G'Day Nick,

3. I've read that a Nissan 8-pole distributor can be modified to replace the existing crank-driven Twin Spark distributor (ie removing the need for the cam-driven Twin Spark distributor). What I have not been able to find is information as to what exactly needs to be done to the Nissan distributor to make this a reality. Can anyone help with that level of detail?

This bit I can provide some help with.

You do not modify the Nissan distributor, you modify an Alfa distributor to take a Nissan distributor cap and rotor.

 

Hi Craig,

Thanks for that... do you have any details or informtion as to what needs to be done to the Alfa distributor to make the Nissan rotor arm and cap fit? Photos or drawings would be great if you have them, or, alternatively, a local supplier?

Cheers,


Nick

 

I would think that the front distributor would fit the '69 1300. I've got a '71 and don't have clearance issues with radiator in the stock location. While my car was a 1750 originally, the major assemblies should be the same as what you've got on your car. There isn't a lot of room and it is easier to pull the plug wires before putting the cap on or taking it off, but it does fit.

Regards,
Lawrence

 

G'Day Nick,

Lawrence may well be right, I know nothing about 105s.

My playing with the distributor is of the "just for the fun of it" variety.

What you need to do will depend on the donor distributor but basically you need to machine the distributor to take an adapter plate (I used 5mm aluminium tapped to take the Nissan cap screws). You also need to machine an adapter to connect the rotor to the shaft (but I haven't got that far).

The pics are where I am so far.


As for local supply, not sure but you could try Vin Sharp of Pace Engineering (vsharp on the BB).

 

Craig, nice metal work. Unfortunately, my workshop doesn't stretch to that kind of tooling... hence I will follow up with Vin Sharp.

 

There are a couple of photos and a brief description of the job in Jim K's Twincam tuning book.

 

Thanks... I have Jim K's book on order.

 

Just following up... can anyone advise on my original point 2 (see above)??

"I've read conflicting views on what does and does not need to be done to the flywheel on the Twin Spark and and the bell housing on a 105 gearbox to make them mate up properly. I know that I'll need a pilot hole and bronze bush in the Twin Spark crank to take the gearbox input shaft, but my GT 1300 Junior has a manual (ie non-hydraulic) clutch, so I'm wondering if anything special needs to be done to accommodate this set-up when "dropping in" a Twin Spark engine."

 

You need to ensure that the number of teeth on your flywheel are compatible with the starter. If your original flywheel has the same number of teeth as what's on the twinspark, you can re-use it. Otherwise, you'll need to retain the TS flywheel. The earlier starters are too fat and you'll need to use the smaller twinspark starter on the newer engine. The teeth on the starter bendix have to engage the flywheel, making this an important consideration. If in doubt, use the TS flywheel.

I would think the clutch would be a non-issue. I had a hyrdaulic clutch on my car originally and swapped it over unmodified with my original transmission.

Regards
Lawrence

 

Perhaps refrain from advice that is useless chief. You've just suggested putting an alfetta flywheel in a 105. And your starter info is a crock too.

There are a couple of issues you face with the TS to the cable clutch setup.

1st - a 105 type flywheel with the appropriate number of securing bolts - 6 - this means a 2l 105 flywheel. So your early 8 bolter won't fit (Unless someone makes a conversion piece for it like Lloyd Clonan made for my car which involves machining the centre out of the early flywheel and bolting an adaptor piece in).

2nd - the appropriate factory flywheels are setup for the hydraulicly operated diaphragm clutch - your choices are convert to hydraulic operation with a donor pedal box and bellhousing, or keep the cable clutch and fit an special throwout bearing to suit (I seem to recall Alfaholics do one? as does Spruell? Maybe ask Vin Sharp locally?)

3rd - If you stick with the cable clutch, you'll have to get the flywheel machined to accept the smaller ring gear from the earlier flywheel - although some have made it work with a small amount of clearancing of the bellhousing and the later starter.

Another option is to buy a lightweight steel flywheel made for the job - 2l/Twin spark bolt pattern, early ring gear, race clutch/early clutch/late clutch - Alfaholics do them, and PACE get them made by Alloy Race Components.

