Getting an E0 head
- Thread starter StarDiero75
- Start date
StarDiero75":11o8d9jm said:
That's a good question. I think a safe bet is 7.7:1. But you may be able to go higher and still run 87. With my 250 i'm around 8.2:1 dcr iirc and 9.5-6:1 scr @ ~25ft above sea level and I had a lot of problems with pinging under load. But that was timing, the carbs and the shift points of the stiff aod that has since loosened up. It was mostly timing. For a while I was afraid I had to keep the initial timing @ 8-10 and limit the vac advance with a machine screw. Running 91 to keep it in line. But I found that my dist weight was the problem. I was putting in 30 degrees w/ the mechanical advance real quick, add that to 12 deg initial and any remaining vacuum, vac can turn all the way stiff, and I saw 40-50 under load. I haven't tried running 87 since I finally fixed it but I'm going to. Now the vac canister is all the way loose w/o a limit. I'm running 13 degrees advanced and have all the power I need at my foot with no problems. ie... up a hill, foot down in low gear no ping. Or to lite up the tires on a whim
The 250 is more prone to detonation than the 200 b/c of it's long stroke. It's probably a safe bet to push it to 9.2:1 or better with a 200
Yeah just let me know what you findEconoline":1eav7w2n said:
So how do i calculate dynamic compression? Is that something that id done when I chose my cam and what i plan static CR to be?Econoline":h3rk3kxa said:StarDiero75":h3rk3kxa said:
That's a good question. I think a safe bet is 7.7:1. But you may be able to go higher and still run 87. With my 250 i'm around 8.2:1 dcr iirc and 9.5-6:1 scr @ ~25ft above sea level and I had a lot of problems with pinging under load. But that was timing, the carbs and the shift points of the stiff aod that has since loosened up. It was mostly timing. For a while I was afraid I had to keep the initial timing @ 8-10 and limit the vac advance with a machine screw. Running 91 to keep it in line. But I found that my dist weight was the problem. I was putting in 30 degrees w/ the mechanical advance real quick, add that to 12 deg initial and any remaining vacuum, vac can turn all the way stiff, and I saw 40-50 under load. I haven't tried running 87 since I finally fixed it but I'm going to. Now the vac canister is all the way loose w/o a limit. I'm running 13 degrees advanced and have all the power I need at my foot with no problems. ie... up a hill, foot down in low gear no ping. Or to lite up the tires on a whim
Yes I'll be having wsa redo my dizzy advance. I think mine does advance a little quickly too. Hopefully, with the T5, i won't have to worry about it being stiff like the AOD.
Currently im running 12 BTDC but i think im gonna drop it back to 10 since i get a little ping at 30-40 in 3rd with just a slight grade. I mean the 2.8 don't help me but I dont think it should. Maybe im running lean but we shall see. If i get xmas money I'll be buying an AFR gauge from summit. Then I'll know roughly how I'm running.
Howdy All:
Hey Ryan- it's time to start another topic. If you hope to get info and opinions on cam selection, specifications and other information you nee to start a new thread with cam selection in the topic title. While deciding on a cam for your project is critical it is a different topic than your EOxx head. Just a thought.
Adios, David
Hey Ryan- it's time to start another topic. If you hope to get info and opinions on cam selection, specifications and other information you nee to start a new thread with cam selection in the topic title. While deciding on a cam for your project is critical it is a different topic than your EOxx head. Just a thought.
Adios, David
Yeah, with a manual you won't have shift point issues. My main issue was having a 15L weight go all in too soon giving me 30 degrees of mechanical advance at to low of an rpm. My solution was to weld it's gap to a 13L weight, i.e. 26 degrees of potential instead of 30.
Ryan, Pat Kelley's DCR calculator at the bottom of the page in this link is the best one I've come across. And since you download it, once you get it you've got it. The article explains the entire concept behind dynamic and static compression and how the valve timing controls it. Play with the software and you'll see it for yourself clearly as you change cam specs and dish volume etc. If you know the advertised duration, the intake centerline and lobe separation, all the valve timing events will match the real specs every time in the calculator. That's why I know there's something wrong with what's in the tech archive.
http://cochise.uia.net/pkelley2/DynamicCR.html
Hint: start with the middle tab, hit 'calculate' then fill out the first tab and 'calculate' before going to the 3rd tab to tally the results
I haven't heard anything back on the stock specs yet btw
Ryan, Pat Kelley's DCR calculator at the bottom of the page in this link is the best one I've come across. And since you download it, once you get it you've got it. The article explains the entire concept behind dynamic and static compression and how the valve timing controls it. Play with the software and you'll see it for yourself clearly as you change cam specs and dish volume etc. If you know the advertised duration, the intake centerline and lobe separation, all the valve timing events will match the real specs every time in the calculator. That's why I know there's something wrong with what's in the tech archive.
http://cochise.uia.net/pkelley2/DynamicCR.html
Hint: start with the middle tab, hit 'calculate' then fill out the first tab and 'calculate' before going to the 3rd tab to tally the results
I haven't heard anything back on the stock specs yet btw