Bob Engle Posted October 11, 2017 Share Posted October 11, 2017 I have a knock in the engine on the D45. I was concerned about a bad rod bearing or loose wrist pin. I picked up a pan gasket at Hershey from OLSONS Gaskets ( great people to work with). I dropped the pan and checked #1 cylinder wrist pin for tightness and dropped the rod cap and tested with plastigage. Clearance is just under .004". surfaces look good on the journal and bearing. Should I surface grind the cap spacers (.101 Thickness) to reduce the clearance? What is the acceptable clearance range? What is a good torque spec for the rod bolts? Also, I removed the oil pump and check the gears. They show almost no wear and there is only about .001 wear on the bottom plate. What are the clearance limits on the gears to the bottom plate? Thanks for any assistance. Bob Engle Link to comment Share on other sites More sharing options...
Mark Shaw Posted October 12, 2017 Share Posted October 12, 2017 Bottom and top plates should be flat with only swirl marks from the gears rubbing on them. Link to comment Share on other sites More sharing options...
old buicks Posted October 12, 2017 Share Posted October 12, 2017 I like 0.0015 or maybe 0.002" clearance Tom Link to comment Share on other sites More sharing options...
Guest Posted October 12, 2017 Share Posted October 12, 2017 The old rule of thumb was .001" per inch of journal diameter. Link to comment Share on other sites More sharing options...
Bob Engle Posted October 12, 2017 Author Share Posted October 12, 2017 Thanks for your responses. I'll have to take the 1/10" thick shims and mark each for surface grinding to get the clearances tighter. Nothing extreme, but .001 to .0025 removal. Bob Engle Link to comment Share on other sites More sharing options...
bradsan Posted October 13, 2017 Share Posted October 13, 2017 Bob How 'round' is the worn rod bearing hole? If you file the spacers down, then you will only be reducing the diameter in one direction and might still have .004 wear in the other. That's a lot for a 2" rod bearing ( i'm guessing here!) Not familiar with early Buicks but I'm guessing the D45 isn't a pressure fed oil system so it might not be critical like it is with pressure fed bearings. Brad Link to comment Share on other sites More sharing options...
DonMicheletti Posted October 13, 2017 Share Posted October 13, 2017 I wouldnt think tha .004" would cause a knock on a rod. How are the mains? Link to comment Share on other sites More sharing options...
Bob Engle Posted October 13, 2017 Author Share Posted October 13, 2017 It is a dipper connecting rod fed oil from troughs in the pan which is gravity fed from the oil pump. the rest of the bottom end is splash oiled. To the best of my knowledge, all cast babbit bearings have their clearances set with shims on the camps. This controls the clearance in the major load direction. Bob Engle Link to comment Share on other sites More sharing options...
Bob Engle Posted October 13, 2017 Author Share Posted October 13, 2017 I haven't checked the mains yet. I am still trying to decide what to do with the rod bearings. All wrist pins are tight and centered in the piston. I get tempted to pull the pistons just to see what they look like, but I don't know if I want to fool with trying to get them back in the bores from the bottom. Bob Link to comment Share on other sites More sharing options...
DonMicheletti Posted October 13, 2017 Share Posted October 13, 2017 I have never found it difficult to insert the pistons from the bottom. Sometimes I used a ring compressor, but I was also able to "wiggle" the pistons in, the taper at the bottom of the bore was enough to compress the rings. The original thick rings are probably more compliant than if you have newer pistons with the thinner rings. However, if you dont need to pull the pistons you probably shouldnt. Removing shims to get clearances is pretty straight forward. The main lubrication on these engines is a bit problematic in my mind. There is a "trough" with a hole in the upper crankcase that feeds the mains. That trough must be filled by the oil splashing. If the hole gets blocked, the main can starve. I also find that if my car sits for a very long time, it will knock some until the oil gets everywhere, then it quiets down. 1 Link to comment Share on other sites More sharing options...
hidden_hunter Posted October 13, 2017 Share Posted October 13, 2017 3 hours ago, DonMicheletti said: I have never found it difficult to insert the pistons from the bottom. Sometimes I used a ring compressor, but I was also able to "wiggle" the pistons in, the taper at the bottom of the bore was enough to compress the rings. The original thick rings are probably more compliant than if you have newer pistons with the thinner rings. However, if you dont need to pull the pistons you probably shouldnt. Removing shims to get clearances is pretty straight forward. The main lubrication on these engines is a bit problematic in my mind. There is a "trough" with a hole in the upper crankcase that feeds the mains. That trough must be filled by the oil splashing. If the hole gets blocked, the main can starve. I also find that if my car sits for a very long time, it will knock some until the oil gets everywhere, then it quiets down. The buick may have a similar setup to my cad which actually is designed so you can put them in from the bottom, it basically has a taper at the bottom of the bore to compress the rings for you as you push it up. I'm guessing they did that because ring compressors hadn't been invented yet. They go in really easily when the rings are the correct size (and shower you in bits of piston ring if they're not) Link to comment Share on other sites More sharing options...
