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MG Midget and Sprite Technical - triumph 1300

*running the risk of a good flaming*
I know there is much said about the insufficiencies of the triumph 1500 engine (most I would agree with... thrust washers, hefty crank, long stroke etc!), but does anyone ever consider the triumph 1300 as a replacement..
I know it sounds like a retrograde move from the 1500, but the early 1300 from the MkIII spit has a reputation as a bit of a rev-er.. just a thought, I'll be staying with my 1275!
Cheers
Tim
T Dafforn

If a 1300 Triumph made the same power as an A-series it would still weigh a lot more so the car's performance would be inferior with the Triumph engine.
Daniel Thirteen-Twelve

I cant remember what Kate gets out of her fairly hot 1300cc Triumph engined Tifosi Rana which was on our stand at the NEC. It may be bored out to more than 1300cc and it has two pairs of Webbers (45's?) does anyone remember? I've got a fugure of 140bhp at the flywheel but I may well have that wrong.
Gary Lazarus

1300, didn't notice that should have been more attentative! why did she choose a 1300?
Robert (Bob) Midget Turbo

Interesting...
didn't realise there was weight difference between the A series and the triumph lump!
I guess the spitfire guys always cite the better breathing of the triumph head as a great advantage over the A-series.
mind you I have no idea what sort of BHP figures they get!
Cheers
tim
T Dafforn

Had a quick trawl of the web..
http://www.totallytriumph.net/spitfire/engine_building.shtml#Power
has some thoughts on the potential output of a 1300..
(mind you, of course, BHP figures are notoriously variable things!)
Cheers
Tim
T Dafforn

Gary I'm not certain how many BHPs Kate's car boasts or he bigness of her oversize but 130/140 seems to be what was written on the sheet by the car at the MASC stand, ISTR
bill sdgpm

1500 thrust washers do not need to be a problem.
I and several others have these solid bronze washers and love them.
http://www.britishcarweek.org/tr6.html


tomshobby

One difference I can think of... the 1300 uses shells for the cam bearings, while the 1500 doesn't.

BTW, those bronze thrust washers are interesting!

-:G:-
Gryf Ketcherside

A friend of mine had a 1300 Herald many years ago. The only mod was the addition of twin 1.25" SUs and it was quicker than my Morris 1300GT.
Dave O'Neill 2

Triumph has a large cast iron water pump housing and pump V the A-series small alloy body pump.

Triumph has an iron(steel?) lump of an alternator bracket.

Triumph has a cast iron bellhousing.

And so on.

It's possible to replace a lot of these heavy parts with aluminium parts from Canley Classics though of course the price really adds up and you're spending money to get even with an A-series not ahead of it.
Daniel Thirteen-Twelve

Best add a couple of extra cylinders then & go for a 6 pot :-)
Brad (Sprite IV 1380)

I was involved in the building and installation of the 1300 for Kate's Tifosi Rana (as well as the 5 speed conversion).

It is a large crank 1300 (ie a late 1300 as fitted to the Spitfire MkIV) with IIRC a 20 thou overbore.

At Northampton Motorsport it made 103 bhp which surprised me since I would have expected 110+ with the cam and porting it has.

Having said that, it is still running std valves.



[quote Daniel] If a 1300 Triumph made the same power as an A-series it would still weigh a lot more so the car's performance would be inferior with the Triumph engine.[/quote]


Sorry but that is utter horlicks. The Triumph motor weighs just about exactly the same as the A Series.

Aside from the fact that alloy bellhousings are available for the Triumph 4-pot - both for the single rail 'box (aftermarket) and for the three rail box (Herald 948), it is FAR easier to make good power for a street motor with the small crank Triumph than it is with the A Series.

Indeed in std form the small crank motor makes 75bhp which is more than the stock 1275.

In race trim, getting 150bhp from the Triumph is relatively simple with no recourse to offset boring as with our 1380.


Deborah Evans

Do they have 8-port head?

Shame the 1500 midget was not significnatly more powerful than 1275.

A
Anthony Cutler

The quick Spitfires that used to race a few years back all seemed to run 1300 as opposed to 1500 engines...
James Bilsland

Where did the 140 BHP come from then? Thought that was a bit high for an old design of 1300CC
Robert (Bob) Midget Turbo

I think there was an error in translation on the "screen blurb" for the Rana...

Seem to remember a conversation between John and Gary about that

wasnt paying much attention at that stage, I'd only just got there
bill sdgpm

So what DO they weigh? I have seen figures of 220 pounds for a 1500 stripped (no manifolds, no flywheel, etc.). Having manhandled 1275 engines in the past, I have difficulty believing I am that strong...
David "100-pound weekling" Lieb
David Lieb

"Do they have 8-port head?"

