camshafts
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william vd Sman
camshafts
Has anyone experience with non standard camshafts in their Fulvia engine? I'm especially interested in more competition orientated cams for the smaller Fulvia engines (not 1600) and how they behave. In my oppinion the trick for more revs are hotter cams but some may disagree.
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Geoff
Re: camshafts
I have no real experience on this one, but offer you some thoughts on cams and Aurelias - too often people go for duration or high lift, and that is only one part of the puzzle, and not necessarily the most important.
In the Aurelia, the trick for revs was not hotter cams, but rather a better profiled cam - one where the toe or shoulder was better designed. The Aurelia cams are based on a tri-arc geometry and have a pretty hard start-up and closure.
Cleaning up the toe of the curve has given those motors a lot more open feeling, and more revs. I doubt this is directly applicable to Fulvias, but perhaps it gives you another point of view.
Does anyone know what the geometry for the lobe profile for Fulvias was?
Geoff
In the Aurelia, the trick for revs was not hotter cams, but rather a better profiled cam - one where the toe or shoulder was better designed. The Aurelia cams are based on a tri-arc geometry and have a pretty hard start-up and closure.
Cleaning up the toe of the curve has given those motors a lot more open feeling, and more revs. I doubt this is directly applicable to Fulvias, but perhaps it gives you another point of view.
Does anyone know what the geometry for the lobe profile for Fulvias was?
Geoff
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P. de R. Leclercq
Re: camshafts
I think that Geoff has a valid point.
I do know that much work has gone into camshaft profiles in the thirty or so years since the Fulvia was current; all the profiles as far as I know are replicas of period ones.
No doubt if someone had the money, a more interesting cam could be developed. Quite aside from the issue of more modern profiles, I recall that "scatter" timing has been used on Minis to cope with the pathetic head design. Perhaps the Fulvia with its odd ports and mirror-image plug positions would benefit from a "scatter" camshaft?
Paul
I do know that much work has gone into camshaft profiles in the thirty or so years since the Fulvia was current; all the profiles as far as I know are replicas of period ones.
No doubt if someone had the money, a more interesting cam could be developed. Quite aside from the issue of more modern profiles, I recall that "scatter" timing has been used on Minis to cope with the pathetic head design. Perhaps the Fulvia with its odd ports and mirror-image plug positions would benefit from a "scatter" camshaft?
Paul
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Michael Beattie
Re: camshafts
An engine tuner friend of mine, says that basically there have been no "new" performance profiles for cams since the 70s. Modern engines are getting their power from engine management and fuel injection. As Paul says most cams offered are based on "period" designs, with variations on the fabled Cosworth profiles being most common.
Playing with the overlap / timing is where you can vary the performance of a specific cam design.
I am currently using Omicron's "rally" profile in my 1600 HF, which are timed in at 109 degrees. ( i.e. inlet fully open 109 degrees after TDC and exhaust 109 before TDC). They perform very well indeed and the engine is preducing peak power at 7000rpm on std 42 Solex. 109 is a relatively conservative setting compared to other competition engines I have run, for example Paul mentions the "scatter pattern" BMC cams. Kent's Megadyne 286 scatter rally cam is suggested to be set at 106, but advancing it to 102 actually gives better performance figures. But I think I read that the scatter cam was developed for the siamised port on the BMC head, so I'm not sure if that technology applies to the 4 port Lancia?
On twin cam engines, one trick for a powerful, yet torquey engine is to have different profiles on the inlet and exhaust. You can run a "race" type inlet with a "rally" style exhaust to great effect, and playing with the cam timing, i.e. increasing the overlap will effect the power delivery. Trial & error is the only way to find out.
The other factor to consider is that using the same cam on different sized engines gives different performance, with smaller cc engine (say 1300) being peakier on a certain cam, while a 1600 engine will have a much smoother delivery on the same cam. SDo beware of using 1600 style cams.
Geting an engine to rev is also based on how it breathes, in both the inlet and exhaust. You can put all the cams, h/c pistons etc in an engine, but if the exhaust or inlet are restricting the gas flow then it won't perform. How about a competition exhaust system, I know it works on the 1600, maybe some of our more experienced Lancia folk could say what is needed for a 1300.
Michael
Playing with the overlap / timing is where you can vary the performance of a specific cam design.
I am currently using Omicron's "rally" profile in my 1600 HF, which are timed in at 109 degrees. ( i.e. inlet fully open 109 degrees after TDC and exhaust 109 before TDC). They perform very well indeed and the engine is preducing peak power at 7000rpm on std 42 Solex. 109 is a relatively conservative setting compared to other competition engines I have run, for example Paul mentions the "scatter pattern" BMC cams. Kent's Megadyne 286 scatter rally cam is suggested to be set at 106, but advancing it to 102 actually gives better performance figures. But I think I read that the scatter cam was developed for the siamised port on the BMC head, so I'm not sure if that technology applies to the 4 port Lancia?
