03-28-2005, 07:18 PM
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It's not by luck they developed it, it's just numbers. There has been a lot more development on the British motor. Few companies of any size are developing high perfromance Alfa parts.
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03-28-2005, 07:40 PM
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 Quote:
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Originally Posted by Greg Gordon
It's not by luck they developed it, it's just numbers. There has been a lot more development on the British motor. Few companies of any size are developing high perfromance Alfa parts.
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Alfa Romeo on the other hand designed themselves into the Hemispherical combustion chamber that was once seen as the right thing ... but now has been proven to be wrong  ... thus nobody develops these motors as much because you are wasting your time, ie. we know now that it just never will produce the goods.
OR is this a case of the Italians designing by what feels and looks right, while the British have always been into calculating and trying to design what is actually right ... and they do not care how ugly the end result is  ? This has often limited Italian products in the past.
Pete
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'71 1750 Series 2 GTV: http://www.alfabb.com/bb/forums/showthread.php?p=208078
Last edited by PSk; 03-28-2005 at 07:45 PM.
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03-28-2005, 08:00 PM
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Back to the 2.5 Challenge
Clearly even on paper the 510 was a winner from the get-go! Even when allowed the 1773cc motor it only had to weigh 1950 Lbs. We don't know what that engine made, but -I do know the smaller 1600 motor made about 190 h.p.- as told to me by John Morton. Combined with IRS and excellent prep by BRE as I have said before Horst Kwech is my hero! Near as anyone can figure somewhere around 200-205 h.p. was the best they could muster in the day and because of the "exotic" DOHC motor the cars had to weigh @ 2300 lbs.! Thanks for the excellent pics Anthony! It's amazing that the car still wears it's original paint! Fred.
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03-29-2005, 05:44 AM
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Quote:
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Originally Posted by modena782002
I followed the series fanatically from 1969-1972. I was only 10-13 at the time, but my father and I would go to the old Bryar Motorsports Park (now NH International Spdwy), Lime Rock, and Watkins Glen, to see Horst Kwech and Gus Andrey in the Alfa's do battle with the BRE Datsun's. Perhaps I am wrong, but I believe that the Datsun had a 2.5 liter engine as opposed to the Alfa's 1750 & 2000. I also recall that from 1966-1970, the class was a 2 liter class, comprised mostly of Alfa's, BMW's, and even the occasional Mini Cooper. The BMW 2002's were completely outclassed by the Alfa and Datsun. I did witness an Alfa victory or two in those days, so the Datsun (much hated by me then, something that I still hold against Nissan now) didn't have it all that easy.
Nick D'Eri
1992 164S
1968 Fiat Dino Spider
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I got this from "The Stainless Steel Carrot" which was bascially an author following around the Brock team from late '71 through '72. VERY interesting book- reading it, I realized that at the time, the Datsun's were far from popular winners, as most people think they are today. When Alfa FINALLY won a race in '72, there was great celebration.
The other interesting note- Brock and Morton asked Kwecht why he had a big gas tank, Horst replied that he didn't know. And they truly believed him. Very interesting.
The final interesing note: for the '72 season, the BRE team didn't do any preparation, and SHOULD have not won the season. But for some reason, the Alfa's had some really bad transmission problems that would cause the leading teams not to finish. Turns out that Alfa's experimentation with the trans (whatever it was) was worse than Datsuns experiment with the 1800.
If you find the book, GET IT!! It's really interesting! Love Trans Am racing!
Eric
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03-29-2005, 06:05 AM
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I have some questions for anyone out there:
1) Is the new "Hemi" that DaimlerChrysler is promoting pure hype? Have they gone back to an older, inferior design simply to sell vehicles? Are they so driven by marketing that they would willingly adopt a known-poor design just to be able to write "Hemi" on the side of the car and barrage us with stupid commercials? (These are not rhetorical questions, I really want to know! Any Mopar guys out there to justify this "new" engine?)
2) Do any internal combustion engines have combustion chambers that are true hemispheres (literally a half-sphere)? They are all technically "spherical segments of one base". This never seems to be discussed in any books, papers. etc I have ever seen. How does varing the "hemi" aspect ratio change things? I would guess it is largely a question of valve area and placement.
3) It seems as if this thread is convolving two issues. A) Combustion chamber shape, i.e. aspects of swirl, squish, quench, flame-front propagation, etc. and B) Valve placement relating to intake and exhaust track geometry. They are related but separate. It would seem that A trumps B for fuel economy and emissions, but B trumps A for performance. Comments?
(Sorry for the long post. Beats working!)
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03-29-2005, 09:00 AM
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First things first:
Anthony, sweet pics!
Now on with the thread hijacking:
Quote:
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Originally Posted by Greg Gordon
It's not by luck they developed it, it's just numbers. There has been a lot more development on the British motor. Few companies of any size are developing high perfromance Alfa parts.
