L28 oil filter mount

[Chris Riches]

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.

 

[.]

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?

[gilltech]

I agree, the bypass valve should be contained in the bare block itself.

[Chris Riches]

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?

[Zedman240®]

Looks like a ball bearing held in by a washer...Should still be there.

[Chris Riches]

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

 

[Zedman240®]

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.

[Chris Riches]

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.

[ozconnection]

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. 

[.]

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.

[Chris Riches]

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??

[.]

Here is a photo of a block showing the valve.......By the way don't ask me what that head is....its a mystery

[RB30X]

What is the head?

 

It can't be bolted on there.

[ozconnection]

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.

 

 

[DatPilot]

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.

[Chris Riches]

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.

[peter mc]

you can get them at nissan dealers

[nat0_240_chevZ]

looks like an rb head.

yes they bolt on.....

[bryan3976]

a rb head bolts on and works is that right ?

[bryan3976]

i did the same thing

 

where can i find one

[.]

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?

[nat0_240_chevZ]

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