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1976Midget
Jedi Hopeful
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Does anyone know the factory horsepower for a MG Midget 1500. and what can i do oto boost my horse power. i like to make it about 100 HP.
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factory HP for a 1500
- Thread starter 1976Midget
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aeronca65t
Great Pumpkin
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My 1500 racer has about 80 HP, based mostly on track times to comparable cars that have been dynoed.
Facory HP is about 60 with just under 50 at the rear wheels.
To get that I have matched ports, a 2" single race carb and much-modified manifold, header, "Euro spec" cam, 10.25:1 pistons, three-angle valve job, 32 degrees of total ignition advance and a slightly lightened flywheel. The engine requires 100 octane race gas ($6.80/gal). I change rod bearings and thrust washers every 25 hours or so, to keep the bottom-end safe. I use a shift light to keep things below 6000 RPM.
I could get more HP out of this engine, but it would take much more money than I can spare and more maintenance than I have time for.
The 1500 engines have weak, 3-main cranks. In my opinion, you'd need a true race crank ($$$!) plus race rods and pistons to run 100 HP engine. Everything would need to be fully balanced. Also, probably twin HS4s on a Euro twin-carb manifold with race cam. And probably 12:1 compression minimum. Do not plan on running street gas.
Overall, to get 100 HP from one of these would cost at least $6000 in parts and work, I'd guess. And the engine would be a fussy, unpleasant engine for street car.
And a 100 HP engine would fry the stock axles in short order....race axles are about $700/pair.
You can actually get more HP (close to 130 I'd say), but the engine becomes a grenade if everything isn't *perfect*.
Honestly, here's what I'd do:
Put a header and twin-carb HS2 manifold on the engine (this is the European 1500 Midget/Spitfire manifold...came on some Canadian cars too). You can find these manifolds on e-Bay. Add a flow-thru muiffler (this won't really add much HP, but they sound cool). Be sure the engine is properly set up: correct ignition timing, correct valve adjustment, new plugs, air filters, fuel filters, etc. I like to set the total ignition timing at 32 degreees before TDC at 5000 RPM and do not worry about timing at idle speed. I'd run 93 octane (RON) if you set the timing this way.
Then just enjoy the car as is and don't worry about total HP. For my money, it's more fun to deal with a nice, strong stock engine than a cranky, fussy race engine on the street.
The stock 1500 engine is nicely balanced for a street Midget.
And if you have not done so, check the thrust washers. You can get a good idea of their condition by moving the crank fore/aft with a dial indicator in place. Should not be more than about 0.015" of movement. Frankly, if the engine has more than 40,000 miles on it, I'd just drop the oil pan, swap out the thrust washers, "mike" the crank and replace the rod-bearings (with same size) while your at it. This will extend engine life a lot. Sloppy thrust washers are murder on the bottom end of these cars.
Someone here may advise fitting a supercharger (or turbo) , but I think they're a bad idea on the 1500s due to the weak crank.
If you *really* want to build a strong, high-HP engine that'll stay together, build up an older 1275 cc engine (and ribcage trans) for your car.
OK, that my two-cents.
G'luck whatever you decide!
Facory HP is about 60 with just under 50 at the rear wheels.
To get that I have matched ports, a 2" single race carb and much-modified manifold, header, "Euro spec" cam, 10.25:1 pistons, three-angle valve job, 32 degrees of total ignition advance and a slightly lightened flywheel. The engine requires 100 octane race gas ($6.80/gal). I change rod bearings and thrust washers every 25 hours or so, to keep the bottom-end safe. I use a shift light to keep things below 6000 RPM.
I could get more HP out of this engine, but it would take much more money than I can spare and more maintenance than I have time for.
The 1500 engines have weak, 3-main cranks. In my opinion, you'd need a true race crank ($$$!) plus race rods and pistons to run 100 HP engine. Everything would need to be fully balanced. Also, probably twin HS4s on a Euro twin-carb manifold with race cam. And probably 12:1 compression minimum. Do not plan on running street gas.
Overall, to get 100 HP from one of these would cost at least $6000 in parts and work, I'd guess. And the engine would be a fussy, unpleasant engine for street car.
And a 100 HP engine would fry the stock axles in short order....race axles are about $700/pair.
You can actually get more HP (close to 130 I'd say), but the engine becomes a grenade if everything isn't *perfect*.
Honestly, here's what I'd do:
Put a header and twin-carb HS2 manifold on the engine (this is the European 1500 Midget/Spitfire manifold...came on some Canadian cars too). You can find these manifolds on e-Bay. Add a flow-thru muiffler (this won't really add much HP, but they sound cool). Be sure the engine is properly set up: correct ignition timing, correct valve adjustment, new plugs, air filters, fuel filters, etc. I like to set the total ignition timing at 32 degreees before TDC at 5000 RPM and do not worry about timing at idle speed. I'd run 93 octane (RON) if you set the timing this way.
