So a mate came around today for me to weld up a suspension bracket on his Landcruiser, and while he was sorting out the suspension i was just pottering about in the garage. After cleaning up I turned to the car and decided to start getting it ready for the engine to be pulled, thinking it was going to be next weekend.
Got bored yesterday while waiting for parts to arrive, so instead of tidying the garage ahead of the engine swap, i welded in the reinforcement plates to the subframe:
So the MX5 is the first turbo install I have done where its not factory replacement or completely and entirely compromised by packaging, and i generally have a reasonable amount of time on my hands to get little things sorted (yay for no race schedule).
On all the previous cars (even the factory stuff) the water ports have been relatively horizontal, and I have followed suit for other turbo conversions.
However, reading this Garrett whitepaper (mirrored on GCG) [url]https://gcg.com.au/component/rsticketspro/view-article/18-water-cooled-turbos-they-need-water[/url]
they suggest a 20° clock with the inlet down and the outlet up. But also recommend an uphill pipe from the outlet to somewhere else in the engine to enable thermal siphoning after shutdown.
[img]http://gcg.com.au/images/water_p7.jpg[/img]
On the MX5 this is a problem, as the high pressure inlet sources for the turbo are all in the head, and higher than the turbo. Conversely, all the return locations are low in the block or the mixer.
Originally i was planning on just running the high pressure side out of the thermostat spacer at the back of the head, where the heater core comes out. Or as another guy down here has done, inline with the heater core:
[img]https://i.imgur.com/w2TPhkc.jpg[/img]
But that puts the inlet side at 20° elevated, rather than on a decline, and from this graph is more than somewhat undesirable:
[img]http://gcg.com.au/images/water_p8.jpg[/img]
How much am I overthinking this? Just put it in horizontal and leave it be?
Started working out a place for the intercooler and oil cooler, and I think it will end up with them stacked in front of the radiator. A little less than ideal, but nowhere else really works for packaging.
Used it as an opportunity to practice more on the TIG:
Typical that just after I pick up the block i come down sick and am out of action for a week or so. Crawled out of bed today and was feeling a touch better, so started pottering around building the engine.
First up was doing all the calcs for the piston/rod/pin combos:
Check bearing clearances with Plastigage… then find out that your plastigage has gone hard, and go buy ACL Flexigauge. Check bearing clearances with Flexigauge:
Subsequently realise that you cant remember aligning the rings on piston 2, and so remove that to check… thankfully i had actually done it.
CSH time: When i was in high school a kid a couple of grades above got a Datto 1200 for his birthday and proceeded to do it up, so that he could drive it to the Year 12 formal. When it came down to the wire he started it up and it was spewing smoke out the exhaust. Nevertheless he drove it to school proudly.
What went wrong? Well he was a little bit OCD with the car, and so lined up all of the piston ring gaps on the pistons…. :knock:
Taught me that you shouldnt line up piston ring gaps, even before i had built an engine.
Anyway, now waiting for replacement valve springs to come for the head, and then I should be able to screw that together and start thinking about closing up the engine.
Should be good enough to use for now, and i might see if i can source another head for some 1mm OS valves and heavier springs later on.
Need to lap them back into the head, but all my lapping compound has gone hard. So that will have to wait until i can get some more.
Had some sunny-ish weather, so i got out the pressure washer and gave the head and intake a good clean. Played tunes on the intake manifold in honour of MCM:
Started lapping the valves back into the head, decent finish for now, even if it not so shiny as the original:
Debating whether i delete it entirely. Looks like it only has one exposed end where the cam comes through, and i should just be able to remove the butterflies and pull the rod out. Then i can tap a thread in the casting and seal it up that way. Will decide another time i guess.
This seems to be the newer design of rack, with the rectangular tang end, rather than the splined setup. I have some silicon bronze filler on order and toying with just silicon bronzing it up. But if not ill just put in some side stitches in the concave reliefs with ER70S6 and add some silver solder to braze the rest together.
Then as i was pulling the car back into the garage i found out another issue with the idiotic fail of an overflow bottle:
Another month on, rolled the guards, got a wheel alignment for the rear, and started the logbooking process. Currently waiting for CAMS to get back to me on my cage certification so i can put that on the logbook application.
On the way home today i ducked past the waste transfer station to get a weight. Currently 1010kg with 3/4 tank of fuel, toolkit and spare tyre in the boot. 975kg without the stuff in the boot. Not bad given that it still has all the carpet and stuff in it, only ditched AC and door trims, plus added the frame rails and rear subframe reinforcements along with the NB diff.
Overall the NB diff and subframe make it feel a lot more planted in the rear, and it hooks up nicely now. The upgraded brake master makes the brakes feel very on point, and almost slightly touchy, but not to the point of locking up. Need to tweak front/rear bias though as it feels a little forward biased currently.
Next up is to start mocking up the IC for the turbo install so I can put in the oil cooler and thermostat ahead of time. Starting to get new quotes for the engine machine work, given the continued delays with the current shop.
Well getting the master in took embarrassingly longer than anticipated. I blame being sick. Realistically its also that i didnt give myself enough clearance around the T piece for spanner swing, and so i had to disassemble it in bay and then reassemble it within the bay
But its in now, and onto the final few things for this round. Im down a few harness eyelets, so i need to order/find those. Then its just a matter of tidying everything up and a final spanner check and some fresh fluids and its good to go.
Spurred on by Guido buying his, I finally found some time to polish the last 5% of it off. Fitted up the seat properly now, which required switching to hex head bolts for access. Getting the seat in and out is a bit of a pain, basically needing to remove the rear two seat bolts, pivot the seat forward to remove the two rear mount/chassis bolts, then remove the front bolts and out. But its doable.
Can I say too how much of a pain this style of harness strap is:
Took ages to adjust up the crotch strap and get it in the right spot.
Decided to do a gear fluids change, and found that whoever last changed the gearbag oil somehow managed to shove almost 3L into it, the 5sp takes around 1.9L… Oh well.
Gave it a bolt check and got it back down and out for a drive. Initial impressions are that the torsen hooks in nicely, as a torsen should, and the rear end feels a little more settled with the new swaybar.
Holy hell though, the exhaust is obnoxious. 2.5″ on an NA 1.6L is just bloody loud. Not overly droney, although it has a decent rasp up high, and not as loud as the AE86. But loud enough. Thats with the baffled muffler too, so i would hate to think what it would be like with the straight through.
This doesnt quite capture it, as the auto levels on the phone compensate too well, but gives an idea:
[youtube]DuvPaYXLXTU[/youtube]
Rear wheel arches need more of a roll too, the extra track width at the rear really shows:
I had a few quiet moments to tidy some stuff up in the garage in the last few days, and my bias valve finally arrived with some other fittings, so i got to get some stuff done.
Firstly, I finally fitted the water overflow bling:
Just squeezes in there, and replaced the bodgy brass fitting on top with a cheap AN one.
On the bottom i welded in an NPT bung and then squeezed in a 90deg 1/8NPT to -4AN fitting to clear the headlight motor bracket. Filled it up and hopefully it wont leak this time.
Needs the weird banjo to flare adapter for the front port because of the bubble flare fitting, but that is how they came from factory, so it looks pretty standard. Now i just have to contort myself under the dash again to button it up… another time.
