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Enhancing performance with snags...

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Nunyas

Nunyas

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As I'm getting really really close to getting all the mechanicals squared away on my '76 'B, I'm thinking more and more about "improving" the engine performance (using the engine block as it is). However, I have a few hurtles/obstacles that I have to work around or with. Because I live in the wonderful state of California, I have to keep the smog parts on the car. So as a result, my thought's on improving the engine's performance include the following:

-Upgrading the valve train (roller rockers, springs, etc.)
-mild street cam

I realize upgrading the valve train will do little to nothing for performance if the intake and exhaust flows are still the same. So, that's the biggest part of my delima. The exhast seems to be relatively easy to deal with by using headers and performance oriented cats and mufflers. The intake however, seems to be a force to reckon with.

I suppose a "better breathing" intake manifold could be custom made with all the necesary recepticles for the emissions parts, and stick with the original ZS but that kind of defeats the purpose. So, what to do for the carburetion? Are there any 'larger' bore ZS carbs available? If not, are there any other carbs out there that can be used in such an application? From my tinkerings under the bonnet, it looks like the carb needs to have at least 1 vacuume attachment for the EGR valve and one attachment to the float bowl for the ELC (Evaporative Loss Containment) system.

Anyone else around here try to improve the performance on their B while keeping all of the emissions parts on their car? New cars do it all the time, but they have computers. There must be a way to do it mechanically, and still be "smog legal". Thoughts or suggestions?
 
If it were me, I'd go with twin SUs and put the smog gear on a shelf for that occasional smog test. Isn't it only every third year you have to get tested?
 
Start by reading the book from the absolute expert in MGB tuning.
How to Power Tune Mgb 4-Cylinder Engines from Peter Burgess.
This book is simply said extremely good. Peter will tell you where to invest in your engine, what is the biggest bang for the buck, the things to avoid and so on (and let me tell you there are alot).

I followed is receipes with very nice results (all are dyno tested):

Big K&N filters
Change of needles on carbs to compensate for new filters.
Fuel regulator
Head work as prescribed in the book (road version)
PECO big Bore headers and muffler system
Conversion to electronic ignition
Camshahft Piper 270 indexed with degree wheel
Radiator electric fan conversion from mechanical

Peter Burgess
 
I have to smog every 2 years with the possibility of being "flagged" for random testing at any given time. So, my preference is to do modifications that would allow me to pass a test with as little preperation as work possible. A tall order to fill I know, but I'm looking for ideas and knowledge of things that work and still keep emissions down at this point.

One other thing I had on my mind. Do those alloy valve covers really make a noticeable difference in valve tick?
 
Alloy valve covers reduce the valve noise a little, but I've heard many complaints of sealing problems. I was thinking of buying an alloy cover at one point but after checking it out I decided the stock cover was the best route.
 
FWIW I have an alloy cover and I've never leaked a drop from it.
 
You have limited options, as you know.
Getting the ignition timing spot-on and then advancing just enought to be within emission specs is worthwhile.
You could try planing the cylinder head a bit (maybe 0.035") to slightly improve compression). And while you're at it, a three-angle valve job might help a bit.
Running lighter lubricants (or sythetics) in the gearbox and final drive might help a bit (Red Line gear oil is excellent). I'm not a huge fan of sythetic oil for the engine, but if your's is in good shape and doesn't use any oil, it might be worth a shot.
An electric cooling fan (replacing the regular one) might help (or a trimmed-down regular fan).
You might reduce parasitic loss by getting a racing front pully (to slow down the alternator and water pump). I've driven lots of street cars with this modification and everything still works fine.
Finally, a tighter final drive or lower profile tires (for example, 50s) would give the car more scat off the line but cruising speeds would be reduced and so will gas mileage. Be sure tire pressures and alignment are good.
One point: these are perfectly nice cars "as is". The real fun in them is not massive power, but the overall balanced drivng experience. In terms of investment vs. "fun factor", you might be better off to spend your money on suspension, brakes and performance tires.
 
hmmm... good point. I've noticed while crawling around on my back under the car that I have no anti-sway/roll bars on the suspension. Combine that with the 75 series tires that the PO had installed and it feels like the car will flip going around turns at any speed over 15MPH. At 10MPH turns "feel" a lot faster than they actually are, due to the percived lateral G-Forces. Hate to be a party killer, but I don't think the '76 is very "balanced", especially when compared to the siblings of other years. I guess I ought to shoot for correcting that before trying to eek out more engine power.
 
negative ghost rider. I have a white '76 with a black hard top (small side window decal says "Moss Motors") that doesn't fit quite right. It use to be some sort of hideous metallic pea green/yellow, but you wouldn't be able to tell that while driving by. Within 2 blocks of my place, there's a yellow RB MGB with a full toneau and a badly faded dark blue CB MGB GT that I haven't seen move since I first saw it.

Anyways, my 'B is a daily driver and I take it to work everyday. So, if it was in a residential area during this time of day it more than likely wouldn't be me. I work near the ABC building off of "Flower" near "the 5".
 
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