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MGB 1800 bottom end to triumph 1300 or 1500 head, possible or worthwhile?


jiggawhat2k
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Hi guys, wondering if you can help. I have a Herald running the standard gearbox and diff, currently with a 1300 mk4 spitfire engine (large crank). 

The bottom end has popped after a spirited drive, I've taken the head off and it looks fine but one of the pistons doesn't turn when i crank the engine so I assume that piston is toast (broken rod, or maybe crank? Not taken sump off yet). 

I'm going to throw another bottom end in just to get it back on the road. 

I already have a 1300 or a 1500 head that I can use. 

Then I started looking around and saw there is an 1800 MGB engine, and a variety of other MG engine sizes (a 1700 too I think)? I know nothing about MG engines, or the compatibility of the bottom ends to Triumph heads. 

I've very limited space to work, and want a bottom end that will attach directly on to the Herald gearbox which is in excellent condition. 

My questions!

Do any of the MG bottom ends work as a direct swap for a triumph 1300/1500 head? 

If an 1800 bottom end would work, is there any point? Or is it just more sensible to throw in a 1500 and ride the torque. 

The car will be used for track days and the occasional sprint once the madness is done, so it will be used and abused. I don't want to spend too much ideally. I'm planning on starting to build an engine properly once I get a garage in a couple of months, but until then I want it to run!

It also has twin hs4 carbs and 421 manifold plus exhaust.

Thanks as always for the help.

A few gratuitous broken down photos just because.

 

 

 

 

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As the engine in the MGB  was designed by the Austin Motor Company and the Herald, Standard 8, engine was designed by the Standard Motor Company, both in the early 1950's, I doubt there is any compatibility between the two. Two different motors companies.

The MGB engine had an earlier 3 bearing version and a later five bearing version. Both are known as the BMC B series engine.

If you go for the 1500 engine then you will need higher gearing, also overdrive helps. This is because the 1500 is a lower revving engine with higher torque than the 1300.

Dave

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3 hours ago, jiggawhat2k said:

The car will be used for track days and the occasional sprint once the madness is done, so it will be used and abused. I don't want to spend too much ideally. I'm planning on starting to build an engine properly once I get a garage in a couple of months, but until then I want it to run!

On that basis - in the short term sling any cheap assortment of Triumph parts that make up a complete engine into it, just so it runs.

Then take your time and find an EARLY 1300 "small journal" engine - a very good basis for a track/sprint car - it'll rev like mad!

1 hour ago, clive said:

Best bet for trackdays will be to find a small crank engine, Herald GE or spitfire FD engine.

Clive is spot on! (As ever) -  not all 1300 engines were born equal!

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MG 1800 is the B series and weighs as much as the Triumph six.  No Triumph interchangeability whatever.  As Kevin has said, the only overlap is the 1500 used on the rubber bumpered Midgets which is actually a Triumph 1500 as used in the Dolomite and Spitfire with only detail differences.

If you want something revvy, you are best off starting with a small crank 1300 code GE or FD (your Herald should have a GE in it).  I have a GE block, crank, pistons and rods here doing nothing available very cheap.  It will need boring/grinding etc as well worn, but is currently standard size.

You may find it's just the top come off the piston.  They do that sometimes......

Nick

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16 hours ago, KevinR said:

Don’t forget, if you really want to fit an engine from a Morris Garages offering you can always fit a1500 one from a late midget !

get the right clutch plate and it will drop straight in !

👹👹👹

Thanks @KevinR, is there any benefit of an mg 1500 over a spitfire 1500? Thanks again!

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4 minutes ago, jiggawhat2k said:

Thanks @KevinR, is there any benefit of an mg 1500 over a spitfire 1500? Thanks again!

No, in fact the opposite. The Midget has worse space around te engine, more prone to overheating. Sump likely wrong? Engine spec is identical.

Trust me for high revs, 1500 don't last. I ruined one crank at Goodwood, and another at the Prodrive track, and 3 others before I learnt my lesson. Obviously a slow learner.... I eventually put a dolomite 1850 engine into my Toledo. But have just bought a Sprint engine that is hopefully OK (will be stripping it tomorrow)

 

The other thing..... have you checked the regs of the sprint series you plan to enter? If you find the regs require too vast an expensehave a look at Autosolos, or even Targa rallies. No national B licence required, cheap entry, no expensive overalls/helmets etc and brilliant fun. 

