Engine Oil Pressure Gauge Plumbing

Discussion in '1947-1954' started by ltcmikem, Jul 24, 2005.

  1. ltcmikem

    ltcmikem Member

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    None of the gauges in my '49 GMC 3/4 ton work so I'll be posting individually for help with each gauge to assist folks that come after me when they search the archives for help.

    The oil line that goes from the back of the oil pressure gauge ends in a broken line in the engine compartment. There is a fairly new, shiny bolt on the lower left side (drivers side)of the '54 Chevy 235 engine block that I'm guessing was the intended destination for the oil line from the pressure guage in the dash. Does that sound like the correct location for the oil pressure line to connect to the block? What kind of fitting(s) connect the oil line to the block? In addition to the fitting needed at the block I'll need to replace the broken oil line from the gauge to the block. Are compression connectors correct for connecting the line at the block fitting and at the gauge?

    A picture of where I believe the oil line should attach at the block (the shiny bolt)can be viewed at: http://public.fotki.com/ltcmikem/ltcmikem/oil_line.html
     
  2. fab51

    fab51 Member

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    RE: Engine Oil Pressure Gauge Plumb

    Mike-

    That sounds like the right place for the oil pressure line. The block is tapped for NPT (National Pipe Thread) fittings. I don't remember what size they are right off hand. The line to the gauge requires a flare fitting. So, you will also need a fitting to go between NPT and flare. Incidentally, this is also where the oil filter connects.
     
  3. vwnate1

    vwnate1 Member

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    RE: Engine Oil Pressure Gauge Plumb

    Yes Mike , that's it ~ I wonder what boob put a bolt in there , should have used a brass pipe plug .

    The oil pressure gauge line uses compression typ fittings not flared so you'll need a few new ferrules too , use steel tubing or stainless if you can find it , try to avoid copper as it can crack after a time.

    If you can find some junkers you'll prolly find the oil filter cannister anf al the needed fittings too , it's the same for 216 & 235 , there are many different models and brands but all use the same fittings & hoses , Chevy Duty sells the hoses , do NOT use old rotten hoses ! .

    -Nate
     
  4. ltcmikem

    ltcmikem Member

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    RE: Engine Oil Pressure Gauge Plumb

    Tim & Nate -

    Thanks for the help. Will see if I can get the line & fittings to put the oil pressure gauge back in service when I go by NAPA this afternoon. I haven't decided about putting in the oil filter... archived forum posts here and at Stovebolt seem divided on the subject. Those suggesting it isn't necessary to add the oil filter say only 10% of the oil gets filtered and timely oil changes are adequate. I'd appreciate your thoughts.
     
  5. fab51

    fab51 Member

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    RE: Engine Oil Pressure Gauge Plumb

    Actually, I'm pretty torn on the subject of the oil filter. Unless otherwise modified, the 235 uses what is called by-pass filtration. A small amount (around 10%) is diverted from the main oil galley into the filter. The clean oil is then dumped back into the oil pan along with the dirty oil. Not nearly as good as the full flow system, but it is better than no filter. Right now, my newly rebuilt 235 has no filter. I cleaned up a nice Fram filter and installed it, only to find that the bottom leaked like a seive. So, I removed it, and will fix up an AC to replace it. It you decide not to run a filter, just be sure to change your oil more often, say every 1500-2000 miles.
     
  6. ltcmikem

    ltcmikem Member

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    RE: Engine Oil Pressure Gauge Plumb

    Tim -

    Thanks for your thoughts on the oil filter. For the time being I'll walk the fence... will keep my eye out for a filter & the plumbing and do the oil changes at 1500 miles. Most of my runs in the truck are only 10 miles to town... errands & shopping... then 10 miles home. Hardly enough to get her warmed up so I'd probably do the 1500 mile oil changes with or without the filter. Thanks again for your suggestions.
     
  7. vwnate1

    vwnate1 Member

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    RE: Engine Oil Filter

    You really should run a filter , the folks who naysay them are also the folks who are lazy and don't like the mess of changing a canister typ filter .

    If you do any engine work at all you'll understand that it _NEEDS_ not only an oil filter but a nice magnetic oil drain plug or cow magnet dropped in the rocker box too .

    -Nate
     
  8. ltcmikem

    ltcmikem Member

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    RE: Engine Oil Filter

    Nate -

    I got a good number of cows here, but none are magnetic so far as I can tell... and I'm a little reluctent to go into NAPA and ask for a cow magnet. You going to wait for me to take some more line or you gonna set the hook now? :)
     
  9. coilover

    coilover Member

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    RE: Engine Oil Filter

    Man, I bet 75% of the old roundbody chevy pickups were probably sold to farmers or agribuisnesses and now you city slickers don't know what a cow magnet is. It was a rod shaped magnet with rounded ends that you put down the cows throat to capture wire fragments from old baling wire tied bales. This kept the wire from getting in the digestive tract and perforating an intestine. Your auto parts store won't have one but a farm supply store will.
     
  10. ltcmikem

    ltcmikem Member

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    RE: Engine Oil Filter

    Evan -

    Thanks for the pointer. Would have never figured that one out since here in Texas we don't feed the baling wire to our cattle... just the hay. ;-)
     
  11. fab51

    fab51 Member

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    RE: Engine Oil Filter

    Heck, I've lived on a farm for almost all of the 31 years of my life, and I've never heard of that. I guess you learn something new everyday. Of course, I'm pretty certain that "they" quit making bailers that use bailing wire a year or two ago.
     
