WADR - as I posted above: I get valve float at 6200. A shorter gear would just put me on the rev limiter before the traps. The distributor has no advance (don't need it for a dedicated drag car with an auto). The engine made best power on the dyno at 38*. It may launch harder with less timing. I will find out this weekend. The track altitude is 2800 ft.; it should run in the 11s at sea level. The class I am running has a minimum ET of 12.00 so I want to run close to that. I can make the car much faster if I wanted to. What I prefer to do is win some rounds. That means consistency. I could do that with a Toyota Camry. But, I'd much prefer to do it in my Maverick.
I agree with most on here & think that a little stiffer valve springs & a tad more gear will get you where you want to go.
You have "upgraded springs" yet they're still not enough? Did you do that or this engine builder/dyno guy? I'd get all the timing in by 2500 rpm at the latest. If you don't have one yet put a 32 shooter in the front and, as others suggested, get the jetting closer. I'd say 74 front/78 rear like Roberts said. You can't really do anything until you correct that valvespring problem though.
beehive springs and their tiny assed retainers will free up the rev range quite a bit. Only downside is no damper or secondary spring to save you from dropped valves if something goes wrong. And please don't ask me how I know that. Too many bad memories. Which is why I will only use the surface finished/polished versions these days since the failure rates are reduced while the lifespan and load retention is improved.
my old 302 setup with a comp extreme energy cam spun to 8500 without valve float. but I had upgraded springs to be matched with the cam. it stopped producing power at 7200 building was rattling so bad I didnt realize it was spinning that fast so theres got to be more spin left in your engine but Im no expert
Thanks for all the comments guys. I talked to the AFR tech guy on the phone. He says there are no better springs available for the AFR heads. Not sure I completely agree with him and I'm sure other vendors will tell me their springs would be better. But, he says I should run a short-stroke race hydraulic roller lifter and I'll be good to 6500 which is the end of the power band for the XE282 cam, Summit has them for $239. I'm going to go that way shortly. Ran yesterday. Only got in two runs. 12.54 and 12.58 against a 20mph headwind. One practice run and first round of bracket. Lost with the 12.58 on a 12.50 dial-in. Let off early because I thought I had the guy beat, my mistake. Won't run again until May 7. I am going to go to a 650 DP and may get the lifters in before then.
Now that I read back to see the stock roller lifters in your spec's.. I would guess that they are pumping up on you due to metering problems vs the springs not being sufficient. What amount of pre-load are you currently running on them? Also consider that the 1.7 ratio is making the cams already fairly aggressive ramp openings a bit faster(this is what increased ratio does) since it was originally designed for the factory 1.6 ratio. So long as you have around 150 seat pressures then you should be more than fine with those smaller stemmed/lighter 8mm valves. I've run all the way to 1.8's on the XE hydro rollers in the past and a bit of added spring will still allow rev's to 7,000. Do you know the springs brand/spec's right off hand? The point is this, rather than just tossing parts at this thing the simple "pump check" is very easy to do. Simply use 1/16-1/8 turn of preload and see if the engine rev's further towards that cams redline. If it does then the reduced travel lifters will set you straight. If not?.. then you have some other issues going on here other than being lifter pump related. And FWIW, that cam might not make peak power well past 6,000 according to the rest of your combo(frankly, I'd be hunting for the "why not?").. but I have a fair bit of cash in my wallet that says it will EASILY carry some decent power well past 6,500 in a smaller 302 like yours. And despite going past the power peak, that will likely help the shift points and reduce ET a little more. Granted my 383 Chevy was past the development stage that your current combo is at this point.. but it(XE282HR) still revved and held the power to 7,000+ with that nearly same exact hydro roller grind and 1.7 rockers. Well past the expectations for such a mild cam in a bigger motor like mine. So, it's not nearly as small as you think even with those efficient heads on your much smaller airpump. Not trying to argue.. only trying to help you get sorted out a bit faster without tossing any unneeded cash at it.
groberts, good points all. I do not want to throw a bunch of money at this engine looking for a bunch more power. This engine was a budget build just to get me back into drag racing. I really only want to get more rpm out of so I don't have to go through the lights on the rev limiter. It's running mid-12s now, hooks great, and runs straight and is consistent. I really only want to get it closer to 12.00 so I can run fastest in my class. What I also don't want to do is change a bunch of things all at the same time. I'll do one thing at a time and see how the car reacts. This week I put a softer vacuum secondary spring in it and changed the cam on the accelerator pump. There was no noticeable change in ET or 60 ft time. Talked to my dyno guy and he thinks it will run better and launch harder with a smaller 650 DP carb. I will rebuild one this week and get it on the car by May 7. If I can afford them I'll get the short-stroke lifters, too. If I do get them, I'll install them first and run it to see if I can get that extra 500 rpm. Then I'll change the carb to see if the smaller carb helps. Over the winter I'll either build a 347 short block or if I can afford it I'll go to a 408. Right now, I'm still behind the car with my lack of driving skill. I want to fix that before I up the power level. It's been 40 years since I've run a fast drag car. Most folks will tell you that a 12.50 car isn't fast and I'll probably agree with them after I get 30 or 40 runs on it. Right now that 12.50 seconds goes by in about 3.4 seconds.
not sure we're you live in relation to the general public and the po-po's.. but I'd sure as hell be loosening up that lifter plunger pre-load to get a quick "rev range test" before doing ANYTHING else at all to it. Basic troubleshooting 101.. easiest simplest tests first. IOW, the test is extremely simple to see if you were standing the valves open from pump up.. not floating them from loss of control due lack of spring. I seriously think you are closer to 12's with that current combo than you think you are.. no more parts or smaller carbs needed. Plus, like you said.. driving skills and leaving techniques will also improve to help whittle it down by making better use of the power you already have. Video can be hosted on any free or paid sites.. or just use youtube once it has been converted to an FLV video file.. and then link or embed it here. Tons of free youtube converters out there nowadays.. dunno, been a while since I've uploaded there maybe even youtube has one built in these days?
Here's the video posted on my Facebook: https://www.facebook.com/jim.mcknig...870003?notif_t=like¬if_id=1461643466704128
Dangit!.. I can't see it either. I even signed in first and it says... "Sorry, this content isn't available right now The link you followed may have expired, or the page may only be visible to an audience you're not in."