On twin cam engines, one trick for a powerful, yet torquey engine is to have different profiles on the inlet and exhaust. You can run a "race" type inlet with a "rally" style exhaust to great effect, and playing with the cam timing, i.e. increasing the overlap will effect the power delivery. Trial & error is the only way to find out.
The other factor to consider is that using the same cam on different sized engines gives different performance, with smaller cc engine (say 1300) being peakier on a certain cam, while a 1600 engine will have a much smoother delivery on the same cam. SDo beware of using 1600 style cams.
Geting an engine to rev is also based on how it breathes, in both the inlet and exhaust. You can put all the cams, h/c pistons etc in an engine, but if the exhaust or inlet are restricting the gas flow then it won't perform. How about a competition exhaust system, I know it works on the 1600, maybe some of our more experienced Lancia folk could say what is needed for a 1300.
Michael
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P. de R. Leclercq
Re: camshafts
Some good points Michael.
Regarding the scatter idea, of course I am thinking of an inlet camshaft for the Fulvia with its lobes staggered to allow for the different ports; I am sure that this could be worth investigating - the question is which way to stagger the timing? The gas speed in the long ports will or at least should be, greater which would suggest retarding the opening, but then again...
I know that touring cars, being rev-limited, run enormous valve lifts - over 14mm in some cases; this appears to be the modern approach but sadly impracticable for the Fulvia; the acceleartion of the valve must be extraordinary in such cases.
Regarding exhaust systems, I have long held the view that the Fulvia responds very well to exhaust work; sensitive work in the exhaust valve throats works wonders for torque. In "Lancia Racing" Nigel Trow mentions a 1.3HF engine that made 140HP. This was fitted with what he calls a "Caravello" exhaust manifold. Unfortunately there are no details or pictures of this component.
At the time, the works competition manifolds all had blended joints. Years ago a friend and I modified a Gr III manifold, by replacing all the blended joints with collectors. This provided a useful torque improvement without making any other adjustments. All our subsequent efforts used collectors which of course is standard practice in the USA - the home of the "Header".
The Fulvia has little space for a proper manifold which is a pity; plenty to be gained in this area I think.
Paul
Regarding the scatter idea, of course I am thinking of an inlet camshaft for the Fulvia with its lobes staggered to allow for the different ports; I am sure that this could be worth investigating - the question is which way to stagger the timing? The gas speed in the long ports will or at least should be, greater which would suggest retarding the opening, but then again...
I know that touring cars, being rev-limited, run enormous valve lifts - over 14mm in some cases; this appears to be the modern approach but sadly impracticable for the Fulvia; the acceleartion of the valve must be extraordinary in such cases.
Regarding exhaust systems, I have long held the view that the Fulvia responds very well to exhaust work; sensitive work in the exhaust valve throats works wonders for torque. In "Lancia Racing" Nigel Trow mentions a 1.3HF engine that made 140HP. This was fitted with what he calls a "Caravello" exhaust manifold. Unfortunately there are no details or pictures of this component.
At the time, the works competition manifolds all had blended joints. Years ago a friend and I modified a Gr III manifold, by replacing all the blended joints with collectors. This provided a useful torque improvement without making any other adjustments. All our subsequent efforts used collectors which of course is standard practice in the USA - the home of the "Header".
The Fulvia has little space for a proper manifold which is a pity; plenty to be gained in this area I think.
Paul
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Geoff
Re: camshafts
There are some good points here - lets go through them. Having spent a fair amount of time on this issue with Aurelias, I'll contribute from "1950's meets 2005" experiences.
Clearly, modern radical cams with massive lifts and wierd solutions are tailored for today's cars, with newly configured heads, exhausts, injection... absolutely right. So consider taking that approach off the table, as its not too likely for a Fulvia.
Given the V configuration, and port lengths, tuning the exhaust for the car is likely to give good improvements - on the other hand, there was a lot of development work done on these engines at the time, no? So perhaps poking around Italy for a few weeks would be the easiest of those options!
Enrico at Cavalitto told me that even with hot cams in Aurelias, he knows of some who have gained 9 hp just by changing the exhaust to headers. Easier with the 60 degree phasing than the Fulvia.
A carefully built up engine, with modern pistons, and all the bits measured and in careful install will provide improvements too. Some cam timings are not too accurate - tuning an engine on the dyno, and adjusting cam and ignition timing precisely offers (to some of us here) almost 10% improvement. Its amazing what happens when you set one of these up right.
