Twin Spark Swap Owner's Satisfaction Survey
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my buddy had a ts original in his 1.8 75.it was much slower than my 1.8 carb.but the answer was quite simple.he was at 100 kmh at 2700 rpm.i was 100kmh at 3000 plus.it was my gear from a 1.6 that told the whole story.the ts gear was for good fuel economy.couldn't turn in worth sh*t.moral is without the proper gearing don't bother.
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My son and I recently bought a Twin Spark Alfetta (Clark's car, for those familiar); and what a beautiful pairing. I also have a V6 Alfa 75/Milano, and the lighter Alfetta with a similarly powerful and drivable engine makes a favorable comparison.
The installation is a stock 75 TS and we expect to leave it similar. The AFM->MAF conversion discussed elsewhere is attractive. We are planning to rework the harness installation. With the benefit of seeing the current installation and having worked with modern race car electronics, I have a new layout which will simplify the installation, reduce the clutter on the right side of the bay, and consolidate the wiring. The current intake, a cone on the AFM, is crowded, and the harness rework will give us room to ensure air is being pulled from the outside instead of the rear of the radiator.
We also have some tuning to do, as it suffers from a mild surge when starting; and there is a flat spot just off throttle (both of which of course could be the AFM).
We are interested to hear oil recommendations for an 89 TS in 2020. Do these engines prefer a higher ZDDP than modern oils provide? Or are we safe to use a good, current, high-detergent/high shear oil?
We are also interested in recommendations on diagnostics for the engine. Is anyone running some mechanism to warn of fault codes (like a check engine light)?
Thanks!
The installation is a stock 75 TS and we expect to leave it similar. The AFM->MAF conversion discussed elsewhere is attractive. We are planning to rework the harness installation. With the benefit of seeing the current installation and having worked with modern race car electronics, I have a new layout which will simplify the installation, reduce the clutter on the right side of the bay, and consolidate the wiring. The current intake, a cone on the AFM, is crowded, and the harness rework will give us room to ensure air is being pulled from the outside instead of the rear of the radiator.
We also have some tuning to do, as it suffers from a mild surge when starting; and there is a flat spot just off throttle (both of which of course could be the AFM).
We are interested to hear oil recommendations for an 89 TS in 2020. Do these engines prefer a higher ZDDP than modern oils provide? Or are we safe to use a good, current, high-detergent/high shear oil?
We are also interested in recommendations on diagnostics for the engine. Is anyone running some mechanism to warn of fault codes (like a check engine light)?
Thanks!
Late into this thread but here is a UK perspective.
Just about to finish my second twin spark conversion. I wouldn't fit anything else.
The first had JE pistons a cam from a UK supplier a little port cleaning up usual performance valve stuff and throttle body EFI controlled by an Omex ECU.
186bhp (got a map graph) loads of torque and clean starting and running.
The current one has a Alfaholics 190 bhp kit and a lot more head work, EFI again so we will see.
The conversions are really simple so long as you have access to a machine shop for a couple of bits.
Biggest problem is finding a twin spark engine in the UK, a bit like hens teeth over here.
Pleased to help if I can.
Martin
Just about to finish my second twin spark conversion. I wouldn't fit anything else.
The first had JE pistons a cam from a UK supplier a little port cleaning up usual performance valve stuff and throttle body EFI controlled by an Omex ECU.
186bhp (got a map graph) loads of torque and clean starting and running.
The current one has a Alfaholics 190 bhp kit and a lot more head work, EFI again so we will see.
The conversions are really simple so long as you have access to a machine shop for a couple of bits.
Biggest problem is finding a twin spark engine in the UK, a bit like hens teeth over here.
Pleased to help if I can.
Martin
I'm back.
I know there are a lot of folk out there with more knowledge than me and this has been done before so this is just my take having done a couple.
My general MO is do do as much of the time consuming tedious and straight forward stuff myself. So strip, clean the long grind of basic porting and gathering together all required bits. Then hand it over to a good engine builder with Alfa experience. This keeps my cost to a minimum, gives me a level of involvement but lets someone with the knowledge and kit do stuff like grind the cam caps correctly, balance it up nicely and zip it up correctly, a good engine builder is more than a nut and bolt tightener.
Happy to go over the parts recipe if you wish but I won't get long winded unless you want.
I use the head and block from a 75 twin spark and sump from the Nord.
Inlet manifold is a Twin Webber conversion, a couple of places sell them over here.
