Buick 36 HOT OIL PRESSURE Update

[Buick36-49]

Buick 36 HOT OIL PRESSURE Update</SPAN>

Hello All,

</SPAN>I know I have other posts on here.... but still concerned.

Well today I took my 1936 Buick Special series 40 out for a ride. Now I am very fimalar with how the oils and viscosity work. However, my 36 has straight 40 weight in it thinking I could increase oil pressure. At startup I get an even 45lbs cold, but to my shock today I drove for about 40 min and notices that the oil pressure is dropping below 30lbs hot at speeds of 50mph. I believe I am getting around 12 lbs hot idle and 28 to 30 lbs running at around at 45mph. </SPAN>

I pulled off the oil pan and looked at all the rods, and what I find is the rods are no loose not up and down, but left to right (sliding on the crank maybe 1milimeter) they move on the crank. Is this normal? I also pulled off the oil pump and was thinking of stretching the oil relief valve spring, but did not. Should I to gain more hot running oil pressure. I’d like to see it at almost 40 hot. I just don’t want to blow this engine as 36 straight 233 eights are getting hard to find. Overall the engine runs good and smooth. Little smoke on startup and take off, but crusing no big blue clouds. </SPAN>

Buick experts please advise me before I send the whole engine out for $3500 rebuild in which I don’t have the money for. </SPAN>

Thanks</SPAN>

Robert</SPAN>

[Guest wildcat465]

Hook up an accurate mechanical oil pressure gauge and see what you have for pressure. Oil pressure senders are famously inaccurate and the gauges on a 70+ year old dash are something I wouldn't bet the house on. The pressures you are describing are not dangerously low.

[Buick36-49]

Hi Wildcat465

Thanks for your reply

I did hook up a mechanics gauge and the dash gauge is accurate. Same difference. So what I m thinking maybe if I stretch the spring in the oil pump that might help. Engine does have around 90k on it. Does burn a little blue.

I checked the spring in the pump and it is 2 ¾ long.

Robert

[old-tank]

Robert

As stated you have enough oil pressure as long as there is no bearing noise when low. Stretching the spring ruins it (you cannot un-stretch). If the spring were too short or weak then the pressure would be low all the time. If your lower than expected oil pressure is due to a worn pump or other engine parts, nothing other than servicing these parts will help. Drive and enjoy.

Willie

[Ben Bruce aka First Born]

Robert, as others have said, those pressures are pretty normal. My rebuilt 248 is only slightly higher. That oil pressure will vary with coolant/oil temps as well. As Willie said, if there are no bearing noises, ENJOY.

Ben

[Buick36-49]

Hello to old-tank and firstborn.

Thanks for your reply. It’s just weird because my 1949 Buick Super 248 has nice pressure even at idle and when you cursing it goes to upper end of the “N” normal on the gauge where the ’36 is just at 29lbs at around 55mph. Kind of scares me, no weird knocking, just a little piston slap.

I had a 36 Buick engine with the same mileage on it, but I got rid of that engine because of 3 cracks in the water jacket, I remember that one doing about the same thing with the oil pressure. Hot it was at an even ’30 lbs.

I still have all the parts to that engine except the block itself. (Still have the head, crank flywheel and everything.) I was thinking of stretching the spring only from the old pump and putting it in the “new” engine and see what might happen.

I guess comparing the oil pressure of my smooth running '49 to my '36 233 is not a good idea as engines change. The '49 has a dynaflow trans. with insert bearings.

Thanks

Robert

[Ben Bruce aka First Born]

Robert, sounds like you have a gauge in the '36 that is reading in psi rather than L N H as in the '49. Perhaps try a psi gauge in the '49 for comparison. Hummm, got me thinking!!

p.s

Didn't we go through this back in 2011?

