Technical

Building a Merlin

with Andy Hogg

December 2005

Hello everyone, my name is Andy Hogg and over the following months I will be updating you on my build progress. First by way of an introduction a little background on me and how I came to be building a Merlin. While living in Wimborne which is just north of Bournemouth and part way through the build of a Tiger Cat E1, my wife Hansa asked where would we put Rachel our now three year old daughter, OK lets look at the magazines for inspiration came the reply. After a few months we decided on a Merlin+2 and the next month saw an advert for a part built kit, a long conversation over the phone saw myself and Hemmant (my stepson) in a seven and half ton lorry on our way up to Liverpool, the car had only front and rear suspension, arms and wheels so a basic rolling chassis and had been sitting in this chaps lock up for a few years so the untreated metal work had a light coat of rust. Back at home everything was stripped, painted and reassembled with new rubber boots on everything unfortunately at this time I was working 10 or 11 hours a day 6 days a week so progress was slow and all I managed to do was to strip a donor Sierra. Around June this year we moved to Crawley West Sussex the house has a nice garage attached which was cleaned, floor painted, bench and tools installed and I can now get started properly.

An email to Mike asking if he thought my build may be of interest to others and here we are, I welcome your comments via the forum and will be asking for advice and help throughout the build as I get more time off with my new job so progress should be better.

Funny how Hansa has already decided on the colour scheme, the car is the 2+2, Sierra based and will have a Pinto 2litre in the front. My first question is about the petrol tank there is a lot of surface rust on the outside so presumably also on the inside, so where can I get a new one? Or is it possible to chemically clean the inside somehow, the outside is easy to sort clean. That's the introductions over; all that's left is to wish everyone a merry Christmas and happy new year.

January 2006

Firstly let me wish everyone a happy and prosperous new year and hope you had a merry Christmas. The build has been progressing slowly as the boss has kept me busy this month, in fact both bosses have, during the holiday I had to re-decorate the bathroom.

Still, managed to get an engine installed, purchased from e-bay it's a 2 litre Pinto that was reconditioned by an ex Brabham engineer, unfortunately did not come with accessories but I happen to have another Pinto in the garage so parts have been removed blasted and cleaned before installing.

I have read a few articles and spoken to a number of people at shows about engine cooling and with this in mind I have splashed out on a new radiator, not sure if I will use one or two fans but will fit an adjustable thermostat switch from Car Builder Solutions, having seen one in action on another Merlin. The brake lines are my next project and will report on that and hopefully a bit more progress next time. If you have any suggestions, hints, tips etc go through the forum or e-mail me direct.

February 2006

Hello all, got a few odd bits done, but its too cold in the garage so I have done some research as I cannot decide whether to put an electrical fuel pump in or use the standard engine driven one. First job was the radiator, mine does not have the Sierra top mounting 'pegs' so I welded some new ones on then decided the radiator was too low and bent them about a bit then remounted the radiator, bit happier now, just need some hoses that will reach the engine.

Next was the fuel tank, a call to Frost saw the postman dropping off a nice box full of reconditioning goodies. The process was first to put a large handful of pea grit inside and give it a good shake to get rid of the surface rust, yes it is heavy. Next was to rinse it out and then dry it. Then in with this solution to eat the rust and prepare for paint, then rinse and dry, and finally in with this special paint that is resistant to fuels etc and takes 4 days to dry, then wire brush and paint the outside with anti rust paint, job done and very nice it looks to.

Then I got a bit stuck, there where things I wanted to do but was not sure about clearance with the body so decided to fit the body.

After the body was fitted I found there was a lot more room for the rear brake pipe than I thought so this was replaced an the T piece fitted on top of the chassis, much neater. Next was the brake master cylinder as per the manual followed by the pedal box which was stripped, the brake and clutch pedals slightly modified for a better fit in the well, the rust ground of and treated then given a coat of magic paint, the top cover cleaned and treated as well, the accelerator pedal modified and painted then all reinstalled, the battery tray treated the same way, amazing how long this all takes but satisfying.

The ropes? Well they allow me to lift the body clear to work on the chassis, seems to work well so far and do not stress the wheel arches fortunately. That's about it so far, next is sourcing items that where missing from my kit and getting a fan unit (there is a nice twin unit on a diesel Zantia I like the look of if not then a BX fan) and also a carburettor and inlet manifold for the Pinto.

