Joined: Jan 2021 Posts: 162 Threads: 71
Reputation:
0
Location: California USA
Car type: 1929 austin 7 chummy AD
29-05-2022, 02:31 AM
I was driving down the main street in my town which has a 40 mph limit. And when I got to third gear it no longer excelerates it goes to about 35 down a steep hill but thats it. If I move the advance lever it only makes the car run worse. So I downshift and now the engine is running really high. I am at 6300 ft in elevation but I should get a little more out of the car. Any thoughts
Joined: Aug 2017 Posts: 2,748 Threads: 31
Reputation:
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Location: Auckland, NZ
29-05-2022, 07:38 AM
(This post was last modified: 29-05-2022, 07:40 AM by Bob Culver.)
In their day, before possessed by youths in the mid 1950s, ordinary Sevens would very rarely be taken to 30 mph in 2nd (of 3) gears. Cranks stresses are high on a closed throttle and increase with revs squared. Not conducive to long crank life. What speed does it reach in nuetral?
Apart from crank considerations, the usual down hill speed limiter is driver terror.
Is it really downhill or is it some optical illusion?
Joined: Aug 2017 Posts: 618 Threads: 7
Reputation:
7
Location: queensland
ignition timing , butterfly not fully open, rats nest in the muffler
Joined: Aug 2017 Posts: 3,000 Threads: 168
Reputation:
37
Location: Sherwood Forest
Car type: 1938 Talbot Ten Airline
Is this the first time you've driven the car, or has something changed from last outing?
Joined: Aug 2017 Posts: 313 Threads: 9
Reputation:
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Location: TINOPAI NZ
Hi,
At that Altitude you will lose between 2.5 and 2.9 PSI Atmospheric Pressure ,
Which Translates to about a Fifth of of the Engine HP, fitting a High Compression Head would help.
Colin
NZ
Joined: Aug 2017 Posts: 3,000 Threads: 168
Reputation:
37
Location: Sherwood Forest
Car type: 1938 Talbot Ten Airline
A 20% loss of power is a very depressing thought when you've only got 10bhp to start with!
Joined: Aug 2017 Posts: 2,396 Threads: 33
Reputation:
36
Location: Deepest Frogland 30960
Car type: 1933 RP Standard Saloon
29-05-2022, 11:59 AM
(This post was last modified: 29-05-2022, 12:01 PM by Reckless Rat.)
I think verifying that the engine is operating at optimum first is a good starting point, for example, cylinder compression test, valve/tappet clearances, ignition settings etc. I get the impression Vance, that you really don't know what you're doing with this car...
Joined: Feb 2018 Posts: 122 Threads: 13
Reputation:
1
I just checked and here in Blackwood south wales it says that we are 564 ft above sea level and my 1926 chummy easily does 50mph along the flat it is in standard form, I am terrified when its going at that speed and there is only me in the car, if there was a passenger with me there is a fair chance that they would beat me with a big stick when we stopped Regards to all Rob.
Joined: Aug 2017 Posts: 981 Threads: 6
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Location: Scottish Borders
If 50mph is terrifying I suspect you need to increase the castor of the front axle.
Jim
Joined: Feb 2018 Posts: 122 Threads: 13
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it goes where I point it and handles as well as any seven could but that does not take away how vulnerable you feel in such a tiny open car ! does it not worry you regards Rob.