Steves Buick

loss of oil pressure

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How hard would it be to make a new one? I don't see anything there that isn't commonly available and then you wouldn't have to worry about that thin spot coming back to haunt you. You're still going to have to fix that broken stub and sweat at least that joint, and doing so will possibly cause the others to come loose. I'd make an all-new pipe and know that it's done right. I might even use something like Cunifer (copper/nickel) tubing instead of the copper. Cunifer doesn't work harden from vibrations the way copper does. Plus if you make a new one, you can bend a little extra clearance into the areas where you need it.

 

A little extra work, maybe, but you don't want to take a chance with oil supply and you only want to do this once, right?

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Thanks Bloo, Paul, Don, Matt and Mike and everyone for the advice and links,

 I'll fab one up, but the tubing flare at the end of Bnut could be a challenge, early dole fitting??  Really like the Cunifer idea Matt, and yes I  only want to do this once. This forum is a life saver.. mucho grats.

Steve

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Make it all new. Be sure the copper wall is the right thickness. 

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On 6/28/2019 at 1:00 PM, edinmass said:

 obvious. If you missed a line, cracked a line, or some other internal issue, a pressure pot is the only way to find it.

 

 

Nailed it! 👍

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Those "threaded sleeve" tubing nuts are hard to find, but available. I would try like crazy to save the original. It does look a little different than current ones. You would really want to look at the threads and angle before replacing it, just to make sure. I would cut off the tiny bit of tubing sticking out the end, as it will be slightly larger. These tubing nuts bite into the tubing a little bit, so the tubing becomes a smaller diameter right where the flare end of the nut is. You'll have to get rid of that end bit to get the tubing nut off.

 

What size is your tubing? Midland Metals makes those nuts, and Blackhawk Supply has them in at least 3 sizes. I bought 5/16" for my Pontiac fuel lines.

 

 

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That main galley line is probably brass, not copper.   OnlineMetals has brass tubing.   The point someone made earlier about the orifice in the filter line is something I ran into while restoring my 60 series car.  My car had the fitting replace with a much freer flowing fitting and I caught it which is probably a good thing since the engine had about 15 minutes run time on it after a compete overhaul.  The correct fitting is for double compression line, has a dog leg and one branch that feeds the oil filter and other feed the instrument panel oil pressure gauge.  That fitting has the Buick logo stamped or cast on as shown in my picture below and the orifice is sized to feed 1 qt. of oil/5 minutes to the rocker arm shaft at 25mph PER the 1931 Buick Specs and adjustment manual.  Assuming you have the base fitting already that screws into the block you just need to find the branch fitting.  A larger or less restrictive fitting will over oil rockers and front generator bearing and the pressure loss that allows it to flow freely is taking oil pump capacity from mains and rods.   If you have gray muck in the pan carefully inspect main and rod caps for any discoloration that may indicate the bearing got hot.  If in doubt, plasti-gage the bearings.

OF 002 (2)_LI.jpg

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 I drove the car today!!  I ended up silver brazing a sleave over the broken fitting, it took a few trys to get it all in alignment perfectly but I did. I extended the length by 1/8 in and put a slight bend downward of the most forward fitting to make sure I had clearance from the connecting rod bottom. I also placed 2 flat washers in the oil press relief valve end against the spring which brought my press back to 35psi at all speeds. Of course today was warm and my marvel was acting up a bit running rich, so I'll dial that in this week.  All in all I'm pleased with the out come. Thanks to all for the help, Ill post a pix when I get my phone charged!  

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Glad to hear that you got it fixed and that there was no serious damage ! 

 

Paul 

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Posted (edited)
On 6/30/2019 at 10:57 PM, FLYER15015 said:

Steve,

If the bottom plate on your oil pump looks like this (mine), emory it down with 60, then 120 grit till all the dark spots around the perimeter are just GONE.

Put a THIN coat of Permatex #2  around the edge and seal it up.

Distance between the gears and bottom plate should be NO MORE THAN .005"

 

Did mine 5 years ago and she still holds 40 # at a hot idle.

 

Mike in Colorado

035.JPG

You need to be sanding these kind of things on a "surface plate" - a chunk of metal that is actually flat (most good machine shops will have a surface plate) - and you can home try it on a large anvil or block of metal, but ..  

Edited by John_Mereness (see edit history)

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A piece of plate glass on top of a piece of plywood is one way of guaranteeing that the surface is actually flat.  Valve grinding compound and a figure eight motion works great.