Hope it warms up soon.

March 2006

Spring is in the air at last, the garage is warming up and I can be more productive. Its been a funny old month, I spent a week in bed with the flu but managed to get a few bits done. After talking to Bruce Miller and conversing by e-mail with David Harrison, they very strongly recommended modifying the cross member at the rear of the gearbox so I lifted the engine out, cut out and modified the cross member, it is now removable but very secure and pretty strong. As well as some verbal help over the phone Bruce also sent me information on strengthening the rear trailing arms around the weld areas. Some of the members' stories sounded pretty scary so out came the arms and fillets welded into place, hope they are going to be strong enough.

And of course the brake cables had to be remade as well. Also fitted the fuel lines and left them loose at the front, I will need to run brake, two fuel lines and the wiring loom all down the left side of the car to keep it all away from the exhaust which keeps Mr SVA inspector happy, so a bit of forward planning required as space is at a premium down the side of the chassis.

The body is actually supported by two ropes and two car transporter lashings so I am confident working underneath. Targets for this month include, sourcing the fan unit, fitting the fuel pump and pluming, and keep looking for a weber 38 carb, just missed one on ebay the other week. Also making up a shopping list for the Detling and Stoneleigh shows.

April 2006

Hello all, it’s been a bitza month, at the moment I am waiting for the shows, Detling and Stoneleigh, Detling is just over a week away and I have a long list of things to buy, have ordered a modified steering shaft from Car Builder Solutions who have lengthened their standard shaft for me which should fit nicely and still pass the SVA protective steering check, they are taking it to Detling for me to save on postage.

So I have been doing odd little jobs, decided to put some lights on to make it look a bit more like a car, also the grill, do not have the cover for the air inlet on the bonnet so will probably have to make one if I can not find one at the shows. Also fitted the heater unit and fan after stripping and replacing the foam covering the director plates, looks big when shoehorned under the scuttle, will make up an aluminium box around the fan unit to stop engine fumes being blown into the car. Another chat to Bruce and I have re-laid the fuel pipes down the centre of the car as there is enough room between the chassis and the body, looks a lot better now. Got hold of a Weber 38 carb on a pinto manifold, sprayed the manifold to match the rest and will overhaul the carb in due time, need a few parts for it as it has no choke components fitted, noticed there is not a lot of room for an air filter. Also fitted 2 Citroen BX fans, this should keep things cool.


I am in the process of plumbing the cooling system and have fitted one flexi silicon hose and have the rest on order so will have that job finished when they arrive in a couple of weeks.

You may have seen my plea in the forum for help with the wiring loom, nice loom shame there are no diagrams, I guess the loom is made up for the fuel injected or the double over-head cam engine so I am expecting lots of spare bits, never know they might come in useful later on.


Hope to see you all at Stoneleigh, be nice and let me take lots of photos, and ask lots of questions. Here are some photos of the car taken today. 
Bye for now.

May 2006

Hello all, another month to write up on, here goes. I did a few odd jobs before the Detling show as I did not want to get too involved before getting lots of parts, so I fitted the boot lid, wow that hinge is made of some strong stuff, went through 3 drills and only made 4 holes to trial fit it, now have some cobalt drill so that should sort it out, (John Winn told me to use paraffin, an old trick). Then I got called into work which covered the Detling weekend so no show and no parts and away for 12 days so no work on the car, still got those drills and a few other tools, but the USA is not as good for bargains as it used to be. Spent a happy hour or so down the scrap yard (second home!) they had a few Sierras in for a change so got a nicer coolant header tank, steering bits and a few other bits I had not taken of my donor, that will teach me. So ground off the brackets for the old tank and welded new ones on, I feel that I am building this car twice with the number of things that I change. The steering shaft arrived by post, now I needed a support bearing not that easy as the thicker sleeve welded on to extend the shaft 50mm prevented a ball race being slid up to the position opposite the mount so after some talking to a local bearing shop I walked out with a bearing and housing to fit over the sleeve and then welded new mount about 2 inches down from the other with the support vertical, the shaft runs over the normal support in the same place, now I just need a local firm to spline a shortened Sierra top shaft for me. Also had to fabricate the steering column support brackets but now have a working steering system, which is different to the other Sierra Merlins as I have cut off the light stalk behind the wheel, this allows me to move the steering wheel closer to the scuttle, this I hope will overcome a problem common to this type which is that if you are not 6 feet tall you have to stretch to de-clutch or the steering wheel is too close to you, have seen John and Bruce put a block on the clutch pedal to help with this, will let you know if it works. Next fun thing was the fuel filler hose, which catches the bodywork on the vent pipe, am still working on this and have a number of plans, favourite is to modify the vent pipe exit on the fuel filler pipe rather than the car. Then at last came Stoneleigh, that was the fastest 7 and a half hours I’ve spent for a while, was good to put faces to names and thanks to everyone who let me photograph their cars from various angles and gave help and encouragement, sorry did not attend the AGM but had a LOT of shopping to do, managed to forget to by a number of things, still there’s always Donnington in September or the post. That’s about it, here are a couple of pictures of the progress, bye for now.

