The only other thing in my opinion that that is really going to help you
"noticeably" on an 80 model over what you have already done is to raise the
compression ratio substantially. The 80 model is an ultra low compression
engine to meet American EPA, smog, unleaded fuel and fuel economy
requirements and standards. The pistons that come stock in an 80 model are
actually concave, in other words, dished, for low compression. On my earlier
model B, which had higher compression to start with, I bored it .060 over
(that's pretty much the limit and you gotta be lucky to get away with that
much), put in earlier model flat top pistons and I milled the head
substantially (don't recall exactly how much).
In addition to raising the compression ratio, I did a three angle valve job
and ported, polished and relieved the stock head. I also cleaned up the
stock cast iron exhaust manifold and matched it to the head ports as closely
as possible. This all made a tremendous difference in MY B. My engine was
pretty loose and worn before I started so any improvement at all would have
been nice but I got a lot more than just any improvement. It was a major
difference.
I'm sure that if I had also put in a high performance cam it would have also
helped some but I just stayed with the stock cam and was plenty satisfied,
so much so that I never worried about a cam, valve springs (or headers)
later on. I did put a Petronix electronic ignition module in but that was
more for not having to worry about maintenance with the points and condenser
than for anything else.
MG's are not known for high revving and my B wasn't a high revver either but
I had more than enough oomph and torque to peel rubber and squawk the 195 x
60 series B F Goodrich Radial TA tires in second anytime I wanted to. The
3.90 rear axle ratio that it came with didn't hurt either. The mid range
power was so plentiful that I just learned to shift a little earlier rather
than trying to rev to 5000 to 6000 every time. Additionally, it pulled very
strong at 60 to 80 MPH on the highway and was very comfortable as compared
to the previous pre-rebuild engine. I was very satisfied with the results on
MY B, - - - that is, until I bought my new C5 Corvette! My Black Beauty B
roadster was absolutely awesome for a B but nobody driving a B can truly
understand the word "awesome", until they've tried it in a C5 Vette
roadster! Actually "awesome" doesn't cover it. I can't think of an expletive
that does.
Still a big MG fan too. I love my Vette but I miss my B.
Jerry
Jerry Erbesfield
Was - 73 Black beauty MGB roadster
Now - C-5 Black Beauty Vette roadster
E-mail: jerbesfield@mindspring.com
Website: http://jerbesfield.home.mindspring.com
> -----Original Message-----
> From: owner-mgs@autox.team.net
> [mailto:owner-mgs@autox.team.net] On Behalf Of smarc
> Sent: Tuesday, March 16, 2004 11:18 AM
> To: Mgs
> Subject: making power above 3800 rpm?
>
>
> I'm getting ready to R/R front end bushes, and wheel bearings
> on my '80 LE in anticipation of another driving season. Been
> thinking about driving the B's all winter! Can't wait for summer!
>
> Previously I've de-smogged the car, installed an old-style
> exhaust manifold & free flow exhaust. Installed Pierce intake
> manifold with Weber carb, who's performance I was unhappy
> with, and so swapped that out for an earlier OEM intake with
> dual SU HIF's. Runs great now, except... it runs out of
> "oomph" around 3800 RPM. Most of the time I don't drive the
> car too hard at all, but sometimes it would be nice if it
> could pull a little better. I'm no mechanic, but I been
> lurking here long enough to have learned a bit through
> osmosis. Admittedly I don't always understand all that I
> know, so the technical aspects of some of this stuff are
> often lost on me.
>
> Having said that, I surmise that I need to address my
> camshaft/distributor situation. Engine status is 70,000
> miles, clean, no exhaust/vacuum leaks, good compression
> across all four cylinders, very minimal oil consumption. Last
> time I adjusted the valves was late last summer. Very solid overall.
>
> Looking for recommendations as to what, if anything, exactly
> to do about it, ie; what cam, what to do about dist, what
> else needs to be dealt with at this time? I believe someone
> had said the camshaft could be changed with the engine
> in-situ, which I would prefer. Is that correct?
>
> I looked at several of the usual suspect websites, but aside
> from a lot of technical data I'm unable to grok, I haven't
> found anything that helps me.
>
> This car is general road use, occasional 'spirited' driving.
> Not looking to do anything radical.
>
> '73 B (will sell or trade for BGT)
> '80 B/LE (favorite)
> '03 330Ci (Least favorite)
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