Yep, low compression engines need the lowest octane possible. Higher octane is a waste of money.
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| Best fuel for a 225 https://www.slantsix.org/forum/viewtopic.php?t=44880 |
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| Author: | raycycled [ Sun May 08, 2011 3:20 am ] |
| Post subject: | Best fuel for a 225 |
Hi all, just found and joined this list I am in Sydney Australia, my girl friend has a 63 Valiant, and was wondering what the octane rating should be for best performance and economy is it 93 like the old standard petrol or 97 like the old Super ,this is our every day family car, so want the fuel use to be as little as possible,RAY |
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| Author: | AHamilton [ Sun May 08, 2011 6:01 am ] |
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try the lower octane first, if it knocks...get a higher octane. I run 87 in my 63 Valiant convt,it's my daily driver with no issues. |
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| Author: | slantzilla [ Sun May 08, 2011 6:05 am ] |
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Yep, low compression engines need the lowest octane possible. Higher octane is a waste of money.
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| Author: | SlantSixDan [ Sun May 08, 2011 9:12 am ] |
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Everyone remember that North American octane numbers aren't the same as rest-of-world numbers. Rest of world uses RON, as America did before about 1971. RON numbers are relatively high for any given level of antiknock performance. North America uses the average of RON + MON, and numbers are relatively low for any given level of antiknock performance. The three grades of fuel available in North America tend to be 85 to 87 (regular), 88 to 89 (mid-test) and 91 to 94 (high-test). Lower numbers at higher altitudes. In countries that use the RON ratings, the grades tend to be 91-92 (regular), 94-95 (mid-test) and 97-99 (high-test). |
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| Author: | raycycled [ Sun May 08, 2011 4:48 pm ] |
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Hi DAN,Thanks for the conversion, yes I'd say we run 93 and 97 octane fuels here in Australia mostly, the manual says my motor is 8.4:1, I'd have thought that high, my 28 Chev runs 4.76:1 . ? Although I am not sure what this motor has had done to it, I think it might be higher it has great pick up and have had her up to 85mph no worries, and runs extrators, RAY Quote: Everyone remember that North American octane numbers aren't the same as rest-of-world numbers. Rest of world uses RON, as America did before about 1971. RON numbers are relatively high for any given level of antiknock performance. North America uses the average of RON + MON, and numbers are relatively low for any given level of antiknock performance. The three grades of fuel available in North America tend to be 85 to 87 (regular), 88 to 89 (mid-test) and 91 to 94 (high-test). Lower numbers at higher altitudes. In countries that use the RON ratings, the grades tend to be 91-92 (regular), 94-95 (mid-test) and 97-99 (high-test).
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| Author: | raycycled [ Sat May 14, 2011 1:55 am ] |
| Post subject: | Putting a 250 Hollley on our 225 ? |
Ok Have done some math and it is not looking good, we are gettting 18 MPG and thats Imperial gallons, not US, surely I should be getting better than that? I suspect our old carter carby has a problem the new repair kit did not fix? Was contemplating putting the 250 Holley that was on the car when we bought it back on, as there are numerous problems with the carter from not ideling when cold, to spluttering on take off and a smell of fuel when engine under load decelerating, also we have extractors but no hot box so warming up is a bitch. So Should I (A ) go with the carter and get some sort of Hot box to work off the extractors or B go to the Holley with a conversion plate and some other modifications. RAY |
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| Author: | 2 Darts [ Sat May 14, 2011 7:54 am ] |
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I think I'm going to need an English lesson, Australian-style. What is an "extractor"? Some of the symptoms you describe sound like a lack of manifold heat issue (e.g. rough running when cold, hard to warm up, poor fuel mileage). I experienced these on my '73 when I swapped out the manifold, which also corresponded with a carb change. It took a while for me to sort it out. Since I use the Dart for longer runs in a hot climate, the engine gets heated up to a point where I get better mileage without heat than with. However, for short runs and/or cool climate, a heated manifold should give you improved driveability and fuel economy. Two of the things I've run across that a carburetor rebuild kit does not address are the accelerator pump and throttle shaft bushings. You don't seem to have an issue with the former, but the latter can be a source of both fuel and vacuum leaks. I'm not familiar enough with the Carter to of any further use in diagnosing its potential ills. Back in the day, we ran 6s on the cheapest stuff we could buy. In fact, we'd run just about anything with less than a 9.0:1 CR on regular. The 318 could be a little particular about regular. We definitely used premium on anything with a 10.0:1 or greater CR. In my part of the US, only Gulf Oil offered a mid-grade back in the day. My Demon has a 9.3:1 CR and needs mid-grade fuel or retarded timing. |
