Guest Posted August 28, 2002 Share Posted August 28, 2002 I am having oil pressure problems with my 300 engine. It is a 67 300 that has been put into a 65 Special Convertible. Before putting the engine in, all gaskets (except the head gasket) were replaced, the oil pump was rebuilt (new gears, 40lb. spring etc. but no new gear plate) and repacked with vaseline, and a new timing chain was installed. We got the new engine running and it runs great. The car is still idling low as we have not fully timed and adjusted the carb due to this oil problem. At this low idle, the oil light is on. As soon as any gas is given, it goes off. We noticed that the car seems to heat up rather quickly. We looked in the right valve cover, and it does not appear as if much oil is circulating up there. This, along with the quick heating, is worrisome. The car has 10W-30 oil in it. I am considering a couple of things including 1) upping the spring to a 60lb version, 2)Purchasing a high volume oil pump kit from Poston, 3) Purchasing a new thrust plate 4) Trying Gunk motor flush to unblock passages. Does anyone have any advice on where to start with this? I am thinking that I'll try the spring first and then check the gear tolerances in the pump itself. Could there be some sort of air pocket that is inhibiting the oil from getting up to the top? Any other suggestions of how to diagnose/fix this problem?Bret Link to comment Share on other sites More sharing options...
Guest Posted August 28, 2002 Share Posted August 28, 2002 first of all NEVER BUT NEVER under ANY circumstance pack an oil pump with ANYTHING!!!! This is an old trick used in service that is very dangerous. There are other more positive ways of priming thats almost as easy and require NO special tools.It is possible that the rocker shafts are plugged up with sludge or maybe even vaseline. If it does not have rockershafts then the pushrods r probably plugged up. I wish this 'packing with grease and vaseline stuff would go away!!! Link to comment Share on other sites More sharing options...
Guest Posted August 28, 2002 Share Posted August 28, 2002 Could the vaseline really be plugging things up? I read this in both my manual and many posts as being a good way to prime the pump. Bret Link to comment Share on other sites More sharing options...
Gene Brink Posted August 29, 2002 Share Posted August 29, 2002 Bret,Nothing wrong with using vaseline to pack the oil pump. That is why the method is in countless manuals including Buick shop manuals. The melting point for the vaseline is so low it will melt in your hand so it will not plug anything up in your engine. I would not expect to see a lot of topside oil when looking through the filler hole in the valve cover and would say it things are quiet you are getting enough oil. I'd bet the sending unit is marginal and may be setting the light off at too low a setting. If you have a manual gauge that you can plug in to test the actual pressure it would be a good idea. A crankcase of straight weight oil (say 30wt) would be another way to check as it should result in higher pressure at idle. Pump replacement, plate, high volume pump are all good ideas but may not be needed. I would NOT use anything to flush the engine.Good luck, Gene Link to comment Share on other sites More sharing options...
PGBUICK Posted August 29, 2002 Share Posted August 29, 2002 Bret,One of the keys to good oil pump performance is the end gap between the pump gears and the gear housing cover. I don't have my library in front of me, but I seem to recall .005" as being max. Less is better. To determine the end gap, remove the gear cover and gaskets. The gears should be sticking out past the housing slightly. Using a dial caliper or straightedge & feeler guage, you can measure this. The stock gaskets are about .020 (easily measured with the caliper). Subtract the gear protrusion from the gasket thicknes and you are left with the gear end clearance. If you have more than .004 you've likely found your problem which may not be a "problem" at all. Ditch the idiot light and install a guage. It's typical for some engines to idle at less than 20 psi. I believe the stock sending unit is set at 10 psi. KenneBell once tested a 455 by lowering the oil pressure to 5 psi and idling it all day with no ill effects.If you have 60 psi at 6000 rpm you're fine.Also. the gear cover should be fairly flat without excessive scoring. A little is OK. Too much and you should find a better cover or mill that one flat.Good luckPat Link to comment Share on other sites More sharing options...
Guest Posted August 29, 2002 Share Posted August 29, 2002 I have a 340, which is the closest cousin to a 300. 61K on engine, never had the heads off. Installed an Autometer guage set last year. Showed 12 lbs. at idle and about 23 at 65 mph. Engine runs perfect.1966 Buick Chassis manual says 33 lbs. at 2500 rpm. What to do?The consequence? I just accept the Autometer readings as normal and don't worry about it.BTW, I'm YellowLark - don't know why the new board is showing me as anonymous Link to comment Share on other sites More sharing options...
Guest Posted August 29, 2002 Share Posted August 29, 2002 Thanks guys. I will print the info and head to the garage. A buddy of mine who is a former VW/Audi mechanic has been nice enough to offer to stop by with his oil pressure gauge kit to perform an accurate test. He does not seem as concerned as I about this problem and echoed the thought that you would not see a lot of oil splashing around up there. BTW the gear surface had some grooves but did not seem badly scored when rebuilt. Question - each pump gear had a circular mark on the surface that meets the gear surface. Is there a certain way to install these things that these marks indicate? Also, any thoughts on which spring to use - would you guys go up to the 60lb. spring?I will repost with pressure results. After being off the road since November and now having new floor pans, exhaust and a rebuilt tranny, I cannot wait to go cruisin' with the top down this fall.Thanks again.Bret'65 Special Convertible Link to comment Share on other sites More sharing options...
