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Tuning a 1500 engine

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Erik Ohlsson Avatar
Malmo, Skane, Sweden   SWE
Hi,

I'm thinking of ways to add just a bit more performance to my 1500. Not to race, just to enjoy a slight increase in acceleration and some more torque going up hills. Free flow cylinder head, aluminium flywheel, tubular exhaust are a few options which I'm considering. Any other ideas, which don't involve boring out the cylinders or changing engine?

However, I was advised against tuning the 1500 engine as it 'has a weak crank shaft which will eventually break'. Note that I don't intend to push the car very hard and rarely rev higher than the upper 3000s.

What are your thoughts?

Thanks a lot



1959 MGA 1500 Coupe

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Nik Nikolai Sklyadnev
Moscow, Russian Federation   RUS
You can fit velocity stacks.
Nick

gmkjr56 George Kress
Verona, pa, USA   USA
I have a number of MGAs. All are 1600s. When a friend passed away I got his 61 MGA with a 1500 engine in running condition to sell it for his wife. This car ran with as much or more power than any of my cars. He had installed carbs fro a MGB on the car. I am guessing that more fuel made it go.

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Basil Adams Avatar
About 12 miles from Sears Point, CA, USA   USA
A good valve job and a camshaft change are the most bang for the buck - but if you don't want to dig into the engine, you have few meaningful options. Porting the head is expensive and not very valuable without other changes. Getting more air into the head is limited by the throttle plate (butterfly) until you're at wide-open throttleand you shouldn't be tryoing to make a 1500 work by keeping it floored all the time. A lighter flywheel may allow you to spin up a little faster but adds no horsepower. A custom exhaust may help a little but the commercially available systems do very little except look nice and replace old, worn-out parts. If you're thinking about taking the head off, a good valve job will help and 1600 sized valves may help. There are simple DIY carb modifications you can do that will help. But if you want to make a zippy 1500, a good valve job, a cam, (maybe a little compression) some carb work, minor port matching and tuning are the places to start. Best of luck. Basil 707.762.0974 basiladams@yahoo.com



Basil C. Adams
1956 MGA Coupe (Show Car)
1957 MGA Roadster (Driver)
1958 MGA Coupe (Racecar)
1959 MGA Coupe (unrestored)
1960 MGA Coupe (unrestored)
1960 MGA Roadster (Driver)
MKIII Elva Courier (E1056)
1967 427 Cobra
1972 Alfa Romeo Montreal
A coupla late MGBs
1960 Austin Healy BN7
More Cars than Brains

barneymg Avatar
barneymg Barney Gaylord
(Somewhere in USA), Pick one (or more), USA   USA
1958 MG MGA "MGA With An Attitude"
The best bang for your buck will be mini velocity stacks. Installing the mini velocity stacks inside the air cleaners is good for about 4-HP, tested and proven on a dynamometer. See here:
http://mgaguru.com/mgtech/power/pp104a.htm
http://mgaguru.com/mgtech/power/pp104b.htm
http://mgaguru.com/mgtech/power/pp104c.htm
http://mgaguru.com/mgtech/power/pp104d.htm
http://mgaguru.com/mgtech/power/pp104e.htm
http://mgaguru.com/tales/mobile25.htm#stacks
http://mgaguru.com/tales/mobile26.htm#stacks


Change from MGA H4 carbs to MGB HS4 carbs makes no difference at all, using same needles in both. However, with additional air flow with larger valves and/or velocity stacks, you likely get better results switching from GS to number 6 needles.

For 1500 or 1600 engines, fitting an early MGB "18" cylinder head is a good move. That one is nearly identical to the "16" head used on the 1622cc engine in the MGA 1600-MK-II with one size larger valves and better porting, good for about 8-HP with no other mods. You do need to have it (16 or 18 head) shaved slightly to get the right compression ratio, but otherwise a simple bolt-on, and still runs on regular grade pump fuel.

The MGA cast iron exhaust manifold is actually pretty good, better than a lot of people give it credit for. Tubular headers would likely not net more than a couple HP, unless used in conjunction with some other mods. Installing a better cylinder head and velocity stacks might make the headers perform just a bit better, like another 1 or 2 HP. Beyond that you likely need next size larger exhaust pipe to get more out of headers. Headers will also be noisier and will dump more heat in the engine bay. So your choice if you can justify the cost for the minimal gain.

Installing an electric radiator fan and removing the belt driven fan can net a few HP at high engine speed, but only the bold will have enough confidence to remove the original fan. Highly advise to install original cell core type radiator for good cooling.

If you ultimately have fuel boiling problems in hot weather (due to alcohol in modern motor fuel), then install a bilge blower fan in the duct in front of the carburetors to keep the carbs cool in dire circumstances.

If you want to dig a little deeper in the engine (and your wallet), installing a fast street camshaft will get you maybe 7 to 10 HP at higher engine speeds (4000-6000-RPM), with a small loss of torque below 1500-RPM. More radical cams give (and sacrifice) a little more, but may be "uncomfortable" for normal city driving.

Changing the flywheel from original 28 pounds to 20 pounds as used on late MGA 1600-MK-II and early MGB is a good move, apparently all up side on no down side, but requires pulling the engine for installation. The lighter flywheel gives better throttle response at low speed, and slightly better acceleration in the lower gears, but no actual power increase.

