I should've searched first. Thanks. PS. I loved this post!
Ted (11/9/2009)
oldcarmark (11/8/2009)
Hello Ted! I amOK by just installing new correct grooved bearing as part of my stock rebuild or is this cutting a groove in the block a good idea anyway and how deep should this groove be? By restrictors are you meanining plug the return fitting at the end of the shaft or actually putting a restrictor in the feed hole in the rocker support stand?I’m grooving the center cam bearing hole in the block for all Y builds. If the softer cam bearing set is used (usually cost less $), then the grooved camshaft can ultimately cause restricted or no flow to the top end due to the groove in the cam journal being pinched off by the softer bearing material being mashed into it. The addition of the groove in the block behind the cam bearing gets around this. I make the grooves ~.040”-0.055” deep with them being about 1/16” wide.
As far as restricting the oil to the top end, I’m doing it at the pedestal just before the oil enters the rocker shaft. I do still run the overflow tubes but these are partially pinched to allow some oil flow through them to get oil specifically to the timing gear. Leaving them partially open also insures that the rocker shafts are purged of air and full of oil which reduces the tendency for sludging in the shafts by keeping the oil moving at a faster rate. The distributor gear appears to get enough lubricant regardless if the rocker arm overflow tubes are eliminated or not. When eliminating the overflow tubes, there are those who have drilled a small oil hole in the front of the block under the cam thrust plate to provide additional oil to the timing set. That looks to be a viable option also.
Here’s a past thread giving more detail on timing gear oiling mods.
Pressurized timing chain oiling
And here’s a variety of past threads on oil modifications in general.
Center cam bearing
Pressurized rocker shafts
Pressurized rocker shaft more
Rocker arm overflow tubes Cons
Rocker arm overflow tubes Pros
Rocker arm overflow tube More Pros
Timing chain oil trough
Adding lifter valley holes for camshaft oiling
Drilling additional holes for oiling and/or venting
Valley holes for aiding crankcase evacuation
Tanks again Ted, and all of you other Y heads out there!