Turbo Engine Rebuild

[scam75]

No water missing again this morning. All seems good.

On another note, what oil pressure range would be considered "normal" on a fresh engine with a fill of 10w 50 fully synth. I have to caveat that I don't fully trust my dash gauge, and my dash gauge was showing quite low pressures in the end before the engine was pulled (I blamed this at the time on the engine being somewhat broken). Previous to this, with the same oil, on cold start up the gauge would be up past the 5. Now I'm getting 4/4.5 on start up. Hot idle is now just above 2. I used to see 3/3.5 at hot idle. When hot I'm seeing about 4 when driving pulling 3k/4k revs. As I said, I don't really trust the gauge, but it is the same gauge as before and now all seems a bit lower across the board. One theory I had was that the OPRV will now be perfectly clean, and possibly it was a tad gummed up before, causing slightly higher pressures? A total guess though! My other school of though is that I know 1 bar is considered fine for hot idle, and now all engine operation hot and cold seems contained inside the 1-5 scale Porsche saw fit to use on the gauge, whereas previous, when cold, I would often see the gauge max out beyond the 5.

Anyway, some thoughts and comparisons would be nice!

Cheers

Stuart

 

[scam75]

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

 

[scam75]

One last thing to mention. With ignition off, the gauge reads 0. Ignition on it flicks up to about 1.5. This has increased slightly over the years, when I first noticed this years ago it flicked up to 1 with ignition on, now as I say it's 1.5. So, I am unsure of the gauge to say the least. I've had different senders over the years, and this never changed things. Could be the binnacle, the wiring, the rugby balls, who knows! I do have another gauge, but I'm sure the voltage side of it reads way lower than it should so I haven't swapped it over to see if it makes a difference.

So, I suppose my question on this is, is 3 bar on this gauge actually 1.5 bar (subtracting the nominal 1.5 that appears on ignition), or is 3 bar really 3 bar and this is just a nuance of these gauges? Let me know what your gauges do on ignition please!

Edit to add some interweb trawling suggests showing about 1 bar on ignition with engine off is normal, atmospheric pressure? So, the gauge may not be that bad, a 0.5 bar over-read possibly?

Stuart

 

[scam75]

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.

 

[scam75]

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.

 

[Eldavo]

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.

 

[scam75]

That's the ABS sensor sorted. Thanks to Simon from TIPEC who yet again came up trumps with a box of sensors he sent up. I picked the straightest looking one out the box and it fitted with minimal fuss, unlike removing the old one which was a fabulous fun game involving persuading devices, ingenuity and of course skint knuckles! 33 years of marriage to the hub I suppose was always going to be a challenge.

Next up pin my elusive mechanic mate down for a spot of oil pressure testing vs the (low-ish) readings on my dash gauge. Figured I do this first before I start playing with my other gauge, wiring and rugby balls, just in case the gauge is reading ok (at which point we have an altogether different issue but never mind!). Will do the ball joint gaiter on his ramp at same time. Had my super duper new heavy duty ball joint separator arrived in the post this morning, I'd have done it well the wheel was off and it was on an axle stand, but it didn't, so hey ho. At least the new gaiters arrived!

Always something needing done...............NSF fog light (inop, bulb ok, was ok after a harness wiggle last time but went in the huff again) and OS number plate bulb on the hit list after that.

Stuart

 

[scam75]

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.

 

[scam75]

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 fucked. 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

 

[TTM]

Do you know if running-in paste was applied to the main bearings before the crank was installed and girdle tightened?
What oil grade do you use again?

 

[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?

 

[blade7]

Just a thought, was your engine builder familiar with the importance of the procedure to align the crank girdle?

 

[scam75]

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

 

[scam75]

Oil and water still good. Oil pressure still just over 2 bar when oil fully heated, gauge still a bit flicky. New sender and OPRV o-rings have arrived. See what's what next Tuesday at the garage.

Got the OS number plate bulb changed today. Another pain in the bum job, well only because the screws seem to have been painted over a few times! Needless to say, nothing was budging from the outside with a screwdriver. Ended up using a 7/32 socket (I think) and my small 3/8 ratchet to free off the right hand side one then it screwed out without much fuss. Of course, where the left side one is, the lip of the boot is lower by half an inch meaning no access to put the ratchet on the socket. Unless I bought a miniature ratchet set (they must exist), but I didn't. Managed to maneuver my mole grips onto the last fraction of the socket and was able to loosen it a little bit, enough to mean the screwdriver was effective from the outside. Cleaned up all the terminals when I was in and removed the overspray from the plastic lenses. now have both lights working and much brighter than before. Funny that! Anyway, another job ticked off!

Stuart

 

[scam75]

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

 

[scam75]

80 mile round trip today and off-idle pressures all in the acceptable range. Touching 4 bar at 3k revs when oil fully warm. This is higher than before and possibly the contact cleaner is bedding in? Still about 2.5 bar warm idle (850rpm) rises to 3 bar at 1k revs. It's definitely electrical, I think, lol. 2 weeks ago when I done that same trip I was struggling to touch 3 bar at 4k revs on the return journey. That and the flicking has me thinking its 99% probably electrical. Only other explanation is a sticking/not sticking as much OPRV, that's my 1% guess!

Anyway, Thursday I'm off to the garage to get a proper gauge on.

Stuart

 

[TTM]

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.