s30kid Posted June 19, 2015 Share Posted June 19, 2015 hello Hybridz, I have been doin alot of research about building an l28et. I have blown my l28et about 4 times now in the past year and ive decided to go with forged internals and a properly built engine instead of junkyard motors. The plan is to have f54 block with p90 head forged ka24 pistons (89mm) arp head studs (already have) hy35 turbo balanced crank, rods, pistons lots of machine work on the head porting etc. megasquirt (already have) ported intake (already have) fmic (already have) 440cc injectors (already have) meth injection I heard stock rods can handle the power so should I buy forged rods? My question is, would boring the f54 block to 89mm be too much? would the block be weak at that point? I have also ran the L enginge calculator and with l28 rods, p90 head, and ka24 pistons, the comp. ratio is about 6.4:1 with 4.1mm deck clearance. Is that too low? If I were to run 240z rods the comp. ratio is 7.7:1 with 1.3mm deck clearance. which is better? Any other input would be great too. I also have a thread in the wanted section if anyone has parts please message me. Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 19, 2015 Share Posted June 19, 2015 What "blew"? Looks like you're shot-gunning "upgrade" components. A targeted approach might be better. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 19, 2015 Share Posted June 19, 2015 7.4 CR is OK, sixes are far too low. I have a junkyard engine making 350HP more or less since 1985. It's not the interior parts of the engine that is your problem. It's your inability to properly control spark, fuel, and cooling that is causing your problems. If you proceed, all you will do is repeat the blowup and cost yourself another build. My suggestion is to get ONE MORE junkyard block, a couple of head gaskets, and start on fueling and spark in earnest. Get that RIGHT before this 'expensive' build. Until you are above 400HP, the stock L28ET components are still 100,000+ mile parts. Get fueling, spark, and cooling correct on your junkyard engine...and like me you will be waiting, 30 years to 'blow it up' to justify buying those expensive components! After Fueling, Spark, and Cooling.....Head Work and Cam is the next step. That will get you to 450 on the stock bottom end and until you tune that setup to reliably run there's no point in going to the forged components to get that last 1,500 rpms on the top end (7,000 to 8,500 rpms) to make really big power. Then again, 475 hp under 20psi is where you should be by that point...Exactly what ARE your horsepower goals? the 440CC injectors kind of limit you into that 400-500 HP range with the shotgun list of stuff you mentioned ... The stock rods are already forged. Quote Link to comment Share on other sites More sharing options...
s30kid Posted June 19, 2015 Author Share Posted June 19, 2015 400hp is plenty for me for now. My issue is just as you stated, Fuel and timing control. I rebuilt my engine less then 6 months ago with parts of questionable quality, I proceeded to blow the head gasket 3 months ago due to preignition. And 2 days ago I believe I blew the ringlands/rings after turning to boost back up to 15. My engine is smoking like a train from the crankcase vent. Anyway, I have a motor lined up. Its a f54 block n47 head. New itm pistons .020 over with a hy35 turbo. With the n47 head the comp. Is in the 8's. And its not the best head by any means. So I plan to locate a p90, run the hy35, have the rotating assembly balanced and have the car fully tuned on the dyno at a shop here in reno. My plans are to have a reliable ~400hp L28 that won't blow in the next 6 months. I have read a lot about using quality rings and pistons, are itm pistons a good replacement or should I look into replacing them? Quote Link to comment Share on other sites More sharing options...
malibud Posted June 19, 2015 Share Posted June 19, 2015 I thinks you should listen to Tony not sure you need the P90 . Like he said get the afr and timing right . Turn up boost slowly ... Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 21, 2015 Share Posted June 21, 2015 You are running EXACTLY the format I tell people they will go through: two head gaskets...and then on the third the ring lands are probably gone. A set of ITM Turbo Pistons and another head gasket...repeat until tuned properly. How much this costs is ENTIRELY dependent on your ability to learn a proper tuning methodology and make logical, progressive steps in tuning. I go like this: run the junkyard engine until the head gasket blows, at the point when the ring lands sink, replace with ITM, and put in your ARP fasteners on the head and rods. From that point it's pretty easy to go two head gaskets every third head gasket... The gaskets usually blow on the intake/exhaust side... After JeffP sunk two sets of rings on his Rebello Bottom End at a cost of $3,000 each time he saw the logic of $200 OTM Pistons and Fel Pro head gaskets. The MLS Gasket he had in there didn't blow....the Pistons just broke. After swapping to a junkyard bottom end, he went through six head gaskets, and two sets of Pistons getting his system tuned to 475Hp at 17psi and 7,400 Rpms... At this point the map below that point is rock solid. No detonation. Fueling timing and spark is optimized with his higher-flow turbo, and now he's going to listen again and on his first pass make an 8 psi run until power peak of the cam is verified, then CALCULATE airflow and fuel requirements to then get a rough idea on pulse widths and if his turbo will make enough air for that power peak. What he is quickly realizing is with a high flow turbo and cam you don't have to pump the bejezeezus out of it with a Troglodyte Corky Bell Maximum Boost build...but can keep it below 20 psi and everything is MUCH easier. What confounds him most is he had surpassed the 450 Flywheel HP he had before at 25psi boost, running under 17psi now....with less spark issues, and much more "fun" powerband and on a STOCK BOTTOM END!!! I mean he had forged Pistons, Carillo Rods, VO7 stroker crank and 3.0 liters...and now it's a bone stock L28ET bottom end making more horsepower. External Bolt-On components. It's kind of crazy to sacrifice parts...but sacrificing to the God of Speed is best done with relatively low cost parts. It hurst less losing a set of Pistons for 375HP or 475HP and being out $300, than doing EXACTLY the same thing and having it cost you 10X as much! This is not MY suggestion. 