Helpful ReplyHot!Turbo Engine Rebuild

OK, so I just found this. Which would indicate all is as it should be. Still would like your feedback though!
 

submitted by George Beuselinck [HV] on Mon 09/26/2022 01:53 pm
I'll start with a description of normal oil pressure readings from Clark's Garage Shop Manual:
"The 944's oil pressure should run 4-5 bar at idle when the engine is cold. It will gradually decrease to 2-3 bar at idle as the engine oil warms to normal operating temperature. Once the oil is at normal operating temperature, the oil pressure should indicate around 4 bar at 5,000 rpm. It takes the oil longer to reach its normal operating temperature than the coolant. Therefore, don't be surprised if oil pressure continues to decline after the coolant temperature has stabilized at its normal operating temperature. Occasionally, you may see your oil pressure drop to less than 2 bar. This may happen on very hot days when the car has been driven particularly hard. You should be extremely concerned if the oil pressure dropped to less than 1 bar. This is indicative of an problem with the oil pressure indication or the oiling system itself. Under these circumstances, the car should not be driven until the cause of the low oil pressure indication is determined and corrected."
http://www.clarks-garage...shop-manual/lube-03.htm
The oil pressure on your gauge is indicated in bars of pressure; each bar is about 15 psi. When the needle is pointing at the 2 mark, it is indicating about 30 psi, which is adequate to protect the main bearings and the rod bearings in your engine at idle.
If you want to have the gauge show a slightly higher reading, then use the heaviest weight of oil that Porsche recommended for your car, namely 20W50 or 15W50 oils. Note that your fuel mileage might suffer a bit due to the increased viscosity.
Another possible solution to your concern is a complete rebuild of the engine, focusing on the main bearings and the rod bearings. Over the years, the clearance in the bearings has increased, resulting in lower oil pressure readings. Decreasing that clearance in the bearings will result in slightly higher oil pressure readings. Whether or not you are willing to spend the time and the money on that type of solution is up to you.
George Beuselinck, 924/944/968 Expert, PCA National Tech Committee
 
So, this would indicate my readings previously, were a tad high, and now they are perfectly in spec?
 
Stuart

Water all still good. Oil pressure still same. Have killed a front ABS sensor though, will start a thread to see if anyone has one kicking about 2nd hand. 

blade7
Hot oil pressure on my original gauge is 3 bar,  I've used Millers 15/50 CFS for around 20k miles, changed every 3k miles. And the car has done 103k miles. Does your engine builder have an accurate oil pressure gauge, if not I'd probably buy/borrow another one.

 
He will do. My gauge is not that trustworthy, I will get a decent gauge on it, I would expect 3 bar hot idle, not the 2/2.25 it is showing. Also think should be higher than 4 bar on cold start up.
 
I'll get over to the garage once I get the ABS buttoned back up. Noticed I have a split ball joint boot on the same side as the ABS sensor that's broken. Bit annoying as it was rebuilt with a kit about 2 years ago. The joint is fine but the boot has clearly not been much cop. Hamburg Technic kit I think. Suppose it should at least split easy enough to change it over.
 
Stuart

blade7
Forgot to mention, my gauge shows 5 bar from cold and for a few minutes until the oil starts to warm up. I think it reads zero until the engine is started too, I've just charged the battery, I'll reconnect it and check that. Is there a warning buzzer for low oil pressure on 944 engines? My old 85 Scirocco GTX had one.

No buzzer - but the “Oh Sh!t” warning light will come on if it drops too low.

I'm booked in to see my mate at the garage 6th Dec to get proper oil pressure gauge on. Had a play today and plugged in my other complete clock pod. Same readings with ignition on (nearly 2 bar) and with engine on same 4 ish cold idle, moving slowly all the way down to 2 bar idle when hot and oil up to temp. Cleaned up all the rugby balls and some contact cleaner into the harnesses but not a lot of difference. So, the problem is either the sender, wiring from sender or I do actually have low-ish oil pressure. I'm going to buy a sender anyway and have that up my sleeve when I go to the garage. I'm sure it's a cheapo that's in it just now with a bit broken off one of the terminals, not enough to stop the bolt going on to secure the ring terminal though.
 
In other news I still haven't lost a drop of lovely clean golden oil and the water is still at max after that top up about 100 miles ago. So, I'm happy with that anyway!
 
Stuart

blade7
 I've used Ester blend synthetic oil for over 12 years. It's nearly twice the price of the Quartz oil, but if the oil pressure does turn out to be a bit low, I'd use a higher spec oil. 

