Fitting the Engine – Haynes Roadster

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A trial fitment of the Rover V8 engine goes well. – At first

I forgot how heavy engines are. I haven’t got around to welding up the engine hoist yet, so it was down to the old fashioned way of humping it in. Unfortunately, I was caught and told off by the better half. Luckily, it was already in, it just needed positioning, by which I mean turning up the right way. She’s stronger than she looks!

It is sitting about 6mm too high at the moment, but it is close enough for checking that everything fits. Everything is just propped together on bits of wood and metal bars so fine adjustment isn’t possible yet. The point of this trial assembly isn’t to make my chassis more complete, it is to check my CAD work is correct. The starter motor hasn’t been fitted in the above shot, but everything is sitting almost perfectly. All of the propshaft UJ’s only have a few degrees of bend and the installation looks neat.

The prop-shaft in the above shot is placed very close to where the CAD drawing said.

The front diff has been put in place to check the clearance between the oil filter and the front prop-shaft UJ.

Haynes Roadster 4x4 Front Differential Clearance

As I said the diff is just wedged on bits of wood and I couldn’t get it to stay still without wobbling in the correct position for the photo but hopefully you’ll see there is around 10mm clearance – exactly as the CAD drawings.

All was going well so far.

Next job was to check the bell-housing clearance.

Haynes Roadster Bellhousing Clearance

I’m using a Borg Warner BW35 bell-housing from a 1965 Rover P5B 3.5. I’m tig welding this to a MT75 4×4 gearbox.

The engine is currently clearing the cross tube by about 6mm. Drop the engine 6mm to it’s correct position and we get 12.0mm. Slightly tighter than the 12.9mm I had in the CAD but not too far off!

I’m all smiles so far, but things are about to go wrong. I hadn’t got around to drawing up the P38 Rover 4.6i starter motor (Lucas LRT00169) as a result I couldn’t ‘virtually’ check that the prop-shaft would clear.

Haynes Roadster Starter Clearance

To get the prop-shaft to clear the starter, keeping the prop-shaft horizontal, would mean quite a bend in the central UJ (see above), with that bend replicated at the gearbox UJ. The prop-shaft now occupies the same space as the exhaust down-pipe and a tube would need removing from the central tunnel. A re-think is needed. It’s all going wrong – fast!

Now I have the parts in solid 3D to play with, there is the opportunity to re-shuffle in steel and change the drawing to match. I tried getting the prop-shaft to sit below the troublesome solenoid but I didn’t have a great deal of luck. All these bits are hard to prop or clamp into place and have that familiar habit of dropping on my fingers or simply hitting the floor. – It’s quite frustrating.

Haynes Roadster Front Propshaft clearance

The prop-shaft below the solenoid looks like this.

Haynes Roadster Front propshaft clearance

The trouble, as you can see, is the rear section of the prop now sits on the chassis tube, the urethane mounts for bearing have no natural home and it looks a crooked mess. It will need to bend even more when the engine drops to the correct height.

Instead of the prop-shaft being V shaped sideways, it’s now V shaped vertically. Plus it still hasn’t moved far enough to clear the exhaust manifold.

That solenoid is being a real pain!

If only I could get the prop-shaft to lie in the position shown in the top picture!

One option is to look for another starter motor where the solenoid is above, below or remote. The Morgan Plus Eight / Rover P6 3500 has the solenoid below (Lucas LRS00318). There are always those hi-torque, super fast, compact versions with a gearbox where the motor normally sits and the motor above tight to the block but they are not cheap.

The chances of finding any of these in a scrap-yard are extremely slim.

Another is to investigate extending the length of the front prop-shaft by about 30cm, so the UJ and central bearing can sit next to the bell-housing. Without drawing it, I already think the rear section of the prop-shaft might be a little too short with the two UJ’s almost touching.

I’m afraid it is time to fire up the CAD again. I’m not going to let this hiccup stop me, or even slow me down.

I’m progressing well with the bellhousing conversion on the MT75. My confidence in getting this conversion right has suddenly grown. It’ll be going to the brother in law for TIG welding very soon. Watch this space.

More pictures here

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