Musing on a recent show, a caller said he had an 87 Mazda with 190 k miles which had overheated and destroyed the head. He liked the car & wanted to keep it on the road if doing so made sense. He had already purchased a used head for $30 at the local junkyard, and wanted Ray and Tom’s opinion.
Ray said for a $30 risk, no harm to install the head and hope for the best. Could work.
But here’s my question: Ray suggested besides the head, to replace the rings at the same time. Apparently doing this job is doable for a driveway diy’er by removing the oil pan, disconnecting the rods from the crankshaft, and pushing the pistons out the top.
I got to thinking this ring replacing job is going to be a lot of work. Especially when there’s no indication of a problem w/the rings in the first place. Add to that, there’s a risk the $30 used head might not work. Replacing the rings on this car seems overkill. I think I’d just replace the head, and if it worked, drive it. Whatever fails next isn’t likely to be the piston rings.
If I wanted to spend money beyond just the $30 junkyard head, I’d take the junkyard head to a machine shop and have them rebuild that part. And as long as there’s no metal bits in the drained oil, leave the piston rings alone. Might also ask a the machine shop to check the flatness of the block.
What do you think? Does it make sense to replace the piston rings along with the head in this situation?