gnosez Posted May 28, 2002 Share Posted May 28, 2002 Okay, I got the sensors in, got input from Dave Rebello, drove the car about 140 miles on a leisurely road rallye thru New Hampshire and it started to bog down and back-fire. Changed fuel filters and while it didn't do much to improve the ride it got better after the 60 mile hwy run back. As I cleaned the car that night I noticed a thin black line on the back intake manifold. Of course it was exhaust residue and the manifold was cracked. Off it came, and down to the welders on Monday, Tuesday I'm off to Chicago and get back just in time to get the fixed intake on Friday. In it goes Friday night and I finally get a chance to read JohnC's response about O2 readings at 1/2 and WOT. I reset the SUs (leaner)and took it for a brief run to the store Saturday morning. No problems, so now I'm off for a 120 run later that afternoon and another run on Sunday for 200 miles after I had once again leaned out the SUs. It's running great and my readings are very similar from carb to carb. When I get a chance in july, I'll get it Dynoed again. The first time I got 209 rwp HP, so maybe with the right A/R mixture I'll get a few more. Thanks everyone... Quote Link to comment Share on other sites More sharing options...
DAW Posted May 28, 2002 Share Posted May 28, 2002 How are you "resetting" the SUs? Are you adjusting the jet height (knurled ring adjuster) to affect the mixture across the entire rpm range? DAW Quote Link to comment Share on other sites More sharing options...
gnosez Posted May 31, 2002 Author Share Posted May 31, 2002 Yes, that's right. I've got it down just about right now, but last night I took off the valve cover and now have a new problem. Seems my rocker arms are getting scored. I'll order a new oiler today and see if I have a few good used rockers from my old L24 motor. Quote Link to comment Share on other sites More sharing options...
johnc Posted May 31, 2002 Share Posted May 31, 2002 I forgot if you are running the standard SUs or the 50mm ones. The standard SUs tend to lean out over 6,000 rpm on a 3L engine. Be careful during your testing. Maybe that's why Dave suggested a richer setting. Quote Link to comment Share on other sites More sharing options...
johnc Posted June 1, 2002 Share Posted June 1, 2002 Funny. Jim Thompson at Sunbelt only recommends two oils for all his engines (including the World Challenge Mazda engines): Mobil 1 15w-50 and Redline 50 (15w-50). Mobil 1 if your running in a high humidity or dirty environment and Redline everywhere else. A cam change is not to be taken lightly. You need to match a lot of different things (port flow, intake and exhaust flow, springs, engine managment, etc.) to make an engine work well. Most folks overcam an engine. Quote Link to comment Share on other sites More sharing options...
gnosez Posted June 1, 2002 Author Share Posted June 1, 2002 John, have you seen the EFI FI intake set-up? Any comments? Not interested in a turbo. As to cam selection I have the 480/260 in there now and was considering the 460/270 as a possible replacement. Replaced half-shaft as I found a clip starting to go on a u-joint as I changed tires for AXing this Sunday. Glad to find it before it found me. Had heard a clunk as I drove my son home and was thinking, "man I thought the rear issue was solved". I took some extra time to inspect the diff, etc. when the tires were off. Quote Link to comment Share on other sites More sharing options...
gnosez Posted June 1, 2002 Author Share Posted June 1, 2002 I'm running the 50mmSUs in there now. I've got them down leaner (12.5-12.8 WOT) and the car runs strong. However, notice I said in there now. Last night I was going to adjust the valves and dam if the rocker arms are scored (8 out of 12). I've been using Mobil 1 but now Dave saids he hasn't heard anything good about it and L28 cams. Nice to find out at this point. I changed the oil sprayer, put 20-50w synthetic blend oil in, and am about to order new rocker arms. Nissan or MSA?? The price is about $130. different. Dave seems to think my cam will be find even if I run it for a month or two until I get the rockers in. maybe yes, maybe no. So, if I go in and start changing things do I go with a hotter cam (have 270 now), a new lifter set-up, and FI from say EFI (Pro-Series)??? Hey, it's only money at this point and I don't keep track of the total anyway. Any ideas/suggestions?? Quote Link to comment Share on other sites More sharing options...
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