Also works great on water outlets and water manifolds.

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Posted (edited)

Surface plate, surface grinder, and do NOT put any sealer on that at all. 

 

 

 

PS.......glass is not flat over a large area.........for very small parts it’s ok. 

Edited by edinmass (see edit history)

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Actually, I did mine on my Bridgeport mill table.

And just to check, I did put a THIN bead of Permatex around the perimeter, and "Plastigage" under both gears, screwed the plate tight and got .0035" clearance on both gears.

Took it back apart and reassembled minus the Plastigage of course.

I also stuck a 1/4" nut behind the pressure relief spring, like we used to do on all the old used cars that came in to our Plymouth dealership with "tired" engines.

That was back in the '60's when cars had oil pressure gauges.

 

So far the Buick has 60 @ start up, 40 @ a hot idle and 40-50 cruising @ a comfortable 55, and we did the oil pump 5 years ago.

 

Mike in Colorado

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All I know is that the one in the picture needs to be a lot flatter than it is. End clearance is death to oil pressure, and a little clearance is a lot of pressure loss.

 

It wouldn't bother me to sand that on a piece of glass. It isn't very big, and since I don't have a surface plate, that is probably how I would do it. Use a figure-8 motion.

 

The best end clearance for an oil pump is as tight as you can possibly get it, as long as you do not go tighter than the shop manual allows. There will be wear on both ends of the gears, so it is almost impossible to get it too tight by sanding a cover, but always check it! Repeatedly!

 

Getting it tighter would involve sanding or surface grinding the pump body, or new gears. That might be necessary if the shop manual thinks it is still too loose after you flatten the bottom plate. Moderation is the key. Don't go there unless you are absolutely sure. It is tough to put metal back.

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Posted (edited)

Bloo,

Just to let you know, the picture shown is the part with just a "Kiss" on a belt sander shown to illustrate where the leaks around the perimeter are. The dark spots.

I only had to take the base plate down to where these disappeared, as the plate was not warped, like some are.

Used 60 grit emory, followed by 100, then 120 to finish. I did not want a "mirror" finish and I did not make a gasket from a manila folder, like some do.

Although I did make a manila folder gasket for where the pump bolts to the block.

Just used a THIN bead of #2 Permatex around the base plate perimeter.

According to the Buick forums from quite a while back, this is pretty much a standard fix, and the stated max clearance between the gears and plate is .005"

I got .0035 and called it good. See pressures stated above.

 

Mike in Colorado

Edited by FLYER15015 (see edit history)
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On 7/20/2019 at 3:02 PM, edinmass said:

Surface plate, surface grinder, and do NOT put any sealer on that at all. 

 

My recent restoration now has 700 miles on it.  My oil pressure DASH gauge shows about 33 psi at start, and holds that at 60 mph.  I was afraid the pressure was too low, as the dash gauge drops down very low when warm at idle.  I checked the pressure at the BLOCK with a gauge, and I'm getting about 42 psi at start.  So, my dash gauge seems to be off about 10 psi, but also means I'm only getting 10-15 psi at hot idle.  

So....  I purchased another oil pump from Dave Tachney and sent it out to Egge to be professionally rebuilt.  I just got it back and it definitely appears to have a sealer around the perimeter of the plate.  Do I have to worry about the sealer?  Will it dissolve out or something?

I appreciate your input before I drop the pan and make the switch.

Thank you!

 

 

2104525836_ScreenShot2019-07-27at1_42_13PM.thumb.png.b34dc6b2624b9f643f9002283c9a3a4f.png

At 55 - 60 mph my DASH gauge shows about 33 psi oil pressure.  

The Buick specs call for 45 psi at speed.

 

 

DSC_0152.thumb.JPG.08fddd3b531ebed9d03c836c410f4179.JPG.1b65c7b64d88d6dcfdbef88be25ad081.JPG

So, I checked at the block and I'm getting 42 psi at start up, so my DASH gauge is off by about 10 psi.

 

 

IMG_5720.thumb.jpg.a728f138707be6362bf6ff4d51646539.jpg

I got the rebuilt oil pump back from EGGE and there is clearly a sealant around the perimeter.

 

 

IMG_5719.thumb.jpg.17bee4532c07259ea4d4b6135290deda.jpg

I'm planning on sanding all that extra sealant off the outside before I install it, but is the use of sealant considered a "no-no"?

