More work on the engine swap

July 9th 2017

I'm moving ahead pretty quickly (by my standards) so these items are almost just a memory now.

The list of stuff to do is pretty long and in reality, provided I don't do anything completely out of order it doesn't really matter. 2 hours work is 2 hours work and moves it along nicely.

The thermostat on these Rover K series engines has been the root cause of the bad reputation they have received. Not because it is bad, but because it is in the return from the radiator and is measuring cooled water, rather than the usual "straight from the head" very hot water.
Combined with the fact that lots of fitters didn't bother to read how to bleed the cooling system on the Rover Group cars you get the situation in which cars were boiling up all over the shop. Something this engine didn't appreciate. At least in earlier incarnations.
I have decided, like most Caterham and Lotus users, to remove the thermostat and fit a remote one in the top hose.
But just removing it doesn't help because it alters the flow too much. So cutting just the valve off the thermostat, and replacing the mounting plate seems to be the common advice.

So that's what I did.

Thermostat Mod

That black lump of plastic next to the dipstick tube is the housing.

There's the little bugger.

Bit of anglegrinder-action

and pop the remains back in the housing, without the innards.

So. That's that for the moment.

Engine Mounts

Something to hold the motor in place would be good.
I had made new mounts for the Imp engine which had been flapping about a bit.
Using these as my starting point I just made some new attachment points and stuck them on. On the passenger side I had to remove some of the vertical element from the chassis frame as the exhaust wanted to go that way. I reinforced the remains with some fillets of steel plate to make up for that.
Compared to the wavy bits of alloy plate that the Imp had used this is Forth Bridge engineering.

I don't have many shots of these bits for some reason.



Passenger side

Driver's side

The legs hanging down are to mount the sump guard on.

Suspension A frame

The oil filter assembly is a bit of a sod as it goes where the existing suspension A-frame likes to be.

The black tube is the arm. The oily gasket is where the oil filter assembly would be.

This meant making a new A-frame with clearance for the oil filter.

By marking the 3 attachment points on a plastic board I was free to "design" a new frame, as long as the three bearings were in the right spot. The old frame at the top, new one at the bottom.

As I used a heavier gauge steel tube I reckon I will get away without any bracing, although I retain the right to add some fillets on the inside of the angles if I want !

This is the new frame and oil filter in close harmony. The new oil pressure pipe adaptor is fitted.

I allowed a couple of centimetres (I've gone metric) clearance to allow for chassis frame flexing.

I can't really see any bending occurring, but will keep an eye on it. I may even make a cardboard template so I can check at intervals.

I slightly overdid the welding on the threaded boss for the front bearing. I had to recut the thread as my penetration was bit OTT.

Moving on to the exhaust 

(do we have to?)
This is a major puzzle-job. The original Rover manifold starts promisingly, but then the pipes all drop into a catalyst-type canister pointing downwards.
I don't want downwards, and I don't want 4 into 1.
So I went off to the scrappy and bought some decent exhausts with lots of bends, to make my own sideways exiting 4-2-1 manifold.

I chopped off the canister and fitted the remains to the engine. Then marked where I thought I could get the right flow out to the side from.

With those bits chopped off I could start tagging some bends on to get the right sweep to

a) Get the best flow

b) Look good ( the main objective)

I already posted about this being like 3D chess on facebook. It's not a career move I plan on making any time soon.

Whilst this a looks fairly straightforward, I then had to dismantle some of it to get at the joints that I needed to weld. I am using MIG and frankly, it wouldn't be my choice, but I don't have TIG or gas (which would have been my choice) and for a one-off it's not worth laying out £600 notes or so.
I would be better off paying someone to make it in stainless.
However this only represents £30 investment and a bit of time.


I went for the weld and grind approach. It looks prettier and to be honest, even if it had a small leak here and there, so what?

A bit of VHT paint and it looks much nicer.

Cut down engine mounting on the chassis rail

Yeah. The silencer isn't connected in this shot.

So with no chance of firing up yet I need to carry on to....

The Inlet Manifold

This is more than just a build-it job. The major question is ... What fuel?

A couple of friends have been badgering me to fit LPG. It has many advantages and I can see them all. However, I want this re-engine to be a straight exchange with little extra expenditure. So keeping the SU copy (ISO carb) from the Imp makes a bit of sense. The fact that the Imp ran faultlessly with this carb is also a good point in its favour.

My reasoning is that as I am going to have to go to a an ECU ignition system ,and it is a new motor, I don't really want to add a 3rd variable into the equation at this point.

Later, once I have the motor running well, I probably will go LPG.

Yes the carb is only 38mm, but I am doing this engine swap for more torque and low-end flexibility, not loads of revs.

I got a steel laser-cut flange for the manifold and set off down the same route as I went with the exhaust manifold. 

Making it fit the space. Pedal Box

This is tricky as the pedal box and two hydraulic master cylinders are in the way.

I have looked around the pits at other cars and one option was to fit the master cylinders above and behind the pedal shaft. But in my situation I didn't think I could get the bonnet clearance needed.

This was one installation that appealed.

My clearance above the pivot points was limited and I don't want to alter the bonnet or lower the pedal shaft and risk higher pedal pressures.

I settled on the easiest method of building a new mounting box and moving the brake cylinder more outboard. Using a cylinder with a remote reservoir would make more space as well (I have a couple of spare cylinders for that).

Ditching the hydraulic clutch and going for a cable operated mechanism would save a lot of space and move it above the manifold level as the pedal needs to pull (above the pivot point) rather than push.

I took the old mounting plate out and made a cardboard template. The lever on top of the clutch pedal is only partly done. It needs cranking backwards to make best use of the space.

I used 3mm plate (as that is what I had). Scored it with an angle grinder and "bent" it to match the template

The pipe along the top of the manifold comes from an elbow on the cooling system outlet on the cylinder head. This will form my manifold heating. It feeds back into the cool water inlet at the thermostat housing. It is the by-pass system (heater) from the original Rover installation.

The original mounting plate for the master cylinders was welded in place. I am bolting this one to make mods, and engine removal, easier. 

The master cylinder is mounted at an angle to make the supply pipe from the reservoir clear the carb better. Fitting it in is still tight.

The cable mechanism for the clutch will be mounted on top of this plate, well clear of the carb.

Manifold ( at last)

So now I have altered the pedal box (almost). I was able to measure and make the inlet manifold.

Using the stubs that came with it (it was designed for fitting bike carbs) I marked them so that I could cut and attach a common tract for the single carb to supply all the cylinders.

(note the old pedal box still in place)

This is the feed tract. (I have cut the old pedal box away now). I have left an overlap at the ends as it seems (following research on t'internet, that it helps reduce friction at the bend, for the fuel charge).

I made a flange for the carb from an old exhaust flange and fitted it at the right angle to have the float chamber level (when will it ever be level?).

Welding this lot together was a bit of a nightmare as this one does need to be sealed properly. There is a mm or two distortion along the length of the flange, but before I have it planed I'll give it a whirl as bolting it up to the head I can't get any feeler gauges in the manifold/headface joint. I may just get away with it.

That'll do for now as it's sunny outside and I have a birthday party to attend.

.................................................................................

Next time we should have the Timing belt changed, clutch mechanism finished and possibly the engine management in place.