Re: 4.16 Gears and 30\'s Geared Too Low????
About the speedo, it runs off the rear output shaft in the t-case. It should be dead on with 30" tires/4.16 gears because the 4.16 gears bring the gearing back to stock in high range. However, this is not the case, the speedo is slow. Can someone please explain why the speedo is off?
The rig I mentioned in a earlier post has a 1600cc, weber, DT header, 1300cc head, and a ISKY dual purpose camshaft. It has lots of power throughout the rpm range and winds up to 5500 rpm with plently of power still on tap.
I've got another rig back in the states that has a 1600cc, weber, DT header, and ISKY "torquer" cam. It's a completely different beast. It pulls *very* strong until about 4000 rpm then it seems to run out of steam. Since the main difference between the two engines is the camshaft, I believe that the cam is the "no top end" factor. I have also talked with others that have expressed the same opinion about that particular ISKY cam. Maybe that is what you're experiencing?
Also, both rigs get low-mid 20s mpg. With the 1600cc, torquer cam getting a little more than the 1600cc, dual purpose. Maybe, your carb is jetted too rich? I run 125-130 primary, 155-170 secondary in mine.
I also once experienced a very odd/hard to diagnose problem. A couple of needle bearings froze up in the tranny because it sat too long without oil in it (2 years). There were no obvious noises when driving but the "cold tranny, neutral, crawl" was much more pronounced and it crawled even when it was 70 degrees outside. The rig got horrible gas mileage and had no highway power what so ever. I replaced nearly everything in the drivetrain (including the original 1300, t-case, rear end) before I finally narrowed it down to the transmission. (I had replaced every other component and tested them in another Sam!) I hope this helps.