Oil pressure buzzer (of doom?)

[mbcamper]

In my quest to find a quality engine rebuilder I've come across Andrew Simmons at the Campershack. I've had a long conversation with him and he is a very knowledgeable, patient and honest VW van expert. He would indeed rebuild me a top quality engine with photographic evidence to show all the steps. It works out quite a lot more than the Elite option, but I've confidence that the engineering behind the process is rather better and will last much longer.

However, he is casting doubt on my engine being on it's last legs. It runs well, doesn't rattle or rumble or knock and Ive got a cheap oil pressure gauge from eBay showing impending doom! I have to admit, if I'd not had my dodgy buzzer alarm I'd have never checked the oil pressure. The engine isn't showing signs of impending doom!

Campershack are very happy to replace my engine, but don't want to take my money if it's not needed. I kind of like that.

I'm basically in denial again! I'll take the engine replacement plunge once I'm really convinced and at the moment I'm a little sceptical!

I'm doubting my cheap eBay oil pressure gauge, so I'm planning on getting this, because I'm getting paranoid about engine oil pressure:

https://www.brickwerks.co.uk/t3-parts/t ... 5-bar.html" onclick="window.open(this.href);return false;

Which of course will need one of these:

https://www.brickwerks.co.uk/vdo-sender ... m10x1.html" onclick="window.open(this.href);return false;

However Brickwerks say I also need this which is kind of bringing the price up quite a lot:

https://www.brickwerks.co.uk/oil-pressu ... 3-wbx.html" onclick="window.open(this.href);return false;

The the last item needed?

[kevtherev]

The thing is electric gauges are to me, suspect
I fitted a mechanical gauge, that NEVER lies.

http://www.demon-tweeks.co.uk/performan ... mechanical" onclick="window.open(this.href);return false;
you'll need a T piece and some extra length of tubing

[itchyfeet]

He has bought a cheap mechanical guage NOT and electrical one

http://forum.club8090.co.uk/viewtopic.p ... 8#p8137474" onclick="window.open(this.href);return false;

This shows 3 bar cold idle ( my engine is ready for rebuild and is 4 bar cold)
it has nothing hot idle ( mine is 0.8 bar)
has 1 bar hot 2000 rpm ( mine is 1.5)

So I sounds correct when coupled with the buzzer going off and the fact you tried the guage on the Rover

Try and hook up the guage to a tyre of known pressure to check it, it may not be perfect but it would need to be a long way out to mean your engine was fine.

Buzzer may go off at 1500 rpm but it's common for the revs measurement to be inaccurate, and check with a multimeter or test lamp the state of the switch at 2000rpm ( will be grounded or open circuit to ground)

[mbcamper]

I've actually just been fiddling around connecting my track pump to the oil pump I got from eBay and the results are interesting.

So remember that with my engine hot at 2000 rpm I was getting a worrying reading of a little under 1 bar:



And raising the revs to 3000 rpm I was getting a reading of around 1.5 bar:



Now being paranoid I've also double checked my track cycle pump with another tyre pressure gauge and I'm confident that is accurate.

So I'm quite glad not to have rushed into replacing or taking my engine apart as these readings suggest I've got very normal oil pressure.

My old Rover on the other hand is giving quite high readings based on this.

[itchyfeet]

Well the lesson is never trust one gauge reading, well done to Andrew at Campershack, he could have made some money but he was happy to give free advice



I just checked mine through a tyre and an easy bleed kit and it's bang on my tyre gauge and my electric pump gauge

I have an electric gauge in the van though which confirms mine was not way out

[danmetallic]

This is good news! Nice diagnosing. I would def fit a oil pressure gauge for peace of mind though. V useful for when you're actually going through the revs and driving in different conditions.


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[kevtherev]

This is good news! Nice diagnosing. I would def fit a oil pressure gauge for peace of mind though. V useful for when you're actually going through the revs and driving in different conditions.


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Indeed.
My buzzer went off and the oil light flashed, a quick glance at the gauge calmed the nerves, it was telling me all was well.
However....
it is also another worry gauge
On a long high speed run in hot weather, I watched the needle drop alarmingly low as the engine temp went up.

[itchyfeet]

On a long high speed run in hot weather, I watched the needle drop alarmingly low as the engine temp went up.

Which is why I fit a Golf VR6 thermosrat in summer.

[kevtherev]

On a long high speed run in hot weather, I watched the needle drop alarmingly low as the engine temp went up.

Which is why I fit a Golf VR6 thermosrat in summer.

I did too.
..and a lower temp radiator fan switch

[silverbullet]

A fresh engine will make a damn sight more oil pressure than the above figures.
Petes 2.5 has over 5bar when stone cold, settles back to 3.5 pretty soon and has over 1bar when hot at idle.
Touch the throttle and it instantly makes 2 bar and has 3.5bar when running (hot is a constant 95 deg. C)
This is all with a remote thermostatic cooler and using 15w40

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[silverbullet]

PS the above all measured where the oil returns to the engine, at the sandwich plate (where the filter usually mounts)
If the tappet bores are worn (they all will be by now) then the engine will bleed off hot pressure from there which should be going to the main bearings.
PPS you could always fit a fresh oil releif valve spring, or even put a thick washer under it to restore the preload

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[itchyfeet]

If the tappet bores are worn (they all will be by now) then the engine will bleed off hot pressure from there which should be going to the main bearings.(

What can you do about that when rebuilding an engine? never heard of oversize tappets and they run straight in the engine case, all engine cases are now old and worn.

[mbcamper]

Silverbullet, I'm interested in where you measure your oil pressure readings. What is this sandwich plate?

I took my measurements from the low oil pressure switch location between the push rod tubes. I can now interpolate my readings were okay:

- 2bar at 2000rpm
- 3bar at 3000rpm

The only other place I can see to measure it is the high pressure switch (which is what has failed on my van) which the the grey one near the oil filter at the back of the van.

Is this sandwich place something extra you fit between the engine and the oil filter?

[itchyfeet]

at the oil filter sandwich plate ( Yes an extra add on for an oil cooler) readings will be higher than the low pressure switch

Bentley states test at the low pressure switch, 2 bar min at 2000rpm 80 degC oil temp, this is the correct point
it is opposise the centre drilling in my pic above so as you can see cam bearing or tappet wear will affect it.

[silverbullet]

Why do you consider that the pressure readings would be higher when taken from the point I selected?
By measuring pressure after the filter, thermostat and cooler (all restrictive devices) this gives a true reading of the oil condition before it re-enters the engine oil gallery.
The pressure drop between there and the low pressure switch tapping will be negligable.

As for the tappet bore wear, there must be some because of the pushrod operating angle causing side thrust loadings.
Add dirty oil to the situation and they must wear out of round.
Never measured them, but I might just do it because if this conversation.
Are they repairable? Its not worth the considerable effort or risk imho

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