Just did an oil pressure check on my '89 328, Mobil 1 0W40. Readings for the tester were taken from the low oil pressure light fitting. First two pics are at cold startup/fast idle 2nd two are warm idle, just as cooling fans switched on. As noted, the OEM gauge isn't particularly accurate but the important part is that it DOES move appropriately. A check at 6500 RPM as per Ferrari showed 88PSI on the tester and the OEM gauge basically looked the same as the cold start/fast idle readings - about a needles' width to the left of the 85. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
So what is your concern you can not tell 45 or 50 on the dial in the car the look ok to me the outside gage is with in 2 psi ,go put 10W40 in your car is that what is in your manual ?
I have no concern; I just wanted to compare the factory gauge with a test gauge as a reference. I thought it would be helpful to post that here.
It's good to know when your gauges are giving accurate values, and when they are not. Just because a vintage car's gauge reads 65 psi doesn't mean you actually have oil in the car.
Since you are already to the level of R&Ring the oil pressure switch, why not get a fresh oil pressure sensor too? It isn't uber-expensive, and, IME, a fresh one did raise the indicated gauge values -- just a thought...
Thanks Steve - might as well do that! As you said, can't hurt! TBH, I can't think why Ferrari put a gauge that reads to 170 PSI in a system with a max design pressure of around 85. Seems like a 100 PSI gauge could have been a bit more realistic AND more accurate. What my test showed me was that if you perform the Ferrari spec oil pressure check (6500 RPM/85PSI) , the gauge might (did, in my case) show lower than 85PSI which may lead you erroneously to think there is an oil pump issue when, in reality, the pressure is perfectly OK..
TBH, I can't think why Ferrari put a gauge that reads to 170 PSI in a system with a max design pressure of around 85. Seems like a 100 PSI gauge could have been a bit more realistic AND more accurate. ... and that's one reason why I did a VDO gauge swap years ago ... https://www.ferrarichat.com/forum/threads/308-gauges-out-with-veglia-in-with-vdo.59100/ The initial pictures in this thread show my 80 psi gauge, which I have since switched to a 100 psi gauge and complimentary sending unit. But in hindsight I need not have bothered, as on the 100 psi gauge, the max. oil pressure observed just reaches 80 psi.
Accuracy around "mid-scale" is typically the best. This applies to things like torque wrenches too. For example, a torque wrench that goes up to about 150 foot pounds would be ideal for tightening Ferrari wheel bolts (screws) to 74 foot pounds. Same for voltmeters, ohmmeters, ammeters, pressure gauges etc. etc. In the case of of these Ferrari gauges the faces are pretty small and the dial markings are pretty crude but you still want gauges that read around mid-scale under normal/typical operating conditions. "Pressure Range: A gauge range of twice the working pressure is generally recommended for maximum accuracy, safety, and for extended gauge life. The operating pressure should always be limited to 75% of the gauge range. When pressure pulsations are encountered, the operating pressure should be limited to two thirds of the gauge range." https://www.ametekusg.com/learningzone/pressure-gauges/choosing-the-right-pressure-gauge
Just out of interest (and probably because I will need one at some stage) what torque wrench rating is good to get for working on a 308? Or are you best to get several to count for the wide range of torque values? What's the highest torque value likely on a 308?
FWIW - to be WELL torque wrench-equipped, you need three. A 1/2 drive, A 3/8 drive and a 1/4" drive for small stuff. That being said, the local cheap torque wrenches from Lowes or wherever are better than nothing but are more suited to producing consistent tightening rather than accurate tightening. Good wrenches come with certifications by serial number and, of course, they cost a lot more...think Snap-On and other good quality brands. I did mech work on marine engines/drivetrains, mostly Detroit Diesel/Allison transmissions, and also needed a 3/4" drive wrench (over 900 bucks from Snap-On!!!!!!!!!). It's LOWEST torque setting was 200 lb/ft! Nowadays I have just a 1/2 and a 3/8 drive. Neither has been re-checked/certified in quite a few years now so who knows how accurate they are...kind of like Ferrari gauges! Well, not really, the torque wrenches WERE certified initially so at least we know that when new they were accurate! Keep in mind that torque setting listed in a manual might be for dry or lubricated threads - it should say in the specs. It is generally assumed that if it doesn't SAY lubricated, it means dry but there are exceptions. If you lubricate threads and the spec is for dry, you will be applying 30+% more torque than the spec at the same wrench reading. IOW, if it calls for a dry spec of 30 lb/ft and you lube the threads and tighten to an indicated 30lb/ft, you have actually tightened it to around 40 lb/ft as far as the fastener is concerned. The highest torque for any bolt I have dealt with on the 328 is the wheel bolts. You need a 1/2 drive for that but for most general work that you might do on the car, a 3/8 drive is probably sufficient. Some additional FWIW - torquing wheel bolts can be quite important but not necessarily for safety reasons. I have seen vehicles with distorted brake rotors due to random tightening of the lugs. Once the lugs were loosened/retightened consistently, the rotors ran true.
That's awesome - thanks Mike! I had looked at the Snap-On site and seen the price of their tools, but to me good tools are worth it, and it's all part of the initial cost of owning a Ferrari. I'm putting together a budget of all things required when I finally purchase one - and its looking rather extensive and expensive! But that's what I want to know now, not 1 week after buying one...
What Mike said I have three good quality torque wrenches of different ranges but, as I recall, with a slight "overlap" in range with the others. Then different head sizes can, of course, be useful too... 1/4, 3/8, 1/2 inch.
Another thing to look for when you're buying torque wrenches is a 1/4 one that can do low values - ie, 5 ft lbs minimum. SnapOn and Matco are great pro tools, but Gearwrench and Craftsman are also decent for DIY use.
