Ja defender Posted February 11, 2015 Author Share Posted February 11, 2015 Although I am sure the cam bearings are intact I am now wondering if these bearings are worn. Can anyone say what the effect of worn cam bearing on the oil pressure? I am really concerned about the change in the oil pressure as the temperature increases. Quote Link to comment Share on other sites More sharing options...
Ja defender Posted February 17, 2015 Author Share Posted February 17, 2015 I am in the process of investigating the rocker feed and have removed the head. I am a little puzzled at my findings as on removing the head there was some oil on both sides of the gasket in the vicinity of the restrictor. All bolts were tight and both the head and block have checked out fine without any distortion. Any thoughts on this, is this normal? The current cam bearing is the older type with the larger hole going up the the rocker. I am about the replace that with the newer design bearing with the smaller hole. I have been reviewing the vacuum pump and have noticed the pump uses oil pressure to extend the vanes. Could a less that perfect vacuum pump contribute to my low oil pressure problem? Has anybody experienced a problem like this associated with the vacuum pump? Quote Link to comment Share on other sites More sharing options...
Rangy35 Posted February 20, 2015 Share Posted February 20, 2015 I dont think the vacuum pump will have a influance. But anything is posible, you never know what other peolpe do. Are all the blank off's in the block and none leaking, is there no crack in the main galary? Quote Link to comment Share on other sites More sharing options...
Ja defender Posted February 22, 2015 Author Share Posted February 22, 2015 I have looked long and hard and I have not yet found any cracks and none of the blank off leaks. The search continues. Quote Link to comment Share on other sites More sharing options...
RustyNissanPrairie Posted February 22, 2015 Share Posted February 22, 2015 If your cam bearings are in place then its the o-rings on the vacuum pump/oil pump drive- the bearing assembly where it fits into the block. If either of the 2 o-rings fail then it allows the oil to short circuit and develop lower pressure than normal. Quote Link to comment Share on other sites More sharing options...
Ja defender Posted February 23, 2015 Author Share Posted February 23, 2015 I have already replaced both the o-ring on the outside of the skew gear and the internal one which seal the outside of the vacuum pump. I thank you for the thought nerve the less and welcome any other thoughts you may have. Quote Link to comment Share on other sites More sharing options...
Rangy35 Posted February 23, 2015 Share Posted February 23, 2015 Have you checked the relieve valve and spring. Length, tension of spring, bore clearance etc? Quote Link to comment Share on other sites More sharing options...
Ja defender Posted February 25, 2015 Author Share Posted February 25, 2015 Yes I have checked both the relieve valves in oil pump and the ones for the oil jets. I have even gone furthers by r eplacing the entire oil pump. Quote Link to comment Share on other sites More sharing options...
Rangy35 Posted March 26, 2015 Share Posted March 26, 2015 How is the investigation going? Quote Link to comment Share on other sites More sharing options...
Ja defender Posted April 21, 2015 Author Share Posted April 21, 2015 Folks, I finally found he source of my low oil pressure problem. Someone in previously trying to seperate the number one main cap, used a punch type tool to hit the block just below the cap. This resulted in the creation of a bulge or dimple on the fact of the area where the main cap sits. The size of the bulge created a bearing the crank clearance of .008 in, where the limit is .004 in. To correct the problem I used a file to make the area level again, allowing the main cap to sit properly. The mistake I made was not checking the clearances on every journal previously. What I had previously done was check the rear and middle caps as the crank was just cut to .0010 in undersized. On my second measurement of the clearances I made sure to check the clearances on every bearing. After reassembling the engine I now have 27 psi oil pressure at idel with the engine at normal operation tempature. I want to thank you all for your suggestions and interest and stand ready to share the knowledge I have gained in investigating this low oil pressure problem. 1 Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted April 21, 2015 Share Posted April 21, 2015 Bravo ! Well found. Mo Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted April 21, 2015 Share Posted April 21, 2015 Yup, that's a result, and as a bonus yo know your oil system inside out Was the bearing OK? Quote Link to comment Share on other sites More sharing options...
Ja defender Posted April 22, 2015 Author Share Posted April 22, 2015 Yes the bearings were still in excellent condition, so I reused them. Quote Link to comment Share on other sites More sharing options...
Rangy35 Posted May 19, 2015 Share Posted May 19, 2015 Awesome, some people should just not be left around vehicles. Quote Link to comment Share on other sites More sharing options...
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