June 2006

Hello all, it’s been one of those months where I’ve got what looks like a lot done without much effort. It started with cutting the dashboard to shape from paper patterns, took my time but still a little small in one place so have put some filler on and will exercise any artistic talent I may have and blend it in (no one will know!). Fixed the bonnet on with some Imp hinges, then found that one side stuck up a bit, like with John Winn, and I was about to do the same thing but then after a long pause for thought reasoned that it was fine before the hinges went on, so some packing under one side and presto, not too bad now. Then I spent some fun time adding more bright work and the windscreen frame, I will have to get new glass with the necessary marks to pass SVA. I fitted the wiper system, which took some time as the drive was not long enough and I had to weld an extension piece in the middle, fine now.

The grill you see was not provided with my kit, instead I cut out some 16 gauge mild steel and welded piano wire as the grill, sprayed with chrome, and I am pretty proud of the result. Next was to fabricate the front body mounts from measurements taken at Stoneleigh and fix them on after putting wheels on and trying to get it all as level as possible, next bolted the front half of the body down to the chassis, propped the back up a bit and played with the doors, hope its not me but the fit is, well you probably know, did everyone have to fill as much as I have? I only have one pair of proper hinges at the moment as these are difficult to source.

The locks are a little different to the normal Merlin ones, hope they work ok, they are a bit stiff at the moment and I will have to take them apart and play with the spring. Also fitted the front bumper and a console unit to hide the Sierra heater matrix, got my nice blue silicon hoses and fitted a few of them. Instruments and seat runners should arrive this week so I can play with those, my target at present is to get the body sprayed in July and the car on the road in the new year, the problem at the moment is with the colour scheme which my wife keeps changing every week, so will have to get a plastic kit and spray that to see what she likes best. That’s it for now.

November 2007 to April 2008

Long time since last update, so what’s new? Well the windscreen went on without too much trouble, I used pond liner adhesive which is a sort of silicon/glue and it looks good. Had fun with the wipers, the motor had a 120 degree arc which was amusing as the driver side went way past the edge of the screen so obtained and fitted a 90 cog, all three work much better now.

I welded up a new front bumper and mounts for SVA all nice and round, it does not look that nice but it’s not on for long. The rear lap belts where fitted, had to make and weld on brackets.

Front seats arrived and fit nicely then removed as I forgot to fix on the seat belt to the runner then back on. With the front seats in and with the help of Hansa the brakes where re-bled. A while spent lying under the car, touching up the chassis paint, tidying the wiring making sure everything is tight and that’s about it!

The sun finally shone and the car was pulled up the drive.

The mirror from an old Jaguar and is used for SVA as it can be knocked and will spring back without needing re-adjusting, bracket made and sprayed up to look like a permanent fixing.

The engine eventually fired up after a change of distributor cap and some more permanent coil connections, the carb is in desperate need of tuning to the engine but at least it starts easily and runs. The dials seem to be working ok, unable to check speedo yet!

I need a chassis number, as Merlin can not supply one I have to get it from the DVLA so am in the process of doing that, then I can get SVA, not sadly in time for Stoneleigh but at least for the summer.

That’s about it, have a few things to do for SVA, some rear lights and reflectors need moving and the back will need raising, to be able to get out of my driveway.

By the way, is the camber supposed to be different on each rear wheel!!!! Looking at photos very few cars look the same?

Just had the first run to bed down the brakes, great!