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| Advice on power pack for a 225 cid. slant six https://slantsix.org/forum/viewtopic.php?t=30001 |
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| Author: | Club Dodge de España [ Mon Jul 21, 2008 4:30 pm ] |
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Quote: Quote: Interesting. Do you think you can find the camshaft specifications, perhaps in the service manual? I´ve got the workshop manual and the parts and timing list manual. I´ll see which information I can get from them.   . I´ll go on investigating.
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| Author: | Club Dodge de España [ Mon Jul 21, 2008 5:04 pm ] |
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Quote: Have you conducted measurements to verify the compression, or is this the compression listed in your manual?
8.4:1 is the rate listed in the manual. When we took out the head, we took this opportunity to plain it a bit (overheat warped it somewhat-very little), so maybe now rate has increased slightly. Distributor was regulated again and I think now it´s in maximum power -to be the original one-. I´ve never measured real compression. Maybe we try to change exhaust collector and choose a new cam -one of the mentioned by Slantsix Dan-. I'd check first. 8.4:1 is pretty low to get much, if anything out of a 4 bbl installation. Shoot for 9:1 or better. Without pulling the engine down, checking how far down the hole your pistons are, and measuring the combustion chambers, it is difficult to determine just how much compression you have. There were some pretty large variations from one engine to another. Find out where you are, bump the compression up as necessary, and look into options to increase exhaust flow. Choose a Cam that will fit your intended use as well. Are you planning to race the car, or just want a little more zap around town? A higher stall converter can go a long way to improving acceleration. You are likely to impact bottom end power with a larger carburetor, so may find you will need to address the converter anyway. CJ The use I want to make of my car is rather more zap around town and roads than racing. I was considering tryin a 4 barrel carb too. The idea of a stall converter is interesting. I´d never heard of it. I have looked for information in the web. It seems more appropriate for race style driving, allowing you stunning accelerations. |
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| Author: | ceej [ Mon Jul 21, 2008 5:32 pm ] |
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For a driver you'll want to stay with the original converter. High stall is a Drag Racer's tool primarily. I think DusterIdiot did a "How To" on getting actual static compression of an engine. Mine, like yours, lists compression as 8.4:1 Actual measured 8.0:1, which is barely adequate for a 4bbl, or any of the more aggressive cams. My variation was fairly small compared to some others. I've heard of compression ratio's as low as 7.5:1 from the factory. I now run 9.6:1, and can use much more of the 4 bbl carburetor. If you can measure how far from the top of the cylinder it is to the top of the piston at TDC, and "CC" the combustion chambers, I'm sure one of the local gurus can help you figure out what you have for compression. What is your fuel quality there? I thought there was a different octane rating scale in Europe, but don't know. What grade of gasoline do you wish to use? CJ |
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| Author: | Club Dodge de España [ Thu Jul 24, 2008 4:17 pm ] |
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Quote: Quote: What a lot of ideas!! Yes, I´ve seen that there are several cams at summit racing for the slantsix.
It's a better idea to get a slant-6 cam through Erson, who sell cams specifically designed for the slant-6 rather than old "generic" (usually Chevrolet) patterns on slant-6 blanks of varying quality.Quote: The idea of a bigger ignition power seems interesting. Any tip on a particular equipment? ignition coil+distributor?
HEI upgrade Comments on it are very promising. Thank you! |
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| Author: | Club Dodge de España [ Thu Jul 24, 2008 4:44 pm ] |
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Quote: For a driver you'll want to stay with the original converter. High stall is a Drag Racer's tool primarily.
Well, when I took out the head we also got out pistons, so we saw piston rings had lived more than half their life and decided to retire them. We put new Sealed Power rings of good quality. I hope we have recovered much of the compression. Nevertheless, it´s a good idea measuring compression. I´ll talk with some of our gurus. I think DusterIdiot did a "How To" on getting actual static compression of an engine. Mine, like yours, lists compression as 8.4:1 Actual measured 8.0:1, which is barely adequate for a 4bbl, or any of the more aggressive cams. My variation was fairly small compared to some others. I've heard of compression ratio's as low as 7.5:1 from the factory. I now run 9.6:1, and can use much more of the 4 bbl carburetor. If you can measure how far from the top of the cylinder it is to the top of the piston at TDC, and "CC" the combustion chambers, I'm sure one of the local gurus can help you figure out what you have for compression. What is your fuel quality there? I thought there was a different octane rating scale in Europe, but don't know. What grade of gasoline do you wish to use? CJ Traditionally in Spain fuel quality is not very good. It results in relatively frequent carb malfunction. Gas tank bottoms for our classic Dodges are like marshes and it´s better not waiting too long before filling the tank. Maybe in the last times it´s getting better. Now we use regularly 95 octane and 98 octane gasoline. Dodge 3700GT fuel system was adjusted to use 96 oct gas (most common fuel in the 70´s Spain). I use to add lead substitute though many say slant six heads don´t need it, but I´ve seen many Spanish Slant six with sticked valves and I suspect not using lead substitute (+long time inactivity) has something to do. |
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