Oil Pressure light when braking (very) hard

[Tee Three]

Hi all

Just got my 1983 Westy pop top Joker on the road after two years of graft and the occasional swear word. I noticed today when breaking very (emergency stop) hard the oil pressure light momentarily came on. The oil level is OK and theres no rattles or knocks. The rest of the time, including moderate braking its fine

Its a 1.9 DG VW factory recon unit that was in the bus when I bought it, stripping the top ends down during resto, I seen the milled finish was still on the pistons and everything quite pristeen. End float was within tolerance though I didn't go into the bottom end to check the mains/big ends etc.

Has anyone heard of this before?

Cheers, Greg

[itchyfeet]

If the revs drop below normal idle when breaking or for any other reason then the light can flicker on, you can try adjusting up the idle stop screw slightly but it may be a sign it's not running quite right, timing or air leak or something similar.

still worth checking oil pressure on any wbx even if you had no reason, just to know what condition it's in.

You can buy a wet portable guage for 30 quid, better than paying somebody as you can monitor it every year when you service.

http://www.ebay.co.uk/itm/NEW-Engine-Oi ... 3f2ece50aa" onclick="window.open(this.href);return false;

Bentley states 2bar min at 2000 rpm with oil at 85degc, thats after a good run, switch off fit guage ( need to remove tin guard beforehand) start up and temp will be about right
worth taking measurements at idle and 3000rpm also

I have not bolted my tin pushrod guard back to exhaust, on late you have studs and guard can stretch over, on early
not so easy as its bolts.

[kevtherev]

Hi all

Just got my 1983 Westy pop top Joker on the road after two years of graft and the occasional swear word. I noticed today when breaking very (emergency stop) hard the oil pressure light momentarily came on. The oil level is OK and theres no rattles or knocks. The rest of the time, including moderate braking its fine

Its a 1.9 DG VW factory recon unit that was in the bus when I bought it, stripping the top ends down during resto, I seen the milled finish was still on the pistons and everything quite pristeen. End float was within tolerance though I didn't go into the bottom end to check the mains/big ends etc.

Has anyone heard of this before?

Cheers, Greg

Last oil change?
oil grade?

[Tee Three]

Hi KeV

Its fresh oil and filter after engine rebuild and the grade is titan 15W 40 from brickwerks

Cheers
Greg

[marlinowner]

Could just be the wire to the oil pressure switch shorting somewhere when it moves.

[Tee Three]

Yes...I did renew this wire with a new connector on the end, though its certainly possible

I will explore in the morning

Cheers dude

[kevtherev]

Yes...I did renew this wire with a new connector on the end, though its certainly possible

I will explore in the morning

Cheers dude

Even in the dash.

[ghost123uk]

Not seen it myself on a WBX motor, but this phenomenon is not uncommon. On some engines it is caused by the oil rushing towards the front of the engine under heavy breaking and thereby uncovering the pick-up pipe, which then sucks in a gob of air, causing the pressure to momentarily drop and the light to flick on, then off again. Some rally tuned / race cars have either baffles in the sump to prevent this, or even change the whole system to a dry sump set up (with an external oil tank, like many motorbikes have).

If it was an emergency stop situation I think the above is a strong contender for the cause, second being a dodgy wire moving under that heavy breaking force.

[itchyfeet]

check pressure, stop worrying

[Tee Three]

I was thinking about the surge phenomena as a possibility

will check dash wires too

I went for a long drive last night and it didn't come on once, and I think the flat power is just me being used to a more powerful modern works van...Maybe next year a beefier engine

Thanks a lot Guys, really appreciate it!