  12. vwnate1

    vwnate1 Member

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    RE: Trucks , Cows & Magnets

    Well ;

    I guess I'm just old or somthin' then .

    The most amazing part is : a Texan admitted he didn't know something :p

    Here I'da thought Texas Longhorns chewed up bobwire and pooped out nails or summat ;-)

    Anyway , it's gonna be a scorcher in L.A. , it was 70+ degrees when I rolled out of So. Central L.A. this moring @ 04:30 , windows down , cowl vent and crotch cooler wide open , oldies on the radio , elbow in the breeze .

    Life is good , go change your oil then _DRIVE_ your truck .
     
  13. ltcmikem

    ltcmikem Member

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    RE: Trucks , Cows & Magnets & that

    I STRONGLY suspect Evan is having some fun with us... I absolutely assure you there isn't a cow on this place that's gonna let you stick anything like that down it's throat (except maybe some range cubes ;-)) and even IF that were to happen there ain't no way anything is sticking to that ole magnet as it gets pulled back out.

    Switching gears, but still on the oil pressure gauge plumbing topic... present issue is that DAMM BOLT that the DPO or someone put in the block where the oil pressure gauge line enters. The parts man at NAPA has everything I need to put in the correct ¼" NPT fitting and other parts for the pressure line, but he says that DAMM BOLT has probably screwed up the threads in the block. Assuming that it has... what's your recommended course of action? Are there NPT thread chasers?
     
  14. fab51

    fab51 Member

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    RE: Trucks , Cows & Magnets & that

    [updated:LAST EDITED ON Jul-27-05 AT 10:41 AM (CST)]Yep. You may need to go with the next size bigger tap for the NPT, and use an adapter to drop it down to the right size for the line to the gauge. I shoulda mentioned that earlier, but I guess my head wasn't screwed on right.
     
  15. ltcmikem

    ltcmikem Member

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    RE: Trucks , Cows & Magnets & that

    Tim -

    I just got back from NAPA... got all the fittings and line to put the oil pressure gauge back in operation. They didn't have the stainless steel line Nate recommended... only copper and nylon. I went with the copper. Also got a ¼ NPT tap to chase the threads in the block before attempting to put the ¼ bushing in the block. My hope is that the DAMM BOLT only got in a couple threads before it went tight... I sure hope I don't have to go to the next larger size tap. To clean the hole after I chase the threads should I just crank the engine and let it pump oil out the hole for a short time?

    Won't be able to start that project until Friday. I'm hosting a BBQ tomorrow for the Air Force Combat Control Team (CCT) at Lackland AFB in San Antonio. The rest of today will be getting my act together and tomorrow will be making it come together.
     
  16. vwnate1

    vwnate1 Member

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    RE: Trucks , Cows & Magnets

    You're right on track Mike , use a Q-tip swab if you're worried , I'd not run a chaser in there at all as you need all the meat you can get .

    The good thing is : Weatherhead will make the proper size adapter in various size pipe threads so don't panic if it fits loose or still seeps oil even after you've added Teflon tape to the threads . you may need to peruse the entire catalog to find what you need or go to the local truck shop or job shop where they'll have a full Weatherhead assortment in cabinets .

    BTW : you're obviously a City boy else you'd know getting the magnet into the cow isn't difficult at all and _you_ don't take it back out ~ it , uh , er , " passes through naturally " and comes out the far end of the cow .

    Bulls , well now I don't mess with them as I'm old and want to stay alive :p

    So , why wasn't _I_ invited to the BBQ ? :'(

    -Nate
     
  17. ltcmikem

    ltcmikem Member

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    RE: Trucks , Cows & Magnets

    Thanks Nate. I'm not going to be able to get to the oil pressure fitting until tomorrow after church... got too far behind on the regular chores. Will forego the thread chaser as you recommended and clean out with q-tips. Hadn't thought about the teflon tape on the brass fitting when I go in the block... will do that too.

    Guess you're sorta right about the "city boy" dig. Grew up as a military brat then put 30 years active duty with the USAF... crew chief, pilot and combat controller. Retired to the country with very nearly zero "country smarts", but the learning curve is fast. I can keep my head above water long enough now to play with the '41 JD & '49 GMC.
     
  18. ltcmikem

    ltcmikem Member

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    RE: BBQ

    Nate & all -

    Next BBQ on Armadillo LZ outside Fredericksburg, Texas is 15 Sep. If you can't make the BBQ a no-notice hospitality check is never declined and the suds locker is ALWAYS full of very cold longnecks.
    :9
     
  19. vwnate1

    vwnate1 Member

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    RE: BBQ

    Thanx Mike , you do know I was just funnin' ya , right ? :p

    BTW : thanx for your service ! .
     
  20. ltcmikem

    ltcmikem Member

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    RE: BBQ

    The invitation stands and my BBQ is worth the drive out from sunny southern California. And, thanks for the salute... I'm proud to have served. BTW, my bride is still active duty... stationed at Randolph AFB on the east side of San Antonio. I have become quiet comfortable in my new role as a "kept man".;)
     

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