The Journey: ‘83 L28ET Engine is Reborn with Aftermarket Upgrades.


In April of this year (2007), I posted a request for help on (Car will not start!). The problems were related to oil on the spark plugs (worn rings) and other evils. My sources of information told me that I needed to have this S130 engine rebuilt. With a philosophy of maintenance/efficiency before stranded/repair, I had already made several modifications to this car. First of all, heavier struts (KYB GR-2) & shocks (KYB GAS-a-just) were added at ~130K miles; next, a 3-row radiator from a ’81 automatic turbo and a complete high-performance cam kit (MSA) (no markings) were installed into the L28ET engine, both of these mods were added at ~170K miles; and a new matched set of OEM Nissan injectors (265cc) was installed more recently at ~287K miles. What is next?



After two attempts to find a machinist/mechanic to rebuild this L28ET engine, I found one just north of Jonesboro (AR). During our first conversation, James, the owner of Jim’s Machine & Auto Shop, related to me his experiences rebuilding engines of the L6-series, 300zx, SBC350 and others. In short, this shop was chosen for the following reason: he could do both tasks needed to rebuild this engine; he would listen and answer my many questions; he would incorporate the many upgrades that I had already purchased; he needed to have experience rebuilding Zcar engines; he must be cost-conscious and, once accepted into his shop, his attention would be continuous. My Zcar went into Jim’s Machine & Auto Shop (Paragould, AR) with the many upgrades that were stored in the back of the car (others to come). James became “The Zdoctor” for my car; the term given to the one who takes care of my wheels.



After spending many weeks reading the Guidelines/FAQs/Stickies/threads in HybridZ and sourcing for an engine rebuilding kit for my Zcar on the Internet, the journey became a major challenge to find the right parts for this ‘83 L28ET. Since many of the existing parts were relatively new, I focused on finding the remaining engine parts associated with the head (P90a)/ block (F-54) and to replace the turbo. The sourcing (HybridZ & Google) was difficult; many providers did not even list a 280zx, let alone a turbo engine; the more answers found, the more questions were generated; and what are the limitations or overkill of these parts, etc. I was lost so I e-mailed Paul (HybridZ) and, subsequently, he suggested John (HybridZ) as a good source for the turbo question. In parallel, the information really started to flow into the project. Many answers that I had not generated questions for and, the best of all, it gave the project focus, which, on my end, was lacking. In correspondence, the most fundamental question asked of me was what was your target HP?  Based on the parts that I had already purchased (see below) and the Zcar that I had, the target as noted by John (HybridZ) appeared to be 300+HP. I did not know whether the cam was a turbo custom grind unit; there was not a number on the aftermarket cam.  [The lack-of-markings suggested to me that the kit did not come from MSA as I had originally requested. However, the mechanic who put this cam in was a hot rod specialist and the Zcar ran great when asked.]  From correspondence by John (HybridZ), the following points were also provided: porting of 60 mm TB/intake manifold/runners and the cylinder head; boring 20 thousands or larger; cast pistons vs forged pistons; ARP studs for the rods, mains and head; an OEM oil cooler; an adjustable fuel-pressure regulator (vacuum/boost referenced unit); stock turbo injectors vs higher cc capacity injectors for increased HP; aftermarket EMS to support 300+HP and higher levels of performance; stock J-pipe vs modified downpipe (w/ ports for external wastegate & oxygen sensor) that runs from the turbo to the Cat;  3” vs 2.5” exhaust system; spark plugs and electrical systems; MSD-like for an improved ignition system; air intercooler for turbo preservation; and turbo specifications for 300+HP. For me, this information added clarity in defining the project and provided support information in assimilating the threads, etc. in HybridZ.


After the first week, I visited the shop where the L28ET was being “refreshed”. There were parts in different locations within the machine shop area but organized in categories. The block and head had already been dismantled and cleaned; both were fine. The crank was cleaned and fine. The cam kit was fine with no noticeable wear on the moveable parts; therefore, it was kept intact. The timing-chain kit was fine. The Zdoc stated that the clutch and flywheel, etc. were fine. New engine parts (pistons, valves, etc.) had already been purchased (ITM Engine Components). However, the stock T3 turbo needed to be replaced; it was leaking oil badly.