Edited June 8, 2013 by First Born (see edit history)

[Buick36-49]

Yes, back in 2011 I think I posted the same question. I guess I am still a little nervous running it like this. I must have put about 1500 miles on the car and it still runs fine. Also, I guess that 29 is in the middle of the “N” on the ’49 gauge. The ’49 says I need 35lbs at 45mph and the ’36 is 45lbs at 45mph. So, I have to figure out what is normal. On the ’36 I still am getting at least 12lbs hot idle.

Robert

[FLYER15015]

Robert,

Willie is right, in that you can not un-stretch a spring.

When my oil pressure was low, I rebuilt the pump by polishing down the housing on a flat plate w/ 60 grit emery, and using plastigage to set the drive gear @ .0025" from the freshly ground bottom plate. Mine was at .004+" when I started.

I also stuck a 1/2" nut behind the pressure relief spring. Old used car lot trick.

Now she idles @ 20-25 psi and cruses at about 35-40 psi with Kendal 10w-40w and a pint of STP.

Mike in Colorado

[Buick36-49]

So, what I’ve done was sand paper the cover plate and pump body down a little, than used a feeler gauge to measure the clearance after I’ve tighten up the screws on the cover plate (with out the round baffle). It looks like I got it down to .002. I know that the engine had around 90k on it so it leaves me to think that the whole engine is just a little looser and broken in. The pump probably a little worn, but seems nice and tight. I’ve ordered a new pan gasket and oil pump to body gasket and just waiting for them to arrive and put it all back together again and see what happens.

I’ve been using SAE40 weight now. I used to use SAE 30 and put in Lucus oil stabilizer, seems to help, but that’s what gives me 30lbs at 50mph hot.

I just can’t afford to have the whole thing rebuilt and don’t normally put many miles on the car (500 in a year if I am lucky). But when I do travel to car shows and such, they are usually about an 1 hour away. As mentioned, the car never over heats. Gets a little hot in parades but that’s normal, my ’49 does that too. They should have used fan shrouds back in the day.

Makes you wonder how they did it back in the day in the city at 100 degree weather. :confused:

Robert

[JohnD1956]

Back in the day they did not use these old cars the way we do. When it was 100* they probably stayed home and went to the local swimming hole for relief.

And one thing I would like to add to this discussion is a question? What difference does 25 -40 lbs mean while running? Technically pressure means the oil is moving. More pressure means the oil is backing up because the orifices it is traveling through are still the same size. I do not think higher pressures ensure reduced wear. The thin film of oil between your bearings and the crank or cam shaft is still the same thin film of oil. It's not like that thin film can provide a bigger cushion at 45 lbs than at 25 lbs.

If anything the most important part of the oiling system is that the oil gets through to where it's supposed to go.

[Ben Bruce aka First Born]

John, I did not have the option of not driving just because the temp passed the century mark. Work still called.

I agree with you in principal regards oil pressure. But probably the "designed" pressure at the sensing point was necessary to ensure adequate flow to the extremities.

Ben

[Buick36-49]

Thanks again for the reply,</SPAN>

Yes, I was doing some reading and yes, high oil pressure does not mean that everything is getting “better” oil cushion. </SPAN>

This engine is warn, but still has good compression and runs smooth. I just makes me nervous to se 20lbs when hot going up a hill around 40mph. </SPAN>

Ben, did they over heat a lot back in the day in stop and go traffic. I like watching old movies and seeing the traffic jams, how did they not overheat. I know the Buicks do not have fan shrouds and they start to run hot in parades and such. </SPAN>

[JohnD1956]

John, I did not have the option of not driving just because the temp passed the century mark. Work still called.

I agree with you in principal regards oil pressure. But probably the "designed" pressure at the sensing point was necessary to ensure adequate flow to the extremities.

Ben

Did not mean to offend Ben, and I apologize if I did. My main thought was that not many in the 50's used a 50 Buick in a parade in the 100* heat. Even if they did, the car was new, the metal was new without 50+ years of rust build up and the radiator was also new without several inchies of sediment in the bottom tank. Older cars at that time were still much newer than today.

