B7200 oil preasure

Berry

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Hi folks; I just installed a new oil pressure sensor (electrical) on my B7200. At the same time I changed the oil. I also added some HE Lucas oil treatment as this engine is about 35 years old. I checked on line and confirmed with the Lucas bottle that says to add 20% Lucas to your oil. I understood the oil pressure should be between 15 and 40 PSI. I also thought the Lucas would increase the oil pressure at the same time. After installing all this and test firing the engine, I'm getting about 46 PSI on the gauge. I also noticed a small amount of air in the pressure line to the gauge.
Any thoughts on the Lucas oil treatment, 46 PSI, and the air in the line would be much appreciated.
 

Dave_eng

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Why did you decide you needed an extra treatment?
The main oil gallery relief valve will limit the oil pressure.
Dave
 
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N3BP

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I see anywhere between 10 and 50 psi depending on temperature and rpm with mine so you’re good. I also don’t run any oil additives and personally feel they are a waste.
 
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North Idaho Wolfman

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I'm really confused????
I just installed a new oil pressure sensor (electrical), I also noticed a small amount of air in the pressure line to the gauge., and the air in the line, would be much appreciated.
If you installed a electrical pressure sensor and gauge, you wouldn't have oil in a line, as it's an electrical line.
So did you install a mechanical oil pressure gauge with a tube to the gauge?

If you did, and it's got air in the line, with it idling, crack the fitting at the back of the gauge and tighten it when there is a drip of oil and no air in the line.
 
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Berry

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I'm really confused????


If you installed a electrical pressure sensor and gauge, you wouldn't have oil in a line, as it's an electrical line.
So did you install a mechanical oil pressure gauge with a tube to the gauge?

If you did, and it's got air in the line, with it idling, crack the fitting at the back of the gauge and tighten it when there is a drip of oil and no air in the line.
Yeah mechanical, long day. Yes I can bleed off the air. I was wondering how the air might effect the pressure. Tks Wildman.
 
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Berry

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B7200HST B2551 Blower Scraper Flail Mower Chipper Log Splitter
Jun 7, 2020
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Bancroft Ontario
I see anywhere between 10 and 50 psi depending on temperature and rpm with mine so you’re good. I also don’t run any oil additives and personally feel they are a waste.
Thank you, I'll keep that in mind for the future Since the engine was 35 years old, I thought it couldn't hurt.
 

Berry

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Why did you decide you needed an extra treatment?
The main oil gallery relief valve will limit the oil pressure.
Dave
Ok, good to know. I added the Lucas because the engine is 35 years and counting. I've have used it before in my older vehicles along with synthetic, and they are not even close to 35.
 

PoTreeBoy

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Yeah mechanical long day... I can bleed off

Yeah mechanical, long day. Yes I can bleed off the air. I was wondering how the air might effect the pressure. Tks Wildman.
Air in the line won't affect the reading.
 
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JerryMT

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Hi folks; I just installed a new oil pressure sensor (electrical) on my B7200. At the same time I changed the oil. I also added some HE Lucas oil treatment as this engine is about 35 years old. I checked on line and confirmed with the Lucas bottle that says to add 20% Lucas to your oil. I understood the oil pressure should be between 15 and 40 PSI. I also thought the Lucas would increase the oil pressure at the same time. After installing all this and test firing the engine, I'm getting about 46 PSI on the gauge. I also noticed a small amount of air in the pressure line to the gauge.
Any thoughts on the Lucas oil treatment, 46 PSI, and the air in the line would be much appreciated.
Air on the line is of no consequence to the pressure reading.
 
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North Idaho Wolfman

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Yeah mechanical, long day. Yes I can bleed off the air. I was wondering how the air might effect the pressure. Tks Wildman.
Ok good
And don't worry about the pressure, all it's telling you is the oil pump is good, and the main bearings are good.
 
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GeoHorn

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Air in the pressure-sense line is not a defect…. it’s actually how it should be. Once oil is in that line…it will eventually congeal…and block the gauge from proper readings. Then you’ll have to clear the line of oil…and possibly blow it out with kerosene, etc…then re-install it…. with it properly filled with Air.

Hint: The air will be compressed by the oil-pressure until it is equal to the oil pressure and the gauge will read that pressure…(it is virtually instantaneous)…without being contaminated with oil. Once that gauge is contaminated with oil…and that oil congeals…your gauge will be “stuck” and inaccurate and require replacement.
 
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TheOldHokie

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Ah, the side of the Wolfman that is rarely seen… :LOL:
The air wil be compressed until it equals the oil pressure. The gau

Dan
Air in the pressure-sense line is not a defect…. it’s actually how it should be. Once oil is in that line…it will eventually congeal…and block the gauge from proper readings. Then you’ll have to clear the line of oil…and possibly blow it out with kerosene, etc…then re-install it…. with it properly filled with Air.

Hint: The air will be compressed by the oil-pressure until it is equal to the oil pressure and the gauge will read that pressure…(it is virtually instantaneous)…without being contaminated with oil. Once that gauge is contaminated with oil…and that oil congeals…your gauge will be “stuck” and inaccurate and require replacement.
Bourdon tubes dont care whether they are filled with a liquid, gas, or a mixture. They contain no moving parts and flex under the mechanical stress induced by the difference in internal and external pressure. There is nothing inside the tube to gum up and stick. They will however fatigue after tens/hundreds of thousands of cycles.

Dan
 
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GeoHorn

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The air wil be compressed until it equals the oil pressure. The gau

Dan

Bourdon tubes dont care whether they are filled with a liquid, gas, or a mixture. They contain no moving parts and flex under the mechanical stress induced by the difference in internal and external pressure. There is nothing inside the tube to gum up and stick. They will however fatigue after tens/hundreds of thousands of cycles.

Dan
Correct…except old oil will eventually congeal…and once that occurs to the oil in the bourdon tube …it will not be as responsive as it should be. (i.e., stuck gauge)

Bottom line; Do not fill the sense-line with anything. Leave it empty (full of air.)