howardjnl Posted March 20, 2012 Share Posted March 20, 2012 I very recently bought a 1937 Buick Century with a recently overhauled 320 engine. I have a serious problem with oil burning plus fouling of the rear two cylinders. Talking with the rebuilder, we first checked for damaged lands on these two pistons since the engine had an ignition failure (new HEI system had bad pick up coil) on the way to my home and some serious backfires. But pistons are fine. The intake manifold and ports were dripping oil when I removed the manifolds to remove the head. Further discussion with the rebuilder led to the probability of oil being sucked into the head and manifold around the valve stems. He mentioned having seen these engines before over oiling the rocker arm shaft and oil level rising a bit in the valve cover. He said to check for a restriction in the oil line fittings for the rocker arm shaft, and if not present, add one 0.020 to 0.025 inches in diameter to replace the missing one. In addition, I have sent the head to a local shop to have the valves fitted with valve stem seals as a further precautionary measure.Has anyone else encountered this situation, or heard anything about this oil line restriction? I've seen two references to this "restriction fitting" in posts as something suggested to look at in reassembling an oil system, but no real mention of its function or symptoms of problems with it. John Link to comment Share on other sites More sharing options...
Guest Grant Magrath Posted March 20, 2012 Share Posted March 20, 2012 Interesting issue. Original oil pump? Might be time to fit new valve guides rather than seals.CheersGrant Link to comment Share on other sites More sharing options...
howardjnl Posted March 20, 2012 Author Share Posted March 20, 2012 Has new valve seats and guides and original pump. Oil pressure is good (a little over 30 psi). I'm going with the seals as I'm paranoid :-) . Still wondering is anyone out there has had first hand experience with this "restricted fitting".Thanks for reply, Grant. John Link to comment Share on other sites More sharing options...
Bob Engle Posted March 20, 2012 Share Posted March 20, 2012 I can't speak for the newer engine setups, But it 1932, The oiling system was split with oil pump direct to rods and mains. The secondary oil was run to the filter through a 1/8" copper tube. Then from the filter the oil was routed to the rockerarm shaft. There was a tube at the front of the shaft that directed any excess oil from the shaft to the timing gears on the fornt. Many mechanics when changing from the original style oil filters to the more modern canister filters would replace the 1/8" oil line with a larger one and then had oil problems with excess oil in the valve areas.One other thought, on the 32 engines the oil from the filter goes into a fitting on the block and then through a passage up into the cylinder head. A damaged head gasket could let oil flow into the rear cylinder and the intake has a common port to 7 & 8 cylinders.On the straight 8's oil can very easily flow away from the valve guides through the large push rod openings. I doubt that the guides or the addition of seals will solve your problem.Bob Link to comment Share on other sites More sharing options...
Guest Grant Magrath Posted March 21, 2012 Share Posted March 21, 2012 How's the valve lash on those problem cylinders John?CheersGrant Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted March 21, 2012 Share Posted March 21, 2012 (edited) John, I believe I would run a compression check on those two cyls . Just to remove any doughts. As to the oil line restriction, if it is the same as later models, and I believe it is, the "restriction" is in the fitting that the oil line from the filter, if so equipped, connects to at the front bottom corner of the head. Even if no filter the oil pipe to the rocker arms still connects same place. You can see it in this photo. Ben Edited March 21, 2012 by First Born (see edit history) Link to comment Share on other sites More sharing options...
howardjnl Posted March 21, 2012 Author Share Posted March 21, 2012 I can't speak for the newer engine setups, But it 1932, The oiling system was split with oil pump direct to rods and mains. The secondary oil was run to the filter through a 1/8" copper tube. Then from the filter the oil was routed to the rockerarm shaft. There was a tube at the front of the shaft that directed any excess oil from the shaft to the timing gears on the fornt. Many mechanics when changing from the original style oil filters to the more modern canister filters would replace the 1/8" oil line with a larger one and then had oil problems with excess oil in the valve areas.One other thought, on the 32 engines the oil from the filter goes into a fitting on the block and then through a passage up into the cylinder head. A damaged head gasket could let oil flow into the rear cylinder and the intake has a common port to 7 & 8 cylinders.On the straight 8's oil can very easily flow away from the valve guides through the large push rod openings. I doubt that the guides or the addition of seals will solve your problem.BobThat's one reason I'm wondering about this diagnosis, the capacity of oil that should be able to flow around the push rod openings. I've never come across the concept of too much oil in working with modern engines.The head gasket has no obvious leakage apparent, at least not to the eye. Compression on both of these two cylinders with the recently re-ringed engine cold is about 90 psi; slightly higher than a couple of other cylinders and slightly lower that a couple of others. There's no dramatic, obvious compression problem.This car is missing the oil filter to the rocker arm shaft. The 1/8 line is running directly to the head from the side port. This concerns me as there's no screen of any kind after the oil pump to the rocker arm shaft. I'm going to add one. John Link to comment Share on other sites More sharing options...
