Dr_Thompson said:
hey everyone.ive been doing a lot of research on rod bearings and decided its probably a good idea to change them out.Im still debating whether to change them out myself or take it to a mechanic. I talked to a few mechanics i know and they didnt offer much help. they both refused to do the job. one of them i talked to said doing the rod bearings was like opening a can of worms. I asked him what he was talking about, he said that once you change the bearings out it can show more problems that wernt there before??Anyone know what hes talking about. As long as the bearings arnt knocking there shouldnt be anything wrong with the crank right. As i said, im still debating the job
Most mechanics aren't going to take time being careful and considerate while replacing rod bearings in an installed motor. When the motor is upside down on a stand it's faster going and I assume it's easier to work quickly yet considerately.
If you do them yourself you are going to go slow, use common sense and courtesy of your parts, and heed the pearls of wisdom offered here and elsewhere on the task. Harder to screw things up than to do the job right when taking that approach. A high volume mechanic doesn't have that luxury.
Here's one example of where a mechanic "opens up a can of worms" when doing this job: Oil pan leak after putting it all back together. Cause: RTV should cure 24 hours without exposure to oil and preferably with warmer temperatures and good humidity (not dry, cold air). Mechanic wants to bolt it up, fill it up with oil, and get it the **** out of his way. The RTV silicone gets no time to properly cure, the inner portion of the bead stays gummy due to it's premature exposure to oil, and the oil pan starts leaking a short time later. What mechanic isn't going to make this mistake? They all are going to want to get that car out of their working bay and they could give a rat's ass if the pan doesn't freeze outside while the RTV should be curing in a warmer clime.
Now, there's no reason every home mechanic can't avoid this one: Instead of filling your motor up with oil the minute you finish bolting up the oil pan you put your bottles of new oil on your car seat (so you don't forget to fill before you start). If it's not summer then you rig a light bulb under the oil pan to gently warm it for 24 hours while the RTV cures. Some cardboard taped to the sides of the oil pan can help trap warmth from the lightbulb if it's really cold outside. Shoot, mist outside of the oilpan with water or place a humidifier alongside the lightbulb if it's really dry out. Even a pan of warm water if nothing else. Don't worry about the moisture conditions inside the motor. There'll be enough lingering as combustion byproduct from last time the motor ran.
Yes, as long as the motor is smooth sounding the crank is fine, but as those bearings wear the odds become less and less in your favor. It takes oil in better shape and more of it to keep the crank off the bearings. 20 years ago bearings only got replaced during a full motor overhaul because most cars were hard pressed to make it past 100,000 miles. A SHO motor can go 3, 4 or more times that far and remain healthy if maintenance is adhered to regarding the "soft" parts. Rod bearings are indeed soft parts. You can scratch them with your fingernail. They are cheap and easy to replace. It just takes time and care.
.anyways, ive decided im gonna do the job myself and with the help of a friend. theres enough write ups in case i get in trouble. Question though for those who have done the job, did you use a plastigauge or whatever tool to check the clearance of the rods once there on?On the write ups ive read no one uses them