Hope this helps.

 

Thanks... I have Jim K's book on order

Save yourself some money and do use the search tool on this BB. You will gain FAR more useful info.

I think you may also run in clearance problems in the inside RH inner guard. They are quite different in the earlier cars to the later 1750s and 2000s. I did this swap on my '67 Junior back in 1998. But I ran 45 mm carbs. Back then, I did this sort of thing for fun on my own car and I went the whole hog.... Converted it to a twin point distributor, ran the tacho properly with a cable and welded and new thermostat housing on so the engine LOOKED like it belonged there.

 

They're right regarding the flywheel. Its been a few years since I first got my TS and I had a supreme brainfart around this point. I reused my original flywheel with the TS starter.

There are flywheels with 130 and 131 teeth. To ensure that the starter will engage cleanly, you'll want to verify that the new flywheel has the same number of teeth as the original TS flywheel. I don't think this is a crock, but hopefully La strega will set me straight if this gearing ratio doesn't matter.

Regards,
Lawrence

 

Hi,

Sorry to Hijack this thread, but I would also like to have some information about the flywheel swap for a Twin Spark. I know yhat the subject have been covered several times through the BB but some informations are contradictory. Where's the thruth ?

I have at hand a lightened flywheel for a 2000, from a former 'Squadra Bianca' Giulia racer. (6 holes, 130 teeth)
The 'Alfetta' type ring gear of the TwinSpark is supposed to have 131 teeth.

Assuming that, unless njh1964, the car intended to receive the engine is equipped with hydraulic clutch...

1 - Can I fit this 130 teeth flywheel on the TwinSpak engine, assuming that the 'teeth number' difference (130 vs 131) will not create an issue when reusing the TS starter motor ?
2 - If not possible, can I fit a '105' 9 teeth starter on the 75 TwinSpark block ?
3 - Is there another way that I'n not aware of, apart from replacing the 130 ring gear with a 131 teeth model (same inner diameter ??)

Thank you for your help
Regards
Sébastien

 

Early (cable clutch) flywheels are 105 tooth and use an 8 tooth starter, later cars are 130 tooth and use a 9 tooth starter.

 

Thanks for all the feedback. It's all been very useful.

I managed to get hold of a 2lt gearbox and six bolt flywheel over the weekend... so I'll go down that path with the Twin Spark conversion.

All I need now are the parts to swap out the cable clutch in the GT 1300 Junior with an hydraulic clutch set-up. Does anyone have any of these clutch bits Downunder??

Thanks again to all.

 

Talk to Beninca in Melb... they've been doing twin spark conversions for eons...

 

You cannot use the 105 tooth RG. The 105 RG takes a 8 tooth starter drive. You SHOULD swap (direct fit!) the 131 in place of the 130. That will allow you to use the smaller and lighter gear reduction starter. The 130 should take the smaller 9 tooth starter as used from 72 to 74-5 or so...

 

I just realized that some may get confused.

When I speak about '105', I'm meaning Giulia series, (in opposition to 116 Alfetta's) and not ... 105 teeth

So which model was fitted with a 131 teeth flywheel ?
I'm located in europe and US / European may differ. (Injection was used earlier in US becasue of emissions) but i will try to make an equivalence


BTW what are the differences between 130 and 131 flywheels (apart the teeth number, of course) that prevent from using a 130 teeth flywheel with the later gear reduction starter ?


I'm sticking to it because I already have a lightweight 130 teeth flywheel and I would be very disapointed that this item will have no use.

Regards
Sébastien

 

The 130 tooth flywheel (in the USA) was 1972 to 74(ish). The 131 tooth flywheel was 1975 to 1989. The 130 tooth flywheel is for the 'small' 9 tooth starters with .8ps, the 131 tooth flywheels were for the 1.1ps 'big' starters (the big starters should have a support bracket at the motor mount to help support it). The gear reduction starters for 1986 to 1989 were for use with the 131 tooth RG and for some reason, Alfa went back to a 130 tooth flywheel in 1990 (for spiders) and a different starter. You MIGHT be able to use your 130 RG with a gear reduction starter. SOMETIMES it works out OK and other times it will make too much noise or it can cause the bellhousing to crack (happened to me!). If I were going through the trouble of building an engine, I would do it correctly. Just buy a 131 RG and put it on your flywheel. Then you will not have a problem.

