L28ET piston choices *newbie*

[280-z.com]

After days of searching here,google and other forums, I'm stumped. To give you a quick background, I have a 77 280z, as well as an 83 ZXT that I'm using as a donor car for my turbo swap. I've been using the Ultimate L28et guide as well as the Turbo FAQ as references for my build and my goal is 300-350 HP. The car will be a semi daily driver and I'd like to take it to the strip and play on the street, every so often. Coming from a v8 background, I'm trying to learn all I can about the turbo world, so at this point, I have no clue as to which turbo and what boost I'll be running. I will be running the stock turbo cam, upgraded ecu,440cc injectors,etc.

 

Anyhow, I have the head(p90) ready to go and now its time for the block. In reading the ultimate guide, it recommends using forged pistons if you are going over 300hp. I've looked into several manufacturers (JE,Ross,Venolia) and the price can be pretty steep. Since this is my project car and not my DD, I'm taking my time, as I want the build to be done right, so its reliable(somewhat at least) when I'm complete. I don't mind spending the money on the forged pistons, but based on my HP goals, is this an absolute must or overkill?

 

 

I hate to be that guy that posts a question thats been answered a million times, but I've searched until my eyes are bloodshot lol.

[FlatBlack]

I hate to be that guy that posts a question thats been answered a million times, but I've searched until my eyes are bloodshot lol.

 

I appreciate that you have done research, but come on...

 

You do NOT need to change internals on an L28 for less than 400HP. If you blow it up, just get another stock block, they are super cheap.

 

Example: Big-Phil is daily driving his car AFAIK and it dyno'd ~390WHP ~410WTQ on a stock L28ET. [stock long block, that is]

 

Try this on for size [A guy asking the same question you are]

 

http://forums.hybridz.org/index.php?/topic/61508-convert-na-to-turbo-change-pistons/page__p__566580__hl__na+to+turbo+change+pistons__fromsearch__1#entry566580

 

[bTW I'm running a "high compression" N/A motor with a thinner 1mm head gasket]

Edited July 7, 2010 by FlatBlack

[280-z.com]

thanks for the reply and for going easy on me. Like I said, I'm still learning. I'll stick with the stock l28et block. Thanks again.

Edited July 7, 2010 by 280-z.com

[junglist]

You might as well do a quick refresh of the engine though to make sure its in good shape and give it a better chance of running for awhile and making some better power.

 

-New main/rod bearings (i'm running clevite77)

-new performance piston rings (i'm running perfect circle moly rings)

-new timing chain/set (only like $100)

-new water pump

-new head, oil pan & timing cover gaskets (you can get Ishino which makes the OEM nissan for $20-$30 or felpro)

-get the block cleaned and honed (not bored or you'll need new pistons)

-have the pistons/rods checked and balanced

-get a fresh gasket surface on the head

-have the head checked and check/replace the valve stem seals.

 

It also might be in your interest to get some ARP hardware like rod bolts, head studs and main bearing studs. I skipped the ARP main bearing studs for my build and went with LD28 Maxima Diesel OEM bolts as they take 20 ft/lbs more torque than the stock bolts. I also got a new set of pistons as mine had some foreign object damage and I bought them at partsdinosaur.com for $200.

 

You should check out this thread for more info and more links to different parts places for rebuild/performance L28 parts: http://forums.hybridz.org/index.php?/topic/88757-l28et-rebuild-parts/

 

H-beam rods and forged pistons are expensive and to take advantage of them you'd probably need extensive headwork machining, lots of ECU tuning and a big turbo to really make the power to truly justify them unless you are planning on going out for lots of track days and want a rock solid reliable engine. Then you'd also probably need a MLS steel head gasket, a baffled oil pan, better water pump, head mods to the #5/#6 cylinder for cooling, and all kinds of stuff that adds up quick.

[280-z.com]

Thanks a ton for the reply. That really helped me out alot. Even though I have a p90a head, I picked up a freshly rebuild 0 miles driven P90 and now I'm onto the block. I think I'm going to buy the new parts you suggested and take it into the shop, rather just have them go through it in its current state and tell me what needs to be replaced. Thanks again!

[Xnke]

You really don't *need* to do anything at all to that engine for your power goals.

 

If you have never tuned a turbo motor, you WILL blow a headgasket, so don't put in anything more than a stock gasket. Even the fel-pro gasket is going to risk damaging internal components before blowing; so run the stocker. It will hold your power goals no problems, with a good tune.

 

If the engine had good compression, and good oil pressure before you stripped it apart, don't mess with it. It's in good shape.

 

If you absolutely have to tinker, go with ARP rod bolts and new gaskets, and CHECK all your bearings for clearances, check your bores, chances are they will be pretty dang close to tolerance. The weak point in the stock bottom end is the rod bolts; everything else is pretty damn stout.

 

Now, if you are swapping parts from block to block, i.e, moving the turbo pistons/rods into the nonturbo block/crank (pointless to do this, unless the turbo block has a hole in it or the crank is twisted, yadda yadda) then I'd go with new bearings, as you are changing the wear surfaces.

 

In the end, It's your engine, and your money. But for your power goals, there are folks on this site running factory assembled 150,000 miles motors making that amount of power.

[280-z.com]

Just wanted to update this.. I'm at the point where the block is just about ready to take to the machine shop. Just from a visual inspection, the original pistons appear to be in good shape, so I'm just going to stick with them, instead of forged. I also ordered the following parts:

 

Full gasket set (ITM)

Piston Rings (FM Rings)

Rod/Main Bearings (Federal Mogul)

Rod bolts (ARP)

 

Thanks again for all the input!

 

jason

[jc052685]

dont forget arp head studs.

[280-z.com]

Just wanted to update this thread. I picked my block up from the machine shop and Xnke was right, as far as it being pretty stout. They didn't find any problems at all with it. Everything measured up to spec. He checked and cleaned the rods and said they checked out fine. Here is the question I have now...I had bought new rods back in July, so would there be any benefit to using those, instead of the original ones?

[wigenOut-S30]

Just wanted to update this thread. I picked my block up from the machine shop and Xnke was right, as far as it being pretty stout. They didn't find any problems at all with it. Everything measured up to spec. He checked and cleaned the rods and said they checked out fine. Here is the question I have now...I had bought new rods back in July, so would there be any benefit to using those, instead of the original ones?

 

 

The rods and crank are forged from the factory and can take some abuse. If the rods are in good shape you should be fine to use them.. Unless you just want to use the ones you bought..

 

what kind of rods did you end up buying?

Edited September 16, 2010 by wigenOut-S30

[280-z.com]

The rods and crank are forged from the factory and can take some abuse. If the rods are in good shape you should be fine to use them.. Unless you just want to use the ones you bought..

 

what kind of rods did you end up buying?

 

actually, disregard my post,lol. I checked my email with my parts order and I actually just bought the bearings and not the rods. Thankfully they were in good shape,lol.

[HowlerMonkey]

Do those rods have the oil squirters that spray the bottom of the piston?