Chrysler Sunbeam restoration/ preparation
Posted 19 January 2009 - 01:02 AM
"Oh, if you want to go there I wouldn't start from here" he replied!
It left the Linwood factory as a 1600GLS in Seville Orange with a brown interior trim, and being a GLS also had the rare bronze sundym tinted glass. When I first saw the car I wanted it mostly for the bronze glass to use in my Moonstone Blue Sunbeam Lotus shell, and possibly some other spares.
I had it towed home, washed it once, and pushed it into a corner of my garden until I had a chance to get a look at it. In the meantime I was working away from home and abroad regularly, and for other different reasons just never really got around to doing anything with it, and so it just sat there.
More than ten years had passed by the time I finally got around to taking a closer look at it, and despite living within a few miles of the factory where they were built and were once commonplace these cars were now extremely rare and thin on the ground. I still wanted the glass for my Lotus, but considering its time in the garden without a battery the upper panels of shell weren't in as bad a state as I imagined they might have been, and despite obviously needing a lot of work it seemed a great shame to dispose of it.
By now the front of the car was almost completely covered over by a bush, and a self-seeded tree had grown through a hole in what was left of the front floorpan and completely filled the interior. A bush saw was used to cut through its 3" trunk under the car to allow it to be dragged into the garage for a
From mid doorskin height downwards things weren't so promising. Everything was totally rotten and I wondered how it had survived being towed out of the undergrowth. As I began stripping out the interior I was seriously concerned that it fold in half under my weight.... all that was really left of any floor structure was a small piece of the transmission tunnel! I now wish I had taken some photos of just how bad the shell was at this stage.
After stripping out I welded some temporary bars across the door openings to try to keep some strength in the shell structure and began cutting out/ off the old rusty remains.
Parts that were extinct and needing replaced were:-
Both inner sills
Both outer sills
Rear corners of both rear floorpans
Both front floorpans
Both front chassis legs
Lower rear panel
Both front wings
Both rear wheel arches
Both outer wheel tub sections
Both rear chassis legs
Spare wheel well/ boot
Both front chassis outriggers
Both rear suspension lower arm mountings/ outriggers
Lower rear inner quarter panels
And in addition repairs needed to:-
Both inner panels/ wings at bulkhead and around strut top mounts
Front of bulkhead
Lower edge of heater plenum
Bottom 6" of both 'A' posts
Edges of scuttle panel at windscreen corners.
Both 'A' post to roof joints
Bottoms and tops of both flitch panels
Rear O/S roof corner
Front O/S of roof above drivers door
Rear quarter panels along top edge, lower fronts, lower rears, and around arches.
Bottoms of both doors
Lower sections of both door skins
Rear of O/S inner rear quarter
Rear of both inner rear wheel tubs
With hindsight many of the above panels were still available as the Sunbeam is based on the Avenger, and the Avenger was still being produced in Argentina until 1992 so imported spares are often still available through specialist suppliers. I didn't know this at the time though and with the exception of a pair of Avenger replacement sills which were shortened to fit, everything was going to have to be made from scratch patterened or templated as best as possible from memory of the originals. Luckily my previous work involved sheet metal and tubular fabrication, machining etc, and my attitude was that if it was made in metal I could make another one!
As I said in the Newbie introduction, I'd always wanted to build a Group 4 tarmac spec works replica, and this shell was beginning to look like the one to base it on as it would have needed to be cut about a bit to prepare it like that anyway. I won't go back over the reasons for the choice of engine again here, but to live up to its looks I decided to install an all-alloy 3-litre 24valve B6304 straight six mounted as far back in the chassis as possible to make space for a front mounted intercooler and turbos and plumbing to the offside of the engine.
Here the shell is upside down for ease of working on some of the areas of the floorpan and undersides...
.... by this time I have made and fitted the new inner sills and partly formed the front floorpans as well as forming the front chassis legs from rectangular hollow section box which makes them stronger than original. the lower front panel is just starting to be formed and is so complex it had to be made in six separate pieces and joined together.
The rear chassis legs are made in a similar material but are much more involved with bends, offsets and section changes to complicate things. Time consuming to fabricate but the end result is very strong. The rotten lower rear panel is cut away and both rear inner arches, quarters and tubs have been altered to suit the planned axle/ wheel/ tyre combination. Boot floor repaired and about to fit outer sills.
Right way up again, trial fitting of rollcage and engine / gearbox placement. Almost ready to form new bulkhead and transmission tunnel....
