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Tuning a 1500 engine

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bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
In reply to # 3607464 by ozieagle
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

Met a friend when I was running at the Victoria (BC) hill climb one year. He was running a 1500 with 1800 head and was wondering why he was so slow. I told him that having something around 7.8:1 compression probably had a lot to do with it......



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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Erik Ohlsson Avatar
Malmo, Skane, Sweden   SWE
Actually I have an 18v engine laying around but (a) it requires a full restoration and (b) if opting for an 1800 engine then the 3 main seems to be a much more convenient option ... so I might just see if I can tune the 1500 engine a bit instead.



1959 MGA 1500 Coupe

Darvie43 David Hill
Narellan, NSW, Australia   AUS
If you want to use a 1800 head on the 1500 go for the "O" head, i am running that with an MGA exhaust manifold and 1 3/4" system, runs very nice with good low speed torque (still running the 5/45 50/10 std camshaft,
I cut valve reliefs in the block to suit future cam updates.

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Darvie43 David Hill
Narellan, NSW, Australia   AUS
Forgot to mention engine is in Magnette ZB.

bikermga Avatar
bikermga Peter Tilbury
Surrey, BC, Canada   CAN
Erik,

1800 engine with 5 speed and 3.9 diff. You can cruise all day at 65mph, and revs about 3000.

Peter.

Erik Ohlsson Avatar
Malmo, Skane, Sweden   SWE
Hey Peter,

That is indeed the dream ... But to get there is a bit pricey so I was hoping to first try tuning the 1500 engine and fitting a 3.9 diff.



1959 MGA 1500 Coupe

59mgaguy Avatar
59mgaguy John Terschak
Wakeman, Ohio, USA   USA
1930 Ford Model A "Jenny"
1959 MG 14/28 "Jessie"
1974 MG MGB "Oooops"
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.

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.


What years of early B heads? With the 74 B heads that have the larger valves be used on the 1500 and the 1622 engine?

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bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
In reply to # 3608580 by Erik Ohlsson Hey Peter,

That is indeed the dream ... But to get there is a bit pricey so I was hoping to first try tuning the 1500 engine and fitting a 3.9 diff.

The tuning capabilities of the 1500 engine are limited and whatever you'd gain would be thrown away again when you put the 3.9 in it.

Frankly I would do what Peter said even if it means waiting awhile. Keep an eye out for a 3 main MGB engine you can pick up and work on rebuilding it to suit your needs. And reconside the 3.9.



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

bikermga Avatar
bikermga Peter Tilbury
Surrey, BC, Canada   CAN
Erik,

Had the 3.9 fitted with my original 1500 engine and it was fine to drive.

But my wife complained when we went to Reno Nevada, as I was not keeping up with her in her coupe with 1622 engine, 5 speed, and 3.9 diff. She said I had to upgrade, and I do not argue with my wife!!

Peter.

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Erik Ohlsson Avatar
Malmo, Skane, Sweden   SWE
In reply to # 3608697 by bills
In reply to # 3608580 by Erik Ohlsson Hey Peter,

That is indeed the dream ... But to get there is a bit pricey so I was hoping to first try tuning the 1500 engine and fitting a 3.9 diff.

The tuning capabilities of the 1500 engine are limited and whatever you'd gain would be thrown away again when you put the 3.9 in it.

Frankly I would do what Peter said even if it means waiting awhile. Keep an eye out for a 3 main MGB engine you can pick up and work on rebuilding it to suit your needs. And reconside the 3.9.


Hey Bill,

You have a good point there. As I have a 3.9 I'll fit it this winter and see how the car runs, so that is definitely happening.

The thing is that I have a pretty rough looking 18v engine (US low compression version) which I could restore and rebuild, changing the cylinder head, pistons, flywheel, timing chain, and many other little things to make it a performance engine. However, even that would be pricey and in the end, it would have been much easier to buy a 3-main engine ... Might just wait and keep my eyes open for a 3-main engine ...



1959 MGA 1500 Coupe


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Ballybob Avatar
Ballybob Rob McKellar
Wollongong, New South Wales, Australia   AUS
1958 MG MGA 1500
1968 MG MGB "NED"
1969 MG Midget
So where did the factory find the extra power gains with the 1622 engine compared to the 1500?

I'm guessing its in the head.

I have a new head sitting in my shed for my B and the original still on the motor.


Looks like a head swap is on the cards.

Rob

bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
In reply to # 3610490 by Ballybob So where did the factory find the extra power gains with the 1622 engine compared to the 1500?

I'm guessing its in the head.


Rob

Larger valves, better porting and IIRC higher compression. Same cam.



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

Ballybob Avatar
Ballybob Rob McKellar
Wollongong, New South Wales, Australia   AUS
1958 MG MGA 1500
1968 MG MGB "NED"
1969 MG Midget
In reply to # 3610493 by bills
In reply to # 3610490 by Ballybob So where did the factory find the extra power gains with the 1622 engine compared to the 1500?

I'm guessing its in the head.


Rob

Larger valves, better porting and IIRC higher compression. Same cam.

So if I want to put my 18 head on the 1500 what cc's should I be looking at achieving in the combustion chambers to get the same compression ratio as the 1600?

bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
In reply to # 3610496 by Ballybob

So if I want to put my 18 head on the 1500 what cc's should I be looking at achieving in the combustion chambers to get the same compression ratio as the 1600?

The same chamber volume as the 1500 stock head has - 39 cc. Or better yet, put in some flat top pistons and raise the compression higher than stock - and machine the head to suit the new ratio you want.



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
Hi Rob,
You need the 1800 :O: head ( it has "O" cast into the rear top face where they had"1800"winking smiley, the only problem is you will need cutouts for the valve travel cut into the top of the block, i have one on my 1622cc (1500 bored out to 3"winking smiley in the Magnette and am very happy with it.

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