 

TS to GTJr conversion

I have a 69 GT Jr with 75 TS, with carbs. I bought the car with the conversion, and don't know all the details, but will be happy to share what I know. The tightest fit is between the distributor (8-wire, Nissan/Alfa conversion) and the radiator, and there's not enough room for an airbox - see photos.

I'm considering reverting to the original FI setup - can you tell me what parts I would need for that?
Thanks,

Sfourza

 

The earlier step nose cars have a different inner guard to the later cars. I dont think you will get the original FI set-up to fit.

What exactly is wrong with the car as it is? Looks like nicely executed conversion to me.

I did this conversion back in '98 before any off the shelf components were available. I made a custom airbox to get cold air and keep it quiet: there is plenty of room. The bigest issue I can see with your car is the position of those BIG coils. I positioned some more modern (smaller) ones down near the fuel filter bracket.

 

Further to Clayton105's above comments, has anyone actually managed to fit a Twin Spark, complete with stock fuel injection, into the engine bay of a 1969 GT Junior 1300 step-front (ie Series 105.31)?

My preliminary measurements show it's going to be tight, but, assuming it may be too tight, I'd like to hear from anyone who had to modify the fuel injection intake side of things in order to make everything fit.

 

TS conversion

Good suggestion re the coils - I'll look into that, though the position is not really a problem. It may be the carb setup, but I'm not getting the flexibility and "oomph" I expected. What carbs/setup are you using? Are you using electronic ignition?
S

 

I was using 45 mm DellOrtos with 38 mm chokes from memory. I will say the the manifold was based on the original FI one (with flanges welded on) so it was a bit shorter. I also had curved GTA style trumpets inside the air box so that meant I could have the air box sit up higher than with straight trumpets.

The ignition was a custom made (by myself) hybrid twin-point Bosch/Nissan Dizzy. Was a bit high maintenance....

I notice that you have the cam advance solenoid (no connection) still in the engine. I can't remember if you need to do anything with this to disable the cam advance function (if the donk still has the do-hicky on the cam). As in, does the solenoid rely on volage to advance or retard???? If it relies on voltage to advance, then the inlet will be retarted right through the rev range. The variable cam timing on these was really just to reduce the overlap at low revs for idle.

My '67 junior T-S Junior, had a completely stock engine (internally) apart from the ports cleaned up, cam advance diabled, carbs as above and a nice 4-1 exhaust and had 106 RWHP (as apposed to the stock T-S 75's 92 RWHP. It also gave great fuel consumption and pulled like a train from 1500 - 7000 rpm. This engine replaced a Nord engine with 118 RWHP but was FAR nicer on the street and was far and away the more than enough for me for day to day use.

Have you had this on the Dyno?

 

Have you checked this site out?

Alfa Romeo Performance Engines

 

Hi gigem75, Yes, that site is a great resource, but it doesn't cover the specifics of squeezing a Twin Spark into a step-front GT 1300 Junior.

 

TS in GTJr

What are the critical dimensions that you need? I can measure clearances in my car if that will help.
Sfourza

 

What are the critical dimensions that you need? I can measure clearances in my car if that will help.

Sfourza

Hi Sfourza,

I'll refer to the below photo, borrowed from another posting elsewhere on this site... I hope the owner of the photo doesn't mind

The photo shows a very neat transplant of a stock Twin Spark engine into a later model 105 (ie not a step-front 105, like mine).

As can be seen, the stock fuel injection intake gear just clears the inner guard inside the engine bay.

However, as others have stated, it could be that the inner guard on a step-front 105 is different to later model 105s, and that the stock fuel injection intake gear may not fit (ie unmodified) into a step-front engine bay.

