Total agreement on putting the valve spring baffles back in place under the rockers.  They do a good job of directing oil away from the guides especially in those cases where umbrella seals are being used.  This is one item that I always seem to be short of as most core engines I receive do not have these on them.

Lorena, Texas (South of Waco)

Daniel and all,

Thanks for bringing up this topic.  I've been thinking that my engine is sucking a little too much oil around the intake valves.  I'm running a pair of restricted return tubes, I pinched them down around a small drill bit.  We also cut the center groove deeper on my Schneider cam and I've got the old umbrella valve seals.  Now I'm going to go back to the stock return tubes and also install a set of the old baffles under the rocker arms.  I've got a longer set of pushrods to get the rocker geometry closer to where it should be. 

You mention an article by John Mummert in YBM re. these return tubes- I don't remember seeing it.  Could you give me an idea as to when it appeared?  I can look through my back issues but there are about 14 years worth of them, according to Bruce's notes in the #84 issue that just came today.  Thanks to Ted for a couple of interesting articles in this issue, it saddens me that they wouldn't accept his Y block (2007 Engine Master Challenge)because of the mushroom lifters. 

Have fun, Nick Brann/ K.C., MO

Oops! .110" is larger than 5/64th, not smaller. Not enough coffee yet today.

6 VOLTS/POS. GRD. NW INDIANA

Thanks Ted,



While Verne claims heads should not flood with full pressurization if rockers/shafts aren't worn, your theory re: air/sludge/cooling makes a lot of sense (first time I have heard it).



I notice your restrictor spec. for street motor smaller than FoMoCo 12/63 service letter (5/64th), or John Mummert's YBM article on the subject (1/16th)? I was always afraid a piece of sludge would clog the restriction, and cause severe wear before I caught it. I now think the trade-off in oil pressure may be worth the risk.

6 VOLTS/POS. GRD. NW INDIANA

Here’s the picture of the rocker shaft oiling modification posted elsewhere on the site.

And the link to the original thread.

http://forums.y-blocksforever.com/Topic6985.aspx

Lorena, Texas (South of Waco)

By not blocking the oil outlet tubes, air is purged from the shafts thereby insuring that the shaft stays full of oil.  If these tubes are blocked, then the potential is there for air to be trapped within the shafts.  A constant flow of oil through the shafts by the use of the overflow tubes will purge the air and help to carry off some of the heat rather than the oil potentially stagnating and then sludging up.  On a solid lifter engine such as the Y, the rockers get to relax between valve actions which promotes additional leakage at the bottom of the rocker but on a hydraulic cammed engine such as the FE, that period of relaxation doesn’t occur and this is where pressure oiling would have some additional benefit.  But as John also brought up, allowing the excess oil to bleed off at the overflow tubes also insures that the oil level in the heads does not exceed the ability of the drain holes to carry it away.

To restrict the oil to the rockers themselves, I thread the ‘second from the right’ pedestal at its bottom with a 5/16 X 18 tap and install a set screw that is drilled with the appropriately sized hole.  This could be done in the head as an alternate choice.  An Fe is already sized at 0.125” in the head gasket but the Y is pretty liberal in its oiling up to the rockers if the restriction at the camshaft is freed up.  Not counting the restriction in the oiling at the camshaft, the Y has a 5/16” hole in the block with a corresponding 5/16” hole in the head gasket.  The oil passageway in the cylinder head downsizes to a ¼”and this size is maintained up to the rocker arm shaft.  If the oil is freed up at the camshaft, then that’s a lot of oil flow to contend with.

Another rocker shaft modification would be to grind some angled slots across the lower oiling holes to promote more oil across the inside wear area of the rocker arm.  There’s a picture of this modification elsewhere in the forums.

The oil shields or baffles under the rockers are another story.  This would appear to be another item on the Y that was dropped as a cost cutting measure early on but I do prefer to run them when given the option.  If running a positive seal on the valve guide, then the baffles are likely not worth much but if running the stock unbrella type of seal, then these shields do reduce the amount of oil getting to the guide.

Lorena, Texas (South of Waco)

Daniel,

       what I basically did was join two brake lines togther with one being smaller.  I did this by taking the tube down to a Car Quest store and matching things up.  Pretty straight forward.

                                                Michael

Michael

Sandy Valley, NV

This may be a dumb question but, what are you using to restrict the oil flow into the rocker shafts?

John F

Ballwin, MO

Opinions are wanted here, so here's mine.  I feel the overflow tubes are there to make sure the rocker shafts are always full of oil, but not under pressure.  This supplies drip oiling to the rockers.  It seems to be adequate on all my Ys, even my Crane cammed 6500 rpm supercharged engine with stock 1.54 rockers.  I feel that if the tubes are blocked, then all the oil to the rocker area would have to try to drain away via the two small drain holes in the ends of the heads.  They don't have enough capacity, therefore the oil level can rise in the rocker cover area until it can drain through the pushrod holes.  At that point, the oil level is above the tops of the valve guides.  I also use the grooved block plus the restrictors as Ted explained above.  Without the restrictors I flooded the rocker area even with the overflow tubes in place.

John in Selma, IN

John - "The Hoosier Hurricane"

i'm new here, are the drain tubes the U tubes that go from the top of the shaft and point down at the ends of the rocker shafts? I know the FE guys would insert holley jets to resttrict oil flow in the heads to prevent oil flooding the valves.

but then FE's do have oil baffles under the shafts.

thanks for the input, i'm trying to figure this out as the thread moves on.

This ain't no L-Kamino!