1086 oil pressure

gbs · Feb 14, 2015

our 1086 is losing oil pressure idling at operating temp. manual guage installed shows just above 0 at low idle,speed it up to about a 1000 it will hold 18 to 20 psi,under load at operating temp.it stays above 40 psi, it holds around 20 psi idle cold,new oil pump,plastigage shows rods have .003, mains .002 clearance on old bearings,check pressure regulator no sign of any problem, while it was apart a .060 shim was put under the spring, were could the problem be?

the tractor vet · Feb 14, 2015

It is really hard to get a good reading on the mains when the crank is hanging down on the caps so that reading you got is probably more in the line of five or better and on the rods with any left over oil you are more like 3.5 -4.5 on them , THEN what about the cam bearings . . I think NOW is the time to pull her down and do a major . Yes you can roll mains and rods in , BUT what does the crank mic. out at and what about cam bearings . How many hours on the block ?? might be a good idea to have it line bored and the rods done also . Myself i don't mind doing the first rebuild in Chassis but not the next one . I get real fussy on the second rebuild i like to have them line bored the deck dusted and contour bores recut and new cam bearing installed then go thru the head all the way .

pete 23 · Feb 14, 2015

I have never seen only .002 on a main in those engines.New crank and bearings will run over .004 up to .006. Plasigage is for those who don't have proper micrometers to check actual clearance. Like Vet says, unless you supported the crank your reading is useless. You have serious leakage at mains, rods, cam bearings, relief valve or worn out pump or someone left a plug out of oil gallery somewhere. Can't tell you from here.

gbs · Feb 14, 2015

I agree that the mains at ,.002 is is most likely incorrect as for the rod it's close as it was clean and dry when checked, galley plugs were mentioned where are they located,i once saw a 396 chevy that had oil pressure problems and that is what was wrong with it,is it possible to replace the cam shaft and bearing without removing the engine

Jim Naden · Feb 15, 2015

(quoted from post at 20:05:26 02/14/15) I agree that the mains at ,.002 is is most likely incorrect as for the rod it's close as it was clean and dry when checked, galley plugs were mentioned where are they located,i once saw a 396 chevy that had oil pressure problems and that is what was wrong with it,[b:32a029fb09][i:32a029fb09]is it possible to replace the cam shaft and bearing without removing the engine[/i:32a029fb09][/b:32a029fb09]

The engine needs to be removed to replace the cam bearings.

Then, if you don't want to remove the cylinder head, after removing the push rods without removing the rocker shaft, the engine needs to be turned upside down to get the lifters out of the way to facilitate removal of the camshaft.

Then you can replace the cam bushings. Be careful to get the oil holes properly aligned during bearing installation.

1086 oil pressure

gbs

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the tractor vet

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pete 23

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gbs

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Jim Naden

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