Hi I had my 350 Chev engine rebuilt last year and it has only done about 3000km and was going through heaps of oil and fouling plugs, we decided to pull it down to check it out. We found that there were no hone marks left on the thrust and non thrust sides of the pistons as though the bore had been polished, all bores were the same. I have been told that leaving honing paste in after the rebuild would do this. The engine rebuilder told me it was caused by not having a cover under the PCV valve on the rocker cover.
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Re: 350 Chev Engine Irregular Bore Wear
What sort of rings were used.you could cut open the oil filter and see whats in there what condition were the bottom end bearings in.running too hot?what sort of pistons,forged or cast?how was it run in
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The only two possibilities are it's leaking into your cooling system due to a blown head gasket, or you are burning it due to engine wear such as worn valve guides or piston ring/bore wear. Have a compression check done. (By the way it's losing not loosing)
Either it's leaking into your cooling system due to a blown head gasket, or you are burning it (oil) due to engine wear such as worn valve guides or piston ring/bore wear. Have a compression check done. (By the way it's losing not loosing) Is the exhaust very blue in colour? that indicates burning oil
Wow.. 1967 ... 427.. I would start by checking the dist cap and spark plug wires and coil. .. this is such a valuable car you want to go first class on parts.. Performance cap rotor, plug wires like accell or better.. Bascially give it a good tune up..it is a carb car check the level of the flotes in the carbs. excess gas could be fouling the plugs.. Valve seals is a good place to look for oil comsumption.. If it is the Valve stem seals.. it will smoke when you first start it after sitting overnight or over day/.. during the night oil runs down the valve stem and collects on the top of the piston.. Last one these i rebuilt the machine shop installed the wrong cam bearings and the oil did not make up to the valve train.. had to pull motor and dissemble and replace the cam bearings with the correct ones.. seems like sometime during the year Chev, changed the location of the oil feed holes for the cam.
Determining what caused sudden slack in valves would be of concern to me, as in perhaps, changed oil brand, grade or filter incorrect? Most small block chevy's have adjustable rocker arms. Is that not the case with yours?
there are a lot of posability's mineral oils form carbon buildup in the rings over time as engine cilinder wear changing to detergent oil after years of mineral oil can flush out carbon causing engin to burn oil, or excessive ideling glazes the bore which causes oil consumsiom, both require cylinder hone and new rings, a hole in air cleaner will dust engine and score cylinder and wear main and big end bearings full rebuild required,but it can be simply a valve seal and oil leaks down engin valve or a blocked air cleaner causing the engine to **** air threw the polution nose sucking air and oil from sump
As an engine wears the ring lands on the pistons wear also. In addition to ring land wearing on the piston, the bore in the cylinder develops a wear pattern. Has the engine been rebuilt? If the pistons have worn ring lands and were re-used it may allow the rings (new or old) to twist in the grooves and catch on any ridge in the cylinder, thus breaking them.
When the engine is apart you must check for proper ring land wear. You need to consult the piston manufacturer for proper wear specs, typically around 0.006in.
If you're getting a visible amount of smoke/oil from the breather after the rebuild something is not right. The rings are not seating. I would definitely recommend boring/honing the cylinders and going with a new set of pistons/rings so you don't have to pull it apart again. A little more now can save a lot in the long-run.
Unfortunately, you hit the nail on the head, i assume being a 1992 model, that the transmission has not been overhauled or rebuilt in it's almost 20 years of service. If it hasn't you have done very well.
It is normal wear and tear in your case, not being overworked, but just by doing its job. In an automatic transmission there is clutches, not one (like a manual) but several, and they are immersed in the oil (they are called wet clutches, for this reason), now because they are in the oil, they tend to last longer, but as they wear (similar friction material as in a dry clutch) the dust and small particles are absorbed by the oil and it degrades the oil as well. Thats why I always recommend and a firm believer in regular servicing, but if this is the first time you have had a rebuild especially in a 4 x 4, then continue what you have been doing.