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Qustions about Turbo pistons, and strokers.


Guest JAMIE T

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Guest JAMIE T

As most of you know, I have been getting parts together to build a 3.0 or 3.1 L6. I've got the Deisel crank, the 9mm 240Z rods, and a F54 block, blah, blah, blah. I am in the process of buying a complete 280ZXT engine(I believe it is a '81). I know we feel like it very expensive to build a stroker turbo L6. I've got most of the parts to do it. I mainly am concerned abou the pistons. I do not have the bling to afford to have Top End or Robello to build an engine. Who has done this themselves? I have not priced pistons for this package yet, but have seen guys posting numbers like $900 for a set of pistons. What is wrong with this picture? I paid that much for 10 CUSTOM nitrous pistons for a Street Outlaw 351W Ford!!! someone is RAPING Datsun L6 users. I would have called JE for a quote already, but I don't really know what to ask for. I mean, I'm a standard measurer, whats a MM(J/K)? I don't know the compression height of the pistons required. All I know is 133mm rods, and 83mm stroke, and a 89mm bore(or however much overbore one of my F54 blocks can go). I'd rather not buy a set of pistons, then have to mill .5mm off the top. I think a set of quality forged pistons SHOULD be about $600 at the most. What is the limit of the 9mm rods once they have been polished, shot peened and ARP bolts installed? I'm going to polish and knife egde my LD28 crank, then get the whole assembly balanced. Has anyone ever used Hardblok in a L6 block to strengthen it? If anyone has a part number or a contact for pistons for this application, please post it here.

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it cost to be the boss. you can do it at home, but there is some notching and some work to be done on the bottom end to get everything to like being 3100 downthere, and i dont trust myself with anything more than a simple rebuild of bearings and rings, you can always hollow out the block and have it sent to do the machining to cut down the costs. but it still cost to be the boss.

it hurts i know, i might have to spend 500.00 into a turbo motor i bought for 85.00, but hey thats how the ball bounces, and imma need a spare motor, cause its time to BOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTYYYYYYYYYYYYYYEEEEEEEEEEEEEEEAAAAAAAAAAAAAAAAAAAAAAAAAHHH HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

i think the best bang for the buck is a stock turbo motor with the following relatively inexpensive internals. arp bottom end fastener kit, a nice balanced stock crank, new timing chain, gapless rings, a nice b and b, a steel headgasket with ARP headstuds, and a de carbonized stock p90 head, with the ports deburred. with this you make a bullet proof engine missile proof, and begin to boostin.

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Guest JAMIE T

I feel that Len, Oh Yeah! I'm gonna put the L28ET in my '73 stock, stock, with an IC and some other goodies that is. Abuse that for awhile, and start on the stroker. I have built stoker V8's in the past, and feel fine about grinding the block and clearancing for the stroker. Shoot, I'm gonna knife edge the crank myself! Same for polishing the rods! I've got no problems building an engine to this level, It just seems like the answers are hard to get for deminsions, like for the pistons. I build ALL of my own engines. I have a local shop do the machine work(which I triple check behind them). I just don't think they have much experiance with L6's. And they certainly don't have torque plate for one. I just REALLY want FORGED pistons(even if they are stock demisions for the ZXT engine). I want to BOOOOST!!! I haven't even taken delivery of the L28et, and I've already started looking a SDS, and some other ECU's.

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GOD, its so dang fun. i would get the car running with stock efi first, once you understand it fully the switch to sds wont take more than a week or so, im having great fun just driving the car around, i have 15k driving time in only three and a half months of doing the swap, and its been pure bliss. im running a weanie 7psi right now until i can get it on the dyno with an intercooler , but once i figure out how much boost i can get away with, IMMA GET AWAY WITH IT.

plus im gettin a little over 26mpg with it at freeway speeds averaging mid 80s. once i do some more supporting bolt ons, imma turn the boost and hit the track, i cant wait, this time ill be in the import lane, instead of me in the v8z going heads up with the top fuel dragster or another funny car, and getting my boots stomped, oh man, lining up with the imports, oh boy.

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Guest Zcarsmakemyheadhurt

I respectfully disagree with you guys, work the stock efi to learn about setting up a fuel system....no. Your chasing gremlins with the factory EFI just to get the thing to run right most of the time. Len your doing good and I wouldn't change a thing but that means not trying to boost it too hi, your going to work some majic to have success after 12psi. As for Jame stroker's are way cool but when your dealing with boost displacement isnt always as critical as say a 351W NOS car or natural asperated engine. Consintrate on the fuel system and turbo set up if you feel you have to up the anti then build a bad boy stroker engine, youll have the fuel system for it.