I can see your point about the pressure being used to ensure adequate flow to the extremities. I think that most manufacturers consider longevity to be of value, and design stuff to extremes in the anticipation that at half the wear there would still be adequate coverage. Even today reputation is first and foremost. What sells when consumers bad mouth a product? They probably did not anticipate engines sitting around for 10- 30 years without being touched, and fossil oils hardening in the engine's arteries, then someone simply dropping gas down the carb and spinning it over to see if it would still go. At any rate, I do not think 20 lbs oil pressure going up hill at 40 MPH is of concern. It's not a new engine statistic, but it's also not a new engine. The engine is quiet and has sufficient power and is not blowing oil out of the seams, then it may as well be driven 1500 miles per year with peace of mind.

[Buick36-49]

Yeah, </SPAN>

I know when I take it out on the highway after a long run the pressure goes to 30lbs at 50mph. 50mph is all I do in those cars. </SPAN>

In fact after a long run, the engine seems to run smoother. Does not run hot, prob around 185 and starts right up after you shut it down.

I hooked up a mech. oil pressure gauge and it shows around 12lbs hot after a run. Book calls for 10lbs at hot idle.

Did not mean to offend Ben, and I apologize if I did. My main thought was that not many in the 50's used a 50 Buick in a parade in the 100* heat. Even if they did, the car was new, the metal was new without 50+ years of rust build up and the radiator was also new without several inchies of sediment in the bottom tank. Older cars at that time were still much newer than today.

I can see your point about the pressure being used to ensure adequate flow to the extremities. I think that most manufacturers consider longevity to be of value, and design stuff to extremes in the anticipation that at half the wear there would still be adequate coverage. Even today reputation is first and foremost. What sells when consumers bad mouth a product? They probably did not anticipate engines sitting around for 10- 30 years without being touched, and fossil oils hardening in the engine's arteries, then someone simply dropping gas down the carb and spinning it over to see if it would still go. At any rate, I do not think 20 lbs oil pressure going up hill at 40 MPH is of concern. It's not a new engine statistic, but it's also not a new engine. The engine is quiet and has sufficient power and is not blowing oil out of the seams, then it may as well be driven 1500 miles per year with peace of mind.

Edited June 11, 2013 by Buick36-49 (see edit history)

[Ben Bruce aka First Born]

No offense, JohnD, And I agree with you. I think 36-49 is worrying a bit much, but appreciate his concern. Robert, just drive it and don't worry so much.

Ben

[Buick36-49]

Thanks Ben,</SPAN>

Yeah, I just got in my gaskets and am going to put the oil pan back on. Should see what happens. </SPAN>

I’ll keep you all posted.</SPAN>

Robert</SPAN>

No offense, JohnD, And I agree with you. I think 36-49 is worrying a bit much, but appreciate his concern. Robert, just drive it and don't worry so much.

Ben

[Buick36-49]

Hey All,

I know I’ve been driving you all crazy with the oil pressure issue. Well, I put the car back together. Nothing has changed with the oil pressure, I do get high cold oil but hot it’s prob around 26lbs at 50mph.

I was using Lucas oil stabilizer and had higher oil pressure around 30lbs.

I took it for a 16 mile ride yesterday and the pressure went as low as about 26lbs and the engine felt like it was straining and starting to run a little rough. So, I am going to put Lucas back in seems to like it better. I am using SAE 40 but at high RPM (50mph steady) the oil seems to get hot and break down anyway.

I guess a rebuild is in order. But will nurse the engine along with Lucas oil stab., I guessing a rebuild for that engine will prob be around 2k.

Thanks all for helping on this.

Robert

[buick5563]

Yes, back in 2011 I think I posted the same question. I guess I am still a little nervous running it like this. I must have put about 1500 miles on the car and it still runs fine.

So what is the question?

