Moss Motors, Ltd

I need performance. I've considered engine swaps, but I'd only consider V-8s and they just don't fit too well without hacking things up. Considering how unmolested this car is, that may not be wise.

There is little information on the web concerning how much power is generated by the various mods on the MGA/B engines.

I'll make a few presumptions on making power and you can tell me if I'm the right track.

-- Power is made by breathing. The major contributors are the cam and head.

-- The MGA/B heads are not built for power. Can I assume the alloy crossflow head is markedly better?

-- If the above is true, then a minimum intake combo would be a side draft weber with a proper intake. The only exhaust would be headers.

-- Cubic inches equal power. A large bore MGB block would be best. I've seen no stroker kits, but the largest bored MGB is around 2.0L.

-- With a decent cam and some alloy roller rockers, this combo should easily hit 125-35hp without the cam being too severe and the revs kept moderate (under 6k).

Your thoughts?

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59 MGA 1500 -- 3rd in the restoration queue

Dollar for dollar I would look at the Moss supercharger kit.  I've never talked to anyone that has been sucessfull with the 2 litre conversion.  I started to build one years ago and the project got shelved.  If anyone else has experiance with this I'd love to hear about it.  All I've heard is that they overheat.  There is also the issue of head gaskets sized for large overbores.  The supercharger on a well built relatively stock 1800 should give you plenty of power.  I don't know what you've read but I don't think it posible to get over 100hp out of a B series below 6000rpm.  HP is a mathmatical formula of torque and RPM.  125hp normally aspirated is going to require a serious cam that shifts the torque curve up in the RPM range.  It probably wouldn't be much fun on the street.  Just my ever so humble opinion.  You did ask for thoughts.

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72 MGB 80 TR8
Pittsburgh PA

So much has been written about these engines by more knowledgable people than I, that I'll not launch into any discussion of it all here. Suffice it to say that there are books aplenty on the subject. Find a book by David Vizard. It'll teach you more than you ever wanted to know about the B Series engine (MGA & MGB). Kent Prather, a heck of a nice guy, and the winner of so many SCCA championships in his MGA that I've lost count, Says that in race trim, a normally aspirated 1622cc MGA engine will top out at about 150 HP. You could never live with this engine on the street.

The real question here is about YOU. How much power do you want? How much money are you willing, or able, to spend. The old saw is, "Speed costs money,sir. How fast would you like to go?" All things considered, my tastes would be in agreement with underdog's. A B engine with a supercharger, well tuned, would be a fine performer. Then again, it won't give you ten second quarter mile times. Consider how far you're willing to go with the other systems in the machine to accomodate the extra grunt. Are you ready to upgrade the suspension and the brakes?

By the way, after talking to knowledgeable folks and some experimentation, I've discovered that if you want that crossflow head,an expensive piece, to really work, you'll have to put in a rather radical camshaft which is designed just for use with that head. This makes carburetter and distributor tuning a can of worms you may not want to pour out on the bench. I've been there. As I said, it's about you. It's about your pocketbook, your patience level, your sense of thoroughness, and most importantly, your desire for performance.

If you want to take the most economical way through this thing, I'd suggest the aluminum non crossflow head on a five main bearing MGB engine, with a stage one or two camshaft. Mill the head for about nine and a half to one compression,and smooth the combustion chambers and the exhaust ports. Don't change the intakes, they are already too big, in my opinion. Now top it off with a DCOE 45 Weber carburetter and enjoy an engine well suited to the stock chassis in cood condition. If there's anything left over in the account, add a five speed. If you don't enjoy that, perhaps a muscle car is better suited to you. No offence is intended, it's just a point of view.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Bill, the downside of increasing power output on a normally aspirated engine is that there is a point where to get the additional breathing you start to sacrifice low end torque which is really the key to a nice driving car. The cross flow head would be a great item, but I'd stick with the twin SUs on that setup unless you plan on racing. They will give you good preformance without hurting the lower end of the power curve and also allow vacuum pickup for the distributor which a Weber won't. For about the same price the supercharger kit is very interesting, lots of torque and still good higher rpm performance. Installing a B 1800 would definitely help with either system, as the added displacement will add torque. I wouldn't punch it out too far unless you just have to have a 'killer' motor, save some for a future rebuild if you can.

It's really hard to advise one option over the other without knowing what your goal is. If it's just to have a quick nice road car then I think I'd go for the B engine, a ported stock head, cam and header and spend the extra money on a 5 speed conversion instead of the crossflow head or supercharger. At least at that point you can still use almost everything for a later upgrade either way if that's not enough power.

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'73 Midget (V6)
'59 MGA (I6) under construction
'73 Lotus Europa
'52 MG TD kit car body project.
'98 Jag XK8

"There is a fine line between a hobby and mental illness"

Motorbill and I seem to be thinking along the same lines and typing at the same time! His experience with the details is valuable, I couldn't furnish those.