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| Author: | rlklaus [ Sat May 14, 2011 8:19 am ] |
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Pretty sure "Extractor" is Australian for "Header". |
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| Author: | SlantSixDan [ Sat May 14, 2011 8:24 am ] |
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That mileage is poor. You may want to put everything to a proper state of tune to establish a reliable baseline before you make modifications. Tune-up parts and technique suggestions in this thread. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download. The engine will require periodic valve adjustment. And you will likely want to check to make sure the crank pulley's timing mark actually corresponds to 0° (TDC) — they tend to slip over the years — and also check for timing chain slop per this post. |
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| Author: | wjajr [ Sat May 14, 2011 12:56 pm ] |
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My Dart is equipped with headers, err, rather extractors that is, a Holley 390 (4160) 4V fitted with electric choke, and Clifford intake manifold. It was cool blooded, and cool temperatures caused carburetor icing at times making the car undrivable and a fuel pig. My solution was to fabricate a hydronicly heated hot spot under the carburetor feed from the heater loop, and the addition of a thremistor attached to the head to retard the electric choke from opening too quickly. Once these modifications were in place, the car became very drivable under all ambient & coolant temperature conditions. Below is the chamber made of two thicknesses of ½ inch aluminum stock forming a small reservoir under carburetor which was spliced into the heater loop for a supply of hot coolant.  Do the things Dan recommended before cobbling up any contraptions. Often these details will yield good results. I believe that a few of the parts suppliers such as Summit have generic hot-air stoves that can be fitted to headers to heat an intake manifold as well. |
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| Author: | SlantSixDan [ Sat May 14, 2011 1:28 pm ] |
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Quote: I think I'm going to need an English lesson, Australian-style. What is an "extractor"?
"Extractors" means "headers".Quote: Two of the things I've run across that a carburetor rebuild kit does not address are the accelerator pump
Um…what? Every carburetor kit, even the cheapest and nastiest one, comes with a new accelerator pump plunger or diaphragm.
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| Author: | raycycled [ Sat May 14, 2011 5:12 pm ] |
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OK yes I'd say extractors are headers and the post about the water heater adapter sounds like an excellent idea, So from the beginning, I have put in NEW points, condenser, dist cap , rotor button, leads and plugs, put kit thru carby, yes there was a new excellerator pump, gaskets, needle valve and little ball bearing that sits in bottom of float chamber but NO throttle shaft, I also have a manual cable for the choke as the auto choke was missing. I have set the timing as per the factory manual. and have a new fule pump and in line fuel filter. So seems to me the carby has a bit of a fault and the manifold is not getting hot enough. RAY I am very mechanically trained I have a 1928 Chev I have rebuilt and run every day for work also a 1927 Indian scout and a list of 70's car as long as your arm this is my first slant thou,and the most modern car i have run is a 1989 toyota ute ( translation pickup ), So very aware of working on older cars. I also fear the previous owner had mucked around with just about every thing on the car so I have to combat that as well.RAY |
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| Author: | SlantSixDan [ Sat May 14, 2011 5:31 pm ] |
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Quote: I have set the timing as per the factory manual.
Not good enough. Go through all the timing checks (timing mark vs. TDC, timing chain slop) I listed above.
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| Author: | Brussell [ Sat May 14, 2011 9:09 pm ] |
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Quote: Two of the things I've run across that a carburetor rebuild kit does not address are the accelerator pump
Perhaps you mean the power valve?http://www.junkyardgenius.com/holley/IM ... alve02.gif Any special places to get throttle shaft pushings from? Wjar - I like your modded manifold, I was thinking of doing this sometime myself but it's for more enjoyment than me necessarily needing it :/ |
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| Author: | raycycled [ Sat May 14, 2011 11:28 pm ] |
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Is that power valve fro a cater or Holley carb? RAY |
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