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Lost Space 
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Part built GTM

Joined: Tue Apr 14, 2015 6:56 pm
Posts: 51
Post Lost Space
Sometime in the distant past, well last year I swopped the 998cc engine for a Mg Metro 1275 engine, nothing unusual there. Get engine running and all was good. Thought I d fit the catches and grills to engine hatch, placed hatch on car and find it is stuck up 20mm. How is this possible? Are the two blocks different? The carb and inlet were swopped from one to the other, everything except the alternator are the same, it doesn't make any sense to me. Any ideas?


Sat Dec 05, 2020 6:03 pm
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Joined: Wed Aug 11, 2010 9:27 am
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Location: Sheffield
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Post Re: Lost Space
Engine mounts are different between mini and metro...?

Also I read the 1275 is taller by about 10mm

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Sat Dec 05, 2020 8:17 pm
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Part built GTM

Joined: Tue Apr 14, 2015 6:56 pm
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Post Re: Lost Space
I have Mini engine mounts, I think the height difference between the two blocks is in the rocker cover. The lid will not fit as the dash pot of hif 44 sticks up to much.


Sat Dec 05, 2020 9:09 pm
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Joined: Wed Jul 31, 2013 11:47 am
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Location: Kano north Nigeria
GTM: Cox/Coupe
Post Re: Lost Space
I doubt its the height of the block, I ran a bored out 1275 S in my old Cox at 1st on 2 x 1-1/4 SU, then later with a 45 Webber, my current car with a bored out 1275 fitted with 45 Webber also fits, though I did have to extend the air scoop to cover the air box.
I would guess the HIF dashpot is taller or the manifold is a downdraft design raising the carb up.
John


Mon Dec 07, 2020 6:33 am
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Post Re: Lost Space
The 1275 block is taller but only by 1/2" or so.

Your problem is likely to be in the architecture of the HIF44 and the Metro manifold.

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Mon Dec 07, 2020 8:17 am
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Joined: Mon Oct 19, 2020 7:27 pm
Posts: 43
Location: Lincoln, UK.
GTM: Libra
Post Re: Lost Space
As others have said 1275 blocks are definitely taller than small-bore blocks, by about 10-12mm as previously mentioned. This can also give you clearance or fitment problems with your exhaust manifold.

Not much can be done with the mounts, you could look out for a Mini Auto front subframe and adapt the mounts to sit the engine lower in the frame - the Auto box was wider than the manual so the gap between the frame is wider.

There are lots of different inlet manifolds out there, and from memory, the HIF carbs are both taller in the suction chamber, and some have a taller damper rod - sort of top-hat shaped rather than flat-topped. You can machine a little of the top of the suction chamber where the damper rod threads onto (as when HIF6's were fitted onto MGB V8's) but I doubt you'd be able to gain 10mm there.

I'd be looking for a different inlet manifold to start with.

Phil.


Mon Dec 07, 2020 12:51 pm
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Joined: Tue Apr 14, 2015 6:56 pm
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Post Re: Lost Space
Hi, thanks everyone for help. I have bought and fitted a MG Metro inlet manifold, to find it is the exact one I already have. Doh. So no gain there unfortunately. The next area for attention was the subframe mounting points to chassis frame. I found some metal spacers in my bits box, two around 8 mm thick and two 6 mm. Carefully slacken front subframe to bulkhead bolts and with a jack under the rear edge of subframe slowly undo four turret bolts. Even with the aid of a crow bar nothing moved! Then I remembered the shock absorbers were holding things together, so with jack taking weight removed shocks and with my trusty crow bar got sufficient space to insert spacers. The four bolts were replaced one at a time with longer bolts and tightened up. So for a few hours work what have I gained? Well around 10 mm, yes 8 + 6 actually equals 10. The subframe tops have a raised spigots of 4 mm which goes into a hole in the spacer so losing 4 mm. Was it worth it? I need to gain another 8mm minimum somehow for clearance. Guess I could prune a few mm of dash pot pie but l am going to have to modify engine hatch, which is one of the few areas of the coupe that is unattractive in my opinion. Hopefully the rear ride height hasn't been too badly effected by this and won't be standing on top toes! I may have a go at fabricating an inlet manifold in the future, does anyone know if dropping a carburettor makes any difference to performance?


Sun Dec 13, 2020 9:30 am
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Joined: Fri Sep 14, 2007 10:34 pm
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Location: In the workshop
GTM: Cox/Coupe
Post Re: Lost Space
When I ran a 1275 in my coupe I had a Hiff38 all I could get at the time, I suspect that is the same overall size as the hiff44, mine all fitted under the standard engine cover, I had an aftermarket mini manifold, cannot remember which one it was suspect it was a generic stage 1. I am sure I had a spacer on it to! I did make an angled intake tube of the carburettor to get it low enough that took the feed sideways to attach an air filter.

So can be done with the right combination.

Neil

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Sun Dec 13, 2020 3:40 pm
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Location: In the workshop
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Post Re: Lost Space
Found a picture!

Attachment:
Apr21_43.JPG
Apr21_43.JPG [ 204.61 KiB | Viewed 563 times ]


Very early days of digital cameras and when I was starting the rebuild.

On another picture I can see I have the approx. 13mm phenolic spacer fitted to.

I did this arrangement as I wanted the air filter under the grill, the horizontal tube just fitted under the boot/engine cover lip trimmed down to approx 10mm. I am sure its still trimmed for it!

I think the mini standard inlet manifold holds the carburettor closer to the engine than the MG and most aftermarket manifolds, again from memory I have not played with A series for years.

Neil

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IF wile e coyote had a GTM he would have one with Nitrous too! watch out road runner! The First GTM into the 11s then the 10s, PB 10.87 @ 125.5 Mph on A048 tyres, and fully road legal at Santa Pod


Sun Dec 13, 2020 3:53 pm
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Joined: Wed Jul 31, 2013 11:47 am
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Location: Kano north Nigeria
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Post Re: Lost Space
Hi CTD, if you did not have before, there is normally a spacer on top of the subframe spring turrets, mine are around 6mm thick, if you did not have and have now added and tilted the rear subframe you have now introduced some suspension castor angle, some say it does not matter on the rear end, but I would try to set mine without castor, just a thought
John


Mon Dec 14, 2020 7:14 am
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