curs2cmine Posted June 8, 2013 Report Share Posted June 8, 2013 Ok I got an 85 720 and I freakin love it! Except........ It has absolutely no power to speak of... Its running really rich to the point of smokin... It has a Weber 32/36 on it new plugs wires cap button and is timed correctly... An yes the secondaries on the Weber are functioning correctly... Im at a loss... I need help! Quote Link to comment
bmacster Posted June 8, 2013 Report Share Posted June 8, 2013 If you haven't already - compression test. It almost sounds like it is more of the issue with the carb though if it is smoking. What color smoke?? Quote Link to comment
curs2cmine Posted June 8, 2013 Author Report Share Posted June 8, 2013 Its blue smoke and smells like straight up gas Quote Link to comment
bryant2482 Posted June 9, 2013 Report Share Posted June 9, 2013 ok your rings are shot and the cylinder walls are probablly all scored up Quote Link to comment
bryant2482 Posted June 9, 2013 Report Share Posted June 9, 2013 its acctually amazing that it even starts Quote Link to comment
curs2cmine Posted June 9, 2013 Author Report Share Posted June 9, 2013 Have anything else? Quote Link to comment
curs2cmine Posted June 10, 2013 Author Report Share Posted June 10, 2013 It cant be anything to serious cause I drive it daily and itll run 65-75 on interstate... Unless I hit a hill then 50-55 is all shes got an it takes 10 years to get to 70 Quote Link to comment
millican Posted June 10, 2013 Report Share Posted June 10, 2013 Like Bmacster suggested, a compression test would tell you a lot. Compared to newer vehicles, these don't have much power even when everything is fine. Quote Link to comment
curs2cmine Posted June 10, 2013 Author Report Share Posted June 10, 2013 I didnt expect it to be a torque monster but surely it should get up to speed faster than it does... Ill do a compression test after work and see where its at Quote Link to comment
datzenmike Posted June 11, 2013 Report Share Posted June 11, 2013 Simple stuff first. Check the valve lash. 0.012" on int. and ex. Timing. 3degrees BTDC When warm is the choke plate full open.... vertical or part closed? Quote Link to comment
bryant2482 Posted June 12, 2013 Report Share Posted June 12, 2013 yea if you have a low compression reading either the rings are done or the valves are not seating properly. of course there is the head gasket but there would be more then just blue smoke coming out the tail pipe Quote Link to comment
filthy forever Posted June 12, 2013 Report Share Posted June 12, 2013 compression test for sure. blue smoke sounds like you're burning oil bud. either rings are bad or like Bryant said the valves may not be seating correctly, or worn valve guides causing oil to be drawn into the cylinder. the rings on my L20 were bad and I be blowing smoke all over the place. :w00t: Quote Link to comment
datzenmike Posted June 12, 2013 Report Share Posted June 12, 2013 It could be lots of things even over filled with oil.... seen that before. Check those things I said first before doing a compression test. A tight valve(s) would also lower compression and drop power. Blue smoke is likely rings but always do the simple/cheap and easy checks first. Quote Link to comment
bryant2482 Posted June 12, 2013 Report Share Posted June 12, 2013 how many miles does it have? Quote Link to comment
curs2cmine Posted June 13, 2013 Author Report Share Posted June 13, 2013 The choke is fully open when warm.... Guess ill be doing a valve adjustment sat and compession test... It has 162,000 on the truck no clue on motor after getting into it so much there are tons of things pointing at the motor not being the original one... correct me if im wrong but the 85's came with two engine options.. The z24 and 24I right? Quote Link to comment
datzenmike Posted June 13, 2013 Report Share Posted June 13, 2013 Yes there were three gas engine options besides the SD25 diesels in '85. The only difference between them was being either carburetor or fuel injection. All Z20 engines were carb but on the Z24, April '85 and on were called Z24i motors. The ( i ) is a descriptor for throttle body injection. Previous to this the Z24 was simply a Z24 or Z24(S) with the 'S' a descriptor for carburetor. No descriptor after the Z24 is automatically assumed to be a carb. The Z24i was also used in the next generation D-21 pickup from 86.5 through '89. Quote Link to comment
curs2cmine Posted June 13, 2013 Author Report Share Posted June 13, 2013 That is a problem as I have a z22 Quote Link to comment
bryant2482 Posted June 14, 2013 Report Share Posted June 14, 2013 you need a KA. or go with the original Z24 Quote Link to comment
datzenmike Posted June 14, 2013 Report Share Posted June 14, 2013 That is a problem as I have a z22 Should have said so. The later trucks (with high torque Z24s) have even lower axle ratios than the earlier ones. Quote Link to comment
curs2cmine Posted June 14, 2013 Author Report Share Posted June 14, 2013 Theres really not that much displacement difference Quote Link to comment
datzenmike Posted June 14, 2013 Report Share Posted June 14, 2013 Displacement yes.... but the Z24 also has a longer stroke which is a stump puller at lower rpms.. 1 Quote Link to comment
curs2cmine Posted June 15, 2013 Author Report Share Posted June 15, 2013 Looks like im in the market for an engine... Any recommendations on where to pick up a good low millage one? Quote Link to comment
curs2cmine Posted June 15, 2013 Author Report Share Posted June 15, 2013 And im assuming it will bolt to the Trans I have currently? Quote Link to comment
datzenmike Posted June 15, 2013 Report Share Posted June 15, 2013 Any Z20/22/24 will bolt up to the transmission you now have. Quote Link to comment
bryant2482 Posted June 16, 2013 Report Share Posted June 16, 2013 you could try ebay Quote Link to comment
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