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03-29-2005, 01:14 PM
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Eric,
Thanks for setting me straight on which engines the Datsuns were using. I loved that old Trans-AM series. It was a lot of fun to watch, in the over 2.5 class, there were the Pony Cars--My favorite were the Orange Mustangs of Parnelli Jones and George Follmer. The Sunoco Camaros were cool too, Mark Donohue was another favorite. His book "The Unfair Advantage" written with Van Valkenbergh was a good, if not dry read. I also remember the white Camaros of Jim Hall's team, with the automatic transmissions, and all of the other factory teams from AMC (later winning the championship with Mark Donohue), Dodge and Plymouth.
I can't get too excited about the current state of the series, but if it's on TV, I'll be sure to try to watch it. Plus, it's way better than anything that NASCAR does.
Nick D'Eri
1992 164S
1968 Fiat Dino Spider
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03-29-2005, 01:33 PM
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Stock vs Stock there is just no comparison between the Alfa motor and a MGB (I don't know about the Datsun but I suspect it's the same way). If mods are limited to what most of us REALLY do during a performance rebuilt, which means compression, cams, exhaust a good valve job and good carbs/injection the Alfa will still easily walk away from the MG. The MG motor has an advantage when we start to factor in high dollar replacement parts that are not even available for the Alfa.
In other words build both motors with the same displacement, 10:1 compression a header dual carbs and fast road cams and the Alfa will kill the MG.
The Hemi is still a great design. It's the ONLY design competitive in Top Fuel cars where absolute power is all they care about. For other factors like emissions it's not so great. Because of that they have changed it somewhat just like all aspects of engines have changed over time, but the Hemi in it's newest versions is still with us and still used on a lot of new FAST cars.
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03-29-2005, 01:59 PM
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I've read that the 510 was essentially a BMW 2002 copy but about 150lbs lighter. I also have a magazine (its in Japanese) that compares a Isuzu Bellett GTR with a contemporary 1600 105 GTV. The cars are almost identical in spec and I assume it is because Japanese companies at the time were lifting a lot of features and design ideas from successful more established cars during the '60s/'70s.
Is that correct about the 510 being similar to the 2002?
Last edited by johnei; 03-29-2005 at 02:02 PM.
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03-29-2005, 03:36 PM
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Quote:
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Originally Posted by MALDI
I have some questions for anyone out there:
1) Is the new "Hemi" that DaimlerChrysler is promoting pure hype? Have they gone back to an older, inferior design simply to sell vehicles? Are they so driven by marketing that they would willingly adopt a known-poor design just to be able to write "Hemi" on the side of the car and barrage us with stupid commercials? (These are not rhetorical questions, I really want to know! Any Mopar guys out there to justify this "new" engine?)
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The secret of a pent-roof combustion chamber is it is very shallow and involves very narrow valve angles. This flatter combustion chamber means that more of the combustion forces actually push straight down on the piston ... increasing efficiency. If you remember that pressure is applied perpendicular to any surface it pushes on and then look at the top of a Alfa Nord piston you will see that a very large amount of the combustion forces are actually wasted trying to push the piston sideways ... instead of down.
That is why the Alfa Nord engine has a hp limitation that NO amount of development ... yep spend $2 million dollars on an Alfa Nord engine and you will still not make as much power as a Datsun, BMW or probably a MGB engine. Other manufacturers moved on with this new technology, Alfa Romeo did not ... just like Ducati (all though to be fair to Ducati they eventually went water cooler and 4 valve too ... with a bit of help from Cosworth).
I do not know how many valves the new Chrysler engine has but I suspect it is technically a pent-roof design ... but for marketing reasons they like the Hemi term.
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2) Do any internal combustion engines have combustion chambers that are true hemispheres (literally a half-sphere)? They are all technically "spherical segments of one base". This never seems to be discussed in any books, papers. etc I have ever seen. How does varing the "hemi" aspect ratio change things? I would guess it is largely a question of valve area and placement.
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Yes have a look at an Alfa Nord cylinder head and it is a lovely dome ... which looks great from a cylinder head containing the forces point of view, but the designers forgot about the fact that we want the forces to push the piston DOWN ... but to be fair to the designers, the hemi combustion chamber was invented in something like 1915.
Not all combustion chambers are "spherical segments of one base". The MGB and Ford Escort have very small chambers around the valves which are dead perpendicular to the top of the pistons. Very simple and very effective. The BMW 2002 and (I believe) the Datsun engine are a hemi type but shallower and interestingly with the BMW the valves are NOT dead opposite ... thus BMW can run larger valves. Something I have never understood with the Alfa engine is why they restricted themselves with that.
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3) It seems as if this thread is convolving two issues. A) Combustion chamber shape, i.e. aspects of swirl, squish, quench, flame-front propagation, etc. and B) Valve placement relating to intake and exhaust track geometry. They are related but separate. It would seem that A trumps B for fuel economy and emissions, but B trumps A for performance. Comments?