Yes. All 1296cc engines have the 8 port head. It was the 1147cc engines that had the siamesed port head (2 inlet ports, 4 exhaust ports). The 8 port head was a direct result of the Competitions Department work on the Le Mans and Rally Spitfires.


"The quick Spitfires that used to race a few years back all seemed to run 1300 as opposed to 1500 engines."

There is a good reason for this (I raced a very competitive Spitfire for a number of years).

The 'small crank" 1296s as fitted to the Spitfire MkIII and Herald 13/60 have commonality in the crankshaft with the 1147cc crank. This was a wide bearing small diameter crank made of EN40b steel.

In 1972 British Leyland were after saving money so they rationalised machining operations such that the bearing journals of the later (MkIV Spitfire) 1296 cranks and all 1493 cranks had their bearing journals increased in size so as to be the same as the 6 cylinder cranks fitted to the GT6 and TR5/6. The upshot of this was that the crank was heavier and causes more rotational losses in the engine (ie saps power), compounded with narrower bearings (on a 3 main bearing design). They compounded this further by dropping from EN40b steel to the far inferior EN16U which means that crank flex starts to become a problem. It is for this reason that the late 1296 and ALL 1493 motors are referred to as "Floppy Crank Motors". None of these will rev like the early 1296 engines and none will produce anything like the same amount of power.

With the 1493 motor this was further compounded by an increase in stroke meaning that the engine will not rev as well and is closer to the failure line owing to oil film breakdown. Furthermore the 1493 rods are weaker than the 1296 types.

It IS possible to make a reliable 1493 race motor but not without throwing $$$$ at it (which is not financially viable because the early 1296's will ALWAYS make more power.


"So what DO they weigh?"

Sorry David, I am in the States ATM (for Xmas and New Year) so I don't have access to my notes.
Deborah Evans

Have found a reference to the triumph engine being
125 Kg
(http://www.totallytriumph.net/spitfire/engine_building.shtml)
How does that stack up with the A-series
Tim
T Dafforn

Deb, while your in the states can you please help Prop firing up his engine, im not sure if he take anymore of it!

LOL!

Dont know about the 1300 but when i still had my 1500(Hs4+K&Nfilter+rally exhaust) in my midget i had no problem outrunning 1275's.
That really pissed of my mate in his 74midget with Marina engine. ;)

Arie de Best

i have found a reference of 114 Kg
witch sounds heavy to me since i could still lift my assembled engine off the bench (not easy but stil) and i am not that strong
Onno Könemann

Thats funny Onno as i have it in my memory the other way around: lifting my mates 1275 marine was heavier then when we lifted my 1500.
Has been a couple years ago tho, so i could be wrong.
Arie de Best

Deb,
If you happen to wander past the Chicago area, let me know! Always happy to entertain Spridgetly visitors.
David "Ok I guess that goes for most of the rest of you lot as well ;-)" Lieb
David Lieb

Most?
David?
Robert (Bob) Midget Turbo

I was very surprised when I brought my 1275 home. Three of us struggled to lift it onto the pickup tailgate. Then my son and I only slowed it's decent onto the cart where it now sits. Much heavier than I thought it would be.
tomshobby

Hi Deborah... yes thought they were 8-port. I don't know merits of 8 small compared with 5 larger ports on ASeries... but would probably go for 8.

I bought my wife a Spit around 1981 ('72 re-styled). It was slow compared with my 1275 Midget, but preferred for longer journeys as less of a buzz-box; the Midget greatly benefited in this respect when I fitted a 5spd box in 1998 - even in 4th, the car was transformed for long journeys.

I broke a piston chasing a 911 in the Spit (no hope really, but the 911 driver wasn't the most capable, so had 10 miles of fun). Anyway, continued journey up to Castleton, and rebuilt engine with piston, shells and timing chain in a day, including tip to Sheffield to collect parts. Was amused by wooden wedges around the mains (oil seal). My friend had air-driven tools, and they contributed to the light-hearted way the engine was taken down and rebuilt at speed.

I also remember my brother's 1300TC - F reg - in around 1976; this was a reasonably heavy saloon for its time, but it shifted very nicely with 75bhp Spit engine; it seemed to do a great deal of revving.

I believe Triumph block and head were better quality steel than the ASeries.

A
Anthony Cutler

Robert,
Dinna fash yersel, ye are on the right list.
I think Prop might need to prove that he is not contagious first ;-)
David "I've got a little list..." Lieb
David Lieb

This thread was discussed between 26/11/2009 and 03/12/2009

MG Midget and Sprite Technical index

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