herm111 Posted October 14, 2017 Share Posted October 14, 2017 (edited) On 10/11/2017 at 11:54 AM, Bob Engle said: I have a knock in the engine on the D45. I was concerned about a bad rod bearing or loose wrist pin. I picked up a pan gasket at Hershey from OLSONS Gaskets ( great people to work with). I dropped the pan and checked #1 cylinder wrist pin for tightness and dropped the rod cap and tested with plastigage. Clearance is just under .004". surfaces look good on the journal and bearing. Should I surface grind the cap spacers (.101 Thickness) to reduce the clearance? What is the acceptable clearance range? What is a good torque spec for the rod bolts? Also, I removed the oil pump and check the gears. They show almost no wear and there is only about .001 wear on the bottom plate. What are the clearance limits on the gears to the bottom plate? Thanks for any assistance. Bob Engle Mr. Tinindian is right, it doesn't make any difference what engine, the setting is .001-00 per inch of shaft. A 2 inch shaft will need .002-00 clearance Minimum, and or another .000-50 thousandths, Maximum. Herm. Kohnke RebabbittingService.com Edited October 14, 2017 by herm111 (see edit history) Link to comment Share on other sites More sharing options...
DonMicheletti Posted October 14, 2017 Share Posted October 14, 2017 One thing. When you start removing shims, do one rod and then crank the engine by hand to insure there is no bind. Do one rod at a time. If you do them all at once, if you do have a bind you wont know which one is the problem. Another way to isolate a knocking rod is to short out the plugs one at a time. The bad actor would stop knocking when the plug is shorted. However, you may be well past that point to test now. 3 Link to comment Share on other sites More sharing options...
Bob Engle Posted October 16, 2017 Author Share Posted October 16, 2017 I got back to work on my rod bearings today. I checked all the shims for the rod caps. I am used to working with engines that had a stack of shims form .0005" to .0100" thickness installed when the bearings were new. As the engine wore, shims could be removed to keep the desired clearance. This engine has a single thick stamped brass shim on each side of the cap. They vary in thickness from .0999" to .1060" thick. They are stamped pieces as one side has rounded edges and the other has sharp edges, They are not of uniform thickness as they vary about.001" across their length. I am considering surface grinding them all to a common thickness and then adding shims to get the desired gap. The crank journals are a nominal 1 3/4" Dia. so according to the above posts a target of .002" should be ideal. A couple other things I found were the hex castle nuts were torqued to about 35ft- #. Specs for a #2 fine fine Thread 3/8" rod cap bolt should be about 17 ft-#. The rod caps had mushroomed at the bolt holes, so I reamed the holes to remove the collapsed metal. I will install new hex castle nuts and torque to 17 ft-#. I would appreciate any thoughts on this plan. Bob Engle Link to comment Share on other sites More sharing options...
JFranklin Posted October 16, 2017 Share Posted October 16, 2017 Are you positive that is not a compressed shim stack that can be peeled/cleaved? Maybe shim packs for a model a Ford could be substituted. Link to comment Share on other sites More sharing options...
Terry Wiegand Posted October 16, 2017 Share Posted October 16, 2017 That was my first thought also. I have seen shims like that. Terry Wiegand South Hutchinson, Kansas Link to comment Share on other sites More sharing options...
Bob Engle Posted October 16, 2017 Author Share Posted October 16, 2017 I double checked again. They are definitely on piece brass. not a stack of laminate shims. It's hard to believe that model A shim would fit the shape of this Buick. I'll check with some local shops to see if they have some similar shims. I hate the thought of having to make a batch of shims to the current profile. Bob Engle Link to comment Share on other sites More sharing options...
DonMicheletti Posted October 16, 2017 Share Posted October 16, 2017 On original old Buick engines I have worked on, the rods have a shim that thick plus additional thin shims attached too. I have seen it on more than one engine. i think that on your engine, all those thinner shims have already been removed. Mc Master Carr has this stuff: https://www.mcmaster.com/#shim-stock/=19u60fv It might be a real job to shape though Link to comment Share on other sites More sharing options...
Bob Engle Posted October 16, 2017 Author Share Posted October 16, 2017 Don: That's the best explanation so far. I taped two planer blades to my granite plate and put the shim between the two and filed them down to 1.001" I have ordered some shim stock at .0005", .0010". .0015" and .0002", I will make two steel pieces and clamp the shim stock between them for trimming. Then it's back to plastigage, torque, remove cap and add shims to get .0002" clearance. Once the rods are all set, I'll remove the main caps one at a time and see what I have there. If I am correct, to remove the front main cap, I must remove the cast piece that is also the lower water pump/starter-generator gear pan. If this is correct, I'll get to inspect the gears for their condition. Bob Engle Link to comment Share on other sites More sharing options...
DonMicheletti Posted October 17, 2017 Share Posted October 17, 2017 Yes you re right about the front bearing cap. I'd hesitate to go to that much trouble unless you find the other bearings have excessive clearance. As far as the gears go, I have seen both steel and fiber gears on the cam shaft. It is a real PITA to remove the front cover since it is also the front motor mount. And I think the "nose" goes through a hole in the radiator. (It has been a while). By the way, what are the worse and best rod clearances that you have found? Link to comment Share on other sites More sharing options...
Bob Engle Posted October 17, 2017 Author Share Posted October 17, 2017 (edited) Clearances have varied from .003" to .006" The shims had been from as thick a .106" to .100". All except one are now.101" thick. Bob Edited October 17, 2017 by Bob Engle (see edit history) Link to comment Share on other sites More sharing options...
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