3.9 v8 oil pressure

**justinc** · 29th July 2012, 06:24 PM

I have held back on this for fear of adding ANOTHER variable into the mix, but have you tried another Timing cover?

Recently I had a customer who purchased and fitted a rebuilt short engine to his 1995 serp D1. Had oil pressure issues from startup, too long to get pressure and low pressure after startup, even hot but not enough to set the light on.

Tried and checked timing gasket, filter, oil pump gears, oil pickup seal etc etc eventually after a frustrating time eliminating all the obvious places I tried a used timing cover and hey, perfect.

Not visible BUT it must have had a crack/ fissure in the pickup/ suction side of the oil pump inlet tract.

All OK now.

JC

**Homestar** · 29th July 2012, 06:34 PM

Originally Posted by MacMan

Thanks Gav. I might have to take you up on it. You about next weekend?

Not this coming weekend - sorry. Off up to Firth Park camping with others from the forum here. Weekend after I would one day up my sleeve - the other I will be pulling the engine out of the Grey Ghosts Series II.

Let me know how you go - JC's post about the timing cover may be another path to look at.

Cheers - Gav

**MacMan** · 29th July 2012, 07:32 PM

Thanks for the idea Justin.

Hard to find these timing covers these days. I've had to modify mine to run the JP timing gear and this will prevent me from doing a quick and simple swap with someone.

I'll have to check and see what other V8s ran this cover.

Gav - forgot about the weekend at Wombat! I might have to scoot up on two wheels to have a look at the turn out.

**MacMan** · 30th July 2012, 09:24 PM

Timing cover is off. Gasket looked OK. Had to stop work before I managed to get my specs out and inspect the timing cover for cracks or damage. Sump off tomorrow to check the pickup. I have found a timing cover but would rather not have to pony up the $220 for an "experiment".

More tomorrow!

**MacMan** · 31st July 2012, 12:29 PM

Sump is off.

Oil pickup is not cracked and was not loose. Gasket looked evenly compressed but not excessively so.

I've cleaned the timing cover and it looks OK. I carefully removed the gasket remnants from the block and there's nothing pointing towards it having a leak on either the block or cover side. It was actually very well adhered to the block surface.

I'm going to attempt to block the suction passage in the block (between the oil pickup and the lower hole in the face of the block which feeds the pump) just to completely rule out a crack or leak somewhere. There's a casting seam between cylinders 4 and 6 that I want to check for leakage since the block has been re-sleeved.

Very, very sick of all of this now.

**MacMan** · 3rd August 2012, 07:55 PM

It's all back together. Now I wait until morning.

If I meet the engineer who designed the power steering pump and brackets, best he be done with making babies. I'm getting the scissors out. Blunt scissors.

**MacMan** · 4th August 2012, 07:03 AM

I couldn't stand the suspense and went out and turned the key as soon as I was up. With HPR Gas 10, two seconds for the light to extinguish, no clattering lifter and oil pressure rocketed up to a happy 30psi cold idle.

I'll have to see it happen more than once before I jump up and down.

Have to fix the power steering pump today... It's absolutely POURING oil after I emptied the circuit completely.

**MacMan** · 5th August 2012, 07:59 PM

The good news is that it IS fixed. Start up this morning was silent and it takes considerable time for the pressure to drop once the engine is stopped.

The other news is that I've put away the scissors and now have a specially blunted piece of broken roof tile for when I meet that engineer responsible to for the PS pump bracket.

The pump refurb was a real PITA. The seal kit had one seal that had no application whatsoever and was missing two o-rings for the high pressure side that, surprise surprise, are thin section imperial items that none of the hydraulics people in town could help with. I couldn't get to the external shaft seal but it's still completely oil tight.

**chazza** · 6th August 2012, 08:55 AM

So what did you do to fix it?

**MacMan** · 6th August 2012, 09:42 AM

I can't say for sure what fixed it, because none of the gaskets were obviously compromised. However something must have been sucking air when parked.

The gaskets for the oil pickup (in sump, between pickup tube and block) and the timing cover were replaced.

All timing cover bolts were installed in with Permatex thread sealer. The small stud that goes into the block and through the timing cover was sealed screwed in with loctite and the nut and washer both given a good coating of Permatex thread sealer. All fasteners were tightened to 20Nm. As incidentals, the oil pump, water pump and sump gaskets had to be replaced also.

When I first built the engine I used a Payen bottom end gasket kit which contained plain paper gaskets. As it turned out, the oil pump gasket was too thick - 0.45mm approximately. The kit appeared to be a generic Rover V8 kit so perhaps it was intended for the older SD1 "short gear" pumps - either way it was completely wrong for the Disco pump. This was the cause of my lower than ideal hot idle oil pressure. The timing cover gasket was made of the same material.

The most recent replacement gasket for the timing cover was a different brand (couldn't see a logo on it) but still paper. I fitted it once again with Hylomar sprayed on both sides, but this time I went to the extra effort of using gasket-goo on the block and timing cover around the oil feet holes and adjacent bolt holes.

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