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'73 Midget (V6)
'59 MGA (I6) under construction
'73 Lotus Europa
'52 MG TD kit car body project.
'98 Jag XK8

"There is a fine line between a hobby and mental illness"

Boss Bill-

When I was a kid I did the whole nine yards on an MGB: Thirty over pistons, ported head, exhaust extractor (Header), recurved distributor, 45 dcoe weber, very hot cam= about 135HP PLUS!

COULDN'T DRIVE IT ON THE STREET!

Well, I could but it wasn't much fun.

Barely idled at 1000 rpm

Ran worse than stock from 2500 to 4000- Major boggy throttle.

 At 4000 it kicked in hard and pulled  past 6000 like nothing.

All the extra power broke the tranny.....Twice! (lost that non-syncro first) No fun to replace plus expensive.

Took the weber off and put the SU s back on and lost alot of the bogginess, gained back some low end

 When looking at performance mods consider whether all the parts of the driveline are up to the task.
  Also, breathing is not the only issue in performance modifications. look for a well matched and balanced combination. You want all the mods working in concert and multiplying eachothers' benefit in a balanced way. If you have one part of the chain that is overkill or underkill it can bring the whole thing down.

Horsepower sells cars- Torque wins races. The supercharger plus some other conservative mods sounds better to me.

LCJUTILA 

Gentlemen -- I was basing my horsepower hopes based upon power made by the 302/5.0 Mustangs that I own. It not very hard anymore to get 450hp out of a 5.0 lter engine that still idles well.. New aluminum heads flow quite well and with a proper cam design you easily double what a 65 Mustang had for original power.

I own many (5) performance Mustangs with my moniker based upon one of them. Although my first car was a 65 Mustang I later sold it for an MGB, non-synchro car. Although I love the sound of a V-8 turning insane RPMS, I was also very fond of the MGB burble with Abarth tips. Still in my top 10 list of lovely exhaust notes.

I don't need massive power, in this, my wife's car. But I don't cotten to being embarrased either. I waa hoping that some newer head tech would up the ante more than you all say. Since I'm Mustang poor, if an aluminum crossflow doesn't net major improvement at other than high RPMs than I'm not interested.

Also I had neglected to consider how delicate the transmission migh be. I blew third out of the 'B', although the rear axle stayed put.

The A came with the 45 weber, although with an intake that required the PO to create a bulge in the wheel well. I also have the original SUs, fully intact. I've been around SUs long enough to have rebushed a few.

As in Ford-land it appears the B suffers from ultra thin walls in the cylinders. What is the overbore limit? I'm actually surprised no one does a stroker.

Overall it appears I'll have to go fast in my track car and simply burble down that country lane next to the river in a more comservative B motor, with an Al or modded head, use my Weber and add a proper header. Better yet, I'll let the wife drive and she'll be tickled.

 

 

 

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59 MGA 1500 -- 3rd in the restoration queue

I really don't consider the walls super thin.  It's just that to get near 2 litre you have to bore over 100 thou.  .060 over is plenty safe.  The engine I started to build, I actually had a crankshaft stroked 1/8 inch for it.  A local shop welded up the jornals & reground it to this stroke.  The problem is that the connecting rod bolt heads then will hit the cam.  I intended to have my machine shop cut the cam down in the area in question to provide adequate clearance.  We're only talking about a 1/16" and it's in between the lobes.  The project got put on the back burner and I've got too many others right now to start fooling with something that runs fine as is.

For what it's worth here is what I have now.  .020 over 8.8 comp pistons AE I believe.  The head was cut to achieve a little over 9 to 1 compression. Runs fine on high test pump gas.   It has the stock size valves with some home done porting.  Crane dual valve springs & retainers and chrome moly pushrods.  Camshaft is an APT VP-12.  Nice noticeable idle at around 900 and pulls up to six grand with no prob.  The power band seems to be strongest from 3000 to 5000.  When I asked about the next step up at APT they said you could probably drive the VP-14 on the street but you'd have to have a real good reason! LOL  I have an MSD ignition with a 6200 chip in the rev limiter.  I experimented with different carb setups, stock 1 1/2 SU, 1 3/4 SU and what I have now a Mikuni side draft.  The Mikuni really broadened the torque curve.  It will pull smoothly from 1500 on up.  For exhaust, I have the stock early manifild and a stainless Falcon single muffler system. 

I've never had it on a dyno but it runs very well.  At a track day at Beaverun, I pulled right past a relatively stock early model Miata.  Since you are a Mustang guy, you may be interested to know that I also passed a GT!  My car has some substancial suspension/ wheel tire upgrades as well and handles like a big go-cart.  So this Mustang is in front of me, a woman driveing.  Soon as we hit the turns, I'd be all over her back bumper.  Naturally on the straights, she would punch that V-8 down & leave me behind.  Soon as we got to the first turn at the end of the front straight, I'd out brake her and be all over her bumper again.  No passing on turns for track days BTW and you have to wait to be signaled to pass.  Anyway after about 2 laps of this the instructor told her to let me by on the straight.  I never saw the Mustang again after that.  Such fun!  I'm not trying to sound like bragging, just trying to give an idea of what you could expect with this level of modification.

