72 BB 454 Handgeschalten

[Wesch]

Hallo

Im Prinziep sollte man nie weniger messen, eben wegen Herstellergarnatie. Mehr geht immer.

Man kann einen gleichwertigen Motor ( und der Grundmotor ist ja gleichwertig, halt Hub x Querschnitt = CI usw ) sehr viel abwürgen mit der Nockenwelle, dem Auspuff , dem Intake , Kopf usw, um etwaige Emissionswerte erreichen zu können. Ist mit wenig Aufwand aufmotzbar.

Das Einzige, wo man limitiert ist, ist der rote Drehzahlbereich, der beim Grundmotor etwas eingeschränkt sein kann ( durch nicht gewuchtete Teile, Gusswelle, unterdimensionierten Pleuel usw ), aber meistens durch den Ventiltrieb limitiert ist. Andere Köpfe bringen da immer was.

Der Unterschied in den Leistungsmessungen um die 70er Jahre beträgt nicht 50 % oder gar mehr, sondern knappe 15 %. Da wurde mehr gemacht, um die Leistung so drastisch zu minimieren.

MfG. Günther

[weltzer]

Hi,

ich habe irgendwo in den Tiefen des Internets mal eine Auflistung der Unterschiede der BBs von 70 bis 74 gefunden. Vielleicht hat da ja jemand Ergänzungen dazu. Hier die Liste (halt leider auf Englisch):

1) All 70-74 Corvette 454 cid engines were two bolt main configuration EXCEPT 1971 LS-6;
2) Most, if not all, 70-72 Corvette 454 cid engines used a forged steel crankshaft. There may have been some exceptions, though, with those using a cast nodular iron crankshaft;
3) All 73-74 Corvette 454 cid engines used a cast nodular iron crankshaft;
4) All 70-74 Corvettes with 454 cid engines, except 71 LS-6, used the same size intake and exhaust valves which, as I recall, were 2.06" intake and 1.72" exhaust.
5) 1970 LS-5 cylinder heads were unique to that year. For 1971-72 LS-5 engines, although different castings were used for each year, the cylinder heads were, essentially, the same. 1973 and 1974 LS-4 engines used cylinder heads specific to each year which were different for each year. As I recall, all 1970-72 LS-5 engines used cylinder heads which had about the same intake and exhaust port volumes. 73-74 LS-4 cylinder heads had smaller intake and exhaust ports, although I believe that 73 and 74 were about the same. All cylinder heads, except 71 LS-6, were cast iron material. 70-72 cylinder heads did not use induction hardened exhaust valve seats, including the valve seat inserts used on 71 LS-6 aluminum heads. 73-74 LS-4 cylinder heads used induction hardened exhaust valve seats;
6) All 70-72 LS-5 engines used the same camshaft, GM #3883986, which was also used on 66-69 L-36 427 engines. 1973 and 1974 LS-4 engines used a different camshaft, GM #353040, which was the same for both years. This camshaft was an "emissions profile" camshaft;
7) All 70-74 454 LS-4 and LS-5 engines used the same connecting rods which were forged steel with 3/8", knurled shank rod bolts;
8) All 70-74 LS-4 and LS-5 engines used cast aluminum pistons. The piston dome configuration was unique to each specific year, however, even though compression ratios may have been the same (72-74). 1970 LS-5 used 10.25:1 compression ratio; 1971 LS-5 used 8.5:1 compression ratio; 1972 LS-5 used 8.25:1 compression ratio; 1973-74 LS-4 used 8.25:1 compression ratio.
9) All 1970-74 Corvettes with 454 cid engine used the same oil pan, including LS-6;
10) 70-72 LS-5 engines used unique-to-each-year cast iron intake manifolds. However, all of the manifolds were similar. 73-74 LS-4 intake manifolds were also cast iron but had smaller port size to match the 73-74 cylinder heads. 73-74 manifolds also incorporated provisions for EGR.
11) All 70-74 Corvettes with 454 cid engines used the same side-specific exhaust manifold castings. 1971 with LS-6 and all 73-74 LS-4 manifolds were drilled and tapped for A.I.R. fittings.
12) All 70-74 Corvettes with 454 used the same valve springs except the 73-74 exhaust valve springs which were shorter to accommodate the rotators used during those years.
13) All 70-74 Corvettes with LS-5/LS-4 engines and manual transmissions used a 14" cast nodular iron flywheel with an 11" clutch. LS-6 used a 14" flywheel with a special dual disc clutch;
14) All 70-74 Corvettes with LS-5/LS-4 used the same oil pump
15) 1970-72 with LS-5 used the CCS (controlled combustion system) exhaust emissions control system. All 1971 LS-6 and all 73-74 LS-4 used the AIR (air injection reactor system) exhaust emissions control system. Many of the horsepower/performance differences, particularly during the 72-74 period, were the result of emissions control system differences.

Grüßle

[Andy1971]

Hi zusammen, bin ein totaler neuling in sachen corvette detail betrifft. kauft denn niemand diese corvette weil die zusatz investitionen zum orginal nochmals fast 20000 franken betragen? oder gibts noch einen anderen grund?
gruss andy