Small Block Oiling System Mods

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GrapeApe

D7 D/Gas and Pro Champ
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I have always performed the oil system mods by blocking the right side oil galleys with the tube and ream package. However, when I put my big roller motor back together this time I was advised by both Crane and CompCams that since I'm using full skirted lifters those mods were obsolete and unnecessary. Historically, I have been able to maintain over 80lbs of oil pressure with great bearing life.

Has anyone had a similar experience with either positive or negative results.?

340 + .020"
.690/.700 roller
Harland Sharp 1:6
Milled Rocker Stands
14:1 Ross slugs
Stock rods
Stock crank
Good X Heads
10.70 in 3200# Duster
 
Welcome to the board.

Cant answer your question but heres a BTT for you.
 
I know it may be the wrong time, but if it were me, I would order a set of lifters and the cam, then install them in the block and check. I dont trust the cam companies..Not because they are out to mislead, but because there is no way for them to know that every single block has the same size passages for each lifter, and it's the casting that determines whether or not the deep skirts will work. For what it's worth, the 416 I'm involved with for a customer we are bushig the lifter bores instead of tubing the block or running the heavier lifters.
 
I assume you mean the height of the lifter bore. Isn't that pretty standard? Are there significant variance in the depth or height of the lifter bore.

You're right, for me it's a shade too late. Actually, they are my old lifters being placed into a fresh block. We chose not to perform the tube process due to the recommendation of not only the cam companies, but a couple of small block builders as well. I did not actually check the bore with the cam installed. Do you think that even if I have good pressure the problem would be lack of volume downstairs?
 
I've recently had a few oil pressure problems with a 360 and hydraulic roller lifters, the lifters themselves were nearly .001" smaller than normal hydraulics and when I checked the lifter bores with a dial indicator [dont have snap guages] there was .008" slop in the lifter bores. No wonder I have oil pressure problems, the block is at present at the machine shop getting the lifter bores bushed.
The funny thing is there was always reasonable pressure at the guage, the problem showed up in the rod bearings, luckily no damage done, just a dark mark on the bearing.
 
What happens in the case of rollers is the U shape cut for the roller itself, uncovers the cast in passage for the lifter bore galley. So there is a momentary low pressure "pulse" for each lifter, as it goes thru the motions. This effectively starves the lower end because the pass side lifter bores are fed first by the pump. The tubing mod gives the galley a liner, so it doesnt matter how far the lifter rises, the integrity of the gallery is maintained. It also stabilizes the flow to the lower end. Lifter bore bushings do the same correction for lifter, but also correct the lifter bore angles, which are never where they should be. Keep tabs on your oil pressure gage during warm up, and an eye on max pressure. I would put it on a dyno, do a little tuning, then pull the pan and check for any problems before putting it in the car.
 
I plan on tubing my 360 block since I will be running solid flat tappet cams. If you aren't planning to run a hydraulic cam, wouldn't you always want to block oil wasted at the lifter bores in some way, either tubing the block or bushing the lifter bores? Or is it a waste of time? My engine will see a max RPM of 6500. Should I just leave it stock?
 
well, it's up to you and your builder. For anything other than a roller cam, I wouldnt bother. Really, 6500 isnt that high, and unless it's being raced SCCA style or similar, you shouldnt have issues. A solid body lifter has no cuts in the bottom to allow pressure to bleed off if the oil passeg uncovered. A street engine needs good drainback, and a decent windage control setup, and that should be fine. Tubing came about when race engines were reaching high rpms and high lifts and the rods were being starved.
 
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