Sunday, Jul 07, 2013 at 18:40
Quoting from your followup
"besides he has also confirmed crank shaft and bearings needs changing."
There is one word in that sentence that I hope is not the case for you. This is the word ''and". Yes it will most likely be necessary to replace the crankshaft bearings, but to replace the crankshaft AND bearings is a very expensive operation I imagine. I have some recollection the crankshaft from a 2h and a 12ht are the same which may save you some money - if that needs to happen. Generally it would just be the bearings, and the crankshaft cleaned up at the machine
shop with a proper lathe.
Regarding the rings. I assume he is talking about the piston rings. In a full overhaul, yes the pistons and rings are replaced. They are unlikely to be a very expensive addition to the cost, so you might as
well agree to having them replaced. There are also bearings inside the pistons where the conrod connects to the pistons.
The pistons are the things that go up and down really fast. The crankshaft is the thing - a long shaft - with lots of bumps in it that act as a crank - an offset lever that the piston pushes on to turn the up and down motion of the piston into a round and round motion that drives the car. In between the piston and the crankshaft is a rod, called a conrod, or connection rod.
There are bearings at the top and bottom of the conrod. One set, the big ones on the bottom that go onto the crankshaft, is called the big end bearings. The other end that go onto the pistons are much smaller, so they are called the little end bearings. There is a heavy rod, called a gudgeon pin that goes across the inside of the piston and the conrod is held in place by this gudgeon pin. The little end bearings are flat bearings, i.e. not roller bearings, that allow the conrod to move on the gudgeon pin.
The big end bearings on the crankshaft are also flat, i.e. not roller bearings, as are the bearings on the crankshaft.
Given your specialists believe you have suffered from low oil pressure, ANY and probably ALL of these wearing surfaces will be best replaced whilst doing this job.
This list would include all engine bearings and piston rings. Not the pistons themselves unless they are damaged.
I trust this helps you understand a bit more of what the mechanics are saying to you and why.
It will also be very important for them to make sure the oil squirters that pump oil onto the underside of the pistons (to keep them cool under the high temperatures created by the direct injection motor), and the oil pickup from the sump, are screwed in correctly with proper sealant to ensure no loss of oil pressure. Bob referred to these issues back at the start.
Tim
FollowupID:
793464