Pistons: hypereutectic cast w/ dished pistons (ITM Engine Components)

Rods: original (re-conditioned)

Rings: new (ITM Engine Components)

Bearings: new (ITM Engine Components)                                                                

Bolts on rods, mains & heads: original [A complete set of ARP bolts is recommended, if target is 350+HP or if runs in the 7000 rpm range are anticipated (HybridZ)]

Others (valves, guides, etc.): new (ITM Engine Components)


These hypereutectic cast pistons are more durable than OEM cast pistons but not as durable as forged pistons. I watched as the Zdoc attached a rod to a piston head; what a difference a little heat will make. The block had been bored (+.030), surface milled and its cylinder walls were honed. The air intake manifold and the junctions between the runners of the intake manifold and head had been ported-to-matched gaskets, but not polished. Also, a 3-angle valve grind and surface milling of the head were done. The airflow capabilities of the P-series heads (P90a on this car) are good up to the 300+HP range, especially with a hybrid turbo (HybridZ). At this HP range+turbo, it has been recommended to put $$$ into an IC unit for cooling the forced air, which generates more HP and preserves the turbo instead of extensive head modification and polishing (HybridZ). The L28ET just became refreshed. Also check out: Car Craft Magazine. “Build a MAX WEDGE for under Seven Grand.” Nov. 2007.


The following week, I returned and the engine had been assembled and it looked great.  It was painted black as I suggested. I watched as the Zdoc put on the 60 mm TB + spacer and the complete turbo barb fuel rail kit with its fuel pressure gauge (60 psi). We talked about purchasing an adjustable fuel-pressure regulator (1:1 vacuum to boost) as suggested by John (HybridZ). I ordered one from the Internet (AEM) and I presented Paul’s schematic diagram and the thread for adjusting the fuel pressure regulator, both from HybridZ. Next, the Zdoc exchanged the OEM hydraulic lifters for solid lifters, which were taken from an ’82 280zxt. [Screw thread inserts were purchased from Time-Serts®.] All of the parts as noted previously have been or will eventually be put in this car. These include the following: a 60 mm TB kit w/ plastic spacer (PAllnet Specialty Automotive Parts) and a complete turbo barb fuel rail system (PAllnet), 105 amp alternator (, cold air induction system (MSA), oil cooler kit (MSA), new turbo oil pump (ebay), turbo high-pressure EFI fuel pump *NR* (95 psi) (ebay), NGK BPR7ES spark plugs (ebay), turbo electronic distributor for 280zxt (ebay) and new distributor cap & wires (local), new water pump (local) and new timing-chain kit for 280zxt (ebay).


L28ET Refreshment: The process

*Modified Block (F-54)

  • Block bored to +0.030, its cylinders honed and block surface milled

*Modified Head (P90a)

  • Head & intake runners ported-to-gasket and not polished

  • 3-angle valve seats and surface milled

  • Solid lifters + screw thread inserts

*Pistons, etc.: ITM Engine Components

      •  Hypereutectic pistons

*Air intake manifold ported-to-gasket and not polished


*60 mm TB + plastic spacer (PAllnet)

*Turbo barb fuel rail system (PAllnet)


Next was to purchase a new turbo; the original T3 unit was completely worn out. Oil had leaked down into the J-pipe; the consequence of a worn out turbo and, most likely, one of the two sources of the problem (“Car will not start!”). As already noted above, there was oil on all spark plugs, which indicates worn piston rings resulting in oil “blow-by” and is common for a 300K+miles engine. The next turbo will be a new Garrett T3/TO4E 50 trim w/ .63 a/r housing (Phoenix Turbo & MFG). This hybrid has a stage 3 compressor wheel and a T04E 50 trim a/r w/ .63 turbine housing, which fits the specs of this car (John at HybridZ). An external TiAL wastegate (38mm), which is normally sold with this hybrid turbo, was purchased from the provider (Phoenix Turbo & MFG). A downpipe (2.5”) and flanges were constructed by the Zdoc with ports for the wastegate and oxygen sensor; both the Cat and the piping/muffler will eventually be changed out. The Zdoc is taking this procedure step-by-step. After attaching the downpipe, the time came to see if the engine/car would turnover; she did and ran fine at accelerated rpms but rough at idle.  [I wish I had been there!] However, after next day starts and warm-ups, the rough idle bug continued and the engine ran rich and then shut down. This went on for several days; eventually, adjustments recommended by Peter (HybridZ/ were made to the EFI components (AFM, etc.). Then, another bug showed up, a vacuum leak that was corrected. The cold start senor and hydraulic lifters were still under suspicion. I did not change out the existing turbo injectors; these (265cc) are relatively new and a match OEM set from Nissan. I wonder, with a new high-pressure fuel pump, a new fuel rail system and a new fuel-pressure regulator with vacuum:boost capabilities (1:1), if this new fuel system will increase the HP that this set of injectors normally generated under the original OEM fuel system. Some believe this to be true (nienberg.11: thread in HybridZ).  If a major step-up in HP is desired, this will be the first down-the-road mod. From what I have read in HybridZ: 1cc = 1hp, in general. Collecting information to a folder regarding what size/type of injectors that will work best/fit the head (P90a) and fuel rail of this newly refreshed Zcar. Currently, she runs tight/heavy on the road but  She is alive!! 


