1098cc or MG 1275cc Engine? (Fast Road/Race)

[Oddball67]

I'm 'Slowly' restoring a 72 Austin Pick-Up and contemplating what to do with the engine.

Should I fit the original 1098 or a MG 1275cc engine. I've already acquired a few bit & bobs and these include a fully reconditioned MG gearbox, 3.9 diff, EN24 Race half shafts, HIF 44 carb with heated inlet manifold, MG 1275cc engine.

My dilemma is this, I'd like to rebuild either engine, but planned on making it a litle more rapid than standard. Obviously there are a few drawbacks with the minor engine but, I was drawn to the idea of keeping the Pick-Up fairly original if I were to go down this road. I did think about having the block pocketed and fit a 1300 cc head, etc.

I accept the MG 1275 engine has a lot more potential, 1380cc etc, but I thought I'd see what the messageboard has to say before a route is decided.

Also, does anyone know who races a minor? I'd like to open some dialogue with them about what they've done and experienced.

I did consider a Zetec but, costs are waaaaaayyyyy to expensive.!!!!!

[chrisryder]

bmcecosse will be along shortly...

[bmcecosse]

Hah! Obviously the larger capacity engine is more powerful - but don't get suckered in to '1380' etc - likely to be nothing but trouble...........for little extra poke. But a good 1098 is perfectly satisfactory for a road going car if that's all you need. Is either engine fit for use 'as is' ??

[chrisryder]

if the 1098 engine is the original from your pickup. does that make it a low compression one?

i'm not sure where to low compression is achieved. whether the head is deeper, or machined differently, or if the pistons have a deeper dish.

if you do keep the 1098, and intend to modify it, you may want to increase the compression by un-doing whatever makes it low compression in the first place!

[chrisd87]

The low compression comes from more deeply dished pistons, so fitting normal high compression pistons should be enough. Given the choice I'd fit the 1275 plus the other bits you mentioned, but otherwise leave it fairly standard. This would result in an engine with more low-speed torque than a tuned 1098 plus a stronger crankshaft.

Keep the low comp 1098 with the car though, just in case you fancy putting it all back to standard at some stage.

[rayofleamington]

A standard 1098 pickup would be a nice addition to the fleet. ;-)
whilst a boy racer engine setup gives a lot more power it also changes the character a lot.
One nice option (that most would hiss at) is to run the 1275 with standard Minor carb and exhaust - you get bags of torque and still keep the original Minor sound and feel - albeit a bit quicker than average.

[Sam_Finlay]

I've been wrestling with the same dilemma but it's more complicated than just whacking in the bigger engine. You will need to fork out for a custom pick-up / van exhaust with a LCB manifold, up rate the brakes to discs and worry about the handling at the speeds it will be capable of..

There's not a lot of weight in a pick-up and the back end is more than happy to skip about if you are fond of sticking your foot down. I've got a 1275 Midget engine sat on my garage floor that I will probably end up putting in a 4 door salon I acquired for all the reasons stated.

I have a 1098 Spridget engine on the bench as my reserve power unit for the pick-up instead. It should be more than fast enough with a 3:9 diff and everything else left as it is.

[Oddball67]

Having read the replies, I'd fortunate that I already own a restored 69 Pick-Up with a slightly modified MG 1275cc engine and all the bits to bring it slightly upto date (5 speed, Disc brakes, Anti roll bar etc) I also own a 58 Van that also has a MG 1275cc, running MG gearbox and standard Morris Carb. So I'm quite spoilt as it is.

I like the MG 1275cc as I like the performance it gives me on the A-roads and motorways. Been soooooo long since I've driven a standard powered M.M. I've forgotten what they're like.!

I kind of have in mind how I'd like the Pick-Up to look when finished, and hence why I'm just asking what a 1098 can offer. I've actually heard that by putting a decent head on a 1098cc, Cam, DCOE 45 webber, you can actually obtain around 110bhp at the fly wheel. Is this correct?

I forgot to mention that I've got the LCB exhaust manifold, and exhaust in my stock of items.

Still interested to talk with anyone who races/or has raced a Minor on the track.

[bmcecosse]

HA HA! NO - you will absolutely NOT get 110 bhp from a 1098 engine - indeed you will struggle to get that from a 1275 without spending a small fortune. The 1098 is not a strong engine - and even in big mains form - should not be run over 6000 rpm for any length of time. If you want high power - 1275 is the way - and be happy if it gets a genuine 90 bhp in road useable form. Yes more is possible - but they begin to be bad tempered and have short lifes!

[chrisd87]

Not quite sure who told you that 110bhp is possible from a 1098 . Realistically you're looking at maybe 70bhp maximum from the spec you've described. As has been said above the 1098 is not an engine you can rev to the heavens and has a fairly weak crankshaft, so is only really suited to moderate tuning. Race cams are a no-no as not only will they make the car horrid to drive on the road but are designed to make power at very high RPM.

