Hi Don,
Gee, a little adversity and he wants to fold
up his tent and go home :) I would start with the easy things first. First,
drain the transmission oil and see if there is any metal in the oil. This would
be an easy way to get a "free" peek at what may have happened inside the box and
point you to the next decision. Lots of metal and you are into a big problem and
no metal is probably a little problem. The metal, by the way, may not be
steel... the shifting forks, for example, are often made of brass/bronze.
Assuming that the oil looks fine then, If it is possible, I would remove the top
of the transmission with the transmission still in the car, and see what is
going on. Your description of the problem sounds like something a little strange
might be happening ie. every thing works fine except 4 gear and it only grinds.
At this point if you haven't found the problem you will have to pull the
transmission.
Changing to a 5 speed might be nice. The 4 speed
you have has a long shift pattern which really isn't bad once you get used to it
and the ratios are a little wide but the engine has lots of torque so it really
doesn't matter. Changing to a 5 speed only makes sense if your 4 speed is trash
or if you just want a 5 speed in my opinion.
Swapping engines is generally a bad idea. The
possible exception is when your car model was offered with two different engine
options and you switch to the engine your car didn't come with
originally. The first "problem" with engine swaps is that you destroy
the value of your car since you now have, essentially, a kit car. Recently there
was a TVR on Ebay that had been extensively modified and whoever did the work
really knew what they were doing. This car had the best of
everything including a blue printed Ford or Chevy V8. The owner quoted 1/4 mile
times from the drag strip so the car was not only beautifully done, it actually
ran. The paint and interior was also beautifully done which is unusual in these
type of conversions. The final bid price was less than $12,000 which is less
than it would cost for the parts the owner had changed. It was also (probably)
less that the same car would have brought IN THE SAME CONDITION if it had been
left stock. A beautiful car but... Even if the "value thing" isn't a concern
(Don has money he hasn't even counted yet :)), there are a lot of other problems
with engine swaps. Will the other components like the drive shaft and rear end
take the additional strain. Cooling will probably be an issue. Fuel consumption
and gas tank size will be a problem. So as you solve each of these problems (and
they can all be solved) your car become less and less of a Marcos and more and
more of a "kit car".
Buying a Ginneta is a good idea. It will give you a
car to drive as you are working on the Marcos.
Mike Denman
Chassis # 4079