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72 MGB 80 TR8
Pittsburgh PA

Ah yes,

To each his own. I continue to be somewhat surprised at how most all of the discussions concerning modification of our cars center on the production of engine torque and horsepower. For myself, I would prefer to spend the same time and effort on handling and brakes, and the saving of weight. And as I recall in the dim past, that's what set sports cars apart from other types of "performance" machinery.

Even when most folks start speaking to the issues of braking, suspension, and tires, it's couched in terms of "handling the extra power" generated,or soon to be generated, by massive engine mods. I'll go on record right now as saying that I'm not all that interested in power generation. I'm far more interested in building up a machine that generates it's performance through its ability not to have to shed speed in turns in the first place. Power is always relative, and you can always buy more of it. Chassis development and the technique of optimizing it through skillful driving are a more artfull, and in my opinion, more satisfying, pursuit.

I suppose that's why I've always enjoyed racing classes wherein the power is equalized and limited through a conservative formula. That leaves the individual or team to become more creative with the parts of the car that reflect "outside the box" engineering solutions and preparation. I'm not saying that raw power is bad, or that I find it boring.

I'm a fan of big time drag racing, where massive power and its skillful application are an art/science of their own. But those ain't sports cars. I suppose I'm just saying I'd like to see as much discussion of roll center, mass centroid axis, pitch coupling, and anti-dive/anti squat characteristics, and the pure discussion of handling and chassis dynamics, not related to extra HP, as I would like to see the throwing around of terms and specs concerning mind numbing torque curves and what differential will tolerate 500 ft. pounds of twist in a Spitfire.

Now I'll shut up.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Underdog-

Don't mean to burst your MGB RACER bubble.

THAT LADY PROBABLY HAD TO STOP FOR GAS!!!

I've got a 69 Mustang w/ a 351 and the only thing that car can't pass?......... A GAS STATION.

 

It handles well too. 

LCJUTILA

(I know, we've all heard that joke) 

Motorbill-

I really do agree with your above comments. Especially about how the weight of the car is so important. It is the one modification that affects every aspect of performance and can be very challenging to change.

However, sports cars are about balance,  Strengths and weaknesses and improving what is perceived by the owner as a weak point or points.

The smaller british cars that we deal with could almost all use alittle more umph. They already outhandle most cars on the road. I'll argue about whether the brakes are better though 

Most Rock Musicians want to play alittle louder, most Car Owners want to accelerate alittle faster.

LCJUTILA 

LCJUTILA, 

You'll note I started off by saying, To each his own". These are just toys in the end, and every one of us who has one, has his or her own reasons and desires attatched thereto. I am not here to judge, believe me. I, indeed do engine performance upgrades for my customers all the time. But there is a difference between making sure your old roadster can keep up with a Camry and insisting on dragster grunt. I'm not advocating or in any way trying to dictate what other sports car owners ought to do. I'm only trying to add my own perspective and my own preferences to the discussion.

With respect to brakes and handling, no the brakes, in stock specification are not up to date. I don't believe I stated that they were. I will, unfortunately, have to disagree with you concerning the handling issue. Most cheap sedans on the market today can generate better skid pad numbers than MOST of our old front engined roadsters. And in transitional handling characteristics they are also superior, with notable exceptions like Europas and Super Sevens and the like.

Those are the areas of fascination for me, maybe not for others, where I would like to put the greater emphasis. I'm not looking to start a personal debate. I'd just like to see more inquiry into those areas. Cheers.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Motorbill-

I'm not arguing with a word you're saying-just thinking out loud. And all you real racer guys who get a chance to take your cars out on the track- any jokes I make are out of jealosy!

As far as these cars being just toys-Even though my Lotus is one of only approximately 200 REAL JPS' it was my daily driver before the rebuild began and will be when it's done. Many people have chastized me for that but the car is very challenging and when you manage for that brief thirty seconds at a time to drive it correctly it is absolutely sublime. 

LCJUTILA 

lcjutila:

Underdog-

Don't mean to burst your MGB RACER bubble.

THAT LADY PROBABLY HAD TO STOP FOR GAS!!!

I've got a 69 Mustang w/ a 351 and the only thing that car can't pass?......... A GAS STATION.

 

It handles well too. 

LCJUTILA

(I know, we've all heard that joke) 

 

FYI  thanks but my bubble is still intact. 

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72 MGB 80 TR8
Pittsburgh PA

Underdog-

I thought of another thing my Mustang couldn't pass....   A SMOG TEST!

LCJUTILA