Without writing a book, does anyone know if the camshaft oil holes that feed the rocker is drilled straight through the cam journals or on the same angle of the cam bearing oil holes which would allow oil to be supplied up to the heads or one head at a time. I can supply the back story if you board and need to read. I am using a oil pressure tank to prelude this engine after a main and rod bearing replacement and have No oil being supplied up to the heads. FYI the cam bearings were no touched. The manual illustration indicates the rockers are feed from the cam bearing apparently through the cam itself. Any feed back would be appreciated.
451B or 450B ? 207 diesel ? Did you reinstall the rocker arm assemblies exactly as they were before the tear down. That also applies to the bolts for them. One of the bolts is hollow and is cross drilled to supply oil to the rocker arms. My memory is getting bad but I think the front bolt is the hollow one.
This Engine is in a Case 1150B bull dozer. The engine model is a 451BD. Thank you for replying
Thanks for the clarification. Each head has an oil tube that supplies oil to the rocker arm assembly. I'm sure you already know that. I would suggest that you remove one of the rocker arm assemblies and then use your pressure tank to determine if oil is coming out of the tube. If there is, I am guessing the problem is with the rocker arm shaft. Each head should have a continuous supply of oil to the RA shaft. An unlikely scenario could be the camshaft bearings have rotated in their bore and the oil holes are no longer aligned with the oil gallery's in the block.
While I still had the rocker shafts removed I charged the oil system and didn’t get any oil up to either of the three heads. Looking at the manual illustration it appears the camshaft journal is drilled which I assume allows oil to feed the rocker feed hole in the cam bearing. I just don’t know if the cam shaft drilled oil holes are straight through holes or are they drilled at the same offset angle the cam bearings are drilled at. I imagine this would determine whether the cam can be positioned momentarily to allow a line up so the charged oil system can delivery oil supply to the rockers or perhaps one head at a time or if the oil delivery is interrupted as the engine assembly is rotating this metering the amount of oil delivered. The rockers certainly don’t require primary oiling but can’t be run dry either.
Usually there is a groove in cambearing that the oil goes through to upper hole in cam journal to block fit. If there is not enough oil pressure in the main oil gallery the oil will just leak out at the cam bearings journals and none will make it to the top. If there is too much clearance between cam and journal, there will be none or hardly no oil to top rocker housings unless if engine is at high rpms with high oil pressure. If cam bushing journal is installed wrong, should be no oil to only one rocker housing not all. How much oil pressure did you put on oil gallery. Should put 60 pounds to make it work. If all the bushings were installed wrong the cam would probably seize. Have built a lot of blocks, just not yours. Simon C
I always replace cam bearings when doing an overhaul. I use an LED flashlight and look down the oil gallery and verify that I have the hole in the cam bushing aligned perfectly with the gallery. I have extra long bushing drivers that have a line scribed on them. I can line the hole in the bushing with scribed line, then I position the line up with the exact center of the gallery and install the bushing. I never pound them in. I use a long piece of all-thread and pull them in from the rear of the block. Is it possible someone in the past has installed your bushings and they didn't get them in correctly ? What you describe is exactly what happened. The rockers should be getting a continuous supply of oil.
I didn’t touch the cam bearings I actually went into this engine because of what I understood as low oil pressure. Spec called for 45 to 60 psi at 2000 RPM. It could only develop 42 and at idle dropped to 25 psi. Some reply’s on here stated that these engines didn’t have a lot of oil pressure. I purchased this bull dozer used and abused. For my own use I decide to do some work to restore. Investing in new undercarriage parts now I have more money in this project than I want to admit. Hey it’s my Tonka Toy lol. Anyways. Long and short the previous mechanic had 0.020 under rod bearings on a 0.030 under crank so I found the smoking gun for the low oil pressure. How ever the service manual also mentioned the rocket shaft orientation and O-ring on the rocket shaft supply tube being a possible cause for low oil pressure. With that said, I went into the rocker shaft to inspect them. There were signs of running dry at one time but nothing was black or blue. I performed minor Cleanup. Now I have everything back together getting ready to set cold lash. I figured I’d use my oil pressure tank and charge the oil system. My oil tank was able to develop 30 psi accord to the engine oil gauge. However I’m getting no oil up to any of the heads. Unfortunately I can only go by picture of the cam bearing and the cam. The bearing picture does not illustrate any grooves just three drilled holes, the cam journals are drilled according to the picture.
