MGA MGB engine versus original in 1957 MGA Coupe?????

[SteveTR]

Folks,

How much would I notice the imrprovement of a bored out, and cam improved MGB engine over the stock MGA engine currently scheduled for my 1957 MGA Coupe?

I want this project to be original; yet, I cannot help but wonder about a finger on the socket - British pocket rocket. Okay, that was a bit much.

Help!

 

[DrEntropy]

Umm.... go for the GB five main "B" engine and don't look back.

...just my opinion, mind you!

 

[tony barnhill]

I had an MGA with an hot little MGB engine in it once...Jerri called it my "rolling casket"!

 

[DrEntropy]

There's nothin' wrong with a five main B engine! :wink:

 

[Steve_S]

If you want original, don't use the 5-main. Early MGB engines with 3 main bearings are nearly identical in every way to the late model MGA engines. Only those who really know what to look for can tell the difference. You even get to keep the mechanical tachometer. 3-mains also rev more freely which makes them popular with the racing crowd. Unfortunately this popularity has also reduced the number of surviving units and they are getting harder to find.

5-main engines are more durable, leak less oil and are easier to find. But they are less of a bolt-in item.

 

[bob67bgt]

If you go the 5 main route you will need to adapt a rear engine plate from a mGA to fit a seal at the back.Then get a different pilot bush.Add electric tach. OR combine a early MGB trans with a 1600 tail stock and use the mga steel speedo gear. I am with Steve on this one. 3 main and use your mga backing plate. Space the radiator forward about 1/4 inch and be happy!It still will not be a rocket but will be better than the 1500. Go to 3.9 gears in the diff and convert the front to disc brakes. Then enjoy it. Bob

 

[Deleted member 3577]

I'd stick with the standard engine...
Get a nice cam and have someone who knows what they are doing work on the head.
The 'old' engine will put out 100hp & 100lb/ft without much messing around.

If you want to put a 5 main 1800 in go here.
https://mgaguru.com/mgtech/power/pp201.htm

 

[tony barnhill]

since it is a coupe.....my 1800 MGA was a roadster.

You might want to do some research on the MGA Coupe before you jump into irestoring it.

 

[Deleted member 3577]

Also...
Don't bother taking your old engine out until you have a new one sitting on a pallet.
Rebuildable 1500 engines are $150
Then you won't be without your car, as I was while waiting on my new engine.

And get rid of that [boat anchor] 29 lb. flywheel.
Fidenza makes a nice aluminum 10 lb. one.
You will notice the difference in that alone

 

[Steve_S]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]It still will not be a rocket but will be better than the 1500.[/QUOTE]I have a 3-main 1800 in my A and relatively speaking, it's a rocket. The car really moves.

 

[billspohn]

I like the 3 main MGB for MGAs. And I can't see wasting the money on an alloy flywheel when you can just cut down a stock one for much less.

 

[Deleted member 3577]

And I can't see wasting the money on an alloy flywheel when you can just cut down a stock one for much less.

I have been chastised for having an aluminum one and no scatter shield.

I won't do a cut down cast iron one
Best you can save is 10 lbs
(Assuming 6500+rpms you're optimistic it will hold together

)

But I've never run a stock one that light...
I defer to Bill S.
He has much more practical experience.

 

[Hap Waldrop]

Igot a buddy with a MGA coupe, putting a 5 main engine in it now, give me a call or pm (below listed website) and I hookmyou you up with him, he didn't do anyhting fancy with his MGB engine, pretty stock, but there's alot involed in making the switc and it's still fresh for him, so could be a wealth of info.

 

[Steve_S]

Other than race cars, no one runs 6500+ RPM in an MGA.

 

[billspohn]

Other than race cars, no one runs 6500+ RPM in an MGA.

Quite.

And I guess I'll have to watch using a steel flywheel to run to 7800.....but then it has only lasted for the last 30 years......maybe it's too soon to tell?

 

[Deleted member 3577]

Point taken...
Let me say then that a lighter flywheel would improve the sportiness of the car.

So far as 'bolt-on' performance enhancing components...
It's a pretty easy modification.

 

[marinmg]

One thing you might want to consider is being able to STOP before you GO.

Your 57 MGA coup comes with front drum brakes which with the stock 1500 engine I feel is marginal.

If you want to up grade your engine I would advise upgrading to front disc brakes from a 1600.

I am running a fairly stock 1500 with a little head porting and I got to tell you I am very happy with the power that it puts out. With the early mgb rear end I am very happy with freeway crusing speeds from 60 to 80 easily.
I upgraded to front disc brakes because as a daily driver I really needed to for freeway driving.
I think the BIG improvemet with the 1800 mgb engine is the rear oil seal. Not having to worry about pouring oil on friends driveways has to be a good thing.
So...
You might want to consider sticking with the 1500, do a little head work to improve the flow, improve the exhaust flow, maybe a mild cam and it really should be all you need. Check the mga guru site about spending $$$ and try to look at the big picture.

Basically, just get in it and drive it and have a little fun with it.

Liam

 

[SteveTR]

Thank you all for your advice.

I have much to think about.

Cheers,