Meistre
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 posted on 6/10/16 at 09:17 AM |
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E46 vrs Sierra - genuine decision crossroads...
OK, Ill try to make this simple and quick.
I am starting/continuing on a Haynes IRS, a project for myself and the kids as they grow older; plus something I can hack around in (post motorcycle
times) but I've a budget of nadda and even less than that.
So the original plan was to do a Haynes based on a E46 which I now have but I have also acquired some other bits and I am now at a real cross roads as
to deciding which way to go based on the following parts list available:
I currently have:
- Haynes chassis only. 95% complete, needs a few extra bits welded on such as seatbelt points, radiator mounting etc
- Sierra differential (bolt on) but no drive shafts, currently unknown ratio - I need to check
- Sierra steering column complete with switch gear
- Escort steering rack and a short extension
- Sierra front hubs (I think they are Sierra anyway)
And then there's the Beemer
- E46 2.8ci on a T plate. Originally acquired for the princely sum of bugger all and "told" that she was in good working order
(couldn't test drive on the grounds that the rear brakes had seized) whereas the reality is she's had a bit of a hard life and some form
of monkey doing to maintenance.
What I do know is this: The engine is going to be rebuilt, turns out the head gasket may have seen better days, so whilst she's in this mugwire
I'll do a M50 conversion on her at the same time. I kinda like the idea of 240 bhp (ish). So the engine and box will go in to the Haynes. I have
a friend who works with performance engines and says he will do a computer to run the engine therefore I'll not be needing the "man
mounting" of electrical controls from the beemer (Christ there's a lot of wire in one of these).
My issue is the rest of the hardware from the donor. Bearing in mind I do not have driveshafts, wheels, brakes, propshaft, loom and all the other
ancillaries from a Sierra but I do have them from the Beemer then I'm kinda stuck but have 3 basic options:
1) Ditch the donor, use only the engine and gearbox and make the rest run on Sierra running gear. Push costs up but makes for an easier build.
Unlikely to make much from the sale of the parts on the Beemer if any.....lots of time wasters on Fleabay and there's a time delay (I really
need to get the donor stripped and off the driveway). Downside, is the Sierra differential on borrowed time with the power output from the engine?
2) Sell the Sierra bits and just use the Beemer parts: Little or no available designs for the modifications. Can't justify a whacking great
chuck of payment on the wife's credit card with GKD to resolve the issue (no matter how many times I offer to do the washing up  ) and will
almost certainly involve a lot of trial and error (basic mechanical skills are good, knowledge of suspension geometry and design is crap)
3) Go for a hybrid option. Use donor front hubs, brake assembly, wheels, tyres and Escort steering system. Don't know what to do at the back end
but it would need to be able to support BMW wheels if I choose this option but using the Beemer differential and driveshafts again is going to be
challenging and will require coming away from the book's design and into the heap of unknown!
I did consider a fourth option which mostly involved a villa is Tuscany.
So, given the above list of bits and such, what would be your advise? I'm looking for creative and inspirational thinking to get this hole
I've created sorted out.
Craig....
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JC
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| posted on 6/10/16 at 09:31 AM |
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I would keep the Ford front end.
Then either keep the entire sierra back end - all you will need is a modified prop shaft to mate sierra diff to BMW box.
Or... if the sierra diff ratio doesn't suit, use BMW diff but get driveshafts made to go from BMW diff to ford rears.
Option 1 is the least redesign work as far as I can see!
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jps
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| posted on 6/10/16 at 09:57 AM |
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Even if full Sierras are hard to find now, Sierra parts are not hard to find. For simplicity with the design i'd say keeping the full Sierra
back end would be right - even if you end up having to obtain another Sierra diff / diff internals. But I guess it depends how confident you are on
going off-piste!
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sdh2903
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| posted on 6/10/16 at 12:08 PM |
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I'd go option 1.
I've built a GKD. All be it the prototype chassis for the 4 cylinder engine. The chassis at the time was only meant for e36 rear diff, you would
need to chat to Peter if he's still the owner of gkd if the 46 is compatible.
The problem using the bmw running gear is
a. It's heavy, very heavy.
B. It uses 5 x 120 stud pattern. Not easy to find reasonably light wheels in 15" any bigger is too big on a 7 Imo.
C. If it's still e36 diff only. You will struggle to find a small case lsd to fit. The only ones available were in the early e36 3.0 m3 or very
rarely in the 318is diff. Because of rarity they are expensive.
D. Using bmw stuff your choices for aftermarket brakes etc are limited unless you want to start manufacturing all your own brackets etc.
Use the ford or even mx5 running gear, all readily available, lsds are plentiful in different ratios, wheels available in whatever size you want,
brake upgrades off the shelf the list goes on.
Keep the bmw engine and box as it's a belter!
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Nickp
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| posted on 6/10/16 at 01:32 PM |
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Option 1 for me - literally 
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