Chris Riches Posted September 16, 2010 Share Posted September 16, 2010 I am currently rebuilding my L28 engine from my series 2 280zx and my engineer seems to think there should be a bypass valve of some sort in the oil filter mount but there is none. The workshop manual shows a differnt type to the one fitted to mine which is a plain right angle mount with no valve Can anyone tell me if they changed the oil filter mount from series one to series two and whether there is anything unusual about the bypass mechanism is the oil filter setups on these engines. Many thanks. Chris Riches. Quote Link to comment Share on other sites More sharing options...
. Posted September 16, 2010 Share Posted September 16, 2010 If by "mount" you mean the L shaped bracket that points the filter upward toward the bonnet instead of out toward the right wheel, then correct that does not contain the bypass. My understanding is the bypass valve is in the side of the block. You need to remove the L shaped bracket before it would be visible. You don't have a sandwich plate on there do you? Quote Link to comment Share on other sites More sharing options...
gilltech Posted September 16, 2010 Share Posted September 16, 2010 I agree, the bypass valve should be contained in the bare block itself. Quote Link to comment Share on other sites More sharing options...
Chris Riches Posted September 16, 2010 Author Share Posted September 16, 2010 Many thanks for the replies. Don't know what a sandwich plate is. The mount just bolts to the block with four bolts and a gasket. What does the bypass valve in the block look like? Maybe it has dropped out while the block was being bored etc? Quote Link to comment Share on other sites More sharing options...
Moderators Zedman240® Posted September 16, 2010 Moderators Share Posted September 16, 2010 Looks like a ball bearing held in by a washer...Should still be there. Quote Link to comment Share on other sites More sharing options...
Chris Riches Posted September 16, 2010 Author Share Posted September 16, 2010 The engine has been laid down. transported, been in a cleaning bath and generally moved about and now the engineer says it is not there. I guess it must have fallen out. Any idea where I can buy another one?? Thanks again, Chris Quote Link to comment Share on other sites More sharing options...
Moderators Zedman240® Posted September 16, 2010 Moderators Share Posted September 16, 2010 Its not on that alloy oil filter mount that's on an angle; you have to remove the four bolts, take of that filter holder then you will see the valve mounted in the block. Its not on the alloy filter holder. Quote Link to comment Share on other sites More sharing options...
Chris Riches Posted September 16, 2010 Author Share Posted September 16, 2010 The right angle alloy mount was removed before the engine was cleaned. etc. and the valve was not noticed at the time. Does it have a spring in it? Will need to buy another one from somewhere. Quote Link to comment Share on other sites More sharing options...
ozconnection Posted September 16, 2010 Share Posted September 16, 2010 You don't really need the bypass valve, which is a captive steel ball with a light spring behind it. I'm having my L28 rebuilt too and I deleted the bypass by removing the ball and spring and tapping the hole and installing an allen headed pipe plug. The bypass valve is designed to bypass the filter when the oil filter clogs. Solution, change your oil and filter at the proper intervals. Better solution...do as I've done and end the problem altogether. Post a picture of what you have if you're still in doubt and we'll go from there. Cheers. Quote Link to comment Share on other sites More sharing options...
. Posted September 16, 2010 Share Posted September 16, 2010 I don't agree. My understanding is when the engine is at idle the valve is closed forcing almost all of the oil to pass through the filter. as the pressure builds the valve opens and allows a percentage (maybe as high as 75%) to bypass the filter. If the bypass is not working it is either always closed or always open. If it is always closed your oil pressure will find other ways to escape.....through a gasket somewhere. Thats just a guess. I am sure someone will educate us. If it is always open you will not have enough oil passing through the filter.....Thats the worse scenario. Good luck with the diagnosis. Quote Link to comment Share on other sites More sharing options...
Chris Riches Posted September 16, 2010 Author Share Posted September 16, 2010 Have found a light tapered spring on the floor but no sign of a steel ball. Would prefer to have the bypass working as the reason it is being rebuilt is because it ran a big end in a motor which was otherwise in good nick and the engineer stated that this could have caused by dirty oil. Maybe the steel ball was missing all along after earlier work on the motor?? Quote Link to comment Share on other sites More sharing options...
. Posted September 16, 2010 Share Posted September 16, 2010 Here is a photo of a block showing the valve.......By the way don't ask me what that head is....its a mystery Quote Link to comment Share on other sites More sharing options...
RB30X Posted September 16, 2010 Share Posted September 16, 2010 What is the head? It can't be bolted on there. Quote Link to comment Share on other sites More sharing options...
ozconnection Posted September 16, 2010 Share Posted September 16, 2010 Have found a light tapered spring on the floor but no sign of a steel ball. Would prefer to have the bypass working as the reason it is being rebuilt is because it ran a big end in a motor which was otherwise in good nick and the engineer stated that this could have caused by dirty oil. Maybe the steel ball was missing all along after earlier work on the motor?? You could be onto something here. If the ball was missing, why would any of the oil want to be fed through the filter? The thing here is, oil or any other fluid in this or a similar situation will always find the path of least resistance, so I would imagine that none of your oil was being filtered....none of it! I'll say it again, the bypass system built into the side of the engine block is designed to compensate for two primary conditions that may occur at some point during service. (remember these engines were fitted to pedestrian sedans as well as sports cars, meaning that servicing wasn't always going to take place regularly, and in some cases, at all) 1) To prevent the oil filter from leaking/splitting/rupturing when the engine is cold and the oil is thick and the engine driven enthusiastically. 2) not to limit or restrict the flow of oil through the engine when the filter is excessively dirty. Good luck with whatever you decide to do. Cheers. Quote Link to comment Share on other sites More sharing options...
DatPilot Posted September 17, 2010 Share Posted September 17, 2010 My uncle has a few heads like that that he plays with on the old Z, he says the were off a Mercedes. very nearly bolts on from last coversation. Quote Link to comment Share on other sites More sharing options...
Chris Riches Posted September 17, 2010 Author Share Posted September 17, 2010 Many thanks to everyone who has taken the trouble to help me. I have decided to put the bypass valve back in and will need to buy one from somewhere. Anyone got any ideas or maybe even one for sale?? Many thanks. Chris. Quote Link to comment Share on other sites More sharing options...
peter mc Posted September 17, 2010 Share Posted September 17, 2010 you can get them at nissan dealers Quote Link to comment Share on other sites More sharing options...
nat0_240_chevZ Posted September 19, 2010 Share Posted September 19, 2010 looks like an rb head. yes they bolt on..... Quote Link to comment Share on other sites More sharing options...
bryan3976 Posted September 21, 2010 Share Posted September 21, 2010 a rb head bolts on and works is that right ? Quote Link to comment Share on other sites More sharing options...
bryan3976 Posted September 22, 2010 Share Posted September 22, 2010 i did the same thing where can i find one Quote Link to comment Share on other sites More sharing options...
. Posted September 22, 2010 Share Posted September 22, 2010 looks like an rb head. yes they bolt on..... No Way!!! .....really?? Why haven't we heard this before? It mustn't work very well....Or maybe its because you might as well but the whole RB engine in? Quote Link to comment Share on other sites More sharing options...
nat0_240_chevZ Posted September 23, 2010 Share Posted September 23, 2010 works.......well i never said that..... cyl spacing, headbolts line up but...... cam drive external, not inside timing cover. oil galleries way out water balleries are massive in comparo to the L. nat0 Quote Link to comment Share on other sites More sharing options...
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