Throttle bodies are Jenvey, these match the Webber bolt pattern.
The valve springs are Kent race with new valves and guides. I kept standard valve sizes.
Piston compression ratio 11:1 (but depends a bit on if your head has been skimmed). Seems a lot but with a high overlap cam it retains the cylinder pressure (getting into physics I'm a bit iffy on here).
Standard rods on the first but am fitting Carrillo on the next.
As you need two 4 cylinder coil packs and a lot of 4 cylinder ECU's won't drive them you need get them to make one with no internal amplifier and use two external amplifiers in parrallel (more info if you need it).
I have always used a good rolling road for set up, so much better but now I have my first map and one supplied by the ECU supplier to choose from for running in.
I've used a lot of different suppliers in the past but have pretty much settled with Alfaholics for most of my Alfa stuff, they can be pricy but there stuff is proven and good quality, they are also a font of expert knowledge.
So I guess its a case of knowing my limitations and cherry picking between my cheap time and the experts expensive time.
I seem to be rambling so will stop, any specific bits I can help with let me know.
Martin
PS Power curve attached
![1666499]()
I know there are a lot of folk out there with more knowledge than me and this has been done before so this is just my take having done a couple.
My general MO is do do as much of the time consuming tedious and straight forward stuff myself. So strip, clean the long grind of basic porting and gathering together all required bits. Then hand it over to a good engine builder with Alfa experience. This keeps my cost to a minimum, gives me a level of involvement but lets someone with the knowledge and kit do stuff like grind the cam caps correctly, balance it up nicely and zip it up correctly, a good engine builder is more than a nut and bolt tightener.
Happy to go over the parts recipe if you wish but I won't get long winded unless you want.
I use the head and block from a 75 twin spark and sump from the Nord.
Inlet manifold is a Twin Webber conversion, a couple of places sell them over here.
Throttle bodies are Jenvey, these match the Webber bolt pattern.
The valve springs are Kent race with new valves and guides. I kept standard valve sizes.
Piston compression ratio 11:1 (but depends a bit on if your head has been skimmed). Seems a lot but with a high overlap cam it retains the cylinder pressure (getting into physics I'm a bit iffy on here).
Standard rods on the first but am fitting Carrillo on the next.
As you need two 4 cylinder coil packs and a lot of 4 cylinder ECU's won't drive them you need get them to make one with no internal amplifier and use two external amplifiers in parrallel (more info if you need it).
I have always used a good rolling road for set up, so much better but now I have my first map and one supplied by the ECU supplier to choose from for running in.
I've used a lot of different suppliers in the past but have pretty much settled with Alfaholics for most of my Alfa stuff, they can be pricy but there stuff is proven and good quality, they are also a font of expert knowledge.
So I guess its a case of knowing my limitations and cherry picking between my cheap time and the experts expensive time.
I seem to be rambling so will stop, any specific bits I can help with let me know.
Martin
PS Power curve attached
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741 Posts
76 junior with stock gearbox, 2000lsd, TS front calipers, koni reds, stock TS with motronic. Converted 10yrs ago, never misses a beat. 37mpg
Thats good mpg, don't think mine will do that.
Martin- thanks much for your detailed reply, it helps narrow the choices down and is always good to know what has worked for others.
Looks like your motor is still making h.p. through 7k rpm. Don't know what you had previously to compare to, but did you notice any drop off of bottom end torque or notice around town drivability issues with this combination ?
I think I follow you about the ignition setup, assume you are firing the plugs directly from the coil packs- no distributor(s), but used the CPS to control spark timing ? Also curious about ITB size- 42 or 45 ? Maybe the most convenient reply for you and interested others is to list your "build sheet". It might save some repetitive questions. Don't know if you have enough posts here yet to enable the private message feature and you can do that if you prefer although I think others here would be interested in your recipe.
Your general approach resembles mine. I did all of the grunge work and cleaning, strip-down, and leg work farming out ancillary parts to rebuilders, and to machine shops for balancing, etc. then I gathered it all up an gave it to a local experienced Alfa shop for final assembly. That was probably my wisest decision and was money well spent, as you have suggested. In my case it was necessary to machine deeper valve reliefs in the stock pistons due to necessary head skimming and wound up with at least 10.5 to 1 CR, but had no problems with pump fuel.
Thanks again for contributing to the general knowledge of this thread and keep us up to date. Also we loves pictures...got any ?
