oil pressure gauge

pburke · Post by **pburke** » Thu Oct 22, 2009 5:56 pm

450B normally aspirated engine has oil pressure sending unit behind and above starter. Turbo engine has oil line for turbo at that point. Trying to put wet gauge in machine. Put fitting in block mid way to turbo but pressure is low. Is this right place to do this? Thanks Pete

special tool · Post by **special tool** » Fri Oct 23, 2009 4:42 am

Where mid-way in block?
You must tap into oil gallery before the bearings.
And "tapping" is extremely risky because any drill shavings will go directly into the first downstream bearing.
Why not just tee into the turbo oil feed?

pburke · Post by **pburke** » Fri Oct 23, 2009 6:27 am

Sorry, turbo line has junction block. Steel line coming from engine to it then pressure hose on to turbo. think not restrictive enough to read pressure right. Should have application for sending unit with turbo to get right reading but where?

special tool · Post by **special tool** » Fri Oct 23, 2009 5:11 pm

What is the pressure you are getting cold idle?

pburke · Post by **pburke** » Fri Oct 23, 2009 8:47 pm

Five pounds maybe? Been using machine all summer so can't be right or would have cratered by now. Know where 450C is sitting so going to look at it tomorrow to see how plumbing is on it. Engine may be different size but all wiring and sending units are same.

special tool · Post by **special tool** » Tue Oct 27, 2009 4:25 pm

pburke wrote:Sorry, turbo line has junction block. Steel line coming from engine to it then pressure hose on to turbo. think not restrictive enough to read pressure right. Should have application for sending unit with turbo to get right reading but where?

Also - don't be confused by hose size - a hose doesn't have ANY effect on pressure, it can't not be "restrictive enough".
You are confusing pressure and flow (PSI - CFM)

Let me clarify - which is easier to breathe through - a garden hose, or a straw?
A garden hose, because you don't need as much pressure (neg or pos) to maintain the same amount of flow (air, so you face doesn't turn blue).

Also - keep in mind that oil pressure guages are "dead end" guages - they are not affected by flow, because there is no flow through them.

My 450-b has the turbo engine - you want me to take pics?
I would just have to e-mail them to you because this website needs a URL, and I haven't had to address a photo like that for any website since 1998......

pburke · Post by **pburke** » Wed Nov 18, 2009 2:31 pm

Should have gotten back here sooner. Looked at 450C and pressure gauge tied in exactly same as I did so that not problem. Thanks for pic offer but don't need them now. That oil line also feeds turbo oil cooler so thought being it was volume with no back pressure to make correct reading. Rigged valve to shut off flow so would only go to gauge. Made about ten pound difference. Still only about 30 at half throttle at start-up. Think going to have to get deeper into engine. Thanks

pburke · Post by **pburke** » Wed Dec 02, 2009 9:42 pm

Been all over this machine. Got hold of guy in Penn. Bought some parts from him. Told me about spring in front of engine that regulates pressure. Bought one, put it in and pressure went to 55 at fast idle. When close valve that i rigged in line, pressure goes to almost 70. I'm happy now

. Spring cost about 4.50.

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