I'd like to hear from anyone who has dropped a stock fuel injection Twin Spark into a step-front 105. I'd like to know if it fitted OK, or, if they needed to make modifications to get it to fit, what were these modifications.

Regards,


Nick

 

Project Update

Still haven't heard from anyone who has actually fitted a stock EFI Twin Spark engine into a GT 1300 Junior step-front engine bay (ie does the EFI intake gear clear the inner fender).

However, with the help of my mechanic last weekend, we've fitted the flywheel from a 2lt Berlina onto the Twin Spark crankshaft... and, believe it or not, the pilot hole is already there in the crankshaft

We then fitted up the 2lt bellhousing and dry fitted the 2lt gearbox... this confirmed the presence of the pilot hole, but, of course, we now need the felt washer and bronze bushing to go into the pilot hole.

More good news, the 2lt flywheel mates up to the existing Twin Spark starter motor. We confirmed this by hooking the starter to a battery and running some juice through it for a few seconds... the result was a normal start-up sound, and a nicely rotating flywheel.

So, after the Twin Spark sump has been swapped for a 105 sump, we'll be "dry fitting" the Twin Spark engine (complete with EFI intake gear) to see if it will squeeze into a GT 1300 Junior step-front engine bay... watch this space. I seem to be on a bit of a roll at the moment, but those can come to a quick and grinding halt, as we all know

 

twinspark hints

Nick-- I'm not a stepnose expert, but Im pretty sure you can shoehorn the factory TS setup in there with careful attention to the three "close" places: 1.) front dizzy to radiator, 2.) throttle cable bracket/belcrank on top of throttle body where it may foul the underside of the bonnet, and 3.) the inner fender (wing?) to intake plenum. Sounds like you have avoided the first w/ your 8-wire dizzy. The second can usually be helped by grinding down the bracket which positions the throttle cable on the throttle body and/or slotting it's mounting holes to move it downward. The third area can be helped by fabricating new, shorter plenum to intake manifold rubber spigots (even 1/4" shorter helps as it moves the plenum toward the motor), slotting the plenum brace lower mounting hole to allow for some up or down adjustment as needed, and potentially most helpful is juggling different available right side motor mounts to tilt the motor slightly toward the exhaust side-- guess I can't say passenger side in your case, huh? I don't know any way other than trial and error fitment as you go complemented by beer, careful measuring, helper(s), more beer, etc. Good luck!

 

Twin Spark Fender Clearance

Nick-- I'm not a stepnose expert, but Im pretty sure you can shoehorn the factory TS setup in there with careful attention to the three "close" places: 1.) front dizzy to radiator, 2.) throttle cable bracket/belcrank on top of throttle body where it may foul the underside of the bonnet, and 3.) the inner fender (wing?) to intake plenum. Sounds like you have avoided the first w/ your 8-wire dizzy. The second can usually be helped by grinding down the bracket which positions the throttle cable on the throttle body and/or slotting it's mounting holes to move it downward. The third area can be helped by fabricating new, shorter plenum to intake manifold rubber spigots (even 1/4" shorter helps as it moves the plenum toward the motor), slotting the plenum brace lower mounting hole to allow for some up or down adjustment as needed, and potentially most helpful is juggling different available right side motor mounts to tilt the motor slightly toward the exhaust side-- guess I can't say passenger side in your case, huh? I don't know any way other than trial and error fitment as you go complemented by beer, careful measuring, helper(s), more beer, etc. Good luck!

Hi Capp,

Thanks for the feedback.

I agree... the inner fender clearance is going to be the big issue. I'm thinking that if the Twin Spark plenum won't clear the fender, then I'll remove the rubber spigots between the plenum and intake manifold, and weld the two pieces together. I've seen this done elsewhere on the Alfabb site with a Twin Spark conversion. It seems to involved a bit of fiddling around, but it should deliver that all important extra 20-30mm of clearance.

Thanks also for the throttle linkage tip. I hadn't thought of that, and it would be a rude surprise to re-fit the bonnet (hood?) only to find the bugger won't close properly.