Looks like your motor is still making h.p. through 7k rpm. Don't know what you had previously to compare to, but did you notice any drop off of bottom end torque or notice around town drivability issues with this combination ?
I think I follow you about the ignition setup, assume you are firing the plugs directly from the coil packs- no distributor(s), but used the CPS to control spark timing ? Also curious about ITB size- 42 or 45 ? Maybe the most convenient reply for you and interested others is to list your "build sheet". It might save some repetitive questions. Don't know if you have enough posts here yet to enable the private message feature and you can do that if you prefer although I think others here would be interested in your recipe.
Your general approach resembles mine. I did all of the grunge work and cleaning, strip-down, and leg work farming out ancillary parts to rebuilders, and to machine shops for balancing, etc. then I gathered it all up an gave it to a local experienced Alfa shop for final assembly. That was probably my wisest decision and was money well spent, as you have suggested. In my case it was necessary to machine deeper valve reliefs in the stock pistons due to necessary head skimming and wound up with at least 10.5 to 1 CR, but had no problems with pump fuel.
Thanks again for contributing to the general knowledge of this thread and keep us up to date. Also we loves pictures...got any ?
Hi Capp
Drivability good pulling smooth from the bottom, the beauty of efi and mapped ignition.
Used the standard Twin Spark trigger wheel. Body size 45mm.
A couple of pics attached. As can be seen I didn't do much about the valve recesses on this one, my next has a lot more flaring out there, I ground an old valve down to sit low into the valve seat to protect the seat insert before attacking with the Dremmel.
You sure folk interested in the complete recipe, happy to list if you think worth it.
Martin
![1666771]()
![1666772]()
Drivability good pulling smooth from the bottom, the beauty of efi and mapped ignition.
Used the standard Twin Spark trigger wheel. Body size 45mm.
A couple of pics attached. As can be seen I didn't do much about the valve recesses on this one, my next has a lot more flaring out there, I ground an old valve down to sit low into the valve seat to protect the seat insert before attacking with the Dremmel.
You sure folk interested in the complete recipe, happy to list if you think worth it.
Martin
OK here goes and apologies again to all who know all this already.
Starting point a 2 Litre Twin Spark from an Alfa 75 and the original Nord, mine was a 1600.
Head and block of Twin spark mates up to sump off Nord.
Fist step for me after stripping and basic clean is have it all soda blasted.
Bead blasting I find nice on the external parts but not for internals.
Machining required.
Crank possibly for spigot bearing.
If you are going for a performance cam then the VVT variator has to go so a cam sprocket off the old Nord has to be machined down to the same length a a twin spark one to replace it.
I like to machine the front pulley down for a single belt.
Port cleaning up, I wouldn't call it wild porting or flow bench stuff but just cleaning up, a bit removed behind the valves and matched to the inlet manifold. I don't polish as current thinking is a roughish surface is beneficial to fuel atomisation.
Other parts
All new bearings and seals, race spec if possible.
Highish lift, high overlap camshafts (torque not max power the factor here, I once read that power is for bar room bragging, torque wins races).
Kent valve springs, standard valves.
11:1 JE pistons with JE pro-seal rings (although I've gone Carrillo on my second)
I kept standard rods for the first, good to 7,000 rpm, Carrillo for my next should be good for a little more.
Nord high volume oil pump
A two output water pump to replace the original so you don't have to block off any pipes.
Lightweight fly wheel.
I am a firm believer in having everything properly balanced.
Jenvey fuel injection throttle bodies Pico brown injectors.
I make the loom myself twisting all the cables and finishing in heat shrink polyfine tubing.
Alfaholics Stainless exhaust system. Alfaholics alloy radiator with integral Oil cooler controlled by thermostatic take off.
Custom Omex 600 management, external ignition amplifiers with double coil packs.
Just for info' I used a 1600 diff with a Quaife LSD, better gearing for British roads.
I have used various suppliers in the past but I am now a firm Alfaholics addict, they are good.
I have no doubt missed something so don't be afraid to ask.
OK non of this is cheap but you get the money back and more if and when you come to sell. It also makes a powerful and good driver.
Martin
![1666812]()
Starting point a 2 Litre Twin Spark from an Alfa 75 and the original Nord, mine was a 1600.
Head and block of Twin spark mates up to sump off Nord.
Fist step for me after stripping and basic clean is have it all soda blasted.
Bead blasting I find nice on the external parts but not for internals.
Machining required.
Crank possibly for spigot bearing.