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16 hours ago, Nick Jones said:

MG 1800 is the B series and weighs as much as the Triumph six.  No Triumph interchangeability whatever.  As Kevin has said, the only overlap is the 1500 used on the rubber bumpered Midgets which is actually a Triumph 1500 as used in the Dolomite and Spitfire with only detail differences.

If you want something revvy, you are best off starting with a small crank 1300 code GE or FD (your Herald should have a GE in it).  I have a GE block, crank, pistons and rods here doing nothing available very cheap.  It will need boring/grinding etc as well worn, but is currently standard size.

You may find it's just the top come off the piston.  They do that sometimes......

Nick

Cheers Nick very helpful. Sounds like the 1800 is well and truly a dead end!

I'm not in a position to be able to build anything up myself due to a lack of indoor space (in the process of moving house), thanks for the GE offer though!

Good point on the piston top! Hadn't occurred to me. Will check once I pull it apart (not able to do so at the moment though). Thanks

 

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16 minutes ago, clive said:

No, in fact the opposite. The Midget has worse space around te engine, more prone to overheating. Sump likely wrong? Engine spec is identical.

Trust me for high revs, 1500 don't last. I ruined one crank at Goodwood, and another at the Prodrive track, and 3 others before I learnt my lesson. Obviously a slow learner.... I eventually put a dolomite 1850 engine into my Toledo. But have just bought a Sprint engine that is hopefully OK (will be stripping it tomorrow)

 

The other thing..... have you checked the regs of the sprint series you plan to enter? If you find the regs require too vast an expensehave a look at Autosolos, or even Targa rallies. No national B licence required, cheap entry, no expensive overalls/helmets etc and brilliant fun. 

Thanks @clive triumph it is then.

Fair point on the 1500, I enjoyed the torque from my spitfire 1500 but have since broken a 1500 in the herald already. Sounds like you've been busting them for a while! Probably just replacing the 1300 is the smart move for now. 

I've put a listing in the parts wanted!

 I'll take a look at autosolo, sounds fun from what I've read. Also less strain on the car for it's first outings...Cheers as ever Clive

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18 hours ago, Nigel Clark said:

It would be much easier to install a Triumph 6 cylinder than mate an MGB engine to your Herald.

Nigel

Cheers Nigel yep it appears so. Six might make it a bit nose heavy so seems like a 1300 or 1500 (probably 1300) is the smart choice!

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Smart choice is something modern, but (a) most people underestimate the grief of engine swaps (b) you end up in the "specials" class. In fact even fibreglass panels do that in competitions. However, I have had some success in said specials class, despite my lack of driving skills. Even beaten the odd caterham! 

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  • 3 months later...

Been a while since I posted and you chaps have all been so helpful, so an update (not hugely exciting but hey!). Long post apologies!

I talked to Geoff at wins international who was very helpful and happened to have a good condition large crank 1300 from an aborted restoration. I snapped it up and got a pallet to my house. 

On looking into it, it seems that the engine had recently been rebuilt and possibly not even run in. Internals either new or virtually new, it was absolutely spotless. 

I spent a Saturday taking the old engine out (with the help of a friend) and then another Saturday swearing a lot while trying to mate the new engine to the gearbox on my own, using my engine crane on my small gravel drive. I think I did a dance when it finally clunked in after hours of frustration. 

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Plumbed everything back in and it fired up, miracle. There was an annoying ticking which I was pretty sure was a leak at the manifold, but I could still drive it. 

I've been busy since then, refitted the manifold and carbs and now no leaks. 

Also fitted a spitfire accelerator instead of the flat herald type, way nicer on my foot (in my mind anyway). 

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Fitted 2 speakers behind the door cards, there is a perfect speaker sized hole. Now it has 4 speakers up front (2 in footwell door pods I made from wood and covered, nice and hidden, 2 in the doors) a new Sony he'd unit that I've mounted in reach but under the dash, plus a sub woofer in the boot (ridiculous I know but I love it). 

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Replaced a fuel sender, after some initial irritation that I bought the wrong type (I got a screw one type rather than the one with bolts), so now I have a working fuel gauge. And a garage that smells of the fuel due to various accidents... 