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Guest JAMIE T

Alex, as soon as I take delivery of the engine, I'm going to be calling you. I AM going to go sand alone. Can you get me a stand alone as cheap as SDS? Other things will follow, as I will need a IC core you mentioned in another post, and probably a turbo upgrade. I was talking about the engine itself. I want to make over 350 rwhp, actually, as much HP as I can. I'm no stranger to high HP, just turbo's. I like the quote on somebodies sig that says Boost is the only substitute for cubic inches. I'll cut my teeth with this L6, then move on to bigger things.

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First off I would not recommend a 3.1 liter for a turbo application. 3.0 is good enough. That will give you a good bore to 88mm and the diesel crank for the stroke.

When a person strokes a turbo engine it is not for the displacement but for the extra torque that you will get with the longer stroke. On a N/A engine it is for the displacement. Remember swept volume is just that, swept volume, so if you increase the swept volume you are going to get a stronger engine if you ar doing a N/A application. The 89mm bore on a L28 engine is getting a little thin on the cylinder walls in my opinion.

Next thing, the pistons, well the turbo piston has a dish in them to decrease the static compression. Je makes a set of pistons for about 650.00 and you can get total seal rings for about 30.00 a set.I went with a 8.5:1 compression ratio in my engine because I wanted a little more power off boost then the stock compression would give me.

The 240 rods will give you a 1.65:1 rod/stroke ratio and that will work, but with the 240 rods, if you leave the piston pin boss at at stock bore heigth, that will put the piston up above the deck by about .020. So what most guys have done is use a 2mm head gasket. I also dont suggest this as a way to compensate foran incorrect parameter and creates poor squish in the combustion chamber. that will make the engine more susceptable to pinging. People have also milled off the top of the piston as well, which cuts down on the heat sink capabilities of the piston to dissipate heat. All of this stuff will work, but it is not the correct way to solve the problem in my opinion. What would be the best method is to have the piston maker drill the pin boss to the correct heigth and be done with it.

The block, well there again you will have to more then likely have to grind on the oil gally area on the inside of the block to get the rods to clear the side of the block, leave about .050 clearance between the rod and block and you should be good. You can do that work yourself if you like, a good little grinder will do the trick just fine.

You can also do the "micro polish" that shops charge about 100.00 to do. Get your self some mineral spirits and 2000 grit sand paper. Cut the papre to fit the journals, dip it in the mineral spirits and start in on the journals. If you can chuck up the crank in a layth, and I am guessing you can to knife edge the crank, then go at it that way until the journals are mirror finish. It really doesn't take that much to do it, and you should still be well within spec on clearances when you are done.

Call Je and ask them for a cost on the pistons, or you can call Robello and buy them from them. I think they have stock on ready to go pistons. Talk to Dave and tell him Jeff sent you.

I would also suggest ARP main studs in the bottom end and in the head also, and if you dont go after market on the rods then get them for the rods as well. You are looking at about 300-350 for all that stuff.

The pistons, get the high silicone piston so you will be able to fit them in the bores at 2- 21/2 thousands for a tight engine.

Just keep in mind, you are building a turbo engine, not a N/A engine, so some of the stuff you would do for a hyper N/A engine is not required for a turbo application.and there again, some of the stuff you would not do for a N/A engine is required for a turbo engione, like the piston ring land configuration, you will want a ring further away from the top of the piston then on a N/A engine requires.

anyway, hope that helps.

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The stock system is fine if you are trying to build power in the 200-250 range, but when you go to higher hp levels the stock system is not going to get you there. Being an 8 bit(digital processor) and analog inputs, especially the AFM is going to really limit your capabilities. I got my car running just fine with the stock system, but when I had to go to larger injectors, it was easier to just change out the system and start there.

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i think the 250hp cap is for a completely stock setup i think, down to the fuel pump and regulator, i know two people who are putting down nearly 300hp wheels with stock efi, with 370injectors, bigger fuel pump, fpr, and some afm touching, and i think it just takes some know how down there to make it happen. i know that for hp levels 300hp and beyond, its takes more than a programmable system to make that power as well though, im only shooting for 300hp with this efi setup, and im gonna do it slow, and with 8 injectors :D

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