Help with the Sierra based build

The following is a compilation of three letters John wrote 28. 7. 1996, I have just finished (apart from carpets and a spare wheel cover) my Sierra based Merlin and thought it might assist others who are starting their build to note down some of the solutions to problems encountered. I used a 2 litre OHC engine with webber carb. and distributor -no electronics!

1. The rear body fouled on the top of the handbrake brackets. In order to give clearance I cut them down by 8 -10 mm and rewelded.

2.Initially I bonded the windscreen channels to the screen off the car assuming the curvature at the bottom of the glass would create the right curve for the scuttle -wrong! I then obtained a good fit by bolting the screen to the scuttle whilst the bottom channel sealant was still soft. When finally fitting the screen it required only a smear of sealant on the scuttle to make it weatherproof.

PS To avoid cracking the screen by catching it with the drill -fit the hood studs (keeping close to the edge) before inserting the glass.

3. The exhaust on the OHC is on the driver's side and could have fouled the triangular steering column clamp where it emerges from the bulkhead, particularly when the engine moves under torque loading. I moved the bulkhead hole 10mm upwards and 10mm outwards ( fuel injected engine has its exhaust on the passenger side, so is different).

4.The pedal box needs to be the type with a tube which protrudes through the bulkhead for the clutch cable I think these are post 1985. The type without the tube are no good as the cable boss then presses on the bulkhead and the clutch pedal adjustment is insufficient to obtain an opening clutch.

5.The accelerator pedal assembly needs lifting by about 30mm to align the cable with the pedal box. (I believe the fuel injected assembly is OK.).

6.To make clutch/gearbox removal easier I followed the advice of Bill and Alan Brown of Sutton Goldfield and made the gearbox mounting chassis member removable.

7. One rear corner of the bonnet would not bed down, remaining proud of the scuttle. It needed downwards pressure to flex it into alignment. I used the John Humphries of Manningtree, Essex, solution of small steel quadrants fixed to the scuttle and locating in slots in the rear edge of the bonnet.

8.The running board obscures the threaded hole in the chassis for the front fixing of the seat belts so making it difficult to use it as a drill guide to make the required hole in the body I used a thin flexible wire rod about 20cms long, with a "screwdriver wedge" type end ground as a cutter as a drill which gave an approximate location hole in the body which then could be continuously enlarged into an aligning hole.
PS No provision for mounting the flexible !seat belt stems is made. I made a small subframe of 45 x 45 x 3mm angle fixed underneath, across the propshaft tunnel and secured by the bolts of the inner seat runner. (I believe some seat runners may be supplied with the stem mounts -Editor can you comment? (No, John I'm afraid I can't, not usefully anyway!)

9.The petrol filler hinge seemed a complicated and fragile solution -my cover is removable and locates by a tongue and slot Sturdy and simple but needs careful cutting and fitting.

Quickie Points:

(i) Make and fit the heater airbox with the body not on the chassis, you can then look underneath to see how well the rubber seal fits on the bonnet.

(ii) Check your suspension arms have the necessary welded lugs -mine had no front Spax locations and rear brake pipe tags were missing.

(iii) Ensure the hand brake cable ends are fully "home" in the rear brake drums as the plate on the rear suspension hardly allows enough gap - this was found on the M.O.T.

(iv) Take oodles of photographs ( at least 50) of other people's cars inside/outside/underneath -invaluable at moments of stress, use with a magnifying glass and a large Gin and Tonic!
PS The bottom of tonic bottles make good underwiring protectors behind the rear lights.

(v) Make good friends in the Merlin Club -Bill and Alan Brown and John Humphries were so helpful in many 'phone calls -Thanks.

(vi) I'm still trying to work out a cooling system which is really satisfactory. Power steering pipework limits rear radiator space and the Citroen BX front mounted blower keeps the temperature down but wants to run continuously.
Problems have to be part of the fun. I am thrilled with the car. Hope to see you at Sandown.

2.8 1996 - One or two other points may be worth a mention:

1.Bill and Alan Brown made a body stand for their build which they kindly let me have, free. Invaluable as the body is safe when working on the chassis, and as my car was sprayed in the garage, perfect for that job. They have agreed I can pass it to a new builder on the same terms - free Now available for collection.

2.Fingers crossed -I think my cooling fan problem was just that the Kenlow adjustable thermostat set on "N" ( range is C -N -H ) was too low. On checking the water temp. in the expansion tank with a jam thermometer, it gave 75 degrees C, a small adjustment towards "H" gave a temp. of 85 degrees C. Now the fan rarely cuts -in, only at a longish traffic light delay or when restarting after parking.

3. When I first assembled the steering U -Js and turned the steering wheel they almost locked up. The noses of the splines fouled against the opposite members As the noses protruded I ground a greater chamfer which solved the problem.

29.8. 1996

My notes are becoming a bit of a saga, so edit out as you wish, ( I wouldn't dare, John, our members like all the details! I could be deposed! -Now there's a thought!! ) but three more points may be worth a thought.

1. Fuel Filler
I purchased the Ford parts specified in the assembly manual and found: (i) The vent pipe needs cutting and a short section of hose inserting in order to bend and fit.
(ii) The tank came under suction from the pump when I first ran the engine -the cap is non-venting! I drilled a small hole in the side of the finger grip on the cap which has overcome the problem.

2. Electric Cooling Fan (Citroen BX)
The system coped with a half hour start/stop queue at Dartford Tunnel on the hot Sunday of the Sandown weekend. However as I have an amber light on the dashboard which indicates when the fan is running, I find.
(i) Normal running i.e motorways or towns where the car is moving above say 10 mph -the fan stays "off"
(ii) Creeping in town or sitting at traffic lights for say 60 seconds -the fan runs for 2 -3 minutes and drops temperature, switches off and if the situation doesn't change e.g. still in a queue, the fan will restart in another 2- 3 minutes. This indicates that the system is O.K. but has only small thermal reservoir -by comparison my wife's Corsa will tick over for 4 -5 minutes before the cooling fan runs.
As cooling the Sierra-base Merlin, with its sloping radiator, is still an emerging art, perhaps others might wish to comment.
NOTE: Fuse rating of the fan is important. Full load current for the BX fan is about 10 amps and my local auto-electrical workshop advised a 16 amp fuse (continental holder). This blew after 1,000 miles. Obviously the starting current and frequency aged the element as it ran happily on my spare 16 amp fuse. However, I have now installed a 25 amp which should have solved the problem.

3. Front Suspension -a Warning
The Sierra based design does not follow the original Sierra philosophy where, it appears to me, the car's weight is taken on the upper hub bracket. With the Merlin the weight is taken through the Spax from the lower wishbone which is connected to the lower hub bracket via the lower ball joint. Thus the weight is actually taken by the two nuts which pull up the taper pins from the two lower ball joints. When building the car I carefully cleaned the tapers, kept some load on the hub to make the tapers bite (otherwise with nylocs they tend to spin when tightening) and pulled up tight with a ring spanner. At 1 ,000 miles when cornering I heard a metallic scuffing. Inspection showed the Nyloc on one ball joint was loose by three full threads and the ball joint cover had grooved the inside of the brake disc ( the metallic noise ). I guess that during running -in the taper had un-bedded and my good pull on the ring spanner had not been enough -a few more miles could have caused a serious situation.
I have now torqued the nuts to 501b ft and put a touch of paint on the front facing flats so that I can check for any loosening.

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