Small six rocker shaft oiling

[aribert]

A am new to the oiling of a hydraulic lifter small six - I am familier with the oiling of the solid lifter engines that have been in my Falcon.

Yesterday I ran the '78 200 engine with a cut open valve cover and noticed that the oiling of the push rods is much better than the oil dribbling out of the oiling hole and onto the valve stem tip. My previous solid lifter engines oiled the valve stem tips much better. At 1500 to 2000 RPM, there was only minor oil splashing (and most of that was off of the push rods, not off of the valve keepers/springs. I mounted a valve cover with the top surface cut off to minimize the expected mess of oil spray.

After running the engine at a fast idle, for about 10 minutes, some of the ends of the valves only had a few drops of oil on them (most of the oil flow that was dribbling out of the rocker oiling hole was dropping off of the side of the rocker before reaching the valve stem tip). I removed the rocker shaft and the passage ways (groove in the rocker bores, rocker shaft bore and rocker pedstal) were free of oil sludge. I have been running a can of Seafoam in the oil for the past 1500 miles - I had what appeared to sound like a collapsed / sticky lifter.

Should I be concerned about this minimal oiling of the valve stem tips? The 250K mile rockers that were used on my push rod engine(s) shows about the same ammount of wear as these 50K mile rockers. I expect to see more oiling on the valve stems and a bit less on the push rod ends. I am considering grinding a *very* shallow groove (about 0.010 deep) from the groove in the rocker bore to the oiling hole on the rocker.

Your thoughts?

 

[fmartin_gila]

The VW crowd had some oiling problems some years ago trying to utilize the VW engine in aircraft. Airplanes work an engine very hard and continous, which most automotive useage is not. Bob Hoover wrote up a whole series of improvements to the VW oiling system, and one of the items hit on was exactly what you are reffering to, and gave a drawing as to what needed to be done to accomplish it. I don't remember where it was, you will have to search it out. VW engines are a popular engine used to power Experimental Homebuilt Airplanes, I have built two in past years.

Fred

 

[aribert]

Thanks for the posting! With both the name and the brand of engine it did not take long to find. About 2/3 of the way down the page.
http://bobhooversblog.blogspot.com/2007 ... -mods.html

I will follow thru with my proposed oil groove to the inside of the rocker bores but will limit the depth - I am surprised at the groove depth mentioned in the link - I guess they really needed better oiling - I am after only a moderate increase to insure longevity - my two rockershafts from core engines (with hydraulic lifters) are both gaulled on the bottom side where as the rocker shaft on my recentlty "deceased" solid lifter engine, 250K miles of use ont he shaft, has no gaulling and shows about the same wear pattern as the 50K miles shaft on my curreent motor.

When I had the rocker shaft off (before my initial posting), I modified the rear rocker shaft pedstal to increase oil flow by milling a 0.188 dia radius into two of the four corners of the pedstal thereby doubling the potential oil flow but I did not do the same to the rocker shaft since I did not want to over oil the top end and have a large pool of oil sitting on top of the head and seeping out thru the valve cover gasket. I will open up the oil passage way into the rocker shaft also.

 

[fmartin_gila]

I believe you are on the right track to not make the groove as deep so as to limit the amount of oil flow. The difference in the orientation of the setup, the Ford being a horizontal flow and the VW being a vertical flow and needing to push the oil up to get to the valves should require a smaller groove. Good luck with it. Glad to be of some assistance.

Fred

 

[Hot 6t Falcon]

Howdy,

Have you read "Sticky: Rocker Arm Shaft Oiling hints" in the Small Six forum?

It will give you some ideas for cleaning the rockers and getting more oil to the valve train. Also has a picture of the oil flow path in the small six.

Dennis

 

[JackFish]

Yeah, I was wondering what style head bolts you had in there?

 

[Hot 6t Falcon]

Howdy to both.

I use a '78 Fairmont bolt. The shank of the bolt tapers down where the oil flows past the bolt.

I also open up the pedestal with a large drill bit (about 1/16 extra) from the bottom of the pedestal up to the oil passage to the rocker arm assembly.

When my block was apart, I spent LOTS of time cleaning out the oil passage in it where the head bolt is.

I spent time with q-tips and pipe cleaners in the in the head's passage from the head bolt to the rocker pedestal.

None of these passages "boiled" out very well when I had the engine cleaned. The Rocker passages where still almost completely clogged at "boiling". Hence the drill bits seen in the sticky.

 

[JackFish]

Oh sorry I was asking the original poster!

 

[aribert]

Jackfish, All: My engine is a 78 from a Fairmont.

Dennis: Yup, saw the sticky (after posting my question here - I check the small six list almost daily but tend to skim over the stickies since I have read them before). BTW, I have an older copy of your Performance Handbook - Good work!

The rocker pedstal bolt has an undersize shank mounting bolt. There was no sludge in either the rocker pedstal shaft/mounting bolt, rockers or rocker shaft. With the rocker shaft removed and cranking the engine for a while, I get what appears to be a reasonable ammount of oil flow up thru the head. Cranking oil pressure gets up to 20 psi after a few cranking revolutions. SInce I was not getting what appeared to be a reasonable ammount of oil out of the rockers (onto the valve tips) I started to look into increasing the oil flow into the shaft. Observing the ammount of oil flowing out of the rockers and down the pushrods, I am now convinced that there is more than adequate oil into the rocker shaft, just not enough dripping onto the valve stem tips.

 

[Anlushac11]

8)

On top of oiling mods Im planning to get the rocker shaft dry film lubricant coated to reduce friction and chance of galling.