I have a car with a Chevy 350 and now I’m having more problems yet again. This time I do believe it’s rod knock because I took off the oil pan and there was metal dust and a few little bit larger pieces about the size of sand. When I drove it last it started making a pretty bad knocking sound and that’s why I parked it and took the pan off. If the main bearings are screwed can I fix it?
My bigger question is should I just bite the bullet and give up and give the engine to a shop. I have the tools and I know the theory and what (I think) I’m supposed to do. I’m basically 17 and I have this car with this engine because I want to learn and I wanted a project but my parents don’t really think I can do it anymore and I’m starting to doubt if I can. Plus I’m not sure I’ll be able to easily pay for the rebuild.
Should I take it to a shop and how much would it probably cost me? If I fix it myself what should I watch out for and what did I potentially do wrong last time? Thanks for any help.
A crankshaft kit (crankshaft and bearings) is $180 from O’Reilly auto parts. You will need to thoroughly clean the debris from the block, inspect the block main journals and check the connecting rods for damage/out of round.
As much as I’d want you to learn on this one, it may be time to replace it. Who knows where all the damage is? You could have problems all over the place, not just the crank and bearings.
Put back the oil pan and fill the engine with fresh oil. Hopefully the noise will be gone and you could go on with your life. Worst scenario is that the engine knocks again.I would drive or tow it directly to the junkyard.
I’m going to take a different stand. I do agree this could be a big project…but it’s also a great learning experience.
I’d disassemble the block…send it to a machine shop to assess. I’ve dealt with machine shops that sell all the parts you need to rebuild an engine. You might need some help…but it could be fun.
The only caveat is cost. This could be a money pit. How much is it worth.
I looked at MIO’s other threads and I think his parents are correct that this is beyond his current ability . Plus the fact that it appears he does not have the funds to even finish it if he starts this project.
A rebuilt 350 block with head (long block) can be had for about $1600 from almost anywhere. You might find one cheaper local to you. They are ready for you to swap over your manifolds, headers, starters, water pump, basically all accessories, drop in and go. With a warranty. Don’t know if that breaks your budget, but it cold be cheaper in the long run.
I don’t mean this in a mean spirited way so don’t take it as such. Due to your age and inexperience i think you are asking for trouble by doing this yourself and could easily end up with a lot of lost money. There are many inspections and procedures that must be done and many of those are not even listed in service manuals.
A remanufactured or crate engine could easily be the better and more inexpensive way out.
For what it’s worth I did a rebuild on a Ford 5.0 some years ago and used Federal Mogul main bearings. During the setup; I discovered that the thrust main bearing is hour glassed in shape by .005 of an inch. That leads to the question of what is the correct crankshaft end play? Too tight or too loose depending upon whether you base that measurement on the ends of the bearing or the center. Three sets of bearings were like this.
Several calls to Federal Mogul and their engineering department called me back. They had no idea nor would they make a suggestion as to which way to handle this. I chose to go tight and let the shell ends wear off until the thrust surfaces were flat. So far it’s fine but I loathe doing something like this and it bugs me to no end that the engineers at FM were not aware of this or had any idea as to how to resolve it.
They suggested another set of bearings until I told them that was the 3rd set in a row made like this and that I had even taken a micrometer into the parts store and showed them the problem.
See what I mean about the unexpected and things not found in a manual?
I am going to go against the grain here. All of the options which have been discussed on this thread require pulling the motor from the car. If you’re going to do that, why not attempt a DIY repair? As long as you do not remove the pistons from the cylinder bores, replacing the crankshaft and bearings is not difficult, and you can purchase a crankshaft kit which includes all of the bearings so all the measurement is done for you.
Insofar as cleaning, most of the metal shavings will be caught in the oil pump pickup screen and possibly inside the lubricating passage of the crankshaft. It should be possible to clean or replace the oil pump pickup tube, and any debris inside the crankshaft will not matter since it’s being replaced. Carburetor cleaner, lint-free paper towels, and compressed air can be used to clean engine parts.
To be honest, before going through the effort to pull the motor, I might even take apart the connecting rods from below and see if the crankshaft journals are visibly damaged to the point that new bearing inserts aren’t an option. If it’s only been driven a short distance while making noise, maybe the defective bearing(s) have not worn down to the steel backing, and the mating journal surface is still ok. You will need to raise the vehicle high enough to lay on your back underneath and have room to apply the necessary torque. The safest way to do this without a shop lift is to use a floor jack to lift each corner one at a time, and place a steel wheel made for a truck–laying on its side–under each tire.
Not that I know anything about it but back in my youth I knew a couple guys that spent a cold winter night outside under their cars with a trouble light, putting new bearings in. I assumed this was an emergency procedure and have no idea of the long term success. Still for a set of bearings and some plastic gauge, one might ask what is to lose? I sure wouldn’t recommend doing an overhaul though or pulling the engine.
bearing replacement will be only a temporary stop-gap measure
it’s for sure that crankshaft will be found to have some wear, if not a visible damage
pulling the engine and getting replacement crankshaft and bearings may be a better solution in longer-term, but one has to assess the overall condition of other subsystems… it may be that for the lasting repair the parts to be replaced will “cascade”, where you go deeper you discover more and more things to address. a crate/short-block may be a better option in the end
I also had a history of making my own first rebuild when I was 19 or so, on my father’s car, which was in quite a bad shape at the moment and it was a great learning experience, even having book and nothing else as a mentor.
The small block Chevy is likely the most common engine found. Ive seen them in everything from Jeeps to Datsun to a shopping cart once at a drag race.
Assuming its pre-fuel injection its about as simple and forgiving as an engine can get. It’s also the cheapest to buy parts for and no piece is rare or hard to find. If you ever wanted to rebuild one then go for it. If you get it took apart and the block is ruined its still the easiest engine to find used. Finding a used one in any old car/truck/ school bus/ dump truck… is not hard. Plus if you build up a nice engine and the rest of the vehicle is junked you can move it to most any general motors product. (and a lot of non gm vehicles have adapters too)
First I’d like to say thank you for all the replies everyone who did. I had a lot of time to think about it and talked with my parents and they don’t care what I do. This is meant to be a learning experience for me and that’s what I want. I already took the engine out last night and I think I’m going to attempt to do this myself. I have the money for a rebuild and all the time in the world but not very sure if I have the money for a rebuild. If it doesn’t work oh well I tried my best and I lost a couple hundred on bearings and a crank. Worst case scenario I will most likely buy a used on that I know will work. I’m very stubborn and don’t like admitting I’m beaten so I’m going to try again. Again thank you for all the responses it’s always nice to get some other ideas as I have no one around me or that I know who works on cars, so I’m kind of on my own except for the internet. Thanks