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Also managed to avoid what could have been a catastrophic failure due to the rocker cover. I had an aftermarket alloy one fitted, the gaskets kept breaking up so I bought a thinner wide one designed for an alloy cover. On starting the engine, I could hear a loud banging, and the rocker had worked itself loose. See the small circles/dents where they were hitting? The tops of the rockers were hitting it, partly due to less space in the rocker vs standard, and due to the thinner aftermarket gasket. 

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If I'd left it much longer I'm sure small bits of metal would be flying around the head. Switched back and all ok now. 

Fitted the interior back in, not a perfect fit but looks fine in black. Very much helps with comfort and road noise. 

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Last job was the leaky bodged exhaust I built a while ago. Not only had it been damaged by speedbumps, but it was also leaking around a few joins. Bought the right bits of pipe to build a side exit exhaust, partially to help with clearance but also just because I've always wanted a car with one. 

Made the error of buying stainless, thinking a local garage could tig it together. No one could. So I put it together with some decent wide clamps and plenty of putty, it's as solid as I could hope for. All fitted up, at 4 different points underneath. Now no leaks! It's loud, ridiculously loud, I'll fail any noise checks, but we'll deal with that closer to when I hit a track... 

You can see where it comes out, just in front of the driver side rear wheel. I was able to attach it to chassis points all the way, so it's nice and solid (used bushes/hangers). 

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I had some rubbing on the front tyres from the arches and it being so so low (which I like). Instead of raising it, I fitted lower profile tyres (were 80,now 65),problen solved! And they match the rear now. Vibrations way way reduced, suspect the original fronts were not balanced anymore. 

Carbs are now balanced, but rich at the upper end of the rev range so I get quite pleasing but anti social pops on overrun. I've some less aggressive needles to put in, see how that goes. 

Now I'm using it, rain or shine, for the weekly shop and it's just brilliant. 

Thanks everyone for the help with my endless questions, it's on the road mostly due to advice from this forum.

A far-too-long video of the first drive after tuning up with the side exit. 

 

 

 

 

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Great stuff!

Just to say on the exhaust, you can weld a stainless exhaust with a Mig, using ordinary mild steel wire.  It works just as well, you just get the welds going rusty before the exhaust does.  Or you can just buy a small role of stainless wire and use that on the Mig, same gas.  I do it all the time, no problems.  I do Tig as well, but for exhaust repairs it's just easier to use the Mig which is much more user-friendly for an exhaust that's still on the car!

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On 02/11/2020 at 11:43, Roger K said:

Great stuff!

Just to say on the exhaust, you can weld a stainless exhaust with a Mig, using ordinary mild steel wire.  It works just as well, you just get the welds going rusty before the exhaust does.  Or you can just buy a small role of stainless wire and use that on the Mig, same gas.  I do it all the time, no problems.  I do Tig as well, but for exhaust repairs it's just easier to use the Mig which is much more user-friendly for an exhaust that's still on the car!

Nice, didn't know that! 

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I am liking this. Well, I probably wouldn't like the exhaust, but the idea is good🙂

If you are serious about trackdays, the TRR is currently working alongside the MGCC to offer trackdays. They split into groups according to experience, and a very friendly bunch. (but you need to sort the exhaust, all the tracks are very twitchy about noise, both at the initial noise test and drive by. I got pulled a couple oftimes when I had a "wheelbarrow" exhaust but it was always just within limits. And I mean just. Car now has 3 boxes fitted, 1x18" 3 1/2diameter between chassis rails, plus a 14" and a 32" 4"diameter boxes at the rear. All 2 1/4" pipe, all straight through boxes. 

If you wanted a std vitesse front pipe, goes from std manifold to the rear of the car, I have one in Brighton FOC. They do tuck up nicely, and a good exhaust box between the spare wheel well and the outrigger gives good clearance too. Just a thought for trackdays etc.

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On 02/11/2020 at 14:03, Pete Lewis said:

as for the mullered drum retaining screw.  not really required it only stops the drum falling off when there is  no wheel in place 

probably more use on the production line than any other time to stop drums falling on some guys head 

Pete

Thanks yep, I assumed as much and just didn't put it back in, glad to see for once that my corner cutting isn't putting me in mortal danger! 

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