The cam then... well, the issue seems to be how good is the cam design? And thus the question, did they use the cam profiling approach of the older school, the tri-arc, or did they join a more modern approach? I was lucky to find a guy (Dema at Elgin Cams) who was willing to design a lobe profile for the Aurelia that was a bit tweaked, but had the real advantage of the early-in stages opening it up for better flow and controlling accelleration/de-accellerations better. The problem with the old profiles is not how hot they are, but that they are configured on a fabricator's priority: that the geometry to make the lobe profile is what is governing the design, not what is optimal for the valve andperformance. Of course, at the time, they didn't know as much about valves and flow as we know now.
So when we go back to those cars - we can update the profile, but not too much in terms of the old terms. Its not duration or lift that are the real issues - but rather the profile.
If you want to read some more on this - I posted the research on the Aurelia cams at:
http://homepage.mac.com/geoffreyg/FileSharing14.html
In the end of this article are some discussions from cam people about these issues.
Also, what was of interest in the Aurelia cams was how Lancia used their ability to fabricate in house to control and to modify cam design. I suspect the same logic, but not necessarily the same details, applies to the Fulvia, only (really) some 10-15 years later. It would be interesting to see if that's true. Someone could do a comparison of profiles and of cam timing of the various Fulvia cams.
It is typical in Italy not to change the lobe profiles so much, but rather to tinker with the timing of the cams. For example, the hot Stratos setup in the late 1970's was not in fact newly designed cams, but rather simply using replacing the exhaust cam with an intake cam for its profile and timing!
The Aurelia is a bit more interesting, as they fiddled with both timing, lobe profiles, and size of the lobe over the car's life. I'll bet the Fulvia has its own story to tell!
Geoff
Clearly, modern radical cams with massive lifts and wierd solutions are tailored for today's cars, with newly configured heads, exhausts, injection... absolutely right. So consider taking that approach off the table, as its not too likely for a Fulvia.
Given the V configuration, and port lengths, tuning the exhaust for the car is likely to give good improvements - on the other hand, there was a lot of development work done on these engines at the time, no? So perhaps poking around Italy for a few weeks would be the easiest of those options!
Enrico at Cavalitto told me that even with hot cams in Aurelias, he knows of some who have gained 9 hp just by changing the exhaust to headers. Easier with the 60 degree phasing than the Fulvia.
A carefully built up engine, with modern pistons, and all the bits measured and in careful install will provide improvements too. Some cam timings are not too accurate - tuning an engine on the dyno, and adjusting cam and ignition timing precisely offers (to some of us here) almost 10% improvement. Its amazing what happens when you set one of these up right.
The cam then... well, the issue seems to be how good is the cam design? And thus the question, did they use the cam profiling approach of the older school, the tri-arc, or did they join a more modern approach? I was lucky to find a guy (Dema at Elgin Cams) who was willing to design a lobe profile for the Aurelia that was a bit tweaked, but had the real advantage of the early-in stages opening it up for better flow and controlling accelleration/de-accellerations better. The problem with the old profiles is not how hot they are, but that they are configured on a fabricator's priority: that the geometry to make the lobe profile is what is governing the design, not what is optimal for the valve andperformance. Of course, at the time, they didn't know as much about valves and flow as we know now.
So when we go back to those cars - we can update the profile, but not too much in terms of the old terms. Its not duration or lift that are the real issues - but rather the profile.
If you want to read some more on this - I posted the research on the Aurelia cams at:
http://homepage.mac.com/geoffreyg/FileSharing14.html
In the end of this article are some discussions from cam people about these issues.
Also, what was of interest in the Aurelia cams was how Lancia used their ability to fabricate in house to control and to modify cam design. I suspect the same logic, but not necessarily the same details, applies to the Fulvia, only (really) some 10-15 years later. It would be interesting to see if that's true. Someone could do a comparison of profiles and of cam timing of the various Fulvia cams.
It is typical in Italy not to change the lobe profiles so much, but rather to tinker with the timing of the cams. For example, the hot Stratos setup in the late 1970's was not in fact newly designed cams, but rather simply using replacing the exhaust cam with an intake cam for its profile and timing!
The Aurelia is a bit more interesting, as they fiddled with both timing, lobe profiles, and size of the lobe over the car's life. I'll bet the Fulvia has its own story to tell!
Geoff
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Michael Beattie
Re: camshafts
Paul
Yes you are right about the "scatter" potential for the Fulvia's unequal ports, I forgot about that.
William
Back to your original remark, that hot cams equal more revs.