Yeah, possibly the oil, but it's always held good pressure before. Thinking back, the pressure was about the same pre-rebuild, and I put that down to the engine being ****ed. Wind forward and I am using the same OPRV and sender, and have same readings. I have a hunch either the sender is faulty or the OPRV needs cleaned (Simon sgl1966 says he had a similar issue on a fresh build, and cleaning the OPRV cured it). I've purchased some OPRV o-rings and a new sender, not the cheapo brass coloured one that you see everywhere, gone for an FAE 14990 from ECP, £36, at least it is silver and the terminals look more substantial than my current one (the cheapo brass effort!). So, I will be armed with these goodies when we get the proper gauge on and see where we are. OPRV could have got a but gummed up while my engine was disintegrating or when bedding in new rings, either way, bar a wiring issue, it surely must be the sender or the OPRV. All will be revealed soon!
 
Stuart

scam75

blade7
 I've used Ester blend synthetic oil for over 12 years. It's nearly twice the price of the Quartz oil, but if the oil pressure does turn out to be a bit low, I'd use a higher spec oil. 

Yeah, possibly the oil, but it's always held good pressure before. Thinking back, the pressure was about the same pre-rebuild, and I put that down to the engine being ****ed. Wind forward and I am using the same OPRV and sender, and have same readings. I have a hunch either the sender is faulty or the OPRV needs cleaned (Simon sgl1966 says he had a similar issue on a fresh build, and cleaning the OPRV cured it). I've purchased some OPRV o-rings and a new sender, not the cheapo brass coloured one that you see everywhere, gone for an FAE 14990 from ECP, £36, at least it is silver and the terminals look more substantial than my current one (the cheapo brass effort!). So, I will be armed with these goodies when we get the proper gauge on and see where we are. OPRV could have got a but gummed up while my engine was disintegrating or when bedding in new rings, either way, bar a wiring issue, it surely must be the sender or the OPRV. All will be revealed soon!
 
Stuart

You won't get higher pressure from the Ester oil, but it may offer better protection at lower pressures. I don't think it's the oil either, is it the original oil cooler?

Blade - It was AMAC engineering who are well thought of and know their way round a 944 engine so I would assume so.
 
Yes, original oil cooler still in place.
 
Thom - I would assume yes based on my previous comment and I'm using Total Quartz Racing 10w/50 fully synthetic oil.
 
We will see when we get a proper gauge on it, at the moment I suspect it's OPRV related if the readings are correct, and sender if they are not. New sender and OPRV o-rings should arrive next week.
 
The pressures were about 0.25 bar higher yesterday across the range with 4.5 bar cold idle and about 2.3 bar oil fully warmed idle. Possibly a result of putting contact cleaner on the binnacle harnesses and rugby balls. The gauge is a bit flicky as well, but not wildly flicky, 0.25 - 0.5 bar fluctuations sometimes which fuels the fire of it being an electrical rather than mechanical issue. I'm certain one of the terminals on the sender has a bit broken off as well hence my just buying another one anyway.
 
Thanks
 
Stuart

Flicky flick flick. So today I'm seeing some bigger flicks, 0.5 and sometimes up to 0.75 bar upwards flicks. I'm more convinced than ever that this is an electrical fault at the sender end. Didn't get the oil up to full temp, but the coolant was up to temp and I had over 3 bar idle, and over 4 bar at 3k revs. When the sender is replaced, I will also make up some nice new connectors for the wiring and eliminate that as a possible cause (I'm sure I removed spade terminals and replaced with rings many moons ago when changing a sender, so maybe reason for an issue there if the crimp has deteriorated over time, or the exposed wire).
 
Won't leave anything to chance of course and should the pressure still be actually low on a proper gauge, we will get the OPRV out for a look. I have o-rings to hand and an OPRV alignment tool on its way (thanks Jim!) so I think the bases are covered!
 
Other thing I was scratching me head over was my oil cooler housing didn't look like anything I could see online, or for sale. PET shows mine to be 951 107 051 00, which it definitely is, however the internet fails to show any pictures of this anywhere. Can find what must have been the replacement, 951 107 051 3R, and it looks completely different from my one. Looking at it, it seems mine has an oil thermostat and spring arrangement next to the oil filter that the replacement part doesn't have. Anyway, just thought I'd add that in case it ever helped anyone identify their oil cooler housing!
 
Cheers
 
Stuart

Couldn't it simply be the gauge itself? Did your car stay damp-ish conditions for long when it was awaiting its engine? Did you clean all the grounds below the dashboard? I bet some oxydation took place a bit everywhere whilst the car was sitting.