Junior Bertone appreciation thread
Discussion
TonyRPH said:
Can someone explain what's going on here?
The engine is clearly a four cylinder, but yet there appears to be eight spark plugs here.
Ok, two plugs per cylinder, fair enough, but the layout is bizarre!
Subject to an engineer getting this exactly right, this is how I recall the set-up.The engine is clearly a four cylinder, but yet there appears to be eight spark plugs here.
Ok, two plugs per cylinder, fair enough, but the layout is bizarre!
If you look at the 4 hexbolts that run down the centreline of the engine, that is the centre of each cylinder.
The valves [just 2 per cylinder] are at 6 and 12 o'clock and the sparks are at 2 and 8 o'clock, the space is very confined so the spark plugs enter [from memory] the cylinder at 38 degrees to horizontal, this allows a lot of 'stuff' to encroach on the tiny bore of each cylinder.
Not sure of the angle now I've written it and it may be 45 degrees, I think it's an early form of pent-roof design for cylinder heads.
I will defer to anyone with proper knowledge and more recent familiarity.
Sort of right I think, but the combustion chamber has hemispherical heads, as have the pistons. At this period of engine design I think that was a good thing, but as power outputs increased the hemispherical geometry limited the amount of power that the explosion could put onto the cylinder, some of the force was being directed almost horizontaly not verticaly. The twin plugs were arranged each side of the valves to ensure the fuel burnt quickly and evenly (fuel mixtures burnt slower in those days), also I think the gap in the centre between the huge valves wasn't large enough to fit a large enough plug in, so the space each side was used.
The contemporary Lotus Twincam had flat topped pistons and although in period couldn't develop the power of the Alfa engine, with modern technology and fuel the Lotus engines can outclass the GTA engine in Historic classes.
All this still doesn't detract from the Alfa Nord being a Masterpiece of 1960's engineering, both the 1750 and 2000 Engines in my cars were producing more power on the rolling road than Alfa claimed at the time, forty years after they were built. They are an absolute joy to use, willing you all the time to use that lovely seam of power
The contemporary Lotus Twincam had flat topped pistons and although in period couldn't develop the power of the Alfa engine, with modern technology and fuel the Lotus engines can outclass the GTA engine in Historic classes.
All this still doesn't detract from the Alfa Nord being a Masterpiece of 1960's engineering, both the 1750 and 2000 Engines in my cars were producing more power on the rolling road than Alfa claimed at the time, forty years after they were built. They are an absolute joy to use, willing you all the time to use that lovely seam of power
Here's a view of the head of a GTA from inside if it helps
http://www.alfaholics.com/2010/07/gta-cylinder-hea...
Just realised it's slightly different from the one in the car pictured earlier, might be because it's a repro one (Doubt it though), or perhaps the 1600's were different to the 1300's..... must look into that
http://www.alfaholics.com/2010/07/gta-cylinder-hea...
Just realised it's slightly different from the one in the car pictured earlier, might be because it's a repro one (Doubt it though), or perhaps the 1600's were different to the 1300's..... must look into that
Edited by velocemitch on Saturday 22 October 12:02
velocemitch said:
Here's a view of the head of a GTA from inside if it helps
http://www.alfaholics.com/2010/07/gta-cylinder-hea...
Just realised it's slightly different from the one in the car pictured earlier, might be because it's a repro one (Doubt it though), or perhaps the 1600's were different to the 1300's..... must look into that
Yes that helps!http://www.alfaholics.com/2010/07/gta-cylinder-hea...
Just realised it's slightly different from the one in the car pictured earlier, might be because it's a repro one (Doubt it though), or perhaps the 1600's were different to the 1300's..... must look into that
Edited by velocemitch on Saturday 22 October 12:02
Now I can see the angles involved, it all makes sense.
I've had a thing for the Bertone GTs since visiting Sorrento when I was 15. I was waiting for a bus and heard it before I saw it. Around the hairpin came a red bumperless GT rasping its way through the hills. I thought it was such a good looking well proportioned shape, and after a bit of research found that they were a great classic drive too. 15 years later and I've realised my ambition of owning one.
Here's mine looking awesome:
Here's mine looking awesome:
velocemitch said:
a Masterpiece of 1960's engineering, both the 1750 and 2000 Engines in my cars were producing more power on the rolling road than Alfa claimed at the time, forty years after they were built.
I concur........my little 1300 books at 89bhp & put out 104bhp recently on the RR.
You know, I've been quite impressed with the Webasto because it has needed no attention at all and has been perfectly watertight the whole time I've had the car. And around 2006/07 it seemed to constantly rain whenever I had a long trip so the roof got some pretty decent testing.
It robs a bit of headroom when wearing a helmet though.
It robs a bit of headroom when wearing a helmet though.
More GTs to drool over:
Alfaholics racer:
This is a great place to visit: http://www.alfaholics.com/our-cars/customer-car-bu...
Alfaholics racer:
This is a great place to visit: http://www.alfaholics.com/our-cars/customer-car-bu...
joesnow said:
This is a great place to visit: http://www.alfaholics.com/our-cars/customer-car-bu...
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