Installing the MGB clutch pressure plate in the MGA is a decent idea with any kind of power upgrade. It goes nicely with the MGB flywheel, but also requires MGB clutch release bearing, release arm, and the front cover from early MGB gearbox. It won't make the car go faster but will give slightly more crisp clutch action for up shifts.

Installing a higher final drive gear ratio gives better acceleration, especially in the lower gears, but runs the engine faster on the highway and limits top speed. Installing lower ratio final drive slows the engine down for more casual highway cruising, but reduces acceleration and hill climbing capability. With the stock MGA engines higher final drive will sacrifice a bit of top speed, because there is not enough torque to pull it to top speed. But some engine upgrade almost demands lower final drive to avoid running past red line in top gear.

Installing overdrive (difficult in the MGA) or a 5-speed gearbox (easy but big $) is a nice option for casual highway cruising while retaining acceleration and hill climbing capability (but does not improve acceleration or top speed).

Next step up from the MGB cylinder head is a complete MGB 1800 engine. Early 3-main bearing MGB engine is a bolt in and looks pretty much the same as any MGA pushrod engine.

Come on guys, did I miss anything short of installing a bigger engine or an expensive supercharger?



Barney Gaylord - 1958 MGA with an attitude - http://MGAguru.com - barneymg@mgaguru.com



Edited 1 time(s). Last edit at 2017-10-06 03:08 PM by barneymg.

Darvie43 David Hill
Narellan, NSW, Australia   AUS
Hi Barney
I think you meant a lower diff ratio to accelrate faster.

bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
In reply to # 3605319 by Darvie43 Hi Barney
I think you meant a lower diff ratio to accelrate faster.

Higher numerical = lower (speed) diff.



Bill Spohn www.rhodo.citymax.com/carstuff.html
Current: 1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1957 Jamaican MGA (200 bhp)1965 1971 Jensen Interceptor (350 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
2007 BMW Z4M coupe (340 bhp)
Recent: 1969 MGC roadster (175 bhp),Jensen CV8 (375 bhp),
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
North Vancouver BC

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wyatt Avatar
wyatt Silver Member Wyatt W
penguin point, drift ice, Antarctica   ATA
cheap and easy, advance the timing a tad, not sure how good this would be in the short/long run but you'll feel it right now.

Grubeguy Avatar
Grubeguy Grube Guy
Washington, DC, USA   USA
What about a supercharger?

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bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
In reply to # 3605981 by Grubeguy What about a supercharger?

You can fit a supercharger or an MGB engine - similar results but the cost is less on the engine usually.

If you already had an MGB engine in it, then the next step would indeed be the supercharger.



Bill Spohn www.rhodo.citymax.com/carstuff.html
Current: 1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1957 Jamaican MGA (200 bhp)1965 1971 Jensen Interceptor (350 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
2007 BMW Z4M coupe (340 bhp)
Recent: 1969 MGC roadster (175 bhp),Jensen CV8 (375 bhp),
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
North Vancouver BC

Darvie43 David Hill
Narellan, NSW, Australia   AUS
A supercharger on a 1500 engine is not a good idea due to the weak conrods.

bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
In reply to # 3606437 by Darvie43 A supercharger on a 1500 engine is not a good idea due to the weak conrods.

Same rods as the 1588 and they can take mild supercharging - they aren't going to get to any heady power levels anyway. You are right that the 1622/1798 had stronger rods, though.



Bill Spohn www.rhodo.citymax.com/carstuff.html
Current: 1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1957 Jamaican MGA (200 bhp)1965 1971 Jensen Interceptor (350 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
2007 BMW Z4M coupe (340 bhp)
Recent: 1969 MGC roadster (175 bhp),Jensen CV8 (375 bhp),
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
North Vancouver BC

Darvie43 David Hill
Narellan, NSW, Australia   AUS
The 1622cc engines made in Australia also had forged steel crankshafts.

Erik Ohlsson Avatar
Malmo, Skane, Sweden   SWE
Thank you all for the great feedback ... Many good ideas, so I will start thinking about how to best approach adding a few extra bhp's to the old 1500 ... without adding a supercharger though, mainly because they're so expensive!

An extra big thanks to Barney who never fails to provide very clear and detailed information.



1959 MGA 1500 Coupe

ozieagle Avatar
ozieagle Gold Member Herb Adler
Geelong Victoria, Australia   AUS
1958 Wolseley 1500 "Wooly"
1966 MG MGB "Bl**dy B"
In reply to # 3605168 by barneymg

For 1500 or 1600 engines, fitting an early MGB "18" cylinder head is a good move. That one is nearly identical to the "16" head used on the 1622cc engine in the MGA 1600-MK-II with one size larger valves and better porting, good for about 8-HP with no other mods. You do need to have it (16 or 18 head) shaved slightly to get the right compression ratio, but otherwise a simple bolt-on, and still runs on regular grade pump fuel.

As Barney mentioned, when you fit the MGB head you must have it shaved. The early, 12H 1326 heads have a 43 cc combustion chamber, compared to the mga's 38 cc. Just bolting the MGB head on would lose you power.

Herb



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