09-02-2019, 05:47 AM
The sports engines run at sustained rpm with reasonable life with original cranks, esp later thick ones. But forces increase as the square of revs, and a modest increase has a huge effect on fatigue life, so consideration of crank life largely determines excesses, esp if car has original thin crank. In stock non sport cars, valve bounce limits revs to somewhere around 4,500, over 60 mph even with the lower geared post 1932 cars. In their day most owners of 1929 thin crank cars would only reach 3,000 when in 2nd (26mph) most now run the later cranks and, if their ears can stand it, routinely hold 30 mph, about 3,500 (about the same rpm as 4speed cars in 3rd, corresponding about 55 in top for those models, above normal top speed)
The temps would seem to be a rare example of an overwhelming case for a thin multigrade! Car could/should be run with the fanbelt removed and radiator blanked off. (My car had a tiny hole in the radiator cap so boiling could be judged!) I guess starting would be the hard part but with a second person and crank not impossible. Where does antifreeze protection end?
The temps would seem to be a rare example of an overwhelming case for a thin multigrade! Car could/should be run with the fanbelt removed and radiator blanked off. (My car had a tiny hole in the radiator cap so boiling could be judged!) I guess starting would be the hard part but with a second person and crank not impossible. Where does antifreeze protection end?