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| | Forums66 Topics126,780 Posts1,039,295 Members48,100 | Most Online2,175 Jul 21st, 2025 | | | Joined: Feb 2007 Posts: 385 Wrench Fetcher | Wrench Fetcher Joined: Feb 2007 Posts: 385 | The valve gear in my 1954 235 engine is so dirty I can't tell how it comes apart. (No oil filter.)
The problems is that there doesn't seem to be any oil flowing to the rockers for cylinders 2 through 5. I know I need to clean out the copper tubing that comes up from the pushrod area.
The question is: Is the rocker shaft hollow or does it just have small oil passageways, and how can I clean it out?
195? Chevy 3800 dump truck 1973 Chevy C30 cab and chassis 1987 Suburban 3/4 ton 6.2L Diesel
| | | | Joined: Aug 2005 Posts: 6,383 Ex Hall Monitor | Ex Hall Monitor Joined: Aug 2005 Posts: 6,383 | Assuming it's the same as on my 216 it's hollow. The oil exits the shaft through holes in the bottom to oil the rocker arms. Some of those are probably plugged. All you need to do is remove the hold down bolts and remove the assembly. Keep track of what goes where so you can put it back correctly when you're done. Just disassemble & clean it good. Put some assembly lube on the wear surfaces when re-assembling it.
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| | | | Joined: Sep 2001 Posts: 29,262 Bubba - Curmudgeon | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,262 | Do what Tiny suggests. If some of the rockers are getting oil, there is no need clean out the copper tubing that feeds the rocker assembly. Take the assembly off, take it apart, and clean everything inside and out. Any solvent and wire brushes will clean it nicely. 1. If the shafts are scored badly, Jim Carter sells replacement shafts. 2. If there is indentation-wear on the surface of a rocker where it mates with the top of the valve stem, grind and polish the mating surface on the rocker arms. This will give you a truer adjustment and this will decrease some of the rocker noise/chatter. 3. If you get the parts out of order, refer to your Shop Manual. Tim | | | | Joined: Feb 2007 Posts: 385 Wrench Fetcher | Wrench Fetcher Joined: Feb 2007 Posts: 385 | Thanks, guys. That's what I needed to know.
195? Chevy 3800 dump truck 1973 Chevy C30 cab and chassis 1987 Suburban 3/4 ton 6.2L Diesel
| | | | Joined: Nov 2008 Posts: 10 New Guy | New Guy Joined: Nov 2008 Posts: 10 | With the engine running you should see oil flowing from the curved overflow tube at the center of the shaft, if you don't, you’re not getting sufficient oil to the shaft.
The rocker shaft is made of two identical hollow pieces. The shafts fill with sludge which restricts oil flow. To minimize confusion when you disassemble the shafts and rockers, lay them out in sequence on an old towel. Clean all parts thoroughly with cleaning solvent and brush then place them back in sequence on the towel. You can get all the sludge out of the shafts with solvent and a wooden dowel slightly smaller in diameter than the inside of the shafts. If the shafts are badly worn, don't bother cleaning them, get new ones.
| | | | Joined: Jul 2004 Posts: 5,708 'Bolter | 'Bolter Joined: Jul 2004 Posts: 5,708 | I believe the outboard ends of the rocker shafts are sealed with a small plug. With the entire assembly removed, it's still tough to get the gunk out of the bore of these shafts with the plugs in.
They can be driven out, the shaft interior cleaned 100% and then tapped in again or new ones installed. I think they're a common Dorman item but don't quote me on that.
Stuart | | | | Joined: Feb 2007 Posts: 385 Wrench Fetcher | Wrench Fetcher Joined: Feb 2007 Posts: 385 | If I have the rocker arm shafts hot tanked, do you think that would clean them out? I wouldn't mind replacing them but am not sure how much the new ones cost. I'm afraid that I would screw them up if I tried to pull the end caps. I don't have anything like a full machine shop to work with.
195? Chevy 3800 dump truck 1973 Chevy C30 cab and chassis 1987 Suburban 3/4 ton 6.2L Diesel
| | | | Joined: Sep 2006 Posts: 2,393 Shop Shark | Shop Shark Joined: Sep 2006 Posts: 2,393 | Even though the rockers are under tension at the spring you can remove the entire assembly at one time by backing out the rocker shaft mount bolts and then just lift the entire assembly off in one unit. Soak the whole assembly in an oil change pan and submerged in water based cleaner like Purple Power or an oil based solvent if you prefer. Periodically scrub with a stiff brush. Once it's resonably clean you'll see more clearly how it comes apart.When you disaasemble the rockers they must be kept in order to ease reassembly. Otherwise you're going to carefully follow a manual to get them right.Based on my experience the inside of the rocker shaft is probably packed with caked oil. I loosened for removal wth a stiff wire then used an engine brush to clean out the bore. Sorry, so long winded, but that's how I've cleaned several of them.
Drew
| | | | Joined: Sep 2001 Posts: 29,262 Bubba - Curmudgeon | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,262 | Drew,
What about the removal and replacement of the end-cap? Do you leave it on and try to clean the shaft as much as possible?
Tim
| | | | Joined: Sep 2006 Posts: 2,393 Shop Shark | Shop Shark Joined: Sep 2006 Posts: 2,393 | No actually I didn't remove any,but it probably would have made the clean up easier.
Drew
| | | | Joined: Aug 2008 Posts: 230 Shop Shark | Shop Shark Joined: Aug 2008 Posts: 230 | you might try to dip them 1 half at a time into a 5 gallon bucket of carburetor cleaner ,it worked pretty good for me ! | | | | Joined: Feb 2007 Posts: 385 Wrench Fetcher | Wrench Fetcher Joined: Feb 2007 Posts: 385 | Hey, old dog, how could you tell when they were clean? I haven't had mine apart yet, so I have no idea what they will look like.
It sounds like your method might work with the shafts assembled. Is that the way you did it?
195? Chevy 3800 dump truck 1973 Chevy C30 cab and chassis 1987 Suburban 3/4 ton 6.2L Diesel
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