Then just enjoy the car as is and don't worry about total HP. For my money, it's more fun to deal with a nice, strong stock engine than a cranky, fussy race engine on the street.
The stock 1500 engine is nicely balanced for a street Midget.
And if you have not done so, check the thrust washers. You can get a good idea of their condition by moving the crank fore/aft with a dial indicator in place. Should not be more than about 0.015" of movement. Frankly, if the engine has more than 40,000 miles on it, I'd just drop the oil pan, swap out the thrust washers, "mike" the crank and replace the rod-bearings (with same size) while your at it. This will extend engine life a lot. Sloppy thrust washers are murder on the bottom end of these cars.
Someone here may advise fitting a supercharger (or turbo) , but I think they're a bad idea on the 1500s due to the weak crank.
If you *really* want to build a strong, high-HP engine that'll stay together, build up an older 1275 cc engine (and ribcage trans) for your car.
OK, that my two-cents.
G'luck whatever you decide!
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So this maybe is the chance to ask my question. It seems like the general consensus is that 1500's can be fragile if not outright POC's. Yet, if you go to Haps website (www.acmespeedshop.com) there are a few photos of rubber bumper Midgets. Why is this if the engines can be problematic?
Thanks
Thanks
aeronca65t
Great Pumpkin
Offline
The 1500 can actually make more power, mostly due to porting and extra displacment. There are plenty of 1500 Spitfires and Midgets that are club racers (like mine), but you really need to keep up with maintenance or they grenade real quick. They have a very long stroke. In my very mild 1500 engine that never goes above 6000 RPM, I swap the rod bearings and thrust washers about every 25 hours.
In a highly tuned 120+ HP 1500 race engine, you might need to do thrust washers and rod bearings after every race.
The 1275 has Siamese ports that can be somewhat restrictive no matter what is done to them.
But the 1275 is more robust and has a much shorter stroke, so you can spin them up much higher and force more power out of them with high compression, radical cam, etc.
By the way, the 1300 Spitfire engine is a nice engine, especially when fitted with the 1500 (bigger valves) head. Much shorter stroke. At one point, I was thinking of putting one in my car. But I bought a nice 1275 parts car this Winter and I'm building the 1275 from that for #11.
In a highly tuned 120+ HP 1500 race engine, you might need to do thrust washers and rod bearings after every race.
The 1275 has Siamese ports that can be somewhat restrictive no matter what is done to them.
But the 1275 is more robust and has a much shorter stroke, so you can spin them up much higher and force more power out of them with high compression, radical cam, etc.
By the way, the 1300 Spitfire engine is a nice engine, especially when fitted with the 1500 (bigger valves) head. Much shorter stroke. At one point, I was thinking of putting one in my car. But I bought a nice 1275 parts car this Winter and I'm building the 1275 from that for #11.
aeronca65t
Great Pumpkin
Offline
Morris:
As far as I can tell, you could do it, but you'd have to saw a heck of a lot off the top of your 1500 block. The 1300 has the same bore as the 1500 (2.90") so they added ALL the displacement on the 1500 through stroke (3.45") and made the engine taller.
The 1300 has even a shorter stroke than the old 1147 Spitfire engine.
At 2.99", it's even has a shorter stroke than the 1275 BMC engine.
Older 1300s have a 6 port head, but a later 1300 with an 8 port head (no Siamese ports) is the hot ticket for small displacement Triumph engines. All 1500s have the 8 port head.
As far as I can tell, you could do it, but you'd have to saw a heck of a lot off the top of your 1500 block. The 1300 has the same bore as the 1500 (2.90") so they added ALL the displacement on the 1500 through stroke (3.45") and made the engine taller.
The 1300 has even a shorter stroke than the old 1147 Spitfire engine.
At 2.99", it's even has a shorter stroke than the 1275 BMC engine.
Older 1300s have a 6 port head, but a later 1300 with an 8 port head (no Siamese ports) is the hot ticket for small displacement Triumph engines. All 1500s have the 8 port head.
Trevor Jessie
Yoda
Offline
Actually Morris, It is possible for motors with the same deck height to have different strokes by varying the piston height and crank "throw". But I guess this is not the case with the 1300 vs 1500.
OP
1976Midget
Jedi Hopeful
Offline
so it sound to me that these things are not like the vw Motors that i am used to where you can throw a crank,cam and big set of piston in it and you have a race car for 400 dollars.i guess i will just stick to the 60 HP beater. I can get 110 octane Fuel at the pump here in town. would it be safe to run a half mix of this in my MG stock motor?
aeronca65t
Great Pumpkin
Offline
Mike:
High test gas (like the 110 octane you mention) does not have any more energy in it than regular gas.
What it has is additives that prevent the fuel for lighting off too quickly (causing detonation).
In a theoretical sense, it actually has slightly less power because it is "diluted" with the additives.