20 years ago Steve "Stealth" Webb and I were talking at the ZCON in Albuquerque NM...and he had blown his "good engine" three days earlier. He had put a bone stock L28ET with hydraulic lifters and 160,000 miles in with his externals...and just for the hell of it they threw it on the Dyno. 460HP....admittedly down from his good engine around 10%, but he said "if I was doing it again, or if anybody asked me I would tell them to just keep that stock bottom end. Rebuild or replace it for $200 when it blows, and get your tuning right on your setup BEFORE you spend the money on a forged bottom end. By the time you're ready for that forged bottom end, you will have made at least one core for that build...you will have learned to tune the right way so the few adjustments you will need to make on your expensive build you can do without blowing it up." Watching guys in the 20 years since has reinforced his words toooo many times to count. Save your money. Blow up a few more stock engines and get your system tuned and stable. Then build your durability engine. But again...if you cam it right, and port it right and get the tuning right...you might be waiting a long time until it blows to give you the justification to build the stroker! 1 Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 21, 2015 Share Posted June 21, 2015 The ITMs are not forged, they are the sacrificial parts you are using to tune the engine. Any money spent outside Pistons and head gaskets is wasted. It will blow until it's tuned right. Having a turbo cam that peaks power around 8,300 rpms calls for forged parts. Cam it so it peaks at 6,500 and you can likely stick with cast. USE AN ELECTRIC EAR TO LISTEN FOR DETONATION. If you don't attend to cooling on a 300+ HP Nissan it WILL detonate to death...Turbo or N/A, how soon is a matter of degrees. Quote Link to comment Share on other sites More sharing options...
s30kid Posted June 23, 2015 Author Share Posted June 23, 2015 Okay so I plan to have the new motor fully tuned on the dyno with methanol injection. Would it be worth the money to have the block bored to 89 and run stock replacement ka24 or z24 pistons instead of forged as well as having the whole rotating assembly balanced? stock ka pistons in a 89mm f54 block, n47 head is a 2.949L engine with 7.012:1 compression, Depending on what headgasket is used. To run the z24 pistons I would either have to find flat top z24 pistons or find the longer rods from a 240z. on the same setup the comp would be 7.59:1 I will also run the ARP head studs that I have. Are ARP rod bolts nessasary? And what cam should I run? I have A stock NA cam in the motor now (n47 head). With the new motor im buying it also has a n47 head. should I find a turbo cam? Quote Link to comment Share on other sites More sharing options...
s30kid Posted June 23, 2015 Author Share Posted June 23, 2015 I didnt mention this but I would like to run 15-20PSI of boost. I plan to buy a Electronic boost controller, im currently looking into the turbosmart e-boost street controller. I also need to buy a methanol injection kit, And from there when I get my tune we will see how much power the engine will make. I dont want to set a HP goal of 400 or so and then be dissapointed when the car only makes 310. But I know this new build will be much better then the motor I have now and with a proper tune the powerband will come on much sooner and hopefully hold a lot longer. Quote Link to comment Share on other sites More sharing options...
Xnke Posted June 24, 2015 Share Posted June 24, 2015 You really aren't reading what is written here, are you? STOCK LONG BLOCK. Just run a STOCK ENGINE. Do the tuning, get it tuned, and it will make your goals. IF you want to exceed the limits of a stock engine, THEN spend the money on a bored/stroked/forged engine. People say the "A" grind camshafts (look on the back of the cam) do well up to the 400HP range, I would take a stock cam and send it out for a regrind. Doing a cam swap invites problems all it's own, so for the money, STOCK LONG BLOCK. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 27, 2015 Share Posted June 27, 2015 Do not bore ANYTHING. The power is in the head, cam, and turbo. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted June 30, 2015 Share Posted June 30, 2015 Listen to the people man. If you are on your 4th motor, in a year, yea maybe they weren't the best, but something is wrong. There is nothing wrong with a junkyard motor assuming that it was not the motor that landed it in the junkyard. Run some basic tests like compression and check for bearing material in the oil pan before you throw the motor in, but don't throw money at it until everything else is set. Megasquirt can control boost, like it has been said in your past posts, it is powerful, make use of it. Stop trying to hit certain boost numbers, the tuner which it seems you are in need of will find the sweet spot for you. Take a step back, NewZed's analogy is spot on. Find the target and aim for it, don't just start spraying and praying especially with expensive parts. Quote Link to comment Share on other sites More sharing options...
bryan3976 Posted July 2, 2015 Share Posted July 2, 2015 do you tune with a afr gauge as well ? Quote Link to comment Share on other sites More sharing options...
Datsun#1 Posted July 17, 2015 Share Posted July 17, 2015 I have a brand new set of factory Nissan turbo pistons with rings.they were installed and never ran.didnt even put a head on the block.decided to go stroker.ill send you pics if you are interested $200+ shipping. 863-271-3786 text. Randall Quote Link to comment Share on other sites More sharing options...
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