Reviving Dead Cobra

[C5GTO]

With the onset of the summer driving season and after more than a year sitting around the garage with a dead engine, I felt compelled to revive the Cobra with a new engine. For some history, I first built this Classic Roadsters Cobra in the mid-90’s and had actively driven it to over 50K miles since then. For the last 25K miles, the car has been outfitted with a Ford Performance X302 which is a roller cam crate motor outfitted with Ford aluminum heads and other go-fast goodies. It was advertised as having up to 340HP of which mine had most but not all of that.

Just over a year ago while doing some spirited driving, an ominous “clicking” sound emerged out of the engine bay. At first, I thought it was a header gasket that started leaking. After a bit more driving, it turned into a “clacking” sound like maybe a rocker arm had become loose. Long story short, I limped the car home and after some basic diagnostics (compression check, rocker arm check, etc.), I determined it was an issue somewhere in the bottom end which would require engine removal.

I didn’t have the enthusiasm or garage space for the tear down so I put a car cover over the car and left it to gather dust. A related issue is that the car really needed an overdrive type transmission like a Tremec as the Richmond Gear 4+1 transmission translated into high engine RPMs at driving speeds in the 70-mph range. So the price tag for the repairs was not only a fixed engine but also a new transmission.

Fast forward to this last winter while the snow was flying and I was starting to have some serious withdrawal symptoms from not having a Cobra to keep driving exciting. I now had a new detached garage so space was no longer an issue and I decided to pull the engine to see what the problem was.



Everything inside the engine looked beautiful except the rear piston on the passenger side which had tried to weld itself to the cylinder wall. Obviously, a lubrication breakdown of some sort had raised its ugly head.



I had been hoping it was a spun rod bearing or something that could be fixed with some parts replacement. This was worse in that it had not only damaged the piston but also the engine block. Not something impossible to overcome but certainly more involved to fix. After some cussing and swearing, I decided the Cobra didn’t have enough power with the old engine and what was really needed is a 347cid engine to go with a new Tremec TKX transmission. After all, what Cobra can’t use a little more punch