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Modernizing engine bay and installing stronger engine


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I'm having a stroker 3.2l FI engine build to replace the stock L28 NA (1981 280ZX, 5-sp). While the engine is going to be out during the swap, what parts should I consider ordering/or service before we install the new engine? My question is specific to things that can only be done when the engine is out, or much easier to do when engine is out. Overall the car is very clean, original with only 16,000 miles on, so not a lot of wear and tear. But I accept things deteriorate, rust-crack-harden, just by age. The new engine comes with certain new components such as a water pump, harmonic balancer, oil pump, and a header.

1. Is it advisable to put fresh engine mounts in? The current mounts show no signs of cracks. But they are 29 years old and the high power engine may potentially put a lot more strain on them.

2. Is it also advisable to upgrade the transmission mount or U joints at this stage?

3. New engine does not come with a clutch pulley for the fan. So, instead of putting the old fan mechanism back on, should I install electric fans? On the outside the stock radiator looks brand new. However since the radiator is going to be pulled out, should I really replace it with a modern aluminum style radiator, or the JTR radiator package from a Chevy? The higher HP motor will create more heat, but I’ve been told the stock radiator should be fine for normal street driving. Perhaps install an auxiliary electric fan to help push air flow at low speeds?

4. I recently had a new Daikin Excedy clutch kit (cover, disk, release bearing) installed specific for 2+2 model, new master cylinder, along with a stock lightened (18lbs) flywheel. Mechanic told me the original flywheel bolts still looked good. The new engine will have substantially more torque. This will be the second time that we will install the flywheel. Is it advisable to get new/stronger bolts? Should I upgrade the clutch to stage 1 organic type?

5. Are there any steering components that are easier to work on when the engine is out, or are they mostly accessible from bottom up? Forgive my lack of mechanical experience here. I can confirm car has power Rack and Pinion. No problems here, but I don’t think the fluid has ever been replaced. There is no visible rust, but I will be doing rust prevention touch up to the cross member.

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My expectation is around 250HP at crank. I'm using a fairly well known racing engine builder in SoCal. He is more optimistic and based on his past experiences expect around 300HP. I've asked for the engine to be tuned for street use. And I'll need to run with stock emmission controls (PCV, CAT, O2, etc). Aftermarket ECU (Adaptronix e420c). Engine will use core from stock 1981 engine (F54 block P79 head, FI manifold). We'll see...

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If you are spending that much for a full rebuilt stroker motor, I'd go ahead and replace everything I possibly could on the engine and around it. New plugs & plug wires, new distributor cap & rotor, new engine & transmission mounts or reinforce them with urethane, new fuel lines, new fuel filter, refurbish/clean/benchmark the injectors (if its not carbed), clean the A/F meter with MAF cleaner, clean the inside of the throttle body or upgrade to a larger one, new thermostat, new heating lines, new radiator hoses, new upgraded alternator (or have the current one checked/cleaned), new/rebuilt starter. But thats just me and what I did and I didn't have too tight a budget at the time, and I hadn't been in a hurry to finish my project so I accrued the parts over a couple months.

 

I'd also flush the steering rack and put in new fluid, new grease everywhere, new boots if it needs them.

 

I'd forget about the stock clutch fan and get an electric fan kit and possibly build a shroud for it or adapt a stock 280zx plastic shroud for that stock look. Your radiator should be fine...fix any bent fins, flush it and clean it inside and out to make sure there are no leaks and if it goes bad later its not hard to replace on a Z with the engine in. If you want to refresh the look Eastwood sells thin radiator specific paint that doesn't retain heat.

 

The flywheel bolts should be fine, I haven't heard of those being a weak point and I know Tony D said he used regular L28 flywheel bolts on one of his builds. I'm not sure about the clutch, it really depends on how much power the engine is making after the rebuild...a "Stage 1" may not even be strong enough if its making enough power/torque...better to ask your builder that if he is familiar with L-series engines and has built strokers before.

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Honestly the ZX is soo clean and all orginal it belongs in a museum. The irony is I actually bought it from a museum. It was the clean original condition of the interior and body and paint that sold me on the car. Untimately I wanted a clean car that would be reliable and fun to drive. In a specific configuration: 2+2 for my son to sit in the back, and t-top since my wife wanted a convertable. It won several 3rd place trophies at car shows. In my experience on the East Coast the top places go to modified Z's. This one had everything except the peformance talk that attracts so many entusiasts. So that brought me to the decision to do the engine upgrade. A few weeks back I advertised the original engine on a few Z car forums but had no responses. So I figured either no one believes the low miles, or the L28 NA configuration is not popular, or folks may think it is cheaper to buy a high mileage engine and rebuild it. I have to sell the original unmolested engine if anyone is interested. It will break my heart to let it go, it runs like a top, but don't have the storage. Ultimately I would have liked to put the performance engine in another Z car and keep the ZX all original as collector car, but I can't afford two Z's. Hopefully the swap is actually going to maintain the overall car's value, or slightly increase it, since the performance engine is technically all new components, remains NA and uses te same block/head codes. Another goal of my project is to maintain as much of the original engine look as possible. The only visual clues of the upgrade may be the header, coils, and replacing the AFM with a modern MAF meter. And the block will be clean/painted and a clean valve cover. The work done on a stock intake manifold (porting, flowing) will hardly be noticable. The rest is internal, even the ECU upgrade.

Edited by bigbreak_2000
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Having had a 325hp NA 3L built, I think you're 250hp crank horsepower expectation is reasonable. Your engine builder's plans are probably not. The main issue you will have is fuel quality and your requirement to use the stock intake manifold.

 

As stated above, since you're going to all this expense you might as well inspect/clean/replace all the components in the engine compartment and definitely replace/upgrade all the engine ancillary components.

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Perhaps $1,000 (usd). I did a quick check on the internet, a rebuilt engine can be anything between $1,200 and $2,500. A scrapyard engine may be around $350 but then it will be stripped and you would not know the condition until you open it or have it running. The good thing about this engine is the cam tower alignment is all stock factory, same with lash pads, rocker arms, etc. This engine is a very desired combination F54 turbo block, flat top pistons and the p79 head. The p79 has a good champer and is one of the less expensive heads to modify for performance. Less than 3,000 miles ago I had the pressure tested, and it was even across all 6 cylinders. I don't exactly remember all the readings but the wet pressure was around 160. When driving the oil pressure is constantly close to 80-90 range. In the winter, on startup, I dont think I ever saw pressure readings below 50. When it is warm at idle maybe it drops to 45-50 range. I dyno checked the engine (Mustang dyno, conservative)and the wheel power came in 149lbft at 2500rpms and stayed over 140 all the way through about 5000rpms. I also had it serviced (incl valve adj) very recently. The local Datsun/Nissan service shop with over 30 years of certified technician experience can vouch for the condition of the engine. I plan to pull the engine first week of September. So the engine is still in the car if anyone cares to test drive it and see the overall condition of the donor vehicle. Location is Charlotte NC. Buyer would have to pick it up or ship at own expense. Email me if you are intested : bigbreak_2000@yahoo.com. Should move this to the classified FS section.

Edited by bigbreak_2000
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