Although the production Lotus uses an axle almost identical to all other Avenger/ Sunbeam models, the works cars used a Salisbury (Jaguar) axle. As I would be putting some extra grunt through the axle later I decided to use the bombproof Volvo 960 estate live axle which comes as standard fitted with an Eaton G80 mechanical locking differential. The Sunbeams standard 4-link and coil spring rear suspension works really well, but relies on deflection of its bushes to allow axle movement. I decided to locate the new axle with my own design of parallel motion 4-link and panhard rod arrangement instead using standard boxed lower arms. The new chassis mountings and channels to clear the RHS upper links can be seen here as well as the chassis panhard rod bracket...
With the car being built for sprints and hillclimbs I wanted to be able to fit alternative wide rims and slicks under the arches, and allowing room for more wheel backspacing was partly why the 960 axle that is 125mm wider than standard was chosen. In combination with the offset of the 9.5" rear Minilites this meant that the tyres would not fit under standard GP4 Sunbeam arches, and so templates were taken from an original set and replicated in sheet steel but with twice the normal width...
This would have meant that the rear track would have been significantly wider than the front, so the front inner wing suspension mounts were modified and strengthened to move them outboard by 45mm each side. New track control arms which were 50mm longer than the originals were designed and fitted as well as modified drag links and brackets, and longer track rods which would together allow the use of wide front slicks without introducing bump-steer. This meant that double width front arches also had to be made. Although a little heavier than the equivalent alloy works arches, the steel versions could be welded rather than rivetted in place which not only looks a bit better in my opinion but adds a tremendous amount of strength to the shell....
While I'm quite happy with bodywork, fabrication, machining and mechanical engineering type of work, beyond the prime and preparation stage my painting skills don't stretch much beyond recoating the garage floor. This is reflected in the quality of the paint finish, but it is meant as a useable road/ competition car after all and is likely to need regular attention, so it would have been crazy to have paid for a top quality professional paint job.....
...Still, good enough for the purpose.
The fuel tank couldn't go in the normal place because of the panhard rod and early works type dual exhaust system, so a new 90 litre tank was made from sheet steel and located within the aluminium enclosure below the rear hatch, with the battery in the smaller section on the nearside.....
The 'almost stock' stage one normally aspirated engine which will be used to shake down the chassis, coupled into an M47 gearbox and hydraulic clutch via an alloy adapter plate. Just after final test run to check for leaks etc before installation....very smooth and sounds nice....
...completion of home brewed dual 2" all stainless steel tig welded exhaust system using standard Audi 80 stainless silencers.... no catalytic converters fitted or required....
....Strut brace copied from works spec one except longer triangulation to reach new bulkhead position and wider spaced strut top sections to suit new centres with additional anti-flex fixings, beginnings of aluminium cowl ahead of SAAB 9000 radiator where intercooler will be housed later, starting to wire chassis electrics (separate loom for engine management already completed)...
Dash panels copied fairly closely in aluminium from original works ones... its all these little bits and pieces that take all of the time, note the additional tie plates on the front cage legs to help put as much structural stiffness into the car as possible....
...just finished and road legal. Photo taken in the car park of the factory offices at Linwood where these were built.
...and first time out..... only a few minor tweeks to do...but going really well...
Posted 19 January 2009 - 10:04 AM
A job well done - what sort of time did this take then, obviously not including the 10 years in the garden
Posted 19 January 2009 - 04:49 PM
Although I worked on it in most of my spare time it was only during evenings , holidays and weekends really..... and at least 6 months of that was spent on engine work (thinking about it, it must have been a lot more!)
I have three engines which have been leap-frog developed. The 'A' spec one fitted has had quite a number of changes made to it but these are mostly to simplify it and make it more compact and lighter and it is in relatively standard tune.
The 'B' spec unit was still intended for natural aspiration but using 3 X Weber 40 DCOE carbs modified with straight tubes instead of chokes to act as throttle bodies but still give a 'period' look, that's why the bulkhead is further back on the passenger side to clear the rear Weber. It will need to use an aftermarket engine management system and I'm swaying towards a Megasquirt MS2 at the moment. This one has more internal changes, with 40 hours of work porting and flowing the cylinder head alone. It isn't yet completed so hasn't been tested, but from what I know of these engines once set up I would expect somewhere around stil very flexible 280BHP while respecting the standard rev limit.
The 'C' spec unit is still a long way off yet....I had hoped to be using it by now but the build just took longer than expected. It will also retain the original rev limit, and uses standard Volvo T5 pistons (except six of them.... the beauty of the modular system). The plan was to use a pair of Garret turbos mounted at the front offside of the engine and plumbed to link to the same exhaust system as now so that switching over atmo- turbo and back in future would be fairly easy. The space on the nearside was left for this, but packaging 2 lots of air plumbing, centre bearing oil supplies, etc will still not be easy and will make the engine less easy to work on. For this reason I'm now seriously thinking about a single large turbo rather than the two smaller ones.
