Noisy Tappets?

[ZXatlast]

Guy and Jon, thank you very much indeed. I do appreciate your concern Guy, seriously. Obviously I gave the impression of a 19year old with his first 'proper' car, but no...

I'm not a novice, I'm a novice to Z's, but hardly my first car/engine. Before the Z there was the fully blue-printed BMW 4cyl sohc (gas-flowed, crack tested, everything oversized, 324degree monster cam, balanced to 1/1000th gram, etc., etc.) and the Rover V8. Concurrent with this Z is a Mercedes V8 and a Toyota (Le Mans homologated) 3S-GTE. God! I love that engine!! But I digress. The BMW 2002 and the Celica are going to be my extreme interpretations of street-going Le Mans racers. The Mercedes V8 and the 280ZX are more traditional, if that's the word, customising projects, the Rover P6B a little less so, but mainly in the engine.

I am more than capable of designing an engine from scratch, starting with the castings; I just can't imagine why I'd bother when there's so much brilliant stuff already out there just 'needing' the appropriate (re)design tweaks.

What I came here for, was to get ahead of the game in the sense of not falling into unexpected quirks that novices to this specific stuff might fall into. And both you have spent time and effort, with gentle consideration for a new member, and have ensured I wont. So to both of you, again, thank you very much, it is much appreciated.

If it helps to understand my approach, I am a Research Analyst often by profession and by 'natural bent'. So I like to gather as much data on something new before I get 'dirty up to my elbows'. As opposed to a very good mate of mine who'll jump in and tweak and pull and take apart without any research up front. He often gets stuff done quicker than I do, but he sometimes breaks a few things along the way, which he then has to fix, and that isn't my natural way.

Now, since you gentlemen have been so generous and forthcoming, perhaps I could get into a more interesting question...? I want to make the L28e 'right' so I can experience the 280ZX in its original intended form. It's about getting a sense of the car's character and a feel for the overall engineering quality and the 1979 'design intention'. This is discerned as much through the senses in the seat of my pants as it is through the logical engineering I can eye-ball.

But even now, after this short time, I can see I wont be satisfied. So I've been playing with ideas. My first thought was that with 8.3:1 compression the L28e has to be perfect for some simple but effective non-radical supercharging. I'm still researching, but the time and agro and cost involved seems a bit counter productive when compared to another option that seems readily available; more or less.

OK, the first thing is to point out is that I acknowledge the 'boulevard cruiser' and 'soft GT' design of the 280ZX. That is exactly what I like about it and why I wanted it and what I want to retain. I don't have an intention of turning this into my third interpretation of a Le Mans street-legal racer. I want to fill that GT-flavoured space with this 280ZX, I don't have another car that does. The limousine-sized Mercedes is sort of on the border but it isn't the same concept really. However, I do want to take it further towards the boundary that once crossed it becomes a racer -- approach the boundary, not cross it.

Which brings us, perhaps, to the most logical, and apparently cheapest option. And that is to replace the L28e and 3-speed auto with an RB20DET and 5-speed auto. Now, all that background was to bring us to this question: So far I have gotten the (hopefully true) impression that unbolting the L28e and 3-speed and then bolting in an RB20DET and 5-speed is a relatively straight forward process. I'm not talking about the engineering required to make it all work, these things I understand already, and what I don't, I'll find out. What I'm asking you about is the physical fit. Apart from reworking the positions of ancillary components, in terms of specifically the engine lump and attached box, is it an easy refit? Apparently, even the tail/propeller shaft bolts straight up, I'm told. But, I'm asking you guys for confirmation, or not, as the case may be.

The ultimate point of this research question is that if I have to cut and weld in a chassis to make it fit (I'm sure that isn't needed, that was a worst case conceptual example), then obviously I'd go looking for the next best option. I'd like to stick with Nissan rather than the apparently common Chevy small block, which also, apparently, slips in easily. Someone else's engine makes it not a Nissan anymore, and I do want to retain the Datsun/Nissan flavour, so the RB20DET is my current favourite.

Oh! One more thing, if I may? Do you guys know how big a wheel tyre combination I can fit and with what offsets and still fit within the standard guards? I can fiddle and find out, but it strikes me that this is stuff you guys would know off the top of your heads.

AND... another one, but more engineering critical: Can I re-torque the head bolts to the assembly specs with the engine hot? Or do I have to leave it to cool down first? I've never worked with hot engines for these processes in the way the factory manual for the L28 sometimes specifies; the 'Euro gear' I'm into is always specified cold.

OK, that's probably a big enough mail for now, and on the assumption that you're still reading this, thank you for that too.

All the best,

Steve

[jmortensen]

If you're wanting to keep the L28, I would suggest turbocharging rather than supercharging. I think the 280ZX Turbo was available worldwide. If not, you could pretty easily import an exhaust manifold from Japan or the US and get it done that way.

If you were going to go with an RB, why not the RB25 or 26? My understanding is that the oil pan is about the biggest issue with that swap, but you can find a lot more info over at hybridz.org on both the RB and L28ET. Wheels/tires info at hybridz.org as well. Search first, ask questions later.

As far as the head bolts, I've never seen a hot torque spec, so I'd do them cold.

[ZXatlast]

Thank you Sir, for that, very much.