The maiden voyage of 21 miles on the road by jkh.

Garrett T3/T04E 50 trim turbo
TiAL External Wastegate
2.5” Downpipe to the Cat



Next was to purchase a front-mounted, air intercooler system (IC). I have read in HybridZ about several variables: three piping routes; less distance the air has to travel, the less drop in air pressure (lag phase); different styles/shapes, design and air flow within each; what & how will this IC/piping kit fit into a 280zx with the AC grill; and how much does an IC cost with its accessories??? Complete kits that I had found were all expensive. The individual ICs on ebay were fine cost wise but which one, bar&plate or tube&fin, composition and efficiency for 300+HP? Not sure which direction to go. From sourcing HybridZ, three IC piping routes were discussed by members of this group (wigenOut-S30); route #3 was declared the best so I selected this route for my Zcar, which meant a same side air intercooler needed to be purchased. This style FMIC unit had been discussed in HybridZ (randy 77zt) and the Internet. The one purchased possesses the following characteristics: turbo application up to 600HP, all aluminum with bar&plate design, and same side inlet (2.5”) & outlet (2.5”) style air intercooler with a core of 18”x6”x3.5” (total length: 20”x12”x3.5”) (XO2 Racing). Next, a universal FMIC intercooler piping kit was purchased with several additional turbo silicone connectors (2” to 2.5”, 2.5” to 3.0”, and 2.5” to 2.5” bends) (GS Infinity). Also, an electric dual fan (Maradyne*) (SRS) (2,760 cfm) was purchased and placed directly in front of the AC grill (AC kept). The opening in the radiator support on the turbo side had to be enlarged so that the pipes from the air intercooler could pass into the engine bay (+ the cold air intake pipe). The top cold pipe returns from the IC to the 60 mm TB, while the lower hot pipe receives the air from the air outlet compressor side of the turbo. The cold air induction filter was positioned between the IC and the Maradyne fan and its tubing passed into the engine bay between the IC pipes to the turbo's air inlet compressor side. The FMIC unit was installed slightly tilted to directly face the flow-of-air through the lower front louvers (the Zdoc). AND the so-call need for an oil cooler was mute because the Zdoc noted that my car already had an oil cooler in the radiator, which the latter was installed at about 170K+ miles.


Take a Deep Breath!  Make HP and Preserve the Turbo! Air intercooler system consisted of a same-side FMIC, cold air intake system and a dual electric Maradyne fan.


Engine bay and FMIC & Cold Air Intake tubing: AFTER the process


She came home Sept. 7th to stay. The cold start issue remains. The break-in procedure has started as described in HybridZ, “What is the best way to break-in a rebuilt engine”. Each day, she is driven for one hour on the open road at constant speed with occasional accelerations and decelerations; current mileage is ~1500 miles of new life. So far the high-way patrol has not pulled me over.


Next a new EMS:  Currently, an ‘83 OEM ECU/AFM/turbo distributor system is governing a completely rebuilt engine with aftermarket upgrades; therefore, a new engine management system (EMS) is needed (Steve, correspondence). Many threads exist in HybridZ on this subject; plug&play+ (eMS-Pro) or standalone (Electromotive, Wolf3D, etc.). Both of these systems have advantages; do I want to drive today or drive after extensive hours of tuning; and, of course, which system is best for my 300+HP goal. Learned that the wiring harness in my car needs to be replaced and tuning versus mechanical maintenance are two separate issues. Need to be selective here due to overlapping of kit parts with existing parts that already have been purchased. Need to be careful because this “refreshed” Zcar is much faster than the original S130 Zcar. She is loosening up. She is a thrill to drive!!! Wheels are running, the text is done and next the hemp will incorporate pictures. We all have come a long ways in this journey. Yes, as Junkman ( stated, do not rush into your decision-making, research your project thoroughly and do it right the first time.


This truly has been a team effort. James, the Zdoc, and his crew has worked timely and diligently on this project. Thanks to John (HybridZ), Paul (HybridZ, Administrator) and Peter (HybridZ and for all your help and, respectfully, your time. You all gave creative skills, suggestions and focus to this project. Thanks to HybridZ and its many members, too numerous to note, who have generated the many threads discussing problems-challenges associated with owning a Datsun Z car. One can never see all of the variables associated with rebuilding a L28ET engine. I have thoroughly enjoyed learning a new intellectual field-of-endeavors. This has become a new way-of-life for me. Again, thanks for your help.

