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Hurmeez

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Posts posted by Hurmeez

  1. I thought I heard somewhere that disabling direct injectors alone can cause them to melt and start leaking combustion pressure? Something about them being designed to be cooled by the fuel flowing through them and not standing up to combustion temps without. Have you ever heard anything like that or am I making it up? 

    • Like 3
  2. 12 minutes ago, yoeddynz said:

    I'll just put this video here. I imagine he's running some high compression and it has itbs etc but certainly no variable valve timing or other alien magic :)  Just pretty oldschool tuning on a fantastic base engine design.

     

    I'm sure the sweet backing track played a not insignificant part in the ET as well. 

    10 minutes ago, yoeddynz said:

    Oh and there are other cams available. I was going to get some. I can't remember who/what brand but it was via the mx6 forums I'd found them.

     

    Yeah allegedly Colt used to do regrinds, though that looks like another example of coming to the K engine party a decade or two late. I've since found a site called CatCams that offers off the shelf billet cams as well, though the way they've displayed their specs is somewhat confusing. Likely an issue in understanding on my end there but. A cousin that happened to build a K engine a year or two back reckons Kelford might have existing regrind profiles too which would be far more convenient, so I've sent them an enquiry in the meantime. 

    Beyond that I suspect you're right, getting the car moving under its own steam should be the first priority and there's a good chance I'm happy with the performance as is. 

    • Haha 1
  3. Regarding needing cam position sensors, would it not be a good idea to do that anyway to allow sequential injection/ignition? Or is sequential more of a discrete position requirement per cycle rather than a continuous reading needed for position control? 

  4. So after doing myself a mischief on my bike a week before Christmas, I've been laid up for a few weeks unable to do any meaningful work. Instead, I've been reading old threads and day dreaming a bit. 

    VVT is very alluring. When it comes to NA optimisation, it looks very valuable in terms of getting the most out of otherwise an otherwise limited platform. 

    For better or worse, I decided years ago to put a Mazda V6 in my Escort. Based on Yoeddynz's Viva thread, and excellent exhaust sound videos on YouTube, it looked like a fantastic option. Of course in the seven years since then, the engines have become increasingly scarce at Zebra, and technologically even more dated. That, combined with limited aftermarket support, means if I want to get more out of it than stock, I'm going to have to do a lot of custom stuff, and ideally with low risk to the engine. I've only got one spare block and I haven't seen one at the wreckers in years. 

    So far the plan is to follow the fairly standard formula of better intake (ITBs) and exhaust (custom headers), but beyond that I'm pretty limited. No one really makes cams, so if I want to keep it NA (which I do for now) that's pretty much it. I could skim the heads to try and bump compression a bit, but that would lead to timing troubles as well. 

    Which after a bit of waffling brings me to the actual point. I'm wondering if it's worth looking into retro fitting VVT. As standard, the timing belt drives the intake cam, which in turn drives the exhaust via a fixed gear. So the options in order of effort would be as below:

    1. Modify the intake pulley to fit a vernia cam gear. No one sells them so I'd have to make my own. 

    2. Modify the intake and crank drive pulleys to fit a VVT version from a different engine. I'm thinking JZ or 4AGE or something. 

    3. Modify intake and crank drive pulleys, as well as decoupling the exhaust cam and fitting a dedicated pulley for that side too. 

    If I were to skim the head, I'd probably have to at least fit a vernia gear to the intake to correct for the shorter belt run. Options 1 and 2 of course would mean both cams are still tied together. I'm not sure what the performance implications of that would be. Option 3 comes with much greater effort, including but not limited to making an adapter to poke the exhaust cam drive out through the head, swapping to smaller cam pulleys to allow clearance, finding a longer drive belt, etc etc. 

    Granted, this is all hypothetical and mostly a thought exercise, but I wonder how useful it actually would be. Given stock cams, would it actually make any noticeable difference? I'm probably still years away from turning the key, and for all I know it'll be plenty grunty for my driving abilities as standard without further modifications. Regardless, it'd be fun as an engineering exercise either way, but I'm interested in wider opinions. 

    Of course the real answer is probably ditch the dated engine and fit a 1NZ like God intended, but I'm a firm believer in the sunk cost philosophy so let's pontificate based on the V6 for now. 

    • Like 5
  5. Just had a thought regarding your fuel rails. We have had trouble in the past at work with intricate printed fluid paths holding trapped print powder that later dislodges and causes havoc downstream. It may be less of an issue for you with the relatively large diameter internal passages, but given it's directly before the injectors without filtration, it's probably worth putting them through some kind of flush before you use them.
    We've used a modified water blaster to get the flow velocity required through small diameter pathways in the past, but that's probably a bit overkill for you.
    We've also used a vibrating flush setup for larger stuff. I was thinking about making a similar sketchy setup to mount to an orbital sander and flush it with tap water for some potential printing you've inspired me to consider.
    I'm sure you've thought about this stuff before, but just figured it might be useful to share some of my experiences nonetheless.

    • Like 6
    • Thanks 1
  6. Yeah you definitely have a point about the quality of the remanufactured panels. It's especially tricky for the Mk2 Estates being a bit of a bodge job of hybrid panels between the Mk1 and Mk2 shapes meaning no one actually offers the correct panels I would have needed.

    Having said that, both outer sills are from Palmside and they're honestly not too far off. Certainly faster to fettle than brand new panels. If seems like a bit of a lottery as to which panels turn up in decent nick or not.

    I've watched a lot of panel beating YouTube since first starting on the car nearly 10 years ago. That's all I can really credit with my improved abilities. Definitely recommend the following:

    Cornfield Customs, Carter Auto Restyling, Make it Kustom, Ressurected metal shaping, Wray Schelin's Proshaper Workshop, and of course Binky (like anyone hasn't heard of that at this stage).

    Jesus maybe I can see why it's taken so long to do the car when all the channels are listed in a row like that. Less watchy more doey is probably wise.

    • Like 7
    • Thanks 1
  7. It may depend on the specific alloy used. I can't say for sure what we use at work but we do heaps of welding of printed parts with no trouble. The main thing I'd say is it seems to be less ductile and more prone to stress riser cracking than billet parts. If you account for that in your design though you can avoid it pretty easily. For an exhaust collector (at the risk of stating the obvious) you'd want to avoid a sharp point in the octopuses gooch where all the tubes come together. Either weld in a brace or put a substantial fillet radius in there. We make lots of something akin to a collector and ours has a brace welded in ~100mm from the gooch.

    I'd also make the actual weld locations oversized in the printed blank and machine them to final size/squareness with your dad's cnc if you can. Makes for a much nicer weld.

    • Like 2
    • Thanks 3
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