I have a tale of my previous 2 litre Alfa GTV engine, where it had a set of fast road C&B 12 mm cams fitted, a much used set up in "Alfa World" !! They should have been good for 165 + bhp, but the car would only produce around 150 hp ( 120 ish at the rear wheels) and it really struggled to rev over 6000 rpm. I checked the inlet porting, which had been correctly modified, played with the cam timing etc to no avail. The head even had slightly larger valves, so it should have flown. What I forgot to check was the exhaust ports, it turned out these were totally standard ! As soon as these were suitably modified, the engine produced the power and rev'ed out to 8000 rpm ( it had Carillo rods fitted by this stage).
So as I said before, getting the engine to breathe is your first port of call, then look at cams. Even adjusting the overlap with the std cams might produce what you want. Look at the inlet manifold to head match and gasket fit, on the std cars there often seem to be bits of gasket and steps between the head and the manifold interferring with the flow. And again to echo what Paul and Geoff have said about the exhaust manifold & system, the guys at Omicron said that putting a modified system on had proved to be one of the first and most beneficial mods in their opinion.
It depends what you want, is it for fast road use or for competition, as the engine characteristics for each are very different.
Cheers
Michael
Yes you are right about the "scatter" potential for the Fulvia's unequal ports, I forgot about that.
William
Back to your original remark, that hot cams equal more revs.
I have a tale of my previous 2 litre Alfa GTV engine, where it had a set of fast road C&B 12 mm cams fitted, a much used set up in "Alfa World" !! They should have been good for 165 + bhp, but the car would only produce around 150 hp ( 120 ish at the rear wheels) and it really struggled to rev over 6000 rpm. I checked the inlet porting, which had been correctly modified, played with the cam timing etc to no avail. The head even had slightly larger valves, so it should have flown. What I forgot to check was the exhaust ports, it turned out these were totally standard ! As soon as these were suitably modified, the engine produced the power and rev'ed out to 8000 rpm ( it had Carillo rods fitted by this stage).
So as I said before, getting the engine to breathe is your first port of call, then look at cams. Even adjusting the overlap with the std cams might produce what you want. Look at the inlet manifold to head match and gasket fit, on the std cars there often seem to be bits of gasket and steps between the head and the manifold interferring with the flow. And again to echo what Paul and Geoff have said about the exhaust manifold & system, the guys at Omicron said that putting a modified system on had proved to be one of the first and most beneficial mods in their opinion.
It depends what you want, is it for fast road use or for competition, as the engine characteristics for each are very different.
Cheers
Michael
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william
Re: camshafts
Thanks everybody for their input. Here's my story.
I own and love my 1200 HF. I have renovated and modified the engine to some extent and according to my belief sporty cams are what's needed to unleash the remaining lurking HP.
Work already done for more power: (insurances for durability not mentioned)
-1300HF head with polished and flowed ports
-1600 size valves
-group 3 exhaust manifold (basicly same model as stock but 2mm bigger tubes) and 55mm main tube with single absorbtiontype silencer.
-35mm dell orthos 31 venturi and manifolds matched.
-MSD ignition
-ASSO 77mm forged pistons.
-4600gr flywheel.
-Cams 818.140 std. set at 13S timing (28-66)
Power at present about 80Hp at the wheels at 6600rpm. Torgue 105Nm at 3700rpm.
I own and love my 1200 HF. I have renovated and modified the engine to some extent and according to my belief sporty cams are what's needed to unleash the remaining lurking HP.
Work already done for more power: (insurances for durability not mentioned)
-1300HF head with polished and flowed ports
-1600 size valves
-group 3 exhaust manifold (basicly same model as stock but 2mm bigger tubes) and 55mm main tube with single absorbtiontype silencer.
-35mm dell orthos 31 venturi and manifolds matched.
-MSD ignition
-ASSO 77mm forged pistons.
-4600gr flywheel.
-Cams 818.140 std. set at 13S timing (28-66)
Power at present about 80Hp at the wheels at 6600rpm. Torgue 105Nm at 3700rpm.
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Michael Beattie
Re: camshafts
Well why didn't you say so the first time !!!! 
I'm sure a set of cams would just be the ticket, but again, what sort of drivability do you want? 80 hp at the wheels is not bad for a 1200 !! If I rember 87 on a 1293 cc BMC A Series was pretty good, so you're not too far off that. So is it for competition or pleasure?
Cheers
Michael
I'm sure a set of cams would just be the ticket, but again, what sort of drivability do you want? 80 hp at the wheels is not bad for a 1200 !! If I rember 87 on a 1293 cc BMC A Series was pretty good, so you're not too far off that. So is it for competition or pleasure?
Cheers
Michael
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william
Re: camshafts
Just for fun! To see what I can achieve with my limited experience but unlimited patience.