XR7 Dave
Registered User
Finally got around to pulling the motor from our XR7, the one that has 200,000 miles on it and has seen 6500rpm, lots of detonation over the years, more than a few lean passes at the track and in the end 440rwhp. Some people thought it would have broken rings, bent connecting rods etc.
Well, no bent connecting rods, no damaged pistons, no broken rings, no scuffed skirts, no spun bearings, nothing. It was almost boring pulling it apart. I've said on here before that I think Mobil 1 is good stuff, and particularly 15w50, and this motor really looks decent for the mileage and use. The main bearings barely show any wear at all except for the front one which shows the typical wear spot due, I assume, to extreme loads on the crank from the supercharger. The rod bearings are worn smoothly down to the copper pretty much like every other SC motor I've ever seen but the journals all seem very smooth to the touch. I'll be checking clearances after a little cleanup. There are no desposits in this engine at all. It will clean up with just a little solvent. Most of the ugly stuff is on the outside due to a cracked oil pan and timing cover (haha, those were my fault).
The cylinders have a ridge and we'll be checking that too for wear just to see what it looks like. Cross hatch is still visible and the motor had about 135psi compression on all cylinders +/- 5psi.
Just thought that might be interesting.
Well, no bent connecting rods, no damaged pistons, no broken rings, no scuffed skirts, no spun bearings, nothing. It was almost boring pulling it apart. I've said on here before that I think Mobil 1 is good stuff, and particularly 15w50, and this motor really looks decent for the mileage and use. The main bearings barely show any wear at all except for the front one which shows the typical wear spot due, I assume, to extreme loads on the crank from the supercharger. The rod bearings are worn smoothly down to the copper pretty much like every other SC motor I've ever seen but the journals all seem very smooth to the touch. I'll be checking clearances after a little cleanup. There are no desposits in this engine at all. It will clean up with just a little solvent. Most of the ugly stuff is on the outside due to a cracked oil pan and timing cover (haha, those were my fault).
The cylinders have a ridge and we'll be checking that too for wear just to see what it looks like. Cross hatch is still visible and the motor had about 135psi compression on all cylinders +/- 5psi.
Just thought that might be interesting.