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Er, don't know ...  
In the end we can all debate the wonderfulness of the Alfa Nord engine to we are blue in the face. I have my feet on the ground and are well aware that the Alfa Nord design, effectively are pre-WW1 design (atleast concept wise) has many limitations and it is amazing that they do so well. BUT there are many, many superior engines ... and that is not surprizing at all, 'cause if you do not update your designs, ofcourse you are going to be left behind.
I'll put it this way: If I was to return to racing, close to the last engine I would choose to race prepare would be the Alfa Nord engine. The only reason I would take one on is if I bought a GTA/GTAm and wanted to enjoy the quaint experience. But then I do not believe winning at all costs matters in historic or classic racing ... it is supposed to be about enjoying yourself.
But for serious racing ... the brand name does not matter, only the power output. 
As a real world example. 2 x 4 cylinder 155's (with the Alfa based engine ... and this would have been a twin plug design, so even better than the single plug Nord) tried to contest the NZ touring car series about 10+ years ago ... it was embarrassing to watch them struggle down the back straight against the Japanese and BMW opposition. I knew the engine builder and they just could not (especially within the rules) get the things to make any power ... the team folded after 1 dismal season. But they looked great
Now ofcouse you will all jump to Alfa Romeos defence and the fact that 155's won the BTCC ... my understanding is they were using the FIAT based engine and I infact wonder if those engines really had any parts based on a production engine at all . Please correct me if I am wrong, but early 155s had the old Alfa engine, while later 155s had the FIAT based engine.
Pete
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'71 1750 Series 2 GTV: http://www.alfabb.com/bb/forums/showthread.php?p=208078
Last edited by PSk; 03-29-2005 at 03:51 PM.
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03-29-2005, 04:04 PM
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Oh Pete, for a second there i thought you were serious! Good joke tho, definitly got me for sure!
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03-29-2005, 05:06 PM
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Quote:
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Originally Posted by 81gtv6
Oh Pete, for a second there i thought you were serious! Good joke tho, definitly got me for sure!
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Remember I am just talking about the Alfa Nord (as in the 105 series, I guess the earlier series would have similar issues ... but they are considered vintage engines anyway ... so more restoration than race preparation) engine, not the many other Alfa Romeo engines. Alfa Romeo makes great engines, all of them!, but the Nord has a much lower power potential than any (recent) other, ie. a Sud or v6 will destroy a Nord engine in a power per cc battle. And that makes perfect sense because the Sud and v6 are much younger and theoretically superior designs.
Thinking about it more ... Datsun must have pissed themselves laughing with the fact that the Alfa Romeos had to carry more weight. Thus not only was the Alfa Romeo stuck with an (excellent) 1950's engine design but they also had a weight penalty. Who made those rules ... Datsun themselves? Weight should have been based on power output not where or how many camshafts the engine had. I take my hat off to Alfa Romeo for winning the years they did ... our company and competitors really know how to go racing!
Pete
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'71 1750 Series 2 GTV: http://www.alfabb.com/bb/forums/showthread.php?p=208078
Last edited by PSk; 03-29-2005 at 05:19 PM.
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03-29-2005, 06:46 PM
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Pete--
Thanks for the reply, I am really enjoying this thread although I think I have hijacked it!
A few points:
1) You say "I do not know how many valves the new Chrysler engine has but I suspect it is technically a pent-roof design ... but for marketing reasons they like the Hemi term." If that is true then in my book calling the new cars "Hemis" is ALL hype. You can call "lead" "gold" all you want but it is still lead.
2) Just out of curiosity I measured the combustion chamber dimensions for a circa 1984 Alfa V6 (not a 4-cylinder Alfa Nord mind you) that I have disassembled on my workbench. I found the radius in the plane of the head (normal to the piston motion) to be 1.75 inches and the distance from the head deck to the top of the dome (parallel to the piston motion) of 0.65 inches. For a height-to-radius ratio of 0.3714. A true hemisphere would have a ratio equal to 1 (exactly). So for this engine the aspect ratio is much flatter than a true hemisphere. To put it in perspective, the volume of the v6 chamber is only 10% of an equivalent-diameter hemispherical combustion chamber. So perhaps alfa did learn its lesson that flatter is better for combustion chambers!
3) Why is the spark plug not at the top of the dome (but is offset to one side)? Is this purely to allow for the largest values possible, or would the plug tip interfere with the cross flow?
4) Lastly, doesn't value-timing overlap on the inatke stroke imply cross flow? That is, not all the incoming charge fills the chamber but some is lost to the exhaust flow without ever being burned. As I understand it some of the incoming charge is sacrificed to smooth the gas flow through the system.
--Bill
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03-29-2005, 08:42 PM
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