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Discussion Starter #1
Hi All - I am currently rebuilding a 1972 Gtv2000. I bought the car totally stripped down to parts & it came without the original engine but did include a 2.0 Twinspark engine from a 75.

Now, I've been trawling through the numerous fantastic threads on here, where people have used the Twinspark engine with good success but I am at a loss to decide what exactly to do with mine...

So, I am asking for advice from those that have been there and done that.

I've tried to weigh up in my mind some deciding (or limiting) factors that could help determine the direction it takes. Listed below, not necessarily in order of importance but just as they fall into my mind...

Cost - this is a reasonably low budget build. I'm afraid I simply don't have the cash to buy top of the range parts, or even a ready rebuilt engine.

Reliability - Once fitted, I'd like to end up with an engine that will give me the minimum of dramas over the coming years. I'm slightly wary of using the original motronic ecu as old circuitry is always prone to failure.

Clean Engine Bay - I know a TS engine will not excite the purists but I would very much like the engine bay to look roughly in keeping with the car, maybe even more minimalist looking - no clutter.

Power - Not looking for ultimate performance 140-150bhp would be just fine. This will be a car for street use only, possibly more touring than anything else. Would be nice to have lively performance but I think that power range would be up to the job.

DIY - I'm happy to have a crack at putting the engine together myself, fabricating/modding parts where necessary - its a good learning curve and another reason why I'm not so interested in shop bought ready to go packages...

Ready to hear all your thoughts! All the best, Tom
 

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Tom- as one who had installed a twinspark into a 115 GTV I say more info. is needed before anyone can give you a meaningful response.
Is the rest of the car complete, i.e.- do you have ALL the pieces such as transmission, interior, trim, glass, etc.? Where are you located ?
Do you have all the bits from the 75 such as the wiring harness w/ relay pack, ECU, and all connectors ? All intake pieces from AFM, throttle body, plenum, etc. ?
How mechanically inclined are you ? Do you have access to simple fabrication tools ? Can you solder, fabricate simple wiring harnesses ?
BOTTOM LINE: your described expectations sound reasonable but frankly, many less-complicated projects than this have stalled out and fallen by the wayside due to the magnitude of the task. Not only are you putting back together a "basket case" GTV, but you have to fit a non-original engine that also requires rebuilding. This is achievable and has been done more than once, but please be realistic about your resolve in terms of time and money.
The twinspark can be fun and rewarding, but I can almost promise you that you'll be better off in terms of hassles and expense by installing an original type 2 liter Nord engine. Intrinsic (resale) value will be retained also. You could probably swap the TS for a more original powerplant, depending on where you are.
If you decide to forge ahead there is plenty of technical and psychological help to be found here:wink2:
 

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Discussion Starter #3
Good points, I'll try to answer...
Car is 99% complete, just in boxes. TS engine appears to be all there, intake, plenum, throttle body, ECU, fuses, relays, loom - which looks like a mass of coloured spaghetti...
I've got a great guy on the welding and paint.
I'm in the UK & car is in a nice dry double garage.
Fairly mechanically minded but this is the biggest project to date. Always had some project or other on the go

Been thinking more about this engine today and still like the idea of the twinspark but am not so keen on it being dependent on an ageing ECU. Not sure what the shelf life of a motronic ECU is and maybe it is symptomatic of today's throwaway mentality but I've no faith in the longevity of this crucial part...
 

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Reliability - Once fitted, I'd like to end up with an engine that will give me the minimum of dramas over the coming years. I'm slightly wary of using the original motronic ecu as old circuitry is always prone to failure.
Tom,

On this point I have evidence that this concern is unfounded. The Motronic 4.1 is very reliable and the AFM is easy to repair and inexpensive to buy rebuilt. Just make sure that the AFM you install is not excessively worn (everything is within tolerance). One of the technical reports I read that I think was authored by BMW said that these systems stay within spec. for hundreds of thousands of kilometers under normal driving conditions.

I've done two TS swaps into 115.01 chassis. Both with the factory supplied induction systems. The total mileage driven with a TS engine in the car is now in excess of 60,000 with no problems on any kind. Based on the rate of wear I estimate the I could drive another 60,000 without problems.

On my first swap, I, like you, wasn't 100% sure how far I wanted to become financially, emotionally and physically involved with the project. Because of this I spent only the minimum amount of time and money to produce a roadworthy car. After driving this car for about a year I started exploring upgrades/modifications to suspension, and replaced the original 4.54 rear-end with a rebuilt 4.11 rear-end from a mid 90's spider. I thought about splashing out $1000 or more for a more modern induction system but I can' justify the cost when I was told by someone who did the upgrade that there was only a marginal improvement in driveability.

One thing I am sure of is that switching to carbs is a waste of money and a decided step backwards in terms of driveability.

Are you really concerned about resale at this point? If you are then I don't see how you can't be disappointed. Regardless of which engine you install you will not make back the cost of a quality restoration.

In 2014 I sold a TS GTV 2000 in Southern California. The buyer paid $32K for a car that at the time would have had a market value of around $25K if it had had the original SPICA nord engine. (I have no idea how large the market is for TS equipped GTV. It is probably not as large as the market for factory original GTV. I sold my TS on the second day it was listed to someone who already had a SPICA GTV. He knew what he was buying.)

