Valve train oiling

[Pfroman]

Hello All-

Been having some rattle and bang come out of the top end of my 64 305E so I pulled the valve cover off the passenger side and took a look at the train while running the engine. Turns out I am getting NO oil squirting or even weeping out of the rocker arm ports. Getting 60-80psi on the gage at the filter, but that pressure is not getting up to the valve train assembly. Thinking that could be a major source of my aggravation.

Looking for some suggestions on where to start here... I am a novice so take it easy on me!!

Thanks in advance.

Phil
'64 GMC 305E

[James]

Remove the rocker arm shaft assemblies from both side of the engine. Disassemble the shaft but keep the assembly order. There is two way the shaft can be assembled, which is why you need to keep in place. The drill passageway in the shafts makes a difference. Cleaned out the inside of the shaft, the end mounts passageway, and the squirter holes in the arms (see attachment). It might be plugged up with sludge. The rear mount in the right head and the front mount on the left head supply oil to the rocker arms. Clean out the supply holes in the heads the best that you can. Lubricate everything with fresh engine oil and assemble it to the head. This would also be a great time to check valve clearances. Once everything is assembled, run the engine. It will take some time to fill up the shafts, but you should see oil flowing out of the rocker arms.

[Pfroman]

Thanks James-
I will attack that when I get the heater fixed in my garage!! thought I would just check the distributor alignment as well.

Thanks again.

[Prowbar]

Good luck. The shafts on my 305E were full of sludge as well, but not to the point that they blocked off the oil supply.

I am of the opinion that these engines supply to little oil to the heads. Therefore I milled out the slots in the camshaft for the 478. The camshaft controls the oiling using a slot/pocket which is cut into the bearing. The slot aligns the oiling hole in the camshaft bearing and the cylinder head, providing time for a "shot" of oil alternating between the cylinder heads.

I basically deepened out the slot to allow for twice the duration that stock and I'm very satisfied with the modification. There is now an adequate amount of oil flowing from the rocker arms, 1. protecting the parts better and 2. cutting down on sludge forming because oil flow has been increased.

[FetchMeAPepsi]

Originally Posted by Pfroman

Thanks James-
I will attack that when I get the heater fixed in my garage!! thought I would just check the distributor alignment as well.

Thanks again.

Order this my brother. Heater is fixed instantly.

https://www.amazon.com/Original-540-...dp/B01BE8FVUK/

[BobBray]

James makes a good point about checking for oil flow at the left front and right rear rocker shaft support. This is the reason for the different sized shaft bolts. As Prowbar states, the oil gallery that feeds the rocker shafts comes from the front and rear cam bearings, so keep in mind that excessive cam bearing wear or a spun cam bearing can cause poor oil flow to the rocker shafts.

[Pfroman]

Originally Posted by James

Remove the rocker arm shaft assemblies from both side of the engine. Disassemble the shaft but keep the assembly order. There is two way the shaft can be assembled, which is why you need to keep in place. The drill passageway in the shafts makes a difference. Cleaned out the inside of the shaft, the end mounts passageway, and the squirter holes in the arms (see attachment). It might be plugged up with sludge. The rear mount in the right head and the front mount on the left head supply oil to the rocker arms. Clean out the supply holes in the heads the best that you can. Lubricate everything with fresh engine oil and assemble it to the head. This would also be a great time to check valve clearances. Once everything is assembled, run the engine. It will take some time to fill up the shafts, but you should see oil flowing out of the rocker arms.

James (all) I got back around to this and have removed the valve train for cleaning. The sludge is not that bad, but my question would be- should I have expected to see a considerable amount of oil in the long tube? I had none in there at removal....I'll get a look at the oil port in the head tonight. Any suggestions on what to clean that out with?

Thanks,
Phil
'64 C1000 305E

[Jim A]

This thread makes me think about what amazing engines these 305's are.
I had to take one head off about 50 years ago to fish out a spark plug cap.
Knocking wood, the valve train has been oiling along for 65 years, although I think smoking after a while at rest may come from valve guides/seals.

[James]

Originally Posted by Pfroman

I'll get a look at the oil port in the head tonight. Any suggestions on what to clean that out with?

I would use pipe cleaner (a fussy wire), or small diameter brush (this is normally sold as an engine cleaning brush), and/or a long handle cotton tip applicator (using this you need to rotate it in the direction that will tighten the cotton on the stick). If you rotate it both way the cotton tip will come off and might end up inside the head, then you will have to fish it out. Then with the spark plugs removed, cranking the engine and let the oil come out of the head along with the sludge. Clean away the sludge and reassembled the rocker arms. Set basic valve clearance. Crank the engine again (without the spark plugs installed) and let the oil come out from the rocker arm assemblies. Once that happen, install the spark plugs and start the engine. Let the engine come up to normal temperature and shut it down. Recheck/set the valve clearance. Then install the valve covers.