99 boxster 2.5 no/low oil pressure after rebuild

[rodonline]

hello all
my names Anthony, new to the forums

i have a reacquiring problem with 1999 Porsche boxster

long story short, i have lots of experience in this and other boxster motors. Ive had this one fully taken apart multiple times.

the problem is i rebuilt the motor because of a spun bearing

Used low miles crank and new rod and main bearings. crank and rods were check and polished, everything check to be good. also while the motor was apart i decided to buy a new AOS while it was going to be out.
now after being reassembled i have a knock from having no/ low oil pressure. i say no because at first start up our external gauge didn't move at all, only after we removed the bolt on the front oil pump with the spring on it( sorry i don't really know what to call it) and put it back in we started to get a little oil pressure (around 5 PSI at idle.)

im stuck and it would really help if someone could lead me in the right direction



1999 porsche boxster 110k miles


any help would be much appreciated

[NOTASIX]

Sounds like you have open clearances within the engine. Oil pressure = resistance to flow.

What were your bear.ing clearances on the mains and rods.

That "bolt on the oil pump" is the oil pressure relief bypass and can create low oil pressure. What oil are you running?

If you spun a rod bearing and didn't source a new crankshaft, I'd be willing to bet that you won't have to look far to find the source of your issue.

You may also have a bad AOS, even though it is new. If the AOS fails it can easily create low oil pressure readings, though many people do not know or understand why.

[rodonline]

UPDATE!

after a few days of thinking. we started to fiddle with the boxster aging. This time we hooked up the air gun a blew air into the hole where you screw in your oil pressure gauge, after a few moments of blowing air into the engine we checked oil pressure and with the engine completely cold were running 25-26 psi at idle.

so that solved our oil pressure problem

now we have a slight, almost a knock sound coming from the engine.

We dont feel safe driving the car yet so time to tinker with it aging

[rodonline]

i have 10-40 motor oil in it right now

[JFP in PA]

Originally Posted by rodonline

UPDATE!


now we have a slight, almost a knock sound coming from the engine.

As there have never been any bearing and journal specs or clearances published for these engines, exactly how did you rebuild this thing? I mean how did you check the clearances, and what specs did you work off of?

[rodonline]

sent them to my machine shop and they said everything check out good

[JFP in PA]

Originally Posted by rodonline

sent them to my machine shop and they said everything check out good

I have no idea how they can say that for the reasons stated above; what clearances did you find when checking during assembly?

[rodonline]

before this problem we have a different sound. the sound was a broken valve spring

while being taken apart we decided to just go a little further and have the crank checked and rods check, just to be EXTRA safe.

before all of this the car ran smooth as silk just had the noise on start up and when you reved it high from the valve spring.


so the clearances on on the rods and shaft are in good order

the machine shop telling us they were good was just for peace of mind
on how the machine shop has the info is beyond me. he told me the measurement of how far it can be off but i didnt pay attention because it didnt matter to me. i knew it was good just wanted to be 100% sure

we didnt take any measurements because we knew it was good to go

[JFP in PA]

Originally Posted by rodonline

so the clearances on on the rods and shaft are in good order.......

Originally Posted by rodonline

we didnt take any measurements because we knew it was good to go.........

Sorry, but both those statements are assumptions, not facts. Machine shops have been wrong before, bearing shells vary, rod and crank carrier bolts do not torque and stretch back to the exact same position; particularly if you reused the original bolts. If you did not check the clearances when reassembling, and replace all the critical fasteners, you took a very large risk, and now have no idea where the engine clearances are, or if they are even remotely correct..........

[matt demaria]

JFP, I greatly admire you for giving professional advice and it is usually advice that is earned the hard way. You have spent a lot of your time trying to help people but most of the time they don't want to listen if it means more work for them. It is very frustrating.
Confuscious said:
A wise man never gives advice
and a fool never takes it.

[syncroid]

When you had the crank out of the carrier, is it possible you lost one or more of the oil venturis or what ever you call them? These can fall out when the main bearings are not in place. Food for thought.

[BYprodriver]

Originally Posted by syncroid

When you had the crank out of the carrier, is it possible you lost one or more of the oil venturis or what ever you call them? These can fall out when the main bearings are not in place. Food for thought.

Piston oil squirters?

[syncroid]

Originally Posted by BYprodriver

Piston oil squirters?

Thank you.