Bob
 

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Discussion Starter #5
Thanks for that, she's a keeper... no thought given to resale

Not interested in carbs on a TS either.

Any links available to your TS Motronic conversion online. I've read so many threads about TS conversion s with aftermarket ECU's, carbs, bike tbodies but not seen much about straightforward TS on Motronic with TS ancillaries?

Maybe that was reinforcing my doubts on using original system in its entirety.
 

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Tom- nunki is spot on on many points!
Admittedly, I have only a little direct experience with aftermarket or d.i.y. fuel injection systems, but I can read about the experience of others and I am old enough to err on the side of practicality. IMO, given your stated objectives you will spend many hours and considerable funds getting any of these other systems to have the turn key, every day driveability and reliability of the stock Motronic system. These other systems do have the potential of making some additional horsepower because they are more readily tuneable and adaptable to other components, but you need the time on the dyno to get beyond a basic tune and realize this potential.
I too am intrigued by the idea of playing around with standalone systems but have decided for now that I enjoy DRIVING my Alfa too much to spend most of the time in the passenger seat looking at a laptop or booking expensive shop time. YMMV !
 

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Discussion Starter #7
An overnight sleep is a good thing - having spent so much time reading the myriad possibilities, doubting the Bosch, going round in circles, I think the best way forward for me is to use the OEM system in entirity.

It ticks most of the boxes in my first post.

The obvious one that it misses with is the "clean engine bay" - more like full engine bay. Perhaps it will be an interesting challenge to see how tidy/neat and minimal it can all be made to look..

Clean wiring, careful treatment of surface finish & possibly minor modification.

Am feeling more comfortable about using the Motronic, having picked up a spare ECU to stash away...

Thanks for pointers!
 

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Tom- you can check out one possible under hood look if you do a search here for "twinspark conversion pix". There should be others available too with a little research.
It will never be mistaken for the classic look of the Nord w/ a brace of weber carbs, but you can accentuate the positive aspects. Getting rid of the AFM would be a good start but requires a bit of keyboard work.:surprise: Also, for some related light reading check out the extensive thread here on "what the motronic can and cannot do".

I really do need to learn how to insert quotes into my text here....anyone want to try to teach an old dog a new trick ?
 

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The obvious one that it misses with is the "clean engine bay" - more like full engine bay. Perhaps it will be an interesting challenge to see how tidy/neat and minimal it can all be made to look..

Clean wiring, careful treatment of surface finish & possibly minor modification.
Thanks for pointers!
Tom,

Think about routing the body wire loom, the one that primarily contains the wires for all the lights at the front of the car, in the front wheel wells. On my next conversion I plan on installing thin walled tubing in the front wheel wells and routing the body loom through them.

I figured out that I can run the Motronic's loom on the firewall inside the passenger compartment. You can also mount the 4 relays and the ECU there. I was left with the twin coils and that section of the engine loom that contains the wire for the VVT, etc. in the engine compartment. I left the coils in the engine compartment because I didn't want excessively long high tension leads. Also, to mount them inside would have meant that I would have to eliminate the heater. Expect several test fitting to find an acceptable layout. (Mine are LHD, cars; what I suggest might not be doable on a RHD car.)

Tips from the top of my head: carefully check the insulation on wires for cracks and damages. Replace all wire with any type of a defect. Use GXL or SXL wire. Use at least 1.5mm wire to get the power to relay S12d. Do not use quick-disconnect T-Taps. While you can use them to tap into the wire loom that was factory installed they look kludgy and are a mark of an amateur. And I've seen them be a point of failure. (Mechanics and stereo installer in the U.S. love to use T-Taps.)

I just used the information provide on this website for my installations. That was it. I had to decide from whom to buy such things as headers and thermostats but I really can't add much of value. (so far, E.B Spares for both because for me they were the cheapest.) I did retain the two distributors and had no trouble with any part of the engine fouling the bonnet or body. My failures or failure for success the first time has been because I assumed something won't matter. See above about electrical wire insulation.

Bob
 

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Discussion Starter #10
Thanks

Thanks Bob - good food for thought there.

Did you delete the AFM?

Time is on my side as it will me a good few months, if not more that I get to the engine insertion.

I had thought that it would be best to use the original loom only as a template and create a bespoke loom using only wiring that is strictly necessary. That will involve gaining an intimate knowledge of the electrical system but that can only be a good thing....

Shame there isn't an off the shelf tailor made loom form such a conversion, from tried and tested basic motronic installations - that would be one part I would be happy to cough up for!

All the best, Tom
 

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I have two TS motors - one is in a 116 GTV and the other is in a 75. Both are original running Motronic and both are bullet proof. They both produce close to 112HP at the rear wheels and are both used as daily drivers (i.e. easy, reliable etc).

With the install in the GTV I tried to make the install as tidy as possible and you can hide a significant amount of the wiring loom behind the motor and the rest underneath the intake plenum. I have also managed to hide both coils underneath the intake plenum as well which neatens things further. The 105 engine bay may a little tighter so not sure if it will all fit as I have done.
 

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Good place for the coils.

I used the space under the plenum to mounted a large fuel filter (5 um cutoff) off the studs that was there for a SPICA part.

It is the type fuel filter called out for cars equipped with fuel injectors. The one I used is called out for a large series of BMWs made during the '90's
 
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