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Just another MX250 build! (Pic heavy!)

23 Apr 2020, 8:42am
Happy that the cylinders and mating surface were as good as they were going to get - it was time to remount the two.

Bottom end ready to go;


Head Gasket in place;


And head fit on and torqued down. I torqued it in 3 goes, 20, 40 then 60 ft-lbs.
23 Apr 2020, 9:26am
Nice work. I'll pinch that tip about using WD40 and a scotchbrite scourer to clean up the pistons and combustion chambers. I've previously used Barbecue cleaner but it didn't do the job as well as your approach.
23 Apr 2020, 9:47am
So continuing the reassembly! Everything seemed to take forever to do, mainly because basically every single part I took off the car was either filthy, corroded, rusty or generally looking worn. So I would wire wheel back each item and then treat/paint accordingly.

This started with me refitting the lifters, cam shafts and cam gears. Cam gears were cleaned and repainted. For anyone doing this - the cam shaft has a small "dowel" on the end mounting end of the shaft - this fits into one of three locations on the cam gear - for the intake side you put it so that it's on the "line" that points to the "I". On the exhaust, on the line that points to the "E".

I then also test fitted all the new coolant pipes.





The next job was putting the Cam belt on - I bought all new belts from Euro Car parts for an absolute steal! They're still on offer now - I got 60% off with their easter code, and the cam belt and each aux belt ended up costing me £6 each! This was a Continental cam belt too not some cheapo.

So fitting the cam belt, you ensure Cylinder 1 is at TDC - This should always be the case when the small notch on the crank gear (which in turns is in line with the pin in the crack shaft) is at 12oclock, or lined up with the small arrow on the case as shown here;



That's the crack aligned, now you need to line up the cam shafts. There are two ways to align these, firstly they should have the small timing mark next to the "I" on intake and the "E" on exhaust pointing directly upwards to 12oclock.


Secondly there are two "aligning" marks on the black cover that sits behind the cam gears. The timing marks next to the "E" on the intake and the "I" on the exhaust should be directly in line with those marks.


These can take some pressure to keep in place, so I found it easiest to put an adjustable spanner on each camshaft, and used that to turn the cams to the correct position, then I clamped them together using a small quick-grip to keep them in place while I put the belt on.

So personally I find the easiest way on the mx5 is to fit the belt around the bottom first, then keeping it tight I pull it around the exhaust camshaft then over the intake and down and tension it up. There should be exactly 19 teeth between the two marks on the cams, and when under tension the intake cam should look like its leaning very slightly towards the exhaust cam.

So with the cam belt on and tensioned up, i did a couple of full revolutions of the engine using a 21mm socket and a long bar to turn it over 4 times, just to make sure everything was still in line and nothing hap slipped etc. All good, so I cleaned and popped the covers back on and test fit the other two belts.

23 Apr 2020, 9:58am
Next I moved on to the intake and cam cover - I knew I wanted these in a nice anthracite colour - so I found one that would work and got to spraying. Again, these took bloody ages to clean up with a wire wheel and lots of elbow grease, but I got there eventually and got them sprayed.




(By this point I had also refurbed the Brake master in the background of the photo - unfortunately I didn't get any pictures - but to remove it there are 4 12mm bolts tucked right up under the dash - I had to remove the seat, lie on my back on the floor inside the car and reach up with an extension to get them - then there's a small circlip on a rod that connects the brake servo to the pedal.

I then cleaned it up, wire wheeled the aluminium to a nice shine, and cleaned and repainted the black brake booster.

Next was fitting the injectors. Mine were abit.. messy. Someone had previously tried to "fix" the injectors leaking by adding 3 additional orings to each seat *DOH*

So I just bought some 2nd hand ones on ebay that were complete, tidied them up and installed.



Fuel rail again, tidied up, repainted and put into place, then bolted in.




Finally, the radiator was toast - it looked like it had been through a flock of birds, THEN a gravel track, THEN a field. So I bought a new one on ebay for the incredibly good price of £33! and got it fit.




Finally the bay was finished for now (I will be adding a turbo soon, so the intake and exhaust are TBC.

23 Apr 2020, 10:42am
Mister Towed wrote:
Nice work. I'll pinch that tip about using WD40 and a scotchbrite scourer to clean up the pistons and combustion chambers. I've previously used Barbecue cleaner but it didn't do the job as well as your approach.


They say acetone eats through carbon really quickly, but to be honest I'd worry about the seals if I used that, atleast I know WD40 isn't corrosive, just a good aid for cleaning!
23 Apr 2020, 12:01pm
I bought two wheels to trial - I knew these would definately be fine on the back (actually they're probably too narrow still) so I got the two for now, then I could try them on the front and see if they fit - then order the front two based on that knowledge.

So here are the wheels - 16x8 et -20 Japan Racing JR19's. I have bought a test tyre - a Michelin Primacy 3 in 225x60 so nice and big sidewall!




I pulled the car out of the garage and started playing around with heights etc, then took a bunch of photos I can spend the night photoshopping some ideas with





I knew I wanted some extra height on the back, as I much prefer the stance when the arse is lifted up - I feel like the body "squats" too much otherwise.

Ultimately, I'm in love with cars from the 60's - but taking the top spot for me is the Shelby Daytona -


So I want to add as much of the styling of that to my build as possible.

After playing around with photoshop and double checking measurements on the car it came down to the final design;



So there are some modifications to the fibreglass that are needed. Firstly - Ive always felt that the wheels people put on these are always really small, and the arches look too oversized for them most of the time. So I will be cutting the arches out to pretty much the mold line you can see on the rear arch - this works with the mx5 body behind the fibreglass, and the photoshop above shows the car correctly sized, with the wheel correctly sied on a 225x60 tyre (which is 676mm wide)

Secondly, I will be modifying the back end. Again, I love what some people have done with theirs, and Andreas's build was always my inspiration - however even his I feel the "arse" of the car looks abit low and abit BIG. So i'll be shortening the back end and making it more "vertical" - more like the Daytona.

The front will also be getting some modifications. Firstly, I will probably be losing the three vents in the front. I;m not 100% on this yet but I just feel they scream "ferrari", and I prefer the ones that don't have them such as Seanicks build.

In regards to the front grill opening, again I'm not a big fan of the circular cut out, I will likely do something more like the TVR Tuscan grill (in regards to shape)