Project Domes shonky autos - Manta 400 - More progress-axle and some engine work

[Matty]

4 hours ago, GingerNuttz said:

That's me finished.  

Dome has to fit the wings and valance once the new engine is in and he's finished the mechanical  stuff.

This should have been finished over a year ago but some retard decided to take an overdose then slit his wrists when he hadn't died, wild times 😂

Volvo next before Saabnut comes looking for me.

 

That is just unreal. Wow. Id love to give you something to do for me but i couldnt afford you 😁

[dome]

58 minutes ago, GingerNuttz said:

I don't even have pictures of it when it came down. 

I can remember it was blue and was full of holes 😂

My two memories of it when I first started stripping it down was that I could stand in the kitchen of the old house and look down through the windscreen of the Manta and see the driveway through where the floor used to be, also when working inside it tools that I put down inside the Manta would often end up outside it on the ground 🤣

[dome]

One owner from new😳

[GingerNuttz]

Oh aye it was worse than I remember, I must have blocked it all out 😂

Only rotten bit I can remember doing is the roof, that was a mission and a half.

[Supernaut]

My 996 is less rusty and has less explodey brakes.

[jim89]

2 hours ago, dome said:

One owner from new😳

The still visible bits look original at least 😬👍🏻

[cort16]

4 hours ago, dome said:

MOT exempt m9

Not once I submit my report to the ministry 😀

[dome]

Yesterday was a good day 😎

 

 

[Supernaut]

[hairnet]

[Saabnut]

On 05/12/2025 at 15:37, GingerNuttz said:

Volvo next before Saabnut comes looking for me.

 

Great news but you know the reuirements about deadlines - they have not changed!

Have a great Christmas and I will pop down to see you in the new year.

[GingerNuttz]

14 minutes ago, Saabnut said:

 

Great news but you know the reuirements about deadlines - they have not changed!

Have a great Christmas and I will pop down to see you in the new year.

I know mate but I'm still gonna get tore in and get things finished.

 

[dome]

Ok, guess I'd better get some work done on this Manta then?

Back axle is the first thing. This is from a Volvo 940(I think). It's got a 4 link kit fitted. The original plan was to use Coilovers but that would mean a lot of strengthening required around the strut tops on the shell so instead we (well @GingerNuttz obvs) cut the spring platforms off the Manta axle and welded them to the Volvo axle. After the 4 link has been fitted. So it's now 6 link, actually 7 when the panhard rod is fitted🤣

Here it is dropped off 

And today I stripped it down to replace all the bearings and so I can get an LSD ordered up.

Amazingly it all came apart easily. All bearings seem decent but it's apart now so I'll replace them all along with the seals. 

I've started cleaning it up and will get some paint on it soon.

It turns out the diff ratio on this one is 3.54:1

The MX5 originally had 4.1:1 so as it is it'd be too high geared. I'll need to try and find a 4.1:1 or similar crown wheel and pinion to fit to this to lower the gearing. 

 

 

[Dyslexic Viking]

If I remember correctly, the 1982 Volvo 244DL 2.1 4 speed I owned had 4.10 gearing.

[Dyslexic Viking]

Rwd Volvos are popular in motorsport in Scandinavia, so there are several that is selling diff parts if you want new but are unsure if they ship to the UK.

Here are two I found.

https://tenacimotorsport.com/product/gear-ratio-4-10-volvo-1031-voc-rally-volvo-original-cup/

https://www.engsmp.com/butikk/understell-2/utveksling  they have English text also.

[dome]

46 minutes ago, Dyslexic Viking said:

Rwd Volvos are popular in motorsport in Scandinavia, so there are several that is selling diff parts if you want new but are unsure if they ship to the UK.

Here are two I found.

https://tenacimotorsport.com/product/gear-ratio-4-10-volvo-1031-voc-rally-volvo-original-cup/

https://www.engsmp.com/butikk/understell-2/utveksling  they have English text also.

That's brilliant, thank you! I guess I need to work out if I have a 1030 or 1031 axle first and I can take it from there. 

[dome]

Been having a little play with a gearing calculator to try and work out what I need. 