howardjnl Posted March 21, 2012 Author Share Posted March 21, 2012 John, I believe I would run a compression check on those two cyls . Just to remove any doughts. As to the oil line restriction, if it is the same as later models, and I believe it is, the "restriction" is in the fitting that the oil line from the filter, if so equipped, connects to at the front bottom corner of the head. Even if no filter the oil pipe to the rocker arms still connects same place. You can see it in this photo. BenYes, Ben, as described in my previous post to Bob, I've run a compression test on the cold engine. The oil line runs directly from the side of the lower block to the head without a restriction or oil filter of any kind.I'm ready to add a restriction, which the rebuilder says to make between 0.020 and 0.025 inches in diameter, but I'm still uneasy about doing so without some collaborative information from a second source. John Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted March 21, 2012 Share Posted March 21, 2012 Does the oil line fitting go directly into the head -or- does it go into another fitting in the head? Ben Link to comment Share on other sites More sharing options...
Guest Grant Magrath Posted March 22, 2012 Share Posted March 22, 2012 Try a leak down test on those two cylinders. It will tell you more than a compression test will.CheersGrant Link to comment Share on other sites More sharing options...
Guest gmorse Posted March 22, 2012 Share Posted March 22, 2012 Hello. I am new to the forums, but I can shed a little light on the restrictor in the oil line to the rockers. my experience has been with a '39 248 engine, but I have been told the 320 uses the same part. After removing the valve cover, you will see a short piece of oil line running to the rocker shaft (at the fron end). On the 248 engine, the fitting that this short line goes into is the restrictor.(It screws into the head). If you remove this fitting, the hole in the center for oil flow should be 1/16 inch diameter. A normal fitting of this size has approx. an 1/8 inch hole. This is all from memory, as it was a number of years ago I had the top end apart. There was a special Buick part number for this fitting, but trying to find one now would take forever.I hope this helps some.Gary Link to comment Share on other sites More sharing options...
Guest gmorse Posted March 22, 2012 Share Posted March 22, 2012 Hello again. After posting the last comments, I dug out my old 38 and 39 parts books. Here is what I found: as I said in the previous post, the '39 models had the restrictor fitting fitted directly into the head. GM part#1308416. It does not list the actual size of the opening. The sizes I mentioned in the last post were from memory, and I still think they are correct.BUT, on your "37 (and '38) the restrictor is an elbow that screws into the number one rocker stand. I have looked thru all my material, and cannot find any mention of the size hole in the restrictor. The size I gave is just from memory when I had my 248 apart. I have copied out of the Buick parts manual two pictures that are very clear in the position of the parts. Unfortunately, I cannot get my scanner to do a decent job on them, or I would email them to you. The next best is, if you want to give me your mailing address, I would be willing to take them to the Post Office. You can email me at gmorse58@hotmail.comHope I can be of help. I have had my '39 model for 13 years, and it has come from very poor to good driver quality (just a litttle less than show quality, although I have pick-up a couple awards in those years).Gary Link to comment Share on other sites More sharing options...
danhar1960 Posted March 23, 2012 Share Posted March 23, 2012 G'day Gary and welcome to the board. Another '39er, love it. The more here to help with input the better.Standard request to all newbies is "pictures, we like pictures" of your beasty. :)Danny Link to comment Share on other sites More sharing options...