If you haven't already got a copy, David Vizard's "Tuning the A-Series Engine" is a book you need!

[faversham999]

I have gone from a 1098cc to 948cc but I still get there eventually.

[bmcecosse]

The 948 is a very nice smooth engine - I wish I had one, or even better - an 848 for best economy!

[IslipMinor]

A 1380 from the last 13 years experience is a very good way to go! With a good head (Peter Burgess) with the later 'S' valve sizes, i.e. the smaller 1 5/32" exhaust valve, 276 cam, either Piper or Kent, HIF6 or 44, LCB with 2" exhaust gives 112bhp at the flywheel and excellent all round performance. I take for granted that you will fit discs and sort out the suspension, wheels, tyres etc. to get the full use from it?

You choose - 1,500 rpm poddling around town in 5th, or 7,000rpm in 1st, 2nd and 3rd on track days! Both work supremely well. I tried a 45 DCOE and on a back to back rolling road session it produced 4bhp more, but that was with the MG Metro airbox, with K&N filter in place. Swapping to a circular K&N gave more with the HIF6 SU and infinitely better driving - doesn't have the classic Weber noise though! For long trips and the Euroclassic across Europe each year we fit the Metro airbox, but for UK use and track days it is the circular K&N filter with stub stack - it is considerably noisier though.

For easy, reliable performance a 1275/1380 is very hard to beat in a MInor. To get the best out of it, you should consider a 5-spd box. A 3.7 diff with the 4-spd box will give the top end speed and motorway driving, but robs performance at slower speeds, as it is really quite a bit too high geared.

[Oddball67]

Richard,

With your 1380 engine and 5 speed, what diff are you running? Do you have a LSD and EN24 Half shafts?

[IslipMinor]

The diff is a 3.9 and I do have an LSD (Tran-X plate) and Peter May's EN24 half shafts. The gearbox is the Toyota T50, which is very quiet and has a very precise gear change, but quite a low 5th ratio (0.865). If you were to use the Ford T9, 5th is 0.830, so I would consider using a 4.22 diff to get a bit more acceleration and not far off the same overall 5th ratio. Depends on what you want from the final result?

[TomLS]

Resurrecting a slightly old thread here, but I read this the other day, and to me it seems a happy medium between a cheap upgrade, keeping the insurers happy, originality, and a bit more poke for some fun:

http://www.minimania.com/web/SCatagory/ ... ticleV.cfm

[bmcecosse]

Ha ha.. Good old Calver -he always comes up with fantastic power figures - take it with a big pinch of salt.......

[TomLS]

Well, this particular paragraph did crumple my eyebrows:

Interestingly, and another 'bonus' of a rolling road visit, is being able to check actual road speeds against rpm. The 998 achieved a 'real' 70mph at 4,40rpm, where the 1100 managed the same speed at a lower 4,300rpm. You'd think they'd make the same rpm to achieve the same speed considering the gearbox ratios were identical. Just further illustration that the 1100 doesn't have to work so hard to achieve the same speeds. The speedo was reading 74mph at this point. Not bad considering I set out to match the FD with the speedo using available speedo drive pinion and spindles. This gives 16.28mph per 1,000rpm. Even more interesting is comparing this with the calculus I presented way back in the September 1998 issue when discussing final drives and how to sort what speeds you get with different wheel/tyre combinations with some accuracy. After all - there are loads of proffered methods for this. My method described there works out on paper to 16.46mph per 1,000rpm. Now that's impressively close!

That's got to be down to the error of the measuring instruments used. If the gearboxes were 'identical' then different figures are a physical impossibility!

[bmcecosse]

Typical Calver confusion I'm afraid.

[chrisryder]

Well, this particular paragraph did crumple my eyebrows:

Interestingly, and another 'bonus' of a rolling road visit, is being able to check actual road speeds against rpm. The 998 achieved a 'real' 70mph at 4,40rpm, where the 1100 managed the same speed at a lower 4,300rpm. You'd think they'd make the same rpm to achieve the same speed considering the gearbox ratios were identical. Just further illustration that the 1100 doesn't have to work so hard to achieve the same speeds. The speedo was reading 74mph at this point. Not bad considering I set out to match the FD with the speedo using available speedo drive pinion and spindles. This gives 16.28mph per 1,000rpm. Even more interesting is comparing this with the calculus I presented way back in the September 1998 issue when discussing final drives and how to sort what speeds you get with different wheel/tyre combinations with some accuracy. After all - there are loads of proffered methods for this. My method described there works out on paper to 16.46mph per 1,000rpm. Now that's impressively close!

That's got to be down to the error of the measuring instruments used. If the gearboxes were 'identical' then different figures are a physical impossibility!

The gearboxes could be identical. The difference would have been in the tyre sizes.

The notion that it is 'further illustration that the 1100 doesn't have to work as hard to achieve the same speeds' is stupid, ok the 1100 is revving slower, so not working as hard, but it's got no bearing on the engine size or power, it must be in the gearing!