I've inputted the MX5s gear ratios and am using a 245/40 r15 tyre for calculation-this seems like it will fill the arches nicely

Ideally I want something that won't be too much of a pain on a motorway. I did think that the Volvos 3.54:1 ration would be too high but it actually looks like it might be ideal.

In each of these I've highlighted 70mph as a cruising speed to see what the RPMs will be like in top gear.

4.1 was what I thought I'd want but 60.9mph at 3000RPM will be a bit busy

 

3.9 Is a another option for final drive, 64mph is a bit better

But here's where I'd be with the current 3.54:1 rear end that I have

That's actually not bad and would save the expense of a new Crown Wheel and Pinion to change the ratio. Always a good thing!

With all this in mind I've ordered up one of these things so I can confirm what size of wheel and tire I can get away with.

 

I want tarmac rally car stance but not stupidly low, also some tire sidewall would be good. 245/50 15 seems to be more for track tires orientated tires too so I'll see where I end up. There'll be plenty more head scratching before I decide I'm sure😶

 

[captain_70s]

Your spreadsheet has 40 profile tyres rather than 50, just saying!

[dome]

7 hours ago, captain_70s said:

Your spreadsheet has 40 profile tyres rather than 50, just saying!

Well spotted! It was a typo by me in the text putting 50, 245/40r15 is the size I'm looking at.

[dome]

Got a bit done in this over the Christmas break.

Axle stripped down, rust treated and painted.

New LSD purchased for OMGSKIDZYO.

I've swapped the crown wheel over from the existing diff, decided to go with the existing ratio.

Ordered up a full set of bearings for it and some seals as it'd be daft not to. Rockauto FTW.

Other than that I trial fitted the exhaust manifold which I knew doesn't fit, it won't clear the steering column.

It's a chunky 4-1 manifold which is very nice but no use to me sadly as it's pretty chunky where it runs down exactly where my steering column needs to be. 

It looks like this.

I've taken a punt on a different style of aftermarket MX5 manifold like this to see if it'll fit.

Not as pretty sadly but needs must. I've found a second hand one cheap so I can sell it on if it doesn't fit, just waiting for it to arrive. 

Finally for now I picked up the bonnet from @GingerNuttz as there wasn't space to collect it when I brought the car home. 

It's got a home in the man cave for now to keep it out of the way. The wings and front panel will be going up in the loft before I start getting stuck into the front end. My other half doesn't know this yet🫣

[dome]

New* manifold arrived.

And.

It'll fit, and I'll be able to steer!

The flange needs some more grinding which is why it's not mounted properly but I'm confident this will work.

Another major headache out of the way and a pile of money saved-i dread to think how much a custom manifold would cost😳

Plus the old one is a quality bit of kit and should sell for decent money 👍

 

[dome]

Things slowed down over the last couple of months, motivation was low as the weather was shite, even though I have a heater in the garage I couldn't be arsed. 

Partly the thought of scraping off the old underseal to redo it and partly that the thought of fitting the new diff to the axle involved lots of fucking about setting up to set backlash and the like.

I did the right thing and took the axle to the place that did the Jeeps rear diff and got that back a few weeks ago. That meant I could get everything assembled, if only to take a picture of it looking shiny. 

New, longer studs fitted to the half shafts to let me run chunky wheels.

New seals throughout and new bearings fitted to the diff and shafts.

New backing plates, discs and calipers too.

And here we are.

I might try and polish up the diff cover, I think it's look pretty good shiny. 

Been pottering away at the engine too. I ordered a new genuine Mazda oil pump which came in a Mazda box with Ford stamped on the pump🤣

I'm using the oil pickup and sump from a US spec Ford Ranger. 

This required drilling out the blanks on the crank ladder to mount it, which was done with a due sense of trepidation and a lot of blue roll/cardboard/masking tape and grease to catch any metal. 

It's still getting cleaned out a million times more before it goes together,  don't worry!

The head has been with an engineering place since before Christmas, I'll need to give them a prod but that'll just mean that bill arrives sooner🤣

I also need to order up timing chain and pulleys, not sure whether to go OE or if there's an aftermarket supplier that's decent?

Next up is to carry on stripping back the underseal on it before I remount the axle, then I can drop the front subframe and engine out and start on that end.