Mike's MX-7, yes its back

Chat to do with your MX5/Miata/Eunos Garage Ride(s).

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lil_mike

Mike's MX-7, yes its back

Postby lil_mike » Fri May 23, 2008 10:45 am

well, been quite a while since i was here. On the positive side the MX-7 is actually running for a change. So i guess some of you are wondering what i have been doing all this time and what stage the car is at? for those that dont know, i own a 1989 NA with a 12A-T in it. Its been an ongoing project since February last year, and is still going :cry: but i have some new photos of it and the work we did to it :D

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well it has been in and out of mechanics shops since May last year and has only come back to me last week. The total repair bill so far has accumulated to nearly $13,000. Now, for that we basically reconstructed the entire driveline and remounted everything including the engine. so i'll start from the beginning.

Engine:
This is where the main problem was. The engine itself sat in the bay on an angle. Around 8 degrees off if i remember correctly. So everything that connected to the engine was point down towards the ground by 8 degrees, including gearbox and tailshaft. By now i think you can see where this is going. The reason that diff snapped was because the whole assembly had been forced in there (back when it had the s6 g'box and 1.6 diff) and was putting a tremendous amount of pressure on both the gearbox, tailshaft and diff. i still have the diff gears at home with one whole side missing from it.

So what we had to do was remove the engine and remount it so that everything would actually align up properly. This was not as easy as it seemed. If you have a look at the engine photos you'll see some burn marks on the left side next to the turbo housing. This was because when the engine was in there originally they just put it in as far as they could go and left it at that, a \"she'll be right\" job if you will. not the case. we had to replace the exhaust headers as the turbo would hit the chassis and no one likes the smell of burnt paint in their car. So with the turbo sitting slightly higher and further forward came the next issue, the sump. The steering comun was in the way of the sump when it was lowered down so a custom one had to be made to go around this. I thought about going dry sump, but the price fiugures quickly dismissed that idea.

While we had the engine out of the car it was checked over. I think we replaced a fair amount of hoses, wires and other miscellaneous items that were torn, shredded, cut or damaged in some way. The engine itself was leaking a number of different fluids out of different holes as well. Lastly it needed new mounts to sit it lower and further back in the engine bay. The total distance lowered was about 6 inches and moved back about two or three so it is quite a dramatic change. lower centre of gravity now thoug so cant complain too much :lol: but after that it was put aside until the gearbox was ready.
Last edited by lil_mike on Mon Jun 09, 2008 11:21 am, edited 2 times in total.

lil_mike

part 2

Postby lil_mike » Fri May 23, 2008 10:54 am

Driveline:
Now when i had it origianlly it had the s6 rx-7 one in there. Bad idea. First of all, its too big to fit. whoever put it in there to start with obviously cant see very well as the gearbox is larger than the transmission tunnel. but again, it was crammed in there. Now, the man who was doing all this work was actually doing a 13B renesis into his own car so he knew exactly what to do. A brand new gearbox was needed, and not just any gearbox but one that could cope with the amount of power we'll be making.

We had a look into many options including the 6 speed mx-5 box (which is identical on the inside to the rx-8 one) but none would live long enough, they were designed for less power. Then he approached me about an idea he had. the minute i saw his name on my phone i had a bad feeling. He planned to take a normal mx-5 housing and stuff it full of rx-7 gears. A normal NA 5 speed and a Series 3 rx-7 (turbo model of course) wre purchased. at least this way it will all bolt up with the PPF and diff and still have enough strength not to die when i put my foot down. time for more custom work it seemed :cry: I've gotta say though, i was thoroughly impressed. Within about two to three weeks he had already finished it and was working on the bellhousing. Tailshaft was sourced from an NB and a 7 inch 3.9 Torsen II was placed at the rear with new half shafts as well. Finally the driveline was complete and it all bolted up without any problems. then came mounting it all in the car.

Since he had already done a test fit on his own car with a similar setup we predicted no major crap ups. It all went in smoothly and sat perfectly neat and tidy. Obviously new mounts were needed for engine accessories such as the W2A intercooler, a few pumps and little bits here and there. Once all of it was back together he gave it a quick tune to fix the idling problems I'd been having.

and the final result......

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I know that the under shot doesnt show much but the car is ridiculously low and i cant get most jacks under it :lol: so all that we have left to do on it is get it engineered (coming out tomorrow morning to do mod plate, thanks boags for Pauls number :mrgreen: ), registered and tuned (booked in for two weeks time with Rotary Motorsport).

One thing i must say is thank you to Tony from Mr Rotary for all his hard work and time (even though i paid him for it). His workmanship is excellent and professional, despite his workshop being located behind his house :lol: If anyone needs any work done in Brisbane i thoroughly recommend going to see him. The invoice i received from him was a summary and it was still three pages long!!! that just goes to show how much work was actually put into this. Also to the guys at Driveline services at Brendale for trying their best. They couldnt solve the problem but they still gave it a go.

Mike

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SKYHI
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Postby SKYHI » Fri May 23, 2008 11:02 am

Always interested to see some of the engineering work that goes into these projects. Keep us updated with a dyno graph when it's done.

Paul.

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Alex
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Postby Alex » Fri May 23, 2008 12:53 pm

interesting gearbox solution, must say I haven't heard of it done like that before
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Postby silvermx5 » Sat May 24, 2008 1:47 am

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Last edited by silvermx5 on Sat Oct 31, 2009 3:48 pm, edited 1 time in total.

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Sean
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Re:

Postby Sean » Sun May 25, 2008 4:49 am

SM wrote:interesting gearbox solution, must say I haven't heard of it done like that before


I'm sure my old car has a S2 turbo gearset inside an MX5 5 speed casing. maybe ony 1-3 from the RX7, can't remcall.
When results speak for themselves - don't interrupt.

fundies

Postby fundies » Sun May 25, 2008 5:44 pm

Just noticed how close the turbo housing is to the top radiator hose. No melted rubber :shock:

lil_mike

Postby lil_mike » Mon May 26, 2008 9:29 am

pm has been sent silvermx5, i've been thinking of getting rid of them since they are destroying the guards.

there is more space between the housing and the hoses, dont worry. just a bad angle.

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Postby Lucky_Luke » Fri Jun 06, 2008 3:12 pm

Now now Duj..

Just for comparison though this is pretty much the original engine bay (from Dujs original Ad)

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Good to see it back on the road.. gotta give her a wipe though.. she looks so sweet when clean! :D

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L.

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Postby Administrator » Mon Jun 09, 2008 12:49 pm

I said it was finished, and it is now. Once again I have removed messages from you and duj.

Please now finish it or you will both be banned!

Back to the whole fun way we use a forum and the MX5 :mrgreen:
Following in Bob's foot steps

lil_mike

Postby lil_mike » Tue Jun 10, 2008 8:19 am

i thought those comments from us were actually quite civilised for a change?

lil_mike

Postby lil_mike » Wed Jun 11, 2008 8:33 am

either way, i updated the pictures with the new ones.

Adam_NAclubman
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Postby Adam_NAclubman » Wed Jun 11, 2008 7:22 pm

Still on SA rego? I thought you drove it for a while after you got it?

lil_mike

Re:

Postby lil_mike » Wed Jun 11, 2008 8:30 pm

Adam_NAclubman wrote:Still on SA rego? I thought you drove it for a while after you got it?

yes i did, but it was rego'd under qld plates then. its not rego'd in queensland at the moment though because the rego ran out about 8 months ago when it was in the workshop. had to hand the plates back in. I merely put those on so the council wouldnt try and tow it. my new qld plates will be here tomorrow as the roadworthy was done this afternoon.


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