As I somewhat expected, putting my brand new ported cylinder head
on my MGB did not result in an instant increase in power. As I also
somewhat expected, it did result in some driveability problems.
Yesterday I had Terry Barnard tune it up on his dyno at the Engine room
(408-247-9005 x17). Terry charges $100/hour for such work.
Our baseline run showed that I was running a little bit lean and to the
wheels was getting 90.2 lb-ft of torque and 75.5 hp. Maximum advance
was at 27 degrees.
(dyno results at http://www.red4est.com/lrc/lday00/dyno000913.jpg)
Since the air/fuel ratio was in the right ballpark, and the timing
seemed a bit retarded versus what Terry expected would be best we
tried advancing the timing. To summarize the results of an hour of
dyno time, we ended up backing the timing off to 24 degrees full advance
and richened the carbs by 5 flats. The results of this work was 90.8
lb-ft of torque, and 75.5 hp. Basically I had already gotten my
tuning pretty close to right for the head. I'm still having
drivability issues though. Ones that I didn't have before swapping the head.
Terry suspects that with a bit more compression and cam, and running on
race gas, I could make use of the added flow of this head and notice a
few horsepower gain. I don't know what the car makes with the stock head,
I'm planning on putting it back on tonight and taking it back to get a
baseline. However 75.5 at the wheels is about what one would expect
from a nearly stock motor.
My goal for the motor was something that was as reliable as an anvil,
good for being driven on the race track (though not racing) as well as
the street, hopefully with a bit more power than stock. I had hoped
that a mild porting job would get me a little bit more power without a
big loss in driveability.
Once I get a baseline with the stock head, I'll see how much power I
gained or lost with the head. If I didn't gain much, I'll probably
find someone who has a hot bottom end that wants a good fresh (1,000
miles) ported head. If I did, I'll likely keep the head for when
I absolutely have to race the car as the head works just fine at full
throttle (i.e. at race tracks).
I found myself doing some serious soul searching on my drive home. I've
done a very good job of building a nice handling classic sportscar
that is works fine on both the street and the track. If I lived in
the pacific northwest (Oregon, Washington, BC) it would even be
legal and competitive in the Conference I production class. It was
definitely faster than the IP Datsun, and with stiffer shocks and springs
would have been nearly as fast as the other MGBGT.
Unfortunately, the car is not as much fun on the street as say a
spridget. I also couldn't make her substantially faster on the track
without throwing a lot more money at her. This may sound heretical,
but if I look at the situation with cold brutal logic, I'd probably
be better off building a "spec miata" and having a car that was not
only a convertible, but faster and better handling than my BGT. That
extra 20 hp would come in very handy when teaching and passing is only
allowed on the straights. Or, I've got a friend who already offered to
give me a very good deal buying back the Mk II sprite that I sold him
ten years ago. All it needs is freshening up the motor, and rebuilding
the suspension, and a paintjob ...
I don't want to give the impression that I am unhappy with Jasmine.
I am certain, however, that there is someone for whom she'd be a much
better car. Probably someone that would like a good solid car that they
could drive to the vintage races, tape up the headlights, put on numbers,
race, then drive home, and then to work the next day. I haven't for
sure even decided to sell her. To be honest, I have no idea what
she's worth. She's probably worth a lot less to anyone except the
aforementioned vintage racer who is looking at what it would cost to
build her. I sort of tallied it up. I put about $5,700 into things
like the roll cage, seats, belts and other racing/go-fast stuff.
I probably put $2,000 into parts and machining for the motor. When I
first put her on the road, I put about $5,000 into rebuilding or
replacing everything on her that could wear out.
In short, if I was given a relatively straight but used up MGB, I
could probably duplicate her for $10-15,000. Plus labor. And she
still needs a paint job. Has anyone bought a mechanically sound
vintage racer MGB lately? What are they worth? I've been shocked by
British car prices before, so she might be worth more than the $5,000
I'd guess, which is a lot less than she's worth to me. It wouldn't
be such a problem if I knew that by keeping her, I'd continue to
throw money at her. I'd like a nice set of wheels for the street,
those are only $600. A quick and dirty paintjob that would make her
all the same shade of yellow, and that the next owner would curse me
for might only cost another $600, rather than $3,000 or so for a good
paint job. Better headlights are another hundred. Cutting the roof
off, welding the bars on top of the cage and replacing the roof ...
That would probably cost me at least a couple hundred for getting the
windsheild pulled and replaced, but then she'd be legal for SCCA and
NASA as well as Conference.
As I said, she's not officially up for sale, but if anyone is looking
at building an MGBGT vintage racer that makes a fine daily driver,
drop me a line at lrc@red4est.com. I could save you an awful lot of
work and I'd know that Jasmine would be going to someone who would
care about, and for her.
Larry
--
Million Monkey Software -
Our code sucks, but you should see this thing we wrote called Hamlet.
lrc@red4est.com www.red4est.com/lrc
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