Discussion in 'Tomahawk Block Buildups' started by Staged70Lark, May 31, 2015.
Can you guys share what size jets you used to oil the lifter valleys?
Two experiences for you.
First build, we had a set of TA lifters with an extra hole in them, that fed oil directly to the upper end right out of the galley.. with that deal, we needed to run set of Holley 2 Barrel jets, they were around 25's.. very small, and it still had a lot of oil up top.
When that motor was rebuilt after 400 some passes, we plugged the hole that was in the galley, and required the oil to pass around the lifter/bore to enter the hole on the valley side of the lifter only..
In this instance, we used no restrictors, and RH bank oiling was good, LH bank was inadequate in my opinion.. After warmup, we pulled the rocker covers to set lash, and noticed that the oil was actually noticeably darker in the LH head.. from heat, and lack of oil flow.. we tested pressure on both sides at the rear, and found them to be nearly the same.. but then looking at it, we realized that the oil restrictors themselves were in the path of oil flow, and volume was restricted to the LH galley.
So we took the restrictions out completely, and used just -6 ORS plugs.
This seems to have equalized oil flow thru the heads.
In this case we are using the lifter/bore clearance as the only restriction to upper end oiling.
That is my recommendation where you start.. No restrictors/ just the -6 ORS plugs.
Thanks for sharing your experiences with this situation.
I have a hole on the lifter valley side of my lifters blocked off because too much oil was getting to the top of the engine with the stock block. Therefore the oil will have to travel around the lifter to get to the pushrod.