Spot The Micra Mini
Posted 22 January 2018 - 11:41 AM
Your photos of your intake manifold reminded me of a car I saw yesterday!
Posted 22 January 2018 - 12:16 PM
Funny that! It was Spot's first time socialising with other minis.
It was a good day to test out the cooling, I've had a radiator upgrade, 2 core but more fins per inch and perforated fins. The fan still stays on a bit but I gave it some for a bit up Macquarie Pass and it held things in check, given it was still about 35 degrees at 5pm I call that a result.
Was your mini there? You can just see me in your photo I'm the hairy bloke chatting away at the side, if minis look like thier owners Spot never really had a hope....
I was actually a little nervous turning up as it was supposed to be a show and shine, but everyone was nice and as you don't see many cg13de minis in Australia kinda curious, nice day out, but hot!
Edited by fuzzy-hair-man, 22 January 2018 - 12:33 PM.
Posted 23 January 2018 - 07:22 AM
My mini was in the far corner, I was the first one in and probably stuck the sticker on your window on your way in. If you’re around for any of the other events we’ve got one on each month this year
Posted 12 February 2018 - 03:02 AM
It's probably time I did a bit of an update on what has been happening over the Christmas holidays and a bit before...
I picked up a spare engine and gearbox with ECU for $100 Australian (56 UK pounds), I've already got a spare parts motor (as it had been crashed and ripped the micra engine mounts of the gearbox and block some of which are used for my engine mounts). So what to do with this engine? Well I've never rebuilt an engine before... and I've been thinking of some cams (773's as they seemed to not compromise low end and mean no messing about with shims).
The aim for the engine was for modest gains in power say 10 to 15hp over the current 90 - 100hp, I didn't really want to go much bigger but more focus on making more power through greater efficiency.
A couple of threads on the micra forums and the owners seemed disappointed with the 773 cams on a standard compression engine so increasing the compression was in order.
The CG10 never came out in Australia and asking Nissan parts places they are unable to find them so initially I was thinking of building it with the CG13 pistons and increase the compression decking both the head and block.
I used 2mm thick solder down the spark plug holes to measure the squish zone in the head, links I'd seen had recommended running 0.038" to 0.042" of squish clearance for best detonation or knock prevention but also combustion efficiency. This meant 0.017" off the top of the block, so the engine was pulled down and sent to the machinist along with the flywheel, crank and harmonic balancer for the flywheel to be lightened and balanced. It came back a 5.7kg from the standard 8.4? they could have gone lighter but all the weight came off the outside inertia rings so the difference it makes should be pretty significant. This is mentioned as one of the best modifications by the Micra guys and the micra is 825kg vrs Spots 630kgs so I had few worries about going too light. Some ultralight flywheels go down to 3.6kg.
A couple of emails and calls to Matt Humphries and plans changed again....
Nissan parts in Australia seem very expensive and they generally seem difficult to deal with, the micra isn't common here so in many cases the parts are coming from Japan anyway so why not the UK where my cams are coming from...
Now after talking to Matt I decided to go for CG10 pistons so as to avoid having to deal with shorter timing chains, unfortunately the block had already been decked before I was able to talk to the machining company as I was concerned the compression ratio might go too high but also that even though the CG10 pistons are supposed to be the same from pin to the top of the piston some variances might eat up the clearances. Fortunately they are as close to identical as I can tell and should be fine.
Other bits I got from Matt, usual big end and crank bearings, rings (bores aren't worn), gaskets, crank pulley oil seal, rear main oil seal, sump seals and some new valve springs and valve stem oil seals.
Valves and valve seats seem ok and should be OK with some lapping.
The il that came out of the engine looked like it had not been changed for ages and came out in lumps, the only damage was a little bit of scuffing on no 4 crank journal which polished out at the machinists and was OK with the original graded bearings.
I've DIY smoothed out the head, I say smoothed as I haven't changed the shape of the ports or anything like that but rather smoothed out imperfections like casting lines and roughness so hopefully it might flow some more... 80 grit on the inlet side and up to 180 grit on the exhaust ports. I must say I was a bit nervous about taking to the head but in the end using the sanding cartridges rather than a burr it wasn't too bad and didn't take all that long, the result seems pretty good too! well from my amateur opinion, but it looks like the books and youtube videos I've been watching...
Working out the compression ratio and double checking this by measuring the head volume and the CG13DE piston dish I get 12.5:1 with the CG10 pistons and 0.017" off the block using 1.35mm as the compressed head gasket width. It's higher than I was aiming for but lower than some builds I've seen, I'm running 98 and some of those were on ordinary 91!
Matt has said they haven't got much gains from balancing pistons and rods up to about 7500rpm but I figure it's something I can do to make it smoother and nicer and all it costs is my time. The landrover engine mounts are considerably harder than the standard micra mounts so it might help limit vibration that ends up transmitted to the cab.
There's still work to be done on the head, hopefully a minimum has to come off. Then I should be able to start putting it back together.
Then I'll go through the gearbox and hopefully acquire a diff as well. Although I recently got new Yokohama A008's and wheel spin seems much reduced.
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