Biggest bore possible

[FlanymanS30]

I have a 280z with its stock 2.8 L L28. I was wondering what the biggest bore I could do to it is? And what I would have to do to make it work. (By the way im new to this)

[datzenmike]

Well the L28 has an 86mm bore. Nissan used to male them in 1mm or 87mm over size but the block is capable of at least 2mm overbore.

 

 

Hmmm haven't time right now but looking at an 89mm bore, KA pistons, L16/L24 rods.  Will work out the displacement and compression. If you can supply the cylinder head volume for your L28.

[Stoffregen Motorsports]

You can go 89mm to build a 3.0 liter. I don't remember the rod and piston combo though.

[datzenmike]

LD29 diesel crank (Maxima)... if you want to stroke it. Hard to find though.

[Stoffregen Motorsports]

You could even go diesel block and crank and build a 3.3L.

 

I built one once with a turbo, it had about 650hp at the wheels. I was closing up shop one night and decided to take it out for a quick spin. Well at around 60 mph I realized that the throttle was stuck about 2/3 open producing lots of boost. Trying to figure out the best course of action, I tried to slow the car with the brakes, well the hp just drove right through the brakes, so I finally just turned the key off. Shutting it down at pretty much full boost, the turbo shaft broke in two. I ad to limp it back to the shop. The next day I had to explain to Dave (Rebello) what happened. The silver lining was that I found the sticking throttle and not the customer.

[FlanymanS30]

That's crazy! I've been reading a lot of pages about 3.0L N42 and how to build them. I'm probably going to try and build one with my spare L28 engine. My other question is there anything else during the build I should I be careful about if I desire to single turbo it in the future after the 3.0 upgrade?

[Stoffregen Motorsports]

Well if you're going to turbo it, you're obviously going to want a forged piston with a modern ring pack. JE and Wiseco are good choices for a turbo application. Also, the lower compression can be built into the custom pistons.

[FlanymanS30]

If Im not able to turbo it right a way could i just use the stock KA pistons, then upgrade to the Forged JE pistons for the KA24 when im ready to turbo?

[Stoffregen Motorsports]

If Im not able to turbo it right a way could i just use the stock KA pistons, then upgrade to the Forged JE pistons for the KA24 when im ready to turbo?

You could, but it seems like a waste of effort. A set of pistons is generally not as expensive as one might think. They run about $150 each for custom (with rings and pins). KA pistons will cost about a third of that (with rings) but then the time to tear it down, etc. Doesn't make sense.

 

Decide now and save in the longrun.