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| Eileen - Camshaft selecting https://www.slantsix.org/forum/viewtopic.php?t=24148 |
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| Author: | Bren67Cuda904 [ Thu Aug 02, 2007 4:18 pm ] |
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Cam is in and it runs.  Broke in cam for 30 min. Set timing at 25 total. Had to turn in throttle shaft screw to keep it idling. Idles good if its not in gear.  I still have to go through the lash again. Couldn't really get on it to much yet- oil pressure is maxing out at 40psi. I need to bump it up a bit before I turn more than 4000rpm. I defently dosen't pull off the line with this 2500 stall converter. It acts like it starts to come alive around 3200rpm.More tuning tomorrow, I am beat. |
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| Author: | Sam Powell [ Thu Aug 02, 2007 7:59 pm ] |
| Post subject: | |
Congratulations. How is your pre-ignition thing now? If you have fixed that, then you are on the right track. Next is the high stall converter. How did you end up timing the cam? STraight up, or slightly retarded? Retarding brings on power up top, but needs the high stall convertor more. Keep us posted. I thought the last thread was long. This one may top that. Sam |
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| Author: | argentina-slantsixer [ Thu Aug 02, 2007 8:43 pm ] |
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great! are you changing the spring in the oil pump for a heavier one? how's oil on the rocker arms? |
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| Author: | Rick Covalt [ Fri Aug 03, 2007 4:01 am ] |
| Post subject: | Compression test? |
And where did your compression come in at? I Hope it is better for you. Keep making progress. Slow and steady wins the race, or something like that. Keep us posted, Rick
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| Author: | Bren67Cuda904 [ Fri Aug 03, 2007 4:41 am ] |
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Theres race fuel still in the tank. I'll have to run that out before I know if I am off race fuel or not. Cam was installed straight up, intake opening at 15*@50. Oil at the rockers is good. Before with the valve cover off it won't really make a mess with it running. Now I have enough oil to cover the whole rocker area and still have a chance to fill up the stand off tube area in 5mins. Before I think the lifter groves drained it back faster than the supply. I plan to shim the pump spring. The final compression test cam in at 205psi. |
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| Author: | argentina-slantsixer [ Fri Aug 03, 2007 5:48 am ] |
| Post subject: | |
205 PSI but your rings are sealing good now... great improvement. Maybe a little tweaking on the lash will reduce that cranking pressure more. don't be affraid of running thight lashes, if you lash it hot chances of burning an ex valve are reduced... I have ran zero lash cams with no problems. |
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| Author: | 440_Magnum [ Fri Aug 03, 2007 9:14 am ] |
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Quote: Theres race fuel still in the tank. I'll have to run that out before I know if I am off race fuel or not.
Don't forget that you may be able to re-work your ignition timing curve now to buy back some of the lost bottom-end torque- perhaps even with pump gas. I'd be careful about doing much to raise oil pressure on a slant, but I'll defer to the experts. As long as you've got good oil distribution and enough flow to avoid starving a bearing at high RPM, pressure really doesn't matter. Oil pressure is just a means to an end, what you really want (the end you are seeking) is sufficient flow and even distribution of oil.
Cam was installed straight up, intake opening at 15*@50. Oil at the rockers is good. Before with the valve cover off it won't really make a mess with it running. Now I have enough oil to cover the whole rocker area and still have a chance to fill up the stand off tube area in 5mins. Before I think the lifter groves drained it back faster than the supply. I plan to shim the pump spring. The final compression test cam in at 205psi. |
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| Author: | Bren67Cuda904 [ Fri Aug 03, 2007 9:32 am ] |
| Post subject: | |
Let me ask this. Higher compression engines have more power potenial? If I where to add 15-20cc to the combustion camber and put back in my old cam, could I expect to have the same power as before with the 50-50 fuel as now with the 93 octane and lower compression. It just seems that this motor was kind of built with torque in mind more so than high RPM. I am running the Offy intake which is gear towards torque. I am running manifolds also toward torque. And a 2500 stall converter. I didn't think it would be this lazy out of the hole and over all the topend isn't really anymore as before, maybe less. The cost to add a header change the intake to the clifford and custom build a converter is much more than adding some CC's My pistons are already fly cut for valve reliefs. Are you saying to cut them more? The head is 64.5 CCs now. Can 20cc's be added to the head without really killing the squish factor? This is a 68-75 head. |
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| Author: | Bren67Cuda904 [ Fri Aug 03, 2007 10:52 am ] |
| Post subject: | |
I am going to pull the motor and send it back to the builder. He said he could add cc's to the head for a total of 83cc's (should be 9.5:1CR) and put my old cam back in. Cost- one 30lb can of R-22 refrigerant and one gallon and coil cleaner.
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| Author: | Bren67Cuda904 [ Fri Aug 03, 2007 11:26 am ] |
| Post subject: | |
Can I expect the idle quality to be the same between 12:1 and 9.5:1CR? I forgot to mention that there is a hint of detonation at high RPM with 25* total timing and a splash of race fuel. (80/20%)  
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| Author: | slantzilla [ Fri Aug 03, 2007 11:30 am ] |
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Quote: Can I expect the idle quality to be the same between 12:1 and 9.5:1CR
I would expect it to idle somewaht milder at 9.5. 
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| Author: | Bren67Cuda904 [ Fri Aug 03, 2007 11:31 am ] |
| Post subject: | |
So less likely to stall while in gear with A/C on? |
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| Author: | Joshie225 [ Fri Aug 03, 2007 2:05 pm ] |
| Post subject: | |
Higher compression engines are more efficient and make more power if the fuel will support it. That's your problem. You can't feed your engine pump gas because your engine combo is whacked. Lower compression long duration cam engines tend to idle worse than with a higher compression ratio. A lower compression engine has more volume at TDC and leaves more spent gases in the chamber diluting the mixture causing the rougher idle. Also, lowering compression reduces torque everything else being equal. How on earth did you end up with a 12:1 street engine anyway? I'd have the builder fix the engine (lower the CR) so that you get what you paid for. A hot street engine, not a race gas sucking weakling with retarded timing. If you don't own David Vizard's Performance With Economy go buy it. Then buy the first and second books in the How to Build Horsepower series. Once you understand the basics of building a high performance engine you'll better understand your own engine, what's wrong with it, and how to fix it. |
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| Author: | CARS [ Fri Aug 03, 2007 2:17 pm ] |
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Quote: I am going to pull the motor and send it back to the builder. He said he could add cc's to the head for a total of 83cc's (should be 9.5:1CR) and put my old cam back in. Cost- one 30lb can of R-22 refrigerant and one gallon and coil cleaner.
Why didn't you do that a month ago when you (and everyone else) relized you had way too much compression?? Now you have a used cam that is less than a week old!I am starting to see why Dan is so frustrated with you 
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| Author: | AnotherSix [ Fri Aug 03, 2007 2:49 pm ] |
| Post subject: | |
Sometimes the only cure for tail chasing is to let them bite it. |
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