Right to left, 'A' spec ready to install, part assembled 'B' spec, and still unstripped stock future 'C' spec....
... after a little trial offering-up of some of the turbo parts....mmm, quite tight...
Looking back, there were a huge number of one-off parts needed during the build. Almost nothing was bought off the shelf, usually because not available, and even the few bits that were often had to be adapted or modified in some way....thats what really eats up the time, making bits from scratch.
One change then effects another. This was my latest home fabricated part, with the tight compacted pedal box area and hydraulic clutch conversion there was no room to fit a balance bar set up, so just yesterday I finished making this adjustable rear brake pressure restrictor which works on forward weight transfer using a G-valve to close off the rear brake line...
.... are these sorts of project ever really finished?
I hope this build thread isn't getting too boring... I just thought I'd give a flavour of what was involved.
Posted 19 January 2009 - 09:16 PM
That is sooo impressive *faints*
Posted 19 January 2009 - 10:35 PM
That is sooo impressive *faints*
...and more power to your elbow I say!!..... The more people who can be persuaded towards saving their older vehicles the better!
Real exotic or historic classic owners might be prepared to spend many thousands of pounds having their cars professionally restored, but on more 'retro' type cars like many of ours this just doesn't make economic sense. The only way they are likely to survive longer term is if their owners can keep them alive?
I'm by no means professional at this, but simply the only way I could afford to keep my cars going is to do the work myself! Its really often not so difficult when you get into it.
Posted 26 January 2009 - 09:00 AM
.... with only this much space available.........
Posted 26 January 2009 - 08:16 PM
A twin turbo setup would be amazing but I agree a single rolling bearing turbo might be a better and more sensible option.
Posted 27 January 2009 - 08:50 AM
Posted 28 January 2009 - 05:47 PM
with modern Turbo technology a single turbo should be just as good as a TT set up
Posted 29 January 2009 - 08:43 AM
There are a number of reasons that would give the twin turbo set up an advantage if it is possible to install them in the available space, with the main disadvantages being what I am faced with at the moment!!
Firstly, there are some technical considerations. On a straight six cylinder engine ( as on other multi-cylinder layouts) the exhaust valve opening periods have overlap between the different cylinders which can cause flow reversion at high turbine inlet pressures with exhaust gas from the later opening valves cylinder (at higher pressure) wanting to head back through the manifold to the earlier opening valves cylinder (at lower pressure) rather than towards the turbine where the average pressure will be higher (usually about twice the boost pressure and often higher). This is for exactly the same reason that the majority of even normally aspirated sixes use two separate exhaust manifolds/ systems, even if they siamese further back where the gasses have cooled considerably and the pressure is lower.
Keeping the individual cylinders 'header' to a smallish diameter (to make use of gas inertia) and separate as close to the turbine flange as possible helps by making it a more difficult route for an exhaust gas 'short circuit' like this. If cylinders 1 to 3 and 4 to 6 are manifolded separately into seperate turbine housings though the valve open overlap is eliminated completely. Single turbo 6 and 8 cylinder engines are not uncommon, whether it be for space restriction or economic reasons, but where higher boost levels and different 'turbo cams' etc are going to be used the advantages of the twin turbos start to become more apparent.
There are also 'twin scroll' turbos available which in effect have 2 separate turbine sections driving a single compressor through a common shaft which have most of the benefits of both twin and single installations.
The other thing is that although waste heat is used to power the turbo in the first place, dividing the total heat between two systems is thought to lead to an increase in the lifespan of the components and improved reliability, less oil problems etc.. If the turbos are all correctly selected for size there should be no real advantage or disadvantage either way in lag, spool time, boost threshold etc..... short of going for VATN turbos.
The second reason is more straightforward. This build isn't a big-budget one, and these Garret turbos being very common are cheap and readily available with excellent parts interchangability from different models and applications. The Garret T2, T3, T35 and T4 all use pretty much the same centre bearing sections allowing a good deal of swapping etc to tailor them to the specific engine use..... (in other words I will be robbing other cars of their equipment and rebuilding them with new bearings /seals etc to get what I'm after rather than buying new to keep costs down).
By choice I'd rather use KKK turbos anyway, but hey.... it was the same when the inferior VHS won over Betamax video recorders!