Guest Mike Hanning Posted March 23, 2012 Share Posted March 23, 2012 Hello John,Gary is correct with what he is saying about the rocker shaft oil feed restricted fitting. FYI, the fitting was changed from a location in the crankcase adjacent to the right front engine mount, just forward of the fuel pump to a new location on top of the front rocker shaft pedastil, (bracket). This change was made in production beginning with eng. No. 3206124 on Series 60-80-90. The only issue I have ever encountered when the restrictor elbow has been substituded with an un-restricted fitting is that of very low oil pressure at hot idle! It won't be causing the oil burning issue you describe.I suspect your engine is fitted with the combination fuel/vacuum pump, in which case the vacuum side of the pump is defective allowing oil to be drawn into the inlet manifold via the windscreen wiper vacuum line. If you have evidence of oil in the inlet manifold towards the back cyls. and your engine is fitted with the combination pump then this explains the problem you are experiencing. Best regards, Mike Hanning BCA#40630 Christchurch New Zealand. Link to comment Share on other sites More sharing options...
howardjnl Posted March 24, 2012 Author Share Posted March 24, 2012 Guys, Wow, I appreciate this very much! Gary, the elbow on top of the rocker shaft indeed has a 1/16 inch hole in it to reduce the opening size. I've also seen this on a Torque Tube article with an arrow pointing right at it. What's been throwing me is the rebuilder of this engine does a lot of these straight eights and insists that .020 to .025 opening is what to use. I think I'll forget him and make sure the 1/16 fitting is clean and stay with that. I'm adding an oil filter to this oil line to the rocker shaft, the car currently has none. I really appreciate your research and feedback, it's been very helpful and reassuring to this '37 Buick newbie.Mike, I do indeed have this combo pump. What you describe has opened a whole new area to check out for me. The wiper does not work and I will be checking out the vacuum transmission this coming week. There are two small lines on the fuel pump that are not connected to anything, someone has cut them off. I've not looked for the line to the vacuum pump yet. Link to comment Share on other sites More sharing options...
howardjnl Posted March 24, 2012 Author Share Posted March 24, 2012 Hmm, now that Mike has mentioned the vacuum system and combo pump, can anyone share with me a disgram or description of the routing of vacuum lines in these cars? Mine's a '37 Century. Like I mentioned above, the vacuum lines to the combo fuell pump have been cut off, and I see no connections to the manifold. I've yet to get into the dash board to trace down what's in there for the wiper motor. John Link to comment Share on other sites More sharing options...
Guest gmorse Posted March 25, 2012 Share Posted March 25, 2012 John, thank you for confirming my memory that the 1/16 inch is the correct diameter for restricted oil flow to the rockers. Now that you are looking at the fuel pump for your oil problems, I hope you find that is the cause. Much easier to replace the pump than dig into the engine internals. After struggling with my fuel pump a few years ago, I installed an electric pump back near the fuel tank, and blocked off the opening where the original pump went. Of course, I realize that "purists" condem this sort of thing, but my car is to have fun driving, not just for show. I put on about 3000 miles a year on the car.By the way, I think you are in VA, I have a son and family that lives in Winchester VA, that we get up to see about once a year. Probably not this year, though. Are you close to Winchester? Maybe some time in the future we could meet to talk about old Buicks!Regards,Gary Link to comment Share on other sites More sharing options...
howardjnl Posted March 25, 2012 Author Share Posted March 25, 2012 Gary, mine too will be a regular driver, not for show. I live just to the southwest of Richmond, not that far from Winchester. John Link to comment Share on other sites More sharing options...
howardjnl Posted March 25, 2012 Author Share Posted March 25, 2012 Guys: My fuel pump vacuum fittings are not connected to anything, and the only vacuum connection on my intake manifold it one coming from the base of the front carburetor (I have two carburetors) to the vacuum advance on the distributor. I don't think I'm facing the oil leakage problem Mike described.I have a PDF copy of the GM 1937 Buick Shop Manual, but it does not include much of anything about the routing of vacuum lines or about the combo fuel pump. Any suggestions about other manuals or documentation I should acquire? John Link to comment Share on other sites More sharing options...
Guest gmorse Posted March 25, 2012 Share Posted March 25, 2012 John, I do not have a diagram of the vacuum lines, but on my '39 series40, the line originated at a fitting on the intake manifold, went from there to the forward fitting on the top (vacuum) part of the fuel pump. Then a line went from the other (rear) fitting on the top of the pump back to a flexible line that went directly to the wiper motor under the dash. There has to be a fitting somewhere tap into the manifold vacuum to make this work. Many of these cars did not have the double ended vacuum boost pump, and ran the line directly from the manifold to the wiper motor under the dash.Gary Link to comment Share on other sites More sharing options...
howardjnl Posted March 27, 2012 Author Share Posted March 27, 2012 Gary, I figure I'll just run it directly to the manifold as well and avoid the complexity of the combo pump for vacuum assist. This is how the wipers are set up on my '47 Dodge truck. The wipers will slow when I press the accelerator, but that's not really a big deal.Thanks, again. John Link to comment Share on other sites More sharing options...
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