Yes it is possible, I purchased this dozer running And it ran long enough for the belly pans to be filled with dirt up to the frame rails. lol. Nothing surprises me on this machine any more. If I had too is it possible to change the cam bearing while it is in the chassis. I realize I couldn’t change number 5.
I have an extra small diameter bore scope I’ll try running it down the oil feed hole to see if I can see the oil feed hole.
No grooves in them like a crankshaft bearing. If you buy a new set of cam bearings they will not all be identical. The number of holes in them and the width of them will likely be different. It is very important to get them in the correct bores. Remove the engine and replace all of them if you do change them. One reason is that you can verify the the plug in the block behind the rear bearing is sealed and seated properly. Some bozo may have previously bumped the camshaft against the plug and pushed it out a little. That would be a disaster waiting to happen.
Okay, it sounds like if I can’t confirm the holes are aligned correctly this weekend I will be making plans to pull the engine. Wasn’t on my bucket list. Lil
Your oil pressure test will be very dependant on the grade of oil specified in the manual, and the rpm and temperature specified. If you were down 3 PSI at high rpm, I would not tear it apart for a hobby machine. If low idle is at 25 PSI, that is very good. You may be able to change upper oil pressure by shimming a relief valve in an oil filter housing or wherever it is. Remember oil pressure relief valve springs will weaken with time. Use super high quality oil and you will be okay. If you pull cambearings out you might find that they are not even standard size. Nothing would surprize me being your rods and crank are not same. Any Questions Fire Away. Simon C
During this discovery and repair I replaced mains and rods bearings along with crankshaft thrust washer. Went through the oil pump checking clearances and changing relief valve and spring. Also found valve springs weak replaced all valve springs. If it wasn’t for this lack of oil getting to the top I’d be starting this engine on Friday. I’m glad I did pull it down because with the incorrect rod bearings installed it was running more that 0.014 inch oil clearance on the rod bearings. With the correct bearings that is closed up to just under 0.004 inch now. I imagine that change alone would have brought the oil pressure up to the spec numbers.
Oil pressure will vary greatly from grade of oil. Just saying, and temperature is another factor. Most oil filter housings have springs and shims. If it opens prematurely it will dump back to pan. What grade of oil was your last test done with.? Simon C
The manual call for straight 30 weight. I’m running Case oil right now
Is the Case oil 30 weight or 15W40. As I said if you actually have in the 20 pound range at idle I would not worry. Cat 3306 can go down to around 7PSI at idle with the specified oil. The important one is that there is some oil going to top end. Has to be some or there is too much bypass happening in cam pocket. Hope it goes. Simon C
Case called for straight 30 weight I did consider trying 15w40 at one point but then decided to pull down the engine, that is when I identified that the incorrect rod bearing were installed. I’m confident that the oil pressure would be much closer to Case pressure spec with the correct rod bearings. I just have to figure why the rockers are not getting fed. I have a small diameter bore scope that works with my cell phone I’ll try to confirm the oil hole align with the cam bearings. I may also try rotating the engine while I have the oil system pressurized with the pressure tank.
Consider a 15W-40 weight oil. I would prefer pure synthetic for easier starting in winter temperatures. I'm sure you read the rocker arm RR procedure in the service manual. Especially the cleanliness of the holes in the rocker arms. The service manual has extensive information on the cam bearing replacement. I am posting a page of the procedure in case someone in the future does not have the service manual.