If I do end up opting for a single turbo I'll be back to square one as far as doing the turbo selection calculations and then finding out what the most suitable units are fitted to as standard.... maybe a big Holset will be wrenched from an old diesel bus and rebuilt to do the same job?
As I said, cost is also a major factor, but I've still got a few ideas up my sleeve......
Posted 08 February 2009 - 11:09 PM
Why the 6 pot though? Why not the T5?
Posted 09 February 2009 - 12:36 AM
There isn't a lot of weight difference between the engines really and all else being equal the six makes 1/5th more power!! In fact the mildly reworked atmo 6 in the car currently is producing as much power as a stock T5.
Seriously though, I also have a fair bit of experience with the 5 cylinder B5204 / B5254 engines as well (and still run 3 of them in mid-engined RWD buggies) which are almost the same mechanically but with a cylinder less. (obviously different crankshaft, cams etc).
As Ford already had a choice of the Duratec or Zetec but opted to use the Volvo designed B5254 in their Focus ST170 instead these units can't be so bad?
Renault also chose to use the 5 in the larger engined Safrane. I treat these heads exactly as if they were YYB Cosworths as far as chambers and porting etc, which says something about just how far production engines have advanced in recent years!
The six has a normal north -south mounting in the rear wheel drive 960 so there is no messing about with the sump casting as it has crossmember clearance already (remember these are partially structural and important to block integrity on the modular whiteblocks), whereas the 5's are all front wheel drive and would need modification to their full length sumps ,oil pick ups ,etc.
The exhaust / turbine manifolding would again be totally wrong and have to be made from scratch (taking away any advantage of using a stock T5 set up) and the exhaust valve overlap between cylinders lies between the six and the inline four B4184 / B4204, so reducing some other options too.
There is of course the standard but rarer low boost twin turbo T6 engine as found in S80's etc with around 280bhp from the factory, but there are a number of compromises involved with the combustion chambers in it as well that I don't like. I prefer to base my engines around the modified B6304.
With the snowy conditions putting a stop on other work, I've spent most of this weekend doing calculations on airflow rates and pressure ratios to suit the planned installation. The Garret T3's I have in 45 trim would have been perfect for what I want from the engine, but realistically can't be fitted in a way that I would be happy with.
I have now more or less decided that I will instead fit a single large turbo, and either the Holset HX35 (unwastegated) or HX35W (integral wastegate) would be what I am after. These are listed as being Twin Scroll types (although sometimes divided scroll ones are wrongly called twin scrolls too) and as The Big Yin pointed out earlier would help keep things much simpler as well as offering most of the other benefits of the twin turbos..... the only problem is I don't have one yet!
The next step though is going to have to be finding and installing a stronger gearbox as I'm already pushing the limits of the M47. The 2 least costly options are both Getrags, either from the Toyota Supra Turbo or the BMW 540i or M5..... 9000 Euro's for a motorsport box is a little outside my budget!
Posted 09 February 2009 - 04:12 PM
Posted 09 February 2009 - 07:46 PM
To make the kind of boost I would need at higher airflow rates it would have to have a high step-up gearing in the drive system and it wouldn't like this much. They aren't very efficient either and produce a lot of heat during compression as well as absorbing power in their drive especially at the higher step-up ratios.
They typically only produce about 7psi of boost at that sort of CFM for this reason, which translates to only about 297 BHP on a B6304, and I can get close to that with a tuned N/A engine (albiet without the bottom end oomph). The turbo/s dont give the grunt in the first 1/3 of the rev range of the supercharger either but will give effortless middle and upper end boost (I'm only after 12psi @7000rpm which is around 366BHP calculated on this engine)
The other major drawback is that what these Eatons change hands for secondhand would on its own take a big bite out of my total build budget!
So, It looks like I will need to find a 2001-on Volvo B7L bus or FM7 truck with the 7.3 litre D7 turbodiesel to rob of its Holset HX35....
Posted 10 February 2009 - 03:40 PM
Keep us posted
Posted 11 February 2009 - 09:39 AM
Posted 11 February 2009 - 05:20 PM
If I had unlimited funds I could just go out and buy all of the ideal bits I was after, but for me part of the fun is in either making the things I need myself or cunningly modifying and adapting what is more easily available (and cheaper!) to do the same job within my budget.
Anyway, work on the 'C' engine will have to stop for now as the end of the winter is in sight and it won't be long before the car will need to be working in earnest again for 2009. There is still quite a bit of development work and tweeking needed on the chassis even to get the best out of the car at its current level of engine output..
Hopefully before next winter I will have sourced a suitable turbo...
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