If you are going for a performance cam then the VVT variator has to go so a cam sprocket off the old Nord has to be machined down to the same length a a twin spark one to replace it.
I like to machine the front pulley down for a single belt.
Port cleaning up, I wouldn't call it wild porting or flow bench stuff but just cleaning up, a bit removed behind the valves and matched to the inlet manifold. I don't polish as current thinking is a roughish surface is beneficial to fuel atomisation.
Other parts
All new bearings and seals, race spec if possible.
Highish lift, high overlap camshafts (torque not max power the factor here, I once read that power is for bar room bragging, torque wins races).
Kent valve springs, standard valves.
11:1 JE pistons with JE pro-seal rings (although I've gone Carrillo on my second)
I kept standard rods for the first, good to 7,000 rpm, Carrillo for my next should be good for a little more.
Nord high volume oil pump
A two output water pump to replace the original so you don't have to block off any pipes.
Lightweight fly wheel.
I am a firm believer in having everything properly balanced.
Jenvey fuel injection throttle bodies Pico brown injectors.
I make the loom myself twisting all the cables and finishing in heat shrink polyfine tubing.
Alfaholics Stainless exhaust system. Alfaholics alloy radiator with integral Oil cooler controlled by thermostatic take off.
Custom Omex 600 management, external ignition amplifiers with double coil packs.
Just for info' I used a 1600 diff with a Quaife LSD, better gearing for British roads.
I have used various suppliers in the past but I am now a firm Alfaholics addict, they are good.
I have no doubt missed something so don't be afraid to ask.
OK non of this is cheap but you get the money back and more if and when you come to sell. It also makes a powerful and good driver.
Martin
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1,166 Posts
different engine setup here: 155 2 liter block (the one with piston cooling in the oil system), 90 mm crank, 85 bore, JE pistons matched to long old nord rods (K1 used) . 10.5 CR 75 TS head with tilted intake ports , short 48mm Jenvey ITB with DTA computer. custom made exhaust and airbox, last dyno 213 hp @ 7200 (over 200 from 6500-8000) and 225 nm torque (peak at 5500 but allready 200 at about 3500). Is my race engine but will hapily crawl up a tilted trailer without burning the clutch.
Looks like a complex mix but that's good power, even with big valves not sure I would get that. Clever stuff, well done.
Hi Martin and Walter
It's nice to see there's a good talk about TS conversion and experience. I might well miss a more telling thread than this one. After spending some winters getting the body back in place, and having started assembling that car after painting, the turn has come for the engine. The engine is a 75 tsp that I have cut together with parts from, Poul Spuell, Alfa Holic, Ferrea, Cat cams and more. I have two questions that I could use help with.
1. according to the picture there is a small hole in the middle bearing fit, it is for lubrication of the valve lifters, I was in doubt as I have not come across it before.
2. I bought an Omex 710 box, as I had a plan to go for full sequential injection, I am missing like everyone else a 720 ° signal, therefore know one of you someone who has used AW-delta´s distributor that could be use both as a engine position, but also for a distribution of the ignition, if I use the old ignition coil system. is there any of you there now if this Is a suitable way to go?
I add a couple of pictures of the engine.
It's nice to see there's a good talk about TS conversion and experience. I might well miss a more telling thread than this one. After spending some winters getting the body back in place, and having started assembling that car after painting, the turn has come for the engine. The engine is a 75 tsp that I have cut together with parts from, Poul Spuell, Alfa Holic, Ferrea, Cat cams and more. I have two questions that I could use help with.
1. according to the picture there is a small hole in the middle bearing fit, it is for lubrication of the valve lifters, I was in doubt as I have not come across it before.
2. I bought an Omex 710 box, as I had a plan to go for full sequential injection, I am missing like everyone else a 720 ° signal, therefore know one of you someone who has used AW-delta´s distributor that could be use both as a engine position, but also for a distribution of the ignition, if I use the old ignition coil system. is there any of you there now if this Is a suitable way to go?
I add a couple of pictures of the engine.
Attachments
Hi Bjarne
Not sure which hole you mean (probably me being stupid) could you post a pic showing it better.
Regarding ignition I always use the standard TS toothed wheel and pick up to drive the ECU. Alfaholics sell blanking plugs for the distributers and fit two 4 cylinder coil packs. I would get in touch with Omex to see if the 710 will drive them or if it needs a modification (removal of internal amplifiers) to drive external amplifiers, they are very helpful.
I may be able to give you a part number if you are stuck.
Martin
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