I have a rod bearing knocking in idle but under a load it tends to not be so loud. I want to reface the journal on the crankshaft put undersized bearing plates on the piston journal. Can I get the main crankshaft out with just removing the oil pan? and pull the defective piston? Or does the whole fracking motor have to be pulled?
These procedures may be performed with the engine in the car. If additional overhaul work is to be performed, it will be easier if the engine is removed and mounted on an engine stand. Most stands allow the block to be rotated, giving easy access to both the top and bottom. These procedures require certain hand tools which may not be in your tool box. A cylinder ridge reamer, a numbered punch set, piston ring expander, snapring tools and piston installation tool (ring compressor) are all necessary for correct piston and rod repair. These tools are commonly available from retail tool suppliers; you may be able to rent them from larger automotive supply houses.
Remove the cylinder head.Elevate and safely support the vehicle on jackstands.
Drain the engine oil. Remove any splash shield or rock guards which are in the way and remove the oil pan. Using a numbered punch set, mark the cylinder number on each piston rod and bearing cap. Do this BEFORE loosening any bolts. Loosen and remove the rod cap nuts and the rod caps. It will probably be necessary to tap the caps loose; do so with a small plastic mallet or other soft-faced tool. Keep the bearing insert with the cap when it is removed. Use short pieces of hose to cover the bolt threads; this protects the bolt, the crankshaft and the cylinder walls during removal. One piston will be at the lowest point in its cylinder. Cover the top of this piston with a rag. Examine the top area of the cylinder with your fingers, looking for a noticeable ridge around the cylinder. If any ridge is felt, it must be carefully removed by using the ridge reamer. Work with extreme care to avoid cutting too deeply.When the ridge is removed, carefully remove the rag and ALL the shavings from the cylinder. No metal cuttings may remain in the cylinder or the wall will be damaged when the piston is removed. A small magnet or an oil soaked rag can be helpful in removing the fine shavings. After the cylinder is de-ridged, squirt a liberal coating of engine oil onto the cylinder walls until evenly coated. Carefully push the piston and rod assembly upwards from the bottom by using a wooden hammer handle on the bottom of the connecting rod. The next lowest piston should be gently pushed downwards from above. This will cause the crankshaft to turn and relocate the other pistons as well. When the piston is in its lowest position, repeat the steps used for the first piston. Repeat the procedure for each of the remaining pistons. When all the pistons are removed, clean the block and cylinder walls thoroughly with solvent.
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If the knocking is from the bottom of the engine, it may be the big end bearings have worn.
Replace them or not? Difficult question.
Replacing the big end (crankshaft/piston rod) bearings may stop the knocking/rumble noise. It depends on the crankshaft..
If the crankshaft has worn oval on its journals, fitting new bearings is unlikely to achieve anything as the bearings may break up due to the oval of the crankshaft. Removing the crankshaft and checking the journals for ovality/regrinding if necessary isn't a 5 minute job.
You say you have good oil pressure. That's a positive.
Personally, in your situation, I would try an engine oil additive that's designed to eliminate knock provided the main bearings haven't worn down to base metal. It's the cheapest option.
Failing that - and again, personally - I would remove the oil pan and fit new big end bearings in the hope that it would work.
The next step, if that doesn't work - would be to remove the crankshaft and have it reground and fit oversize bearings. Or get a 2nd hand engine...
You say the car was given to you for free .. you have nothing to lose. Try an additive first.. molyslip/molybdenum or whatever...
WHEN YOU REPLACE ROD BEARINGS YOU HAVE TO CHECK CRANKSHAFT JOURNALS WEAR.IF TAPER TOO MUCH.CRANKSHAFT HAS TO BE REGROUND OR REPLACE.YOU HAVE TO TAKE ENGINE OUT OF CAR.TO DO A SHORT OVERHAUL.YOU CAN REPLACE BEARINGS IN CAR USING ROLL OUT PINS AND DROP THE OIL PAN.BUT WHEN YOU REPLACING ROD BEARINGS AND MAINBEARINGS CRANKSHAFT HAS TO BE CHECK FOR WEAR.IF YOU PUT NEW ROD BEARINGS IN THEY WILL FAIL PREMATURELY.
It can be done as long as the journals on the crankshaft are smooth. I would use Plasti-gauge to check the clearance between the new bearing and crankshaft. If you have a bad rod bearing already, or the crankshaft journal is really scored, it's a waste of time.
Well the cam bearings will have to do with this also,if it has them,if not it can be the wear in the cam carriers.But most likely the crankshaft journals are worn to much,the crank would need turning,and over size rod,and main bearings would need to be installed.
Does the oil light come on or the knock occur during the engine warm up after a cold start?
There could be a couple of problems causing the issue. You could have an oil pressure pump or pump pressure regulator sticking. I would have a mechanical oil pressure gauge installed and verify oil pressure at idle and 2500 rpms to make sure oil pressure is in normal ranges.
You could also have excessive piston rod bearing, crankshaft bearing or cam shaft bearing wear that will cause oil pressure to drop too low to prevent the rod knock your hearing at 2500 rpm.
You said a knock and not a ticking noise,so I don't believe a lifter is the issue at 2500 rpm.
Start with the oil pressure check and go from there.
Let me know.
Likely you need more than one (not rod, but rod bearings) In most cases you get knocking noise and low oil pressure as symptoms. If caught early you can do this in-car otherwise engine needs crankshaft and all bearings as well as new pump and system flush.
Here's what you don't want to hear...A loud knocking noise from inside your engine is generally caused by a crank or rod bearing...when caught very early, sometimes they can be replaced. however, once the noise is loud, the attending crankshaft journal gets "hammered" out of shape and the job becomes very expensive and in most cases more costly than engine replacement. There is one other item that can cause a loud knock...your flywheel. Bearing problems generally cause low oil pressure. If you have that, it's gone...if not, have the flywheel checked before sending the engine to the scrapyard.