recesses for the Mini frame towers in the Mini's shell. The benefit of this with the Watsons frame is that the engine sits further forward so there is enough room for the standard plenum chamber without modifying the plenum or the bulkhead.

To get the K series frame back far enough in the shell either the back of the subframe needs substantial modification or the bulkhead needs to be recessed to allow the subframe to move back far enough in the shell. I chose to modify the bulkhead.

Below are a mixture of pics of the recessed bulkhead from my car, Mivic and another car.

Watsons Frame bolted in standard position



I needed to mark how much of the lower part of the bulkhead needs cutting out. You can see the black marker line along the bulkhead of where I need to cut.



Once cut out, the frame can be moved back into the recess like this:-



Pic from inside car of hole cut out of bulkhead



It can then be boxed in like this:-



Watsons use side plates to mount the frame to the car. These bolt through the top damper mount holes on each side. The holes need to be redrilled further forward to allow frame to move back. To get this right (after some trial and a lot of error) I made up some slotted plates so I could slide the frame back and forth to get it properly square in the shell



Once the frame was exactly where I wanted it I tightened the bolts and I tacked washers to the plates to fix the position of the holes. The position of these can then be transferred to the Watsons side plates



A couple of points to watch out for when moving the frame back is that you get contact with other parts of the frame and steering rack with the shell. I was looking to maximise how far I moved the frame back so below are the areas of contact. Obviously if you don't want to go as far back then some of these are not necessary.

1) Top arm

The end of the top arm pivot shaft and nut will hit the bulkhead. I halved the width of the nut and cut the shaft down. This will be sufficient unless you are going for the maximum



As I was going for the maximum it wasn't enough so I had to cut a small section out of the bulkhead.



2) In the above picture you'll see two cuts in the bulkhead. Unfortunately the top rear Hydragas captive nut also hits the bulkhead. As this is used by Watsons to mount the side plates it can't be cut away but it can be ground back a bit. Again if you aren't going for the max then it'll probably be enough. If you are then there's no real point grinding back, just cut the bulkhead.

3) Steering rack

There is one definite and one possible area for contact between the shell and the rack

The possible is the mounting block, plate and nut. Depending on how far back you go this will hit the Mini steering rack recess in the floor



You can either box around it or as Mivic did just cut the recessed section out and plate it flat

The definite is the steering box.



This will need a section cutting out and boxing in



One thing I don't have a pic of but becomes very clear is the rear subframe mounts where it bolts to the floor no longer line up and it hits the lower part of the floor pan. These just need marking and cutting shorter. Then new holes drilled in the mount. If the frame was already in the car then you can use the old holes in the shell for a guide. DO THIS BEFORE YOU FINALISE THE POSITION OF THE HOLES IN THE SIDE PLATES AS UNTIL THIS IS DONE AND THE FLOOR MOUNTS BOLTED UP IT DOES TIP THE FRAME UP SLIGHTLY IN THE SHELL AFFECTING THE POSITION OF THE SIDE PLATE HOLES

Once the frame was bolted in place and the engine fitted it did become obvious that the frame mounts the engine quite high so I redrilled the engine side mount on the frame 20mm lower and cut and repositioned the grearbox side mount 20mm lower.

Before:-



After



I'm not sure it could go much lower as the bottom of the gearbox was getting close to the frame.

The Watsons front crossmember (which is already moved back from the standard K series Frame) WILL NOT fit behind the front valance, note it had to be cut out. You could either box around it or mod the crossmember. I didn't get that far with mine



With the wings, bonnet and front panel on it all fitted.







I was using a Hayward and Scott manifold for decent clearance. I didn't try a standard cast one but I don't think it'd go behind the grill.



The rad will not fit and will need work to get to fit



I had envisaged modifying the Gearbox side mount on the frame to bolt in further back to free up some room behind the front panel.

I had also removed the clutch slave cylinder and actuating arm as I was using as Clutchmasters internal slave. This will affect the room you have.

To give an idea of the saving see below comparison between the extended and standard nose, most of the extension on a Watsons Frame is in front of the engine. Note the frame is the same one in both pics.

Before



After



I would note that the engine in most pics is a standard B20 and AWD box as the genesis for trying this was as I was looking at going AWD but the project was shelved for various reasons.

I hope this is some help to people who want the stronger Metro suspension and steering but baulk at the extended nose. Obviously these tips can also be used to reduce the extension if you are happy to accept a compromise of an extended nose but smaller than the usual 90mm

Last edited by Oz; Yesterday at 09:50 AM.
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Old 03-12-2019, 10:24 AM   #2
arterz
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Interesting, I'm in thought about doing this conversion about a year, but it's difficult to find mg parts here, especially a complete front subframe. Anyway, I ll watching your progress and in the end I ll consider again my thoughts.

Also pics doesn't work, please reupload them, they are important
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Old 03-12-2019, 03:48 PM   #3
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@arterz pictures working fine here, also he said he didn't complete the conversation, so I took that mean he wasn't going to either.
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Old 03-12-2019, 04:07 PM   #4
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I'm sure I have miss somthing here haha.
If I find a complete front mgf front subframe then I m gonna try it, I'm a huge fun of standar nose builds, I ve also checked many many times custom-minis.de. They have a lot of std nose mgf builds

Dimitris
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Old 04-12-2019, 10:01 AM   #5
Oz
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The thread is largely concentrating on the Watsons frame which is a modified Metro/MGF frame. You'd be able to use a standard Metro/MGF frame but further mods would be required to it.

Yes, I didn't complete the conversion. I was originally looking at going AWD but for several reasons I decided to go back to FWD and for that I have a Custom-Minis.de frame that I am using instead so I don't have to mod the bulkhead for the plenum or back of the frame and it has been narrowed by 25-30mm from the standard Metro/MGF track so helps getting my wheels under standard sports pack arches.

I consider the project shelved rather than abandonned. I still have all the parts and subframes tucked away and maybe in a few years I will dig them out and try again but it won't be for a while and will likely be on a different car than my Cooper.

I have had issues with posting photos in the past, I don't know why as they are locally hosted on this site. Most people can see them but some have issues with viewing them. I don't know why.

Last edited by Oz; 04-12-2019 at 11:57 AM.
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