high oil pressure and noisy head

[grim_d]

Hopefully the 2 are not related.

I seem to have abnormally high oil pressure, as below (in bar)


Cold start/idle - 7
Cold cruise 6/7
Cold throttle - 8


Hot idle - 2/3
Hot cruise - 5/6
On boost - 8+


On left hand turns it will fall to around 3.


The gauge is a pro plus unit which only goes to 7 bar and I don't entirely trust it but it is consistant. I don't know what grade oil is in it but have bought some Fuchs 10w50 and a new filter which i should have for the weekend, I will also check the sump pan and compression test the engine if my kit turns up. Also going to put standard sender and gauge in too see if readings are the same, I don't have a mechanical gauge to use. Any other areas I should check while I'm at it?


My other problem is I think the head is louder than normal when hot, very quiet when cold, but hoping it just needs shimmed but too thin oil might contribute to this too, I have a video if anyone wants to listen, apparantly it was at fusion motorsport for a check up before I took delivery and he had no concerns but I have been unable to contact him to ask, thoughts


https://www.dropbox.com/s/bynvox09xn48v00/VIDEO0032_01.mp4


For reference spec is,


Forged pistons, cosworth head gasket
Piper 270 cams, head ported and polished
3071r turbo.
Nistune.


Thanks in advance.

 

[splmum]

I would hazard a guess and say the 'oil pressure sender/sensor' is on the way to failing or has failed.

Mine reads and has always been consistent with the following values

Cold start/idle - 6
Cold cruise - 5
Cold throttle - 6

Hot idle - 2
Hot cruise - 4/5
On boost - 5+

Just listened to your vid. I wouldn't be running the engine with it sounding like that.

First off, get the rocker cover off and see if you have anything floating around loose in the top of the head.

That will give you something to start with and some pics will help.

 

[grim_d]

That's the plan for Sunday, once I get it home today I'm going to stick it up my unit until I can get a look at it. It has been like that since I got it but I thought it may have been needing shimmed, it's clear now that's not the case although it does sound worse in the video.

Im thinking it's some sort of clearance issue as it only appears when up to temperature.

 

[warpspeed]

If the clearances are too small the valves won't close properly..not watched the video as my internet connection is too slow

 

[RO_SUNNY]

Hmmmmmmmmm I have the exact same oil pressure as yours @GRIM_d.....and I think that this is 100% correct!

 

[RO_SUNNY]

This is how you shall check for correct oil pressure.

If you can't see the values please note that:
Idle speed hot engine: 0.98 Bar / 14 psi

At 3200 rpm : 3.42 - 4.41 bar / 50 - 64 psi

This are values are for the engine with no load (stand still)

 

[red reading]

Oil pressure is fine if there was an issue you would have oil pissing out of seals or if it was low it would knock the big ends out in no time, sounds like clearences on valves as they do get bigger on these engines as they warm up or could be a blocked oil spray bar for the cams.

 

[grim_d]

I've had a look in the filler cap and cranked it at the same time and the lobe I could see looked dry. I'm going to get the cam cover off on Sunday for a proper look and to clean the spray bars as well as check a bunch of other things.

I want to reshim it later in the year too.

 

[grim_d]

Had the rocker cover off and the spray bars out, one was a bit blocked, so cleaned up and refitted, cranked it over and confirmed all spraying, bit of wear on the lobe but nothing to be concerned with, made no difference to the noise.

Drained the oil, clean as a whistle, no significant metal particles, didn't drop the sump pan as I am almost certain there is no issue with the pickup, plenty oil getting to the head.

Compression checked when hot for good measure, 150ish psi across all 4.

The head has rocker stoppers so removed these to get a good look at everything, I couldn't see any obvious damage or problems.

This surely has to be a clearances issue, shimming?

When cold or idling there is no noise, as soon as you touch the throttle when hot it appears.

here's a link to pics of the head

https://www.dropbox.com/sh/keajwjh3hrqno3s/QgA9ZayLQ9

My only observations were that the rocker arms could be wobbled a bit when their valves were open, didn't alarm me too much though, solid when valves closed.

In the pic of the timing chain, right in the middle of the pic there is what I assume to be the tensioner? There seems to be a pin of some kind not all the way in, dead center of the pic

 

[STU666V]

Cant see any of your pictures but if it's a little pin on the tensioner your meaning? it should be like that! When the tensioner is removed you can push it back in and a little clip holds it closed, thats what the pin is for.

 

[grim_d]

Cheers Stu, good to know.Lobe to rocker clearances checked today, according to the service manual the hot clearance is 0.20 - 0.23mm.

The feelers I bought only had 0.05mm increments but good enough for an initial indication, I'll order some better ones. Numbers below were the last size that would fit

Cold

Intake - 0.25/0.25 - 0.20/0.20 - 0.20/.020 - 0.20/0.20

Exhaust - 0.20/0.15 - 0.20/0.20 - 0.15/0.15 - 0.15/0.15


Hot

Intake - 0.30/0.30 - 0.25/0.25 - 0.25/0.25 - 0.25/0.25

Exhaust - 0.20/0.20 - 0.25/0.25 - 0.25/0.25 - 0.20/0.20

So assuming I measured correctly the clearances when cold are what they should be when hot, especially number 1 intake. Still seems very loud to be this clearance but I can't think of anything else unless I start looking at the bottom end, but it definitely doesn't sound like that.

 

[vss irvine]

Any of the rocker posts moving? Had this before made a fair racket.

You getting plenty oil through the cam caps?

 

[grim_d]

The pivots? I gave them a wobble didn't feel anything alarming, I can have a proper check when I have the cams out to reshim next time I'm off.

As far as I know the caps are getting oil but I havnt actually had them off. What's the best way to check this?

 

[grim_d]

Shimmed 12 of the 14 valves today, other 4 were close enough for me. Noise seems to be gone. I suspect no1 intake was making the noise, amazing how 0.05mm can make such a racket.

 

[red reading]

Hopefully you got a stock of shims from somewhere, If you did this with the dodgy way good luck with putting feeler gauge shims in there, they are not made of hardened or tool steel and they do squeeze out of the sides, if you had of asked I would have sent the shim bank that we have up to you as you seem to know Martyn pretty well.

 

[grim_d]

I did do it the dodgy way, the feelers I bought are supposed to be hardened steel. Not my ideal choice but I didn't know you had a shim bank, if the offer stands then I would love to do it properly.

 

[red reading]

Wait till Martyn gets back and I will send it back up to him and you can do it properly then, better to be safe than sorry.

 

[red reading]

And def never try to shim them on rocker posts as someone mentioned before....can't remember who, but there is so little purchase on the rocker post thread they are best left well alone.

 

[grim_d]

Ok will do, I shimmed inside the buckets.

What cold clearance do you personally aim for between rocker and lobe? I was advised to aim for around 0.10mm and I know the Nissan HOT spec is 0.20 - 0.23mm.

 

[red reading]

Cam specs and company's dictate the clearences, nissans standard cams for a road car I would go 0.20mm hot or 0.10-0.15mm cold, if you go to tight you start risking lubrication failure to the rocker pad and on the cam lobe and once the rocker pad gets scuffed you get very rapid wear, my own track car runs 0.05mm when cold and the car runs very flat and needs warming up properly before hard use.....horses for courses as they say