Bottom line: You can put 110 octane gas in your MG, but it will provide <u>zero</u> benfit in terms of power.
Even 93 octane may be more than you need.
I am helping a friend build a 20 valve 1.8 VW motor for an old-school Rabbit. That's a whole diffent universe from these Brit-cars.
High test gas (like the 110 octane you mention) does not have any more energy in it than regular gas.
What it has is additives that prevent the fuel for lighting off too quickly (causing detonation).
In a theoretical sense, it actually has slightly less power because it is "diluted" with the additives.
Bottom line: You can put 110 octane gas in your MG, but it will provide <u>zero</u> benfit in terms of power.
Even 93 octane may be more than you need.
I am helping a friend build a 20 valve 1.8 VW motor for an old-school Rabbit. That's a whole diffent universe from these Brit-cars.
Hap Waldrop
Yoda
Offline
First off, don't be confused by the late model fiberglass front bumpers (rubber bumper replica) on the race cars on my customer page, all of them are A-sries MG engines, you're just allowed to use that front end if you like in SCCA.
Now with that being said I built about 4 Triumph Spitfire race engines, three of them were 1500s, for such a small displacement engine these things are bricks (heavy) compared to the much more compact 1275 MG motor. A 100 HP 1500 Triumph street motor is very possible, but it ain't cheap. Fiqure a 100 HP 1500 built by me would easily cost atleast $5K, and $3K of that would be in parts. One of the two things I would highly recommend with a 1500 is using a performance cam in 1300 billet, that way you can put 1300 cam bearings in the 1500 block without any other modifications, the second would be to pin the thrust washers (they fall out when they get excessive wear) or either mill the rear main cap to accomondate 4 thrust washers intead of just two. Now here's where I will brutally honest with you, before I slung a buttload of money at 1500 Triumph motor, I would buy a cheap 1275 part car and revert the car to a 1275 motor and ribcage tranny and throw my money toward this engine, much more realiable lump and much easier to find go-fast parts for, The 1500 Midget folks never like to hear this, but it is the truth and the better way to go if you're going to spend the bucks for a hot rod LBC.
Now with that being said I built about 4 Triumph Spitfire race engines, three of them were 1500s, for such a small displacement engine these things are bricks (heavy) compared to the much more compact 1275 MG motor. A 100 HP 1500 Triumph street motor is very possible, but it ain't cheap. Fiqure a 100 HP 1500 built by me would easily cost atleast $5K, and $3K of that would be in parts. One of the two things I would highly recommend with a 1500 is using a performance cam in 1300 billet, that way you can put 1300 cam bearings in the 1500 block without any other modifications, the second would be to pin the thrust washers (they fall out when they get excessive wear) or either mill the rear main cap to accomondate 4 thrust washers intead of just two. Now here's where I will brutally honest with you, before I slung a buttload of money at 1500 Triumph motor, I would buy a cheap 1275 part car and revert the car to a 1275 motor and ribcage tranny and throw my money toward this engine, much more realiable lump and much easier to find go-fast parts for, The 1500 Midget folks never like to hear this, but it is the truth and the better way to go if you're going to spend the bucks for a hot rod LBC.
aeronca65t
Great Pumpkin
Offline
Hap Waldrop said:
Agreed! That's what I'm doing.
It cost me just over $9K to build a 138 HP 1500 for the F Prod Spitfire. It screamed, if you didn't mind doing bearings and thrust washers every other race weekend, and at least one oil pump replacement over the course of the season.
Won two club championships with it, but never again.
Jeff
Won two club championships with it, but never again.
Jeff
Hap Waldrop
Yoda
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Bugeye58 said:
That's right, we've got 125 out of the LP/SCCA 1500s, but they are timebombs. Bottom line the Triumph motors are just kinda iffy at best, Steve Stargis is fastest Spitfire guy on the planet and has won about 4 SCCA national championship but he lost about 7 or 8 championships while breaking with a big lead, if Steve drove MGs, he would have won ateast a dozen championships by now. My favorite of all the Turnip motors is the 1296 small journal.
Hap, if I would have had a 1300 to work with, I would have scrapped all of the 1500 stuff I got when I bought the car!
Now I've regained my senses, and had Huffaker build me a 948 for H. I know I'll probably wind up going the hybrid route, but want to get at least one season out of the 948.
That's what I started with, back in 1969.
Jeff
Now I've regained my senses, and had Huffaker build me a 948 for H. I know I'll probably wind up going the hybrid route, but want to get at least one season out of the 948.
That's what I started with, back in 1969.
Jeff
Hap Waldrop
Yoda
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Jeff for the money they will charge for the 948, you could have built two LP1275s. MY LP 1275 make the same horsepower at the rear wheels as the Huffaker 948s (we have in the orange car) did at the flywheel, do the math that about a 18% improvment for alot less money and tons more reliablity.