78 Engine Rebuild - Goals Attainment
Performance - I spent a lot of time and money on this project. While most of it was done just because I had always wanted to rebuild an engine this way, I did have specific objectives. What difference has tt made?
Goals Attainment - Did It Achieve Them?
Is It Faster? MUCH faster! Like a modern car. A brand new 1978 through 1980 MGB, with all smog equipment on had an estimated 75 horsepower… pretty measly. This one, as modified with all components, is of "undetermined horsepower." Pierce has a similarly equipped and built car that tests at about 160 horsepower . Fitted on a body weighing in at about 2,300 pounds, that’s a lot of power available.
What’s Different? Before the rebuild, I couldn’t lay rubber in 1st… now I can lay it in 1st, 2nd, and 3rd; before, I was dragged down to 45 mph hour going up Mount Rose Grade west of Reno (20 continuous miles of 15%+ grade highway)… now, I can go any speed I want.
Comparison with my 70 B: My 1970 B was always much peppier than the 78 (less smog equipment and on 20K miles vs. 103K); now the 78 will easily not only outrun it, but leave it way, way behind.
Is It a Torquey Hill & Mountain Climber? Used to, I’d drive mountain roads in my red British sports car with the top down… only to have a string of big, fat SUV’s wanting to pass me – how humiliating. Now, they’re dots in the rear view mirror. This car is HOT! This type of conversion is what a friend of mine who used to race MGB’s would do to his car to get it way into the 120 mph + range – MGB’s as manufactured were basically 85 mph top-end cars.
Is It Economical for City Driving? I haven’t yet checked that. I know it won’t be as good as my previous single Weber 32/36 DCAV downdraft (which got 27 city and 33 highway), but I’m willing to sacrifice a good bit. I’m estimating that it will be about 20 mpg or so, according to what I was told by someone else who did an almost identical conversion.
I only drive this car about 2,500 miles per year, so I’m not denting the environment nor my pocketbook very much… it will still be significantly better than the SUV gas hogs!
What I Learned - Things I Would Do Different & the Same
Here’s what I’d do DIFFERENT
Carburetors: I'd probably go with new SU's (HS6's rather than HS4's) They're smaller and very reliable. It's not that the Weber DCOE 45's aren't - but they're HUGE and make the passenger side of the engine compartment unbelievable crowded. I've become very facile at removing and replacing carbs. It took me about 30 - 45 minutes each the first time... and the last time I did it, it was about 10 minutes.
Carb Synchronizing: If you're going to tune your own carbs, I'd recommend buying a vacuum gauge set. They are several different types, ranging from a single float type for about $30 up to very nice chromed four-gauge units that can synch up to four rams at once.
Transmission: As you probably know, you have to remove the engine and transmission together. Then, to re-install it you have to bolt up the transmission to the engine and put them both in at the same time. The overdrive is great. However, installing ANY "B" transmission is difficult. I posted a message yesterday or today about pre-assembling the transmission cross member (including the transmission mounts) while the engine & tranny are still tilted upwards, THEN lowering it and attaching the engine mounts and the cross member. This will save you 45 minutes or more in time and keep you from getting severely cramped and cut fingers.
What I'd do the SAME
Internal Engine Assembly: I farmed out this to a local company that specializes in high performance engines and has done a LOT of MGB’s. Even though I had continuously and even recently done a lot of work on my cars, it had been decades since I rebuilt an engine – thus, I just didn’t want to go through a learning curve on putting together a high performance engine that had $7,000 worth of new parts in it. I’m glad I chose this strategy and would do it again. Believe me, there was PLENTY enough to do for the rest of the project for me to take a sense of ownership… I worked all day, everyday from mid October through mid December, then again from mid January through now. I’m essentially done – and have driven the car – but keep on adding “creeping elegance” touches here and there.
Racing Fasteners: I'd definitely go with the high-performance / racing bolts, nuts, & studs. They cost a total of about $400 for the entire engine. But the cost of materials and labor if a single nut, bolt, or stud ever breaks will usually be somewhere between $1,500 and $3,000... seems like cheap insurance to me.
Engine Warm-Up: The time from when the car starts until it's warmed up is a critical period. The quicker you can get to normal running temperature, the better your oil works to properly lubricate the engine. The oil thermostat (a $30 productwith about $20 worth of hoses) costs about the price of two oil changes and will probably add 10,000 to 30,000 miles to the engine.
Engine Cooling: Anything that keeps the engine cool under running conditions helps make it last. At 3000 to 4000 rpm's typical highway running speed - compared to 1800 to 2200 for a modern car - there's a lot of heat and a lot of stress. I used the combination of alloy head, aluminum valve cover, 19 row oil cooler, cold air intake system, exhaust cooling system, header insulation wrapping, and the overdrive transmission to keep the engine compartment and the engine cooler. The cooling will probably add 20,000 to 50,000 miles to the engine.
Everything Else?... the Same: Since I changed out just about everything, there's not really any regrets. Pretty much everything else, I'd do just exactly the same.
Repeat Performance - Would I Do It Over Again?
Abolutely YES! Thishas been a FUN project and I’d do it all over again. I spent a few hours of most days working on it for about six months.
No Deadlines = Satisfaction: I'm retired and this is a major aspect of my fun time, so I give myself that privilege. After a career as an executive and entrepreneur – where everything was time critical and deadlines were drop dead in nature – it’s really enjoyable NOT caring about exactly when you finish something.
More on Performance Building
An Overview on Performance ReBuilding: I have created a more in-depth presentation on the performance rebuilding process.
A Component-by-Component View: This shows how to match your approach against your objections then examines each component that enhance performance, tells what each one does, then explains (in bullet item formate) the benefits.
This Will
Soon Be Posted on This Website: I'm going to be posting all the slides from the presentation on this website.
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