Tech Article: The Quest for more Power using the L-Series 6 Engines

by Ben Pila Jr.
Member at Large

Part 1

More power, more speed. These are things that "Scotty" tries to get "Capt. Kirk" on the "Enterprise" but more importantly, these are the things that many of us early Z owners would like to have. I am now on my own quest for speed as I begin building a new engine for my own Z. With that said, this and future articles will explain how to put together an engine set-up that will:

1. Gain more power than any stock L6 can make.
2. Return gas mileage better than 20mpg (I believe 27 hwy. mpg is possible.)
3. Still pass (or squeek by,) the California emissions test for 1975-78 engines and most 79-83s.
4. Do this build-up on a low dollar budget.

The charts that I have provided in this article are courtesy of Jim Wolf Technology. Review the charts and familiarize yourself with the specifications they contain. To fully understand the charts, I will need to explain (in the next article,) what each of the different head, block, and piston numbers represent and then I can begin to expand on the combinations possible. In future articles I will explain where you can get all the parts, how much the parts and labor may cost, and what to do with the parts to finish the engine build-up. I will later explain the different induction system options using carburetors or fuel injection and turbo systems. The potential horsepower for the "big" L6 engines should fall in the 175-450 HP range. Yes, 400+ HP is possible and has been done with L6 engines but reliable street performance will be more likely fall in the 175-300 HP range. I believe there can be good reliability from a 300+ set-up (using fuel injection,) but there will be few willing to get to that level. I recommend making a copy of this and all future articles in this series and keep them all in a folder for easy reference. So follow along with this series and your quest for speed may be satisfied.

HEAD VOL. C.C. INT VALV. EX VALV. EXH. PORT PROD. DATES   H/GASKET HEIGHT DIA. C.C. PART #
E31 42.4 42 33 square 10/69 - 7/71   L28 STD 1.25 88 7.60 11044-P7911
E88 44.7 42 33 square 9/71 - 7/72   HKS METAL 1 91 6.50 11044-91MM1
N33 47.8 42 33 square 8/72 - 7/73   HKS METAL 2 91 13.01 11044-91MM2
N33/P50 47.8 42 35 square 8/73 - 8/74            
N42 44.6 44 35 square 9/74 - 7/77   PISTON DIA MM. PIN HEIGHT DISH C.C. PART #
N47 44.6 44 35 round 8/77 - 3/78   KA24E STD.cut .5 89 33.5 0 12010-40F10
P81 44.6 44 35 round 2/79 - 6/80   KA24E +1.00 cut .5 90 33.5 0 12010-40F73
P79 53.6 44 35 round 7/80 -   Z24 STD. cut .5 89 33.5 13 12010-83W01
P90 53.6 44 35 square 12/80 - 7/82 TURB.   Z24 +1.00 cut .5 90 33.5 13 12010-83W03
P99 53.6 44 35 square 8/82 - TURB. HYD.   Z22S STD. 87 35 9.33 12010-06W11
              Z22S +1.00 88 35 9.33 12010-06W13
                       
PRACTICAL PISTON / ROD / CRANK COMBINATION                      
NO. PISTON ROD CRANK PIST/DECK +/- CC VOL +/-   SIZE C.C.s   CRANK STROKE PART #
#1 KA24E STD.cut .5 L24 LD28 0.13 -0.8   3098   L28 79 12201-P3000SV
#2 KA24E +1.00 cut .5 L24 LD28 0.13 -0.83   3168   LD28 83 12201-V0790
#3 Z24 STD. cut .5 L24 LD28 0.13 -0.8   3098        
#4 Z24 +1.00 cut .5 L24 LD28 0.13 -0.83   3168   BLOCK HEIGHT  
#5 Z22S STD. L28 LD28 -1.02 6.06   2960   L28 207.87  
#6 Z22S +1.00 L28 LD28 -1.02 6.2   3028        
#7 KA24E STD L24 L28 -1.37 8.5   2949   R0D LENGTH PART #
#8 KA24E +1.00 L24 L28 -1.37 8.71   3015   L24 133 12100-N0102
                  L28 130.35 12100-A8703
                       
COMPRESSION RATIO USING HKS 1.MM HEAD GASKET FOR ABOVE COMBINATIONS                      
HEAD #1 #2 #3 #4 #5   #6 #7 #8    
E31 11.73 11.98 9.45 9.65 8.67   8.83 9.56 9.72    
E88 11.24 11.48 9.14 9.33 8.41   8.56 9.23 9.39    
N33 10.65 10.87 8.76 8.94 8.08   8.23 8.83 8.97    
N33/P50 10.65 10.87 8.76 8.94 8.08   8.23 8.83 8.97    
N42 11.26 11.50 9.16 9.34 8.42   8.57 9.25 9.40    
N47 11.26 11.50 9.16 9.34 8.42   8.57 9.25 9.40    
P81 11.26 11.50 9.16 9.34 8.42   8.57 9.25 9.40    
P79 9.71 9.91 8.14 8.31 7.53   7.67 8.16 8.30    
P90 9.71 9.91 8.14 8.31 7.53   7.67 8.16 8.30    
P99 9.71 9.91 8.14 8.31 7.53   7.67 8.16 8.30    
Courtesy of Jim Wolf Technology

Rod width at small end must be reduced to fit KA24 and Z24 pistons.
91+ 240SX pistons can be substituted for Z24 pistons.