Tips on rebuilding an 83 N/A engine?

[Mirage775]

Sorry to ask this, I know it's probably been asked a million times, but I've been searching forums all day, trying to find a decent NA rebuild topic and come up with pretty much nothing.... 

 

Anyway, I've decided not to mess with a turbo or carb rebuild....  I've decided to just beef up the NA engine.  I currently have a 82-83 Turbo block, that I have just about gotten totally disassembled.  When I get it all torn down, I'm gonna carry it to the only speed shop in town and see if it can be bored .030"?  Right now, they have my P90 head, doing a cleaning/pressure test on it.  I asked them about regrinding my cam and said they could do it, but why would I want it done and it would probably cost more than an aftermarket came....  I'm not looking to race/drag/autocross it.  I just want a nice little sports car, with a little more pep, without going turbo.  So, here's what I'm wanting info on:

 

Aftermarket cam?  No? Yes? If so, what would the specs need to be?

                                       

Polish/regrind stock cam?

 

Stock cam, no mods?

 

Pallnet fuel rail?  I want as many vacuum lines gone as possible!

 

Headers - Which ones to buy? Ceramic coated?

 

2.5" or 3" exhaust?

 

What muffler should I run?

 

Aluminum Radiator with electric fans?

 

Complete .030" (with Flat Top Pistons), Rebuild kit from zcarsource.com?

 

Aftermarket distributor/coil/etc?

 

3 angle valve job or new SS valves? 

 

New valve seals and springs?

 

Resurface Head, intake gasket side, head gasket side and valve cover side?

 

Shave head any?

 

Port/polish P90 head and OE Intake?

 

60mm 240sx TB?

 

Performance Starter?

 

Lighter Flywheel? Where to buy?

 

New Clutch/TOB/PP?  Which one?

 

CAI? Homemade or K&N?

 

Thinking about removing the AC compressor, (as the freon is gone anyway), for less engine drag? 

 

Thought about removing PS pump for less engine drag as well? 

 

 

I've redone the whole interior on her already and just finished up with a complete front/rear suspension (Urethane)/steering upgrade.  Ordered a set of Konig 16x8 wheels today with 225/50 Goodyears!  Now, I want to move to engine/trans.  I'm sorry for asking so much, but L engines are completely new to me!  I've ordered both, "How to Books", from amazon.  I know I'm asking for a lot, but I know some of you have outstanding knowledge to share on these little engines!  Thanks and again, sorry for asking so much....  Jason

 

[Xnke]

Run the stock engine if it has no issues.

 

The stock engine control computer can not handle very much at all as far as upgrades...to the point that I belive it's just not worth hot-rodding with the stock computer. It will not handle any cam worth the effort and work to install, and will not return optimal results with the cams that are "computer friendly". It does, however, do quite a fine job controlling the stock engine, with all the stock sensors, wires, vacuum lines, and injectors. Make sure all your connections are clean and tight and that everything is hooked up properly, and it'll reward you with a reliable, long-running, peppy car.

 

If your engine had good bearing clearances and low leakdown test numbers, it'll be hard to re-build the engine to the same level of build quality it was when Nissan assembled it. If it was a solid engine before you tore it apart, you quite possibly didn't need a rebuild at all, even at 100,000 miles. It's hard to get matched sets of bearing shells to set the clearances as closely as Nissan did at the factory...they're available, but not easily anymore. Piston rings, too...I have used a number of sets of ITM pistons and rings...the rings are not bad but they are softer than the Nissan rings. ITM cast pistons are quite good and I've run them up much, much higher than I should in a few builds, with no major issues.

 

Exhaust, fuel rail, all that dress-up bit will look nice, but realize that you already have a cold air intake if you're running the stock airbox, that the Hitachi/Nissan starter that came installed on your engine is the same part Tilton and other manufacturers sell today as a "performance" item, and that your stock P90 head was factory-fitted with stainless steel valves and a 3 angle valve job.

 

The stock exhaust manifold is just as good as a header on a stock or stock-ish rebuild. If it's in good shape, it's quieter and more durable than any header.