Thanks for any information before I drop the pan and install this rebuilt unit.

 

Gary

 

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Posted (edited)

I think you're OK in both regards. My 1929 Cadillac manual calls for 12 PSI hot oil pressure at idle and the general rule of thumb is 10 PSI per 1000 RPM so you're fine at idle as long as it goes up as you accelerate. As for whether the sealer is acceptable, I think it should be OK, as Mike explains above. I'm surprised they'd be so sloppy about it, but it should not hurt operation and if they use the right stuff (I presume an oil pump rebuilder knows to use oil-resistant sealant on oil pump. Once it's in there, you should hopefully see a nice bump in idle pressure.

 

 

Edited by Matt Harwood (see edit history)
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Surface plate, surface grinder, and do NOT put any sealer on that at all. 

Agree!

 

Am I missing something in regards to the oil pump? Yes, the surface needs to be flat but why use sealant? shouldn't there be a gasket?

Not a big fan of sealant - you have no control over the thickness and evenness which means all that work lapping the part gains very little when a gasket can be tapped out so easily.

At least with a gasket you know the thickness and that the parts are mated reasonably square - Sealant is the engine builders version of pop-rivets and bondo.

 

 

 

 

 

 

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1 hour ago, Terry Harper said:

.

 - Sealant is the engine builders version of pop-rivets and bondo.

 

I agree............hack work.

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Posted (edited)
10 hours ago, Terry Harper said:

Agree!

 

Am I missing something in regards to the oil pump? Yes, the surface needs to be flat but why use sealant? shouldn't there be a gasket?

Not a big fan of sealant - you have no control over the thickness and evenness which means all that work lapping the part gains very little when a gasket can be tapped out so easily.

At least with a gasket you know the thickness and that the parts are mated reasonably square - Sealant is the engine builders version of pop-rivets and bondo.

 

 

 

 

 

 

Some oil pumps used  brass shims in the pump body to set the end clearance of the pump gears. Later rebuilders assume these are a gasket and use gasket material, which has drawbacks. It often can't hold against high cold-oil pressure and blows out. Plus, depending on how tight the bolts are, the clearance can change as the gasket material crushes to different thicknesses at different clamping pressures. Along comes the next guy and thinks there should be some type of  soft gasketing material- worst being silicone sealer which bits and pieces of can get into places it shouldn't.

 

Paul

Edited by PFitz (see edit history)

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Some oil pumps used  brass shims in the pump body to set the end clearance of the pump gears. 

 

That's correct Paul, I have come across the brass shims as well. The other issue is understanding what oil pressure your engine is designed for. Today we are use to high pressures (40-50 psi)

but back in the day that wasn't the case. For instance my T-head Wisconsin is 100% reliant on full pressure lubrication. There is no splash lubrication at all. A baffle extends the full length of the sump

with only screens at the ends to allow for oil return. The crank throws can't take a dip in the oil at all.

 

The pump is actually two pumps in one  - One half is the scavenger pump which draws oil from the sump through two oil lines extending to each end of the sump and the service pump that sends it to all the moving parts. You would think being 100% dependent on pressure lubrication that the oil pressure would be high - its not.... if your reading between 5-10 psi your good to go! However, your talking large lines and a large volume of oil being moved. The sump holds 5 gallons.

 

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Posted (edited)

So if you think about it a good machinist has 2 surfaces to work with to achieve proper end clearance of the gears and plate after the plate is surface ground flat, the gears themselves and the sealing flange the plate screws to.  Too much clearance- surface the sealing flange, too little clearance, the gears.   I could see an OEM intentionally building the pump with gears set to zero clearance to the plate or even slight interference, then select fit shimming with brass precision shims to get the desired end clearance.  Doing that makes the end clearance serviceable without machining as the gears wear.   Any kind of soft gaskets or sealer should not be used.  if the housing and plate are both flat the leakage would be negligible and it just drops back into the pan in the Buick engines.  Some manufacturers mounted their oil pumps external to the oil pan which make them easier to remove and service and those have to seal perfectly to prevent leakage outside the oil pan.

Edited by Str8-8-Dave
Correct spelling (see edit history)
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I'm with the "no sealant guys"

On the pumps with the pot metal borrom plate, you are asking for trouble if you jack up the oil pressure. They warp with just the 45 psi, jacking pressure up will just make matters worse

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