Enjoying the Ride!!!!!!!!

John (jkh280zx)


* This fan pulled 48 amps, which fried the relays on two separate occasions. Rick put an electric solenoid (relay) (150 amps) and used higher capacity lines that were directly attached to the battery; then to one return he added  a switch, which was attached to the knee board. This circuit incorporated an option to run the fans or not. During the summer or under heavy load, these fans will be used.


Future Modifications:


P&P+ or a stand-alone EMS

TiAL blow-off-valve (BOV)

GripForce F1 Racing Stage 2 clutch kit (purchased via ebay)

Aluminum flywheel (provider to be determined) or shave the OEM flywheel

Re-build T5 transmission (bearings)

Cat converter (3-way & high-flow) (2.5”) / Muffler (high-flow)(2.5”) (RodMoyes in Zdriver)





James & Rick at Jim’s Machine & Auto Shop (Paragould, AR)

John Kurzhals (jgkurz) (HybridZ)

Paul Ruschman (braapz350) (HybridZ, Administrator)

Guidelines/FAQs/Stickies/Threads in HybridZ

Blue & Z Tech Tips

Drax240z HybridZ.  The Ultimate L28ET Guide/What you need for 350+whp!

Nienberg.11. HybridZ. Engine Controls for a N/A '77 280z Converted to Turbo?

Randy 77zt. HybridZ. Cheap intercooler.

WigenOut-30. HybridZ. Intercooler pipe routing (mythbuster style).

How to Rebuild Your Nissan & Datsun OHC Engine. 2001. Tom Monroe. California Bill’s Automotive Handbooks.

How to Modify your Nissan & Datsun OHC Engine. 2000. Frank Honsowetz. California Bill’s Automotive Handbooks.


On-going Update to L28ET-history.htm (July 2008).


Current status of this S130 restoration project: (7-23-2008)

*Block: F54 was cleaned (jet washed) and repainted; cylinders bored (+.030) and honed; surfaced milled; and w/ new dished, hypereutectic-cast pistons (ITM Engine Components); stock rods cleaned and finished; and stock crank is fine.

*Head: P90a was also cleaned; head & runners of the intake manifold ported-to-gasket, not polished; 3-angle valve grind and surface milled; solid lifters + screw thread inserts; and completely rebuilt head with new springs, valves, etc. (ITM Engine Components).

*Intake Manifold: Stock was cleaned and ported-to-gasket with new TB, not polished; 60 mm TB w/ plastic spacer (PAllnet); turbo barb fuel rail system (PAllnet); and OEM Nissan low impendence injectors (256 cc).

*Turbocharger System: New Garrett T3/T04E 50 trim w/ .63 a/r housing; downpipe (2.5 in.) with ports to an external TiAL wastegate (38 mm) and oxygen sensor; and new TiAL BOV (50 mm).

*Ignition and Fuel Injection: New turbo electric distributor and cap, wires; NGK BPR7ES spark plugs and NGK spark plug wires; new AEM adjustable fuel pressure regulator; high-pressure EFI fuel pump *NR* (95 psi); and  (to be determined) either a reprogrammed EMS (Jim Wolf Tech) with Z31 MAF or EMS standalone system. 

*Transmission & Differential: Stock T5 was rebuilt (bearings); GripForce F1 Racing Stage2 clutch kit; stock OEM flywheel was shaved; stock turbo R200 (3.54) differential is fine.

*Cooling System: Oil cooler in the radiator: the latter was taken from a ’81 turbo automatic 280zx; new turbo OEM oil pump; cold air intake kit (MSA); all aluminum, front-mounted air intercooler system (FMIC) (600 HP+) with same side inlets and outlets (2.5”) (core - 18”x6”x3.5”); universal FMIC piping kit; and electric dual fan (Maradyne).

*Exhaust System: A new 2.5” high-flow/3-way Magnaflow CAT with Mandrel bend tubing to a new 2.5” high-flow Magnaflow muffler.

*Body: Louvers cleaned and re-painted; tinted side windows and tinted windshield; and a new coat of paint (to be done).

*Interior: New headliner; re-fabrication of OEM seats & leather covers; and …….

*Miscellaneous: New water pump; new OEM turbo timing-chain kit; stock turbo wheels with Goodyear GTIIs; and 105 amp alternator.




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