 

The 60MM KA throttle body is more to make it easy to fit a few different aftermarket engine management systems than it is for airflow...the stock engine won't see any power or performance benefit from it. The stock 50mm throttle can handle quite a lot, remember you are only feeding one cylinder at a time, and as long as the throttle can re-fill the plenum volume between intake events, then it is not a restriction.

 

In short...if you're planning to run the stock computer, run a stock engine and all the stock equipment.

[Mirage775]

Run the stock engine if it has no issues.

 

The stock engine control computer can not handle very much at all as far as upgrades...to the point that I belive it's just not worth hot-rodding with the stock computer. It will not handle any cam worth the effort and work to install, and will not return optimal results with the cams that are "computer friendly". It does, however, do quite a fine job controlling the stock engine, with all the stock sensors, wires, vacuum lines, and injectors. Make sure all your connections are clean and tight and that everything is hooked up properly, and it'll reward you with a reliable, long-running, peppy car.

 

If your engine had good bearing clearances and low leakdown test numbers, it'll be hard to re-build the engine to the same level of build quality it was when Nissan assembled it. If it was a solid engine before you tore it apart, you quite possibly didn't need a rebuild at all, even at 100,000 miles. It's hard to get matched sets of bearing shells to set the clearances as closely as Nissan did at the factory...they're available, but not easily anymore. Piston rings, too...I have used a number of sets of ITM pistons and rings...the rings are not bad but they are softer than the Nissan rings. ITM cast pistons are quite good and I've run them up much, much higher than I should in a few builds, with no major issues.

 

Exhaust, fuel rail, all that dress-up bit will look nice, but realize that you already have a cold air intake if you're running the stock airbox, that the Hitachi/Nissan starter that came installed on your engine is the same part Tilton and other manufacturers sell today as a "performance" item, and that your stock P90 head was factory-fitted with stainless steel valves and a 3 angle valve job.

 

The stock exhaust manifold is just as good as a header on a stock or stock-ish rebuild. If it's in good shape, it's quieter and more durable than any header.

 

The 60MM KA throttle body is more to make it easy to fit a few different aftermarket engine management systems than it is for airflow...the stock engine won't see any power or performance benefit from it. The stock 50mm throttle can handle quite a lot, remember you are only feeding one cylinder at a time, and as long as the throttle can re-fill the plenum volume between intake events, then it is not a restriction.

 

In short...if you're planning to run the stock computer, run a stock engine and all the stock equipment.

 

WOW!  Thanks for the info.  The engine I've been tearing down was a turbo engine that had almost 300K miles on it!  The NA, that runs absolutely fine, in my 83 only has about 120K miles on it.  It doesn't burn oil/smoke or anything.  It just has a little valve noise, but if I get the P90 head worked, I'll put it on my engine.  I have an oil leak somewhere on my NA engine, that's why I was gonna pull it and replace the front/rear seals and pan gasket.  I do have a turbo ECM, if that would help with any performance upgrades?

[Tony D]

Quit thinking inches, also...

Std overbore is 0.020" (0,5 mm) not 0.030"

After that is 0.040" (1.0mm)

 

I agree on the comments above, chances are anything you get today won't equal the quality of what you took out. The rings were designed to be the wear component in the engine. Chances are the engine won't need over boring....but the later engine blocks were softer so who's to say. Be advised it's not uncommon to see engines with well over 250,000 miles still not worn out to the high end of new assembly tolerance, much less bore or taper wear limit for service replacement!

 

My engine went in the car with 225,000 on it, I've put more than 110,000 on it since. Still has 185 across the board as compression goes...and weak oil control rings that eat oil at 1 l per 1,000 - 1,500 miles. So in another 100K of driving, worst case...I buy 100 quarts of extra oil. Hmmmm... $200, or tear it down and spend $3,200+ doing it right?

 

My only digression comes from using an aftermarket EMS on Turbo Cars. The drivability is better than the ECCS, and Megasquirt is cheap. It lets you do what you want later on, unlike the stock Bosch Licensed box.

Edited September 8, 2014 by Tony D