Stripped the spare engine, long story short, BMW pistons/rods are rubbish, Honda ones aren’t, the new engine is getting Honda K24 pistons and Maxspeeding rods. The crank has been balanced and matched to the lightweight flywheel. BMW engines aren’t balanced at all, just thrown together, which is why M44 are described as lumpy. I’ll put the full details in my M44 modifying thread when I get the time.
I have an amr500 supercharger, possibly converting it to electric drive, that’s long term, more on that when/if I get it to work. ( And if I’m still alive, -.-. that’s not a joke.) That’s back burner’d until I build the new engine, there’s quite a bit work involved in that.
I looked at converting the manifold flange using V10 throttle bodies, it could be done simply by stacking some alloy plate but I was worried the throttle bore was a little excessive since I can’t find the diesel crank required to get over 2L. ( Not in the UK, though I can get one from Lithuania if I part with £450+ carriage + taxes . . Err, No)
So I tried Alfa Dellorto’s. That would also work by stacking, but it was going to be a lot bulkier than I’d like. The throttle linkage was going to be a right pain too since they’re off an opposed engine.
At that point a set of 40mm short Jenvey appeared on the bay, with long carbon ram pipes, at a ‘those can’t possibly be that cheap’ price. But they were. For once it all came together perfectly, as
www.dbilas.com had an offer on an M44 manifold at the time. Thanks for that. End cutter in the drill press to convert four of the studs to bolts to match the Jenvey, job done.
They’re so short there’s no way to run studs both sides. I may polish and anodise the manifold for a laugh. Need to make a back plate ( which has to have a cutout to clear the linkage, again, because they’re so short), and an airbox. The airbox/plenum is just moulding, I can do that sort of stuff in my sleep. Just have to build it capable of withstanding forced induction, in case I live long enough to go that route, pointless moulding that twice. Moulding is fairly simple if you think about it a bit, follow some basic principles and put split lines where you have undercuts. The thing that gets most people in trouble is your buck, the surface finish must be perfect. Even a tiny little pinhole, or scratch, never mind anything else, transfers to the mould, which transfers to your part, which you then have to fix. Fine if it’s being painted, though it’s just extra work, not so much if it’s not. You’ll often hear “ takes as long to make a bad mould, as a good one”. That’s quite funny really, it only comes from people who have never actually made a buck, a mould, then a useable part from that mould. It is I suppose technically true if only counting the actual mould construction time, but poor quality parts are much more time consuming to fix than a decent buck to mould from in the first place.
A friend asked in early ‘25 if I could make him hardtop brackets, so dug out my old patterns and had some plasma cut locally (Inveralmond, Perth). I won’t be using those folk again though, most abysmal plasma cutting I’ve ever seen. Worse , I didn’t notice for weeks, mix of busy and not feeling great ( I was on beta blockers, bp meds and arterial dilators at the time, fine sitting down, awful standing up). Anyway, welded a couple up and we quickly found the little alloy turrets from Ali express/ebay/SCAM DON’T CLICK don’t stay locked if a Z3 goes up a farm track daily. The turrets need trimmed anyway if the brackets are made in original 5mm steel, I suspect if we’d dropped to more available 4mm they wouldn’t. But I expect BMW did FEA and used 5mm for a reason. The turrets are actually for e36/46 Cabrio, no-one makes the smaller Z3 specific turrets, and we surmise it’s the different lubricity of the alloy V steel originals that causes the problem. We made four sets, it was supposed to be ten so we could put them out Really Cheap, but most of the brackets were unusable. Another long story short, they’re now each being trialed on my mates Z up and down his farm track, which isn’t local, for a few weeks each. And modified until they stay locked, it’s only minor filing and we’re pretty sure most cars would be fine, it’s just paranoia. But, not selling anything that’s not 100%, even cheaply just to get rid of them, we certainly won’t break even, . . they have to be right. In any event that’s all been delayed by various things, distance/work/family/illness/weather etc. inc 6 foot snow drifts at his place. With his hardtop coming off now he’s not snowed in it’ll be further delayed.
Off the last of the active drugs from the end of ‘25 with no ill effects, I no longer have to drink 2L by 10am, or, have a quadruple espresso to get my blood pressure high enough to climb stairs at work. Decaff, which I’m supposed to drink is awful, I now understand why all the dacaff’ers dilute it with lots of milk, sugar, syrups, etc, decaff dishwater is not a patch on black Yirgacheffe.
Speaking with a different cardiologist in January I received “since you don’t need the drugs and have no chest pain, just go and do what you want”. So I fully intend to. I can still peg out at any time, but F** it. A little to and fro with MUK and I now have a Competition Licence, Woo Hoo. I hope to get at least 3-4 Sprints or Hillclimbs in this year, unlikely to be in the Z3 though, I think I’d rather just wait until I have the new engine built.
First off was junking the 14kg of yacht ballast from the rear bumper, I have no need of that. I want to revert to fitting the sill stands I never got round to reselling, which necessitates a center rear jack point, easiest way to do that is a 2” receiver that can double up as a cargo carrier. My little ali jack will reach the diff, but I’ll be there all day jacking the thing up, there’s no travel on the handle because the bumper gets it the way.
Why do I need a cargo carrier? To carry wheels. I don’t have a car trailer, or something capable of towing said trailer with a Z3 on it. My V5 has no towing capacity listed, so I can’t legally tow a trailer with wheels in it. Would it matter? Would I be stopped? A car with a cage, number panels and full harness seats, of course it’ll be stopped. Been there, done that. So, 60x40 dimpled box incoming. (Except it’s not dimpled as the hydraulic pump failed. ) 5mm plate horseshoe inserts, some angle, replace the 8mm bolts with 10mm, 12mm plate for the drop bar, mig and tig welded, 12mm bolts through the bar, plate and bulkhead, with crush sleeves, 4mm angle reinforcement for the bulkhead and boot floor inside, welded, and a 12mm bolt into 4mm u channel welded to the plate. 10.9 fasteners for the receiver and boot floor. It’s not going to fall off, or distort, I can bounce on 50mm bar. I have an insert for a hi- lift, another for my ali “Race” jack, and started an insert for a cargo carrier to carry four wheels. Yes, I could carry my great big floor jack and use the diff, but it’s too heavy and bulky. Why the reflective tape? To try and prevent brainless idiots, i.e. Me, definitely ME, walking into it.
The sill stands have 25mm pins, they insert into 25mm i.d. thick wall seamless tube. To plan those out I made Q&D fibreglass forms of the sill corners. Why? Because 2 layers of cured glass fabric is translucent, it’s easier to plan out where the tube will insert into the inner sill. That makes it easy to figure out where reinforcements need to go, and to put an accurate hole on the steel cover sill so the end result is neat. I have a pair of brand new sills, but I’ll rescue the old one I have, the one I bought from Rennie @bmwspares and use those in the first instance.
That idea quickly went tits up, worked at the rear, BUT, the inner sill at the front doesn’t extend far enough to hit the flat point on the outer sill. The tube is going to exit on the slope of the sill and looks positively unsightly. Worse, I hit a reinforcement inside the sill, so I need to relocate 8mm higher. I’m contemplating cutting the end off the sill so I can weld the tube to the reinforcement panel, repairing the sill end and reprofiling the outer sill so the tube exits on flat metal. It may look weird. Fun and games.
So at least one good thing came from the chest pains. Also told friends I’m not doing favours for the foreseeable, can’t work for beer anyway 