GSMAG Posted August 29, 2002 Share Posted August 29, 2002 The 60 lb spring only comes into play when the oil pressure exceeds 60 lbs. It's a high pressure relief spring, it will not increase oil pressure beyond what your engine can produce already. I wouldn't worry about that just yet. Link to comment Share on other sites More sharing options...
Guest Posted August 29, 2002 Share Posted August 29, 2002 bret......., I have just had a very nerve wracking 40 mile journey in my le sabre with the 300 4bbl, when the switch decided to play up and the whole journey had the oil light glaring at me , but a new delco switch completely sorted out the problem !! sooooo.... if the motor doesn't sound like a bag of spanners being shaken, go for the easy fix first!! Also, on idle, you may see a flickering of the oil light, and this is often the case, and just means the pressure is minimal and o.k. ...... take it easy....... TREVOR <span style="font-weight: bold">'64 LE SABRE.......PRETTY MUCH DONE</span> Link to comment Share on other sites More sharing options...
Guest trevor ward Posted August 29, 2002 Share Posted August 29, 2002 WHOOPS...... FORGOT TO LOG IN, ......NEVER UNDERSTAND WHAT YOU GAIN BY ANONIMITY?? Link to comment Share on other sites More sharing options...
Guest Posted September 3, 2002 Share Posted September 3, 2002 Just to let you all know that I was worried for nothing. Oil pressure is 40lbs. cold and drops to 35lbs. at 2500 rpm warm. We timed the car and installed the petronix ignition. My brother in law was worried because he could not see oil circulating when looking through the oil filler hole, but apparently this is not an issue. The car runs great - smooth as a kitten. I was out for 2 hours rolling around yesterday - no overheating, no bad noises, just fun cruising.Thanks a lot for your posts. I'm sure I'll require more consults soon.Bret'65 Special Convertible. Link to comment Share on other sites More sharing options...
Skybeatle1965 Posted April 29, 2021 Share Posted April 29, 2021 I got the same issue on my 1965 Buick Skylark with the 300 engine. I have tried adjusting up the idle. 1 Link to comment Share on other sites More sharing options...
Aaron65 Posted April 30, 2021 Share Posted April 30, 2021 Welcome to the forum, but this is an 18-year-old post. Link to comment Share on other sites More sharing options...
Skybeatle1965 Posted July 3, 2021 Share Posted July 3, 2021 Sorry for jumping onto an 18 year old issue. This was a new issue for me. I had the radiator rebuilt and it appears to have solved the problem. Mine was a self inflicted wound. I added RED antifreeze to the GREEN antifreeze one winter several years ago. The next summer when taking the car out for a drive learned a hard lesson. The two do not mix. I had a mess. Many parts have now been changed. Link to comment Share on other sites More sharing options...
Larry Schramm Posted July 3, 2021 Share Posted July 3, 2021 Antifreeze/Coolant mixing should have nothing to do with oil pressure. 1 hour ago, Skybeatle1965 said: Sorry for jumping onto an 18 year old issue. This was a new issue for me. I had the radiator rebuilt and it appears to have solved the problem. Mine was a self inflicted wound. I added RED antifreeze to the GREEN antifreeze one winter several years ago. The next summer when taking the car out for a drive learned a hard lesson. The two do not mix. I had a mess. Many parts have now been changed. What happened with the mixing of red & green antifreeze? Link to comment Share on other sites More sharing options...
Skybeatle1965 Posted July 3, 2021 Share Posted July 3, 2021 Mixing the two caused them to gel in the cooling system. Ate the aluminum thermostat housing and timing cover housing. Plugged up the radiator. Not sure of the damage internally to the engine. So far it is running fine after rebuilding he radiator. 1 Link to comment Share on other sites More sharing options...
Skybeatle1965 Posted July 13, 2021 Share Posted July 13, 2021 Put gauges in the car. Oil pressure is 45 lbs at start up, then comes down to 35 lbs at idle. Spec say 33 lbs at 2,400 rpm. I am not totally sure of the safe zone. Link to comment Share on other sites More sharing options...
JohnD1956 Posted July 13, 2021 Share Posted July 13, 2021 41 minutes ago, Skybeatle1965 said: Put gauges in the car. Oil pressure is 45 lbs at start up, then comes down to 35 lbs at idle. Spec say 33 lbs at 2,400 rpm. I am not totally sure of the safe zone. The engine is over the spec so it is safe. But 5-10 lbs, at idle, when thoroughly warmed up, is still ok. 2 Link to comment Share on other sites More sharing options...
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