[Buick36-49]

Hi Buick5563.</SPAN>

Well, there is no question, but more of an update on what I was doing. </SPAN>

Just for the heck of it, what would it cost aprox to have an engine like this rebuilt. New rod bearns, mains, cams and such. </SPAN>

Do you need to pull the engine?</SPAN>

Thanks</SPAN>

So what is the question?

[buick5563]

Yeah, I know.

My point was that in the quote that I made bold, you said you had driven 1,500 miles and that it drove fine.

I was just busting BB's.

Yes, you will need to pull the engine if your desire is to rebuild it.

[Buick36-49]

Oh okay, hehe

Thanks for letting me know...

[DonMicheletti]

The issue of rebuilding engines and having to pull them to do the job is interesting. Years ago we never pulled an engine to do an overhaul. Especially babbit bearing engines where you could pull shims to set bearing clearances. All the work was done with the engine in the car.

Really, all we did was a "ring and valve" job.

Of course that assumes the engine does not require a rebore - but even then occasionally an engine would be rebored with it still in the car.

Of course doing this does not necessarily a engine restoration though.

Don

[Buick36-49]

Hey Don,

I was thinking of nursing the engine along as I have been using Lucas oil stabilizer which it seems to like a lot. (If I put 400 miles on it a summer I am lucky) Runs a lot smoother and pressure is a little higher around 30+. For a winter project maybe we will pull the pan again and check the rod clearances. My Dad has a lift in his garage so working on the car might be a lot easier that way. I just can’t work on my back doing this with a jack.

Maybe if we remove some shims will tighten up the clearances. I have to practice using the plastic gauges.

Would you suggest doing this?

Thanks

Robert

The issue of rebuilding engines and having to pull them to do the job is interesting. Years ago we never pulled an engine to do an overhaul. Especially babbit bearing engines where you could pull shims to set bearing clearances. All the work was done with the engine in the car.

Really, all we did was a "ring and valve" job.

Of course that assumes the engine does not require a rebore - but even then occasionally an engine would be rebored with it still in the car.

Of course doing this does not necessarily a engine restoration though.

Don

[DonMicheletti]

In my opinion, the pressure isn't in the danger area. Checking the bearing clearances with plastic age and getting them where they belong and getting the oil pump clearances in spec will probably do wonders for your pressure.

Working under the car isn't fun, but it is a whole lot easier than pulling the engine.

A lot will depend on how you expect to use the car. If it isn't going through a lot of oil ( 1 quart per 1000) resetting the bearings will do you fine.

Don

[Buick36-49]

Hey Don,

Thanks for your advice. Yeah, I don't rum em much ('49 Buick as well). But do enjoy the rides and don't want to have to keep staring at the oil pressure guage and not enjoy my ride and worry if I will make it or not and then oh yeah make it back... It does burn a little oil and leak a little, but that another issue in itself.

RObert

In my opinion, the pressure isn't in the danger area. Checking the bearing clearances with plastic age and getting them where they belong and getting the oil pump clearances in spec will probably do wonders for your pressure.

Working under the car isn't fun, but it is a whole lot easier than pulling the engine.

A lot will depend on how you expect to use the car. If it isn't going through a lot of oil ( 1 quart per 1000) resetting the bearings will do you fine.

Don

[Ben Bruce aka First Born]

In my opinion, the pressure isn't in the danger area. Checking the bearing clearances with plastic age and getting them where they belong and getting the oil pump clearances in spec will probably do wonders for your pressure.

Working under the car isn't fun, but it is a whole lot easier than pulling the engine.

A lot will depend on how you expect to use the car. If it isn't going through a lot of oil ( 1 quart per 1000) resetting the bearings will do you fine.

Don

I agree with Don. And I have and have had a LOT of straight eights.

Ben

[Buick36-49]

Hello Ben,

Here are some video's I do have Lucas oil stab. in this one....

Cold Oil Pressure:

https://www.facebook.com/photo.php?v...54168826962139

HOT OIL Pressure

https://www.facebook.com/photo.php?v...17395448514292

RObert