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1986 Manta Coupe Restomod


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8 hours ago, Exclusive Opel said:

The washer area looks familiar! Mine was exactly the same when my dad had the car and covered it in underseal. Seem to remember it took an age to clean it all up and the battery tray area was covered in it as well!


And the underseal is so thick! Took ages to clean the bits so far, using a combination of heat gun + scraper, knot brush and poly wheels - felt a little bit funny from a the fumes afterwards :blink:

3 minutes ago, IanMc said:

Sounds great, I wish you luck :thumbup

Thanks! It's going to take a while, but i know it'll be worth it - even if my lungs change colour during the process :lol:

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A little more progress over the last week or so, got the brake servo/washer tray repair section welded in


Then moved on to the inner wheel arch repair section - found this a little tricky as what should have been there was long gone, so we didn't really have a point of reference to make repair sections - google images to the rescue!! :D

So after much head scratching we realised there should be a return edge where the inner and outer panels join, forming a protruding lip - perfect work for the shrinker/stretcher machine! Started with a strip of metal for the inner, folded it 90 degrees, then stretched the edge to form the lip


Then did did the same with the outer, except being a larger piece of metal when the edge was gradually stretched, it naturally tried to curve the flat part of the piece, so once happy with the stretched part of the curve a bit of reforming was required to get face flat again


Both parts tack welded together


Then fully welded


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Also some more design progress for the front subframe - a few detail changes for how the bottom arms will locate in the new frame, using laser cut plates that will jigsaw together for strength and better accuracy when fabricated. Also the addition of an upper shock absorber mount to allow us to fit coilover suspension, allowing greater choice of spring rates, which will be very important to us, given that our drive train will be a fair bit lighter than the oe CIH iron block/cylinder head!


Edited by RIR18
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  • 3 weeks later...

A post repair section now - amazing how localised the corrosion was on this part, with paper thin sections next to good healthy material - it's almost like it's been etch erroded with a template! But from reading through the forum here i can see it's a pretty common area - seems they all rot in the same areas fairly predictably :rolleyes:

so we templated it pretty extensively because of it's complex curve, which changes both angle and depth as it heads downwards, and after a first 'prototype' version (bin fodder <_<) we came up with this:


and after some gentle 'adjustment' and welding ......


really pleased with how it came out - also nice to fill up some structural holes!

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passenger side forward section chassis leg and front chassis leg brace/lower radiator mount repairs, step 1 - take ages to remove front brace spot welds, as they are in reaaaly anoyying /places, then rejoice when it is finally free, only to reveal just how rotten it is in the corners <_<


- but is in excellent condition in the main span, so well worth repairing....


step 2, chassis leg repair - this had a historical repair hidden away inside, so was a good job done replacing it


step 3 - reunion!


it's taking time, but we'll get there! Just can't wait to get on with the exciting stuff......:D

2 minutes ago, IanMc said:

Great job :thumbup

Thank you sir! It's slow progress, but like most of us it's being done in our (formely) free time, but really helps being on here looking at what everyone else is up to!

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  • 2 months later...

It's been a busy couple of months on the old 'home front' which has slowed progress on our manta somewhat, however that's not to say that things haven't been moving forward - we've just finished replacing the n/s/f floorpan, lower chassis leg outer, upper swan neck outer and inner chassis leg strengthening section - the later of which we made from scratch, allowing it to be a lot stronger than the original reinforcement piece is. Worth the effort in our opinion, even if it causes our lungs to fail in the process due to airborne metallic particles that are ever present when we work on the car :huh:

Cutting out the old floor, the usual hidden (and not so hidden) rotten chassis leg reinforcement piece gladly removed!


Next we cut the new pan to shape and tack welded it at various points to keep it where it should be. At this point we trial fitted the outer leg repair sections, and soon realised there was a fair bit of fettling to be done! In the end we made the section joining the lower to the swan neck as it was the only way to get everything to fit the pan flush with no gaps - we also had to flatten the return flange on the lower, as it had curled up when it had made. See our high tech jig to prevent weld warpage during fabrication :lol:


Then when we were happy with how it fitted, we used it as a jig to make the inner reinforcement section, ensuring it would fit snugly to both the floor and the inside of the leg. We formed the upper and lower sections first out of strip steel, then made the side sections to fit the profile. These were then seam welded at regular intervals to spread out the heat, again minimising warpage:


Finally the outer section was refitted (after copious amounts of zinc primer were sprayed on the reinforcment piece) using several m6 nuts and bolts through the holes we previous drilled in both the leg flange and the floorpan. Every other hole was left open, to allow us to plug weld the sections together, then those were removed to allow the rest of the holes to be plugged also. At this point the floorpan was fully welded, and the new front jacking point (which also required a lot of modding!) was fitted. All the welds were then dressed, and everything was given a healthy dose of acid etch primer


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  • 2 months later...

More action from the manta welding endurance event! This episode - o/s floorpan/chassis leg......

We cut out all the bad stuff, and were pleasantly suprised that things were not as bad as the n/s! So we started as before by getting the new pan fitting nicely, drilling it ready for plug welding on the front overlap, and then tacking it evenly in place - closely followed by seam welding it all, then a lot of grinding back for that one piece as manufactured look:


Then both parts of the chassis leg - made a big difference knowing how we were going to go about it, having done the other side - think it took us about half the time!


And then all married back together, after some minor repairs to the front subframe mount area of the legs - at last, that's all the front end repairs done 😆 - really pleased with how it's come out! 


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Considering we actually now actually have something of the car to mount it to, we thought we'd better start making some stuff for the wheels to attach to!

Rob has designed a new tubular/sheet steel front subframe and upright package from scratch, so it can be much lighter AND much stronger than the oe setup on the car, whilst still working with the standard steering rack/mounting points on the chassis, making it a 'bolt on' assembly....  at least it will do when we've made it all!!

Lot's of parts to turn/mill, so here's the first parts of the upright - we're going to use a 4.5" x 5 bolt pattern, because it gives us a large choice of wheel sizes/offsets for sensible money, but if we want to go back to the oe 100mm x 4 pattern we can just make another couple of hubs 😎


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