Porsche Enthusiasts Club Forum

Hi all,

After a 9 weekend ordeal my car is back on the road with new clutch and pressure plate, needle bearings, main seal, pilot bearing, timing belt, balance belt, rollers, water pump, ref sensors, engine mounts and a few other bits I broke whilst I took the engine out! Got a new tyre on it yesterday as a result of driving over my circlip pliers - a £90 mistake.

I've never actually driven this car whilst all the bits work and the clutch isn't clunking and when I bought it it would either be very very hot, or absolutely freezing which was later shown to be caused by it having no thermostat and a non working radiator fan.

I've done some searches over various forums but just want to check this:

1. Oil pressure:

I topped the oil up when the engine went back in so it's probably two thirds between min and max on the dip stick. It currently as 10w40 in it, but will be changing that to 10w50 next time I get under it. Pressure is at 5 when the engine starts and settles at between 3-4 when engine hot depending on revs. When the temp gauge is at just over 3/4, when the fan comes on the pressure sits at 1.3ish and sort of flaps about between 0.5 and 2 with the oil light flashing. Drive away and it raises back to 3-4. This corresponds with what I think is a slow idle - 400 ish when hot. Would adjusting the idle screw sort this out? Clarks says that it can be done, but rarely needs it - just want to check its not part of a bigger issue!

2. Idle
As explained above, seems to be around 400 when hot - do I just turn the screw or does this signify a bigger problem? Also, perfectly smooth when I start the engine but when drops to the 400-500 range it's a little lumpy. Perhaps something to do with my ref sensor gapping?

3. Temperature
At the moment, it 20-30 degree weather it tends to raise to 3/4 and is regulated by the fan coming on - is this about right?

Sorry for coming to this forum and blindly asking questions, but it seems most of the info I find on these if from people in America where it's boiling! Car is covered in bird shit as it was parked under a tree, need to get that off ASAP!

Jobs for the future are: new track rod ends and wishbone bushes to the front (slight knocking), might change the rod bearings too next time I've got it on the ramps - figure about 6 hours for the lot - optimistic?

Will

All sounds about right to me. Your Idle is way too low though, should be 800 +/- 50 I think. That'll be idle control valve or something around it like an air leak.

Cheers Jim,

Will go and have a look at lunch time - the valve had been sitting on top of the engine when it was out the car for 6 weeks, so an air leak or stuck valve seems plausible!

Don't get me wrong, it sounds (and feels) like a muscle car on the low idle - but it's not ideal!

Will

Can anyone point me to a parts list / diagram for vacuum lines from inlet manifold - might aswell replace them, but might do it out of non porsche hoses - can't see the harm in that!

Will

Which model and year? OPRV is a well documented issue on series one cars.

It's a 1983, so is the earliest model.

I think I might have found it after going over the various inlet manifold pipes. The small one that comes from the top of the valve under the inlet manifold and connects near the MAF sensor was slightly loose. With the engine running I went pushing pipes about and the revs then went up to 600 which sounds much better. What should the idle be? Wouldn't be surprised if more are loose.

In other news, I have an ants nest in my car!

Ants, they're your problem. I recall a conversation on the TR7 forum a few years ago about a California barn find & all the Brits were saying about no rust. The the owner said, yup no rust but hundreds possibly thousands of black widow spiders had made their nest in it.
They tented it & fumigated it!

As for the idle 99% sure it is 800RPM

If its low at 800-850 but it picks up at 1200+rpm then Id suspect the oil pressure relief valve.

Thanks guys,

I went round the engine with a screwdriver this morning tightening the vacuum hoses and now seem to be at a nice 700rpm which puts the oil between 1.5 and 2 bar.

Seems about right to me!

944 Man, I'll check the OPV when I next have the tools out properly!

Will

3BAR would be better when warm, but too much to expect when properly hot, especially with some of the comedy oil grades that are recommended (0W- by Mobil, the fools) and used by people unwittingly.

The diagnostic clue is the way that the oil pressure jumps in only a few hundred revs. Revised OPRVs are available for cars which have not been fixed. I don't know whether it was a recall or not for certain, but I don't think it was...

3 bar at idle is 45 PSI which is unnecessary at idle when the bearing loads are very low. Although at idle cam lobe loads are highest but oil pressure cannot help this, it is purely down to oil quality.
For average engines the rule of thumb was always 10PSI per 1000RPM. Always served me well & never had a blow up well not from low oil pressure anyway!
High oil pressure can cause other issues such as sheared oil sump drives & blown filters. Also once flow gets too high it will bypass the filter in most engines & go straight to the sum.

Hi All,

Did a little hunt around the other weekend and it seems that my various vaccum lines have seen better days - squeezing various ones improved the idle pretty much instantly. Does anywhere sell a kit for all vaccum lines which won't cost me £millions?

After tightening up some of the jubilee clips I now have an idle of around 600rpm. Oil pressure at idle has improved with this, around 1.5 bar.

Will

try here

http://www.carbuildersolutions.com/uk/vacuum-hose

Halfords have got the proper stuff in for about a fiver a metre ... cheap and quick to get hold of.

Thanks Waylander & Greggers.

Think I'll spend a morning replacing what I can get to. Also need to replace the pipe coming into the underside of the intake manifold and running towards the MAF - the more I look, the more cracked rubbish I have!