As for tilting the engine towards the exhaust/passenger side , I've purchased a brand new pair of 105 series engine mounts from EB Spares in the UK (great price and delivery time, by the way), which I'd rather not mess with if I can avoid doing so. Besides which, if I tilted that lovely flat Twin Spark cam cover, where would I rest my coldie (beer?) when I'm changing the spark plugs??

Once I do get it all sorted out, I'll post a few before, during and after photos so that other step-front devotees can learn from my grunt work... just as I continue to gratefully learn from the experience of others (like yourself) on this site.

Cheers,


Nick

 

Twin Spark Fender Clearance



Hi Capp,

Thanks for the feedback.

I agree... the inner fender clearance is going to be the big issue. I'm thinking that if the Twin Spark plenum won't clear the fender, then I'll remove the rubber spigots between the plenum and intake manifold, and weld the two pieces together. I've seen this done elsewhere on the Alfabb site with a Twin Spark conversion. It seems to involved a bit of fiddling around, but it should deliver that all important extra 20-30mm of clearance.

Thanks also for the throttle linkage tip. I hadn't thought of that, and it would be a rude surprise to re-fit the bonnet (hood?) only to find the bugger won't close properly.

As for tilting the engine towards the exhaust/passenger side , I've purchased a brand new pair of 105 series engine mounts from EB Spares in the UK (great price and delivery time, by the way), which I'd rather not mess with if I can avoid doing so. Besides which, if I tilted that lovely flat Twin Spark cam cover, where would I rest my coldie (beer?) when I'm changing the spark plugs??

Once I do get it all sorted out, I'll post a few before, during and after photos so that other step-front devotees can learn from my grunt work... just as I continue to gratefully learn from the experience of others (like yourself) on this site.

Cheers,


Nick

Twin Spark Fender Clearance



Hi Capp,

Thanks for the feedback.

I agree... the inner fender clearance is going to be the big issue. I'm thinking that if the Twin Spark plenum won't clear the fender, then I'll remove the rubber spigots between the plenum and intake manifold, and weld the two pieces together. I've seen this done elsewhere on the Alfabb site with a Twin Spark conversion. It seems to involved a bit of fiddling around, but it should deliver that all important extra 20-30mm of clearance.

Thanks also for the throttle linkage tip. I hadn't thought of that, and it would be a rude surprise to re-fit the bonnet (hood?) only to find the bugger won't close properly.

As for tilting the engine towards the exhaust/passenger side , I've purchased a brand new pair of 105 series engine mounts from EB Spares in the UK (great price and delivery time, by the way), which I'd rather not mess with if I can avoid doing so. Besides which, if I tilted that lovely flat Twin Spark cam cover, where would I rest my coldie (beer?) when I'm changing the spark plugs??

Once I do get it all sorted out, I'll post a few before, during and after photos so that other step-front devotees can learn from my grunt work... just as I continue to gratefully learn from the experience of others (like yourself) on this site.

Cheers,


Nick

Hi, it seems this question was never really answered. however this is how I made my TS fit a 69 GT Junior stepnose. I used 2 high density 105 mounts from Alfaholics, then I cut 9mm from the LHS engine mount bracket parallel to the engine side mount plate and re welded it. then I used 9 mm spacers between engine and rh mount. this moved the engine sideways and tilted it slightly more than usual. now I need to manufacture a new bell crank for the throttle body and the bonnet will clear easily

 

Sounds as though you have things in hand. A few observations from personal experience, FWIW :

• Motor mounts vary in thickness from year and model, 105/115/116 series. They can be juggled L to R to raise and lower respective sides and/or the whole motor for clearance without cutting anything, IME.
• Be careful moving motor sideways, driveline issues may follow. Rotating the motor about its crankshaft axis (tilting) is OK.
• You should not have to modify the throttle bellcrank for bonnet clearance, but if you do try to maintain the geometry or the eccentric design of the bellcrank throw itself. It affects throttle feel significantly.

YMMV