This is to Richard, but I've put it on-list because I got an undeliverable
mail kick back.
Apologies for using bandwidth
Hi, Richard.
I'm sorry but I don't subscribe to this view. I've had any number of people
talking about putting big carbs on cars and just as many moaning at the
results.
The bottom line is that petrol engines work best at a thing called the
stochiometric ratio of air to fuel. This is about 13.75:1 (I think), no
matter what carbs are used. The error people do make is to think that big
carbs=power and this isn't necessarily true. Overcarbing an engine, without
head work, changes to the cam profile, exhaust and ignition advance curve
can drop the inlet gas speed so much that the fuel doesn't atomise = really
rough running. Equally, too much tune for road use makes an engine a pain at
anything less than about 1/2 throttle.
To me, the only valid part is, 'push the car harder'.
Right, sermon over.
I think that one of two things has occurred, if your problem is indeed in
the block...
(1) The previous owner did cause a wear ridge and higher revs have caused a
ring to touch and break.
(2) There was a ring which was already on its way home and your using the
car harder has found the flaw.
In the first event, sufficient revs to cause a rod to 'stretch' would
probably be very, very high-well past the point of valve or even contact
points bounce, when more revs would just make more noise, not more power.
Also, why only one cylinder?
In (2), the car wouldn't have too do too much work for an existing flaw to
travel.
In any case, assuming you haven't been seeing how far into the red the tach
needle will go, you remain blameless. An MGB may be a Morris Oxford Sports
but the B-Series motor is a tough old lump which can take a lot of
punishment-ask the racers.
I drive my car hard from time to time, in the knowledge that it has good oil
pressure and flow, cools itself and makes no untoward noises. That said, I
temper my enthusiasm with the knowledge that it is pushing 29 years of age
and can't be expected to rev like an undersquare, Japanese motor.
I hope you will mail me with the results of your car's post-mortem, as and
when you do it.
Cheers,
Dave H.
|