Apeiron

I just saw mention of this again in another thread, so lets get to the bottom of it.

Please choose one of the poll options.

cuisinartvette

LMAO!!!

Good stuff there. Pull my hair out when I read cautions about sucking the pan dry..geesh.

Twin_Turbo

iTrader: (25)

This is from the same source as the back pressure is good tale.

DNSTA

My "friend/machinist/hairdresser" also told me this is why my valve cover leaked profusely. Too much oil up there and not enough in the pan.

Twin_Turbo

iTrader: (25)

Well at least there's a little truth to that, it's a known fact that SBCs tend to collect quite a bit of oil in the rocker boxes, thats why improving drain helps a good bit there

Apeiron

It leaked because it wasn't sealed. If it leaked with an HV pump, it would have leaked with a standard pump.

DNSTA

I agree with both of you! I assume improving the drain-back means boring out the holes in the head correct?

Apeiron

Cleaning up the flash, smoothing out the casting around the holes. You can smooth or paint the lifter valley as well. The main advantage to both of those is to minimize the amount of time the oil stays in contact with the hot heads and block, not to keep the volume in the pan up.

3rdgenmaro

iTrader: (9)

what no option for never running a HV pump?

Apeiron

Good point... a sizable proportion of the promoters of the idea that HV pumps drain the pan have never run one.

Sparkytfl

I havent noticed any draining of the oil, and I'm crazy enough to be using a big block pump.

Kat

iTrader: (4)

Never ran the pan dry but collapsed a few oil filters..

ASE doc

When youve spent $1000s building a high performance motor just to see it spin a bearing due to insufficient oiling, youll understand the value of the HV oil pump.

Tibo

iTrader: (15)

Thought I would just post this picture to aid in your explanation. The oil drain holes are at the front and rear corners of the blocks/heads. Make sure that the drain holes between the heads and block line up and not misaligned. I polish all of the sides of the lifter valley but I don't polish the center of the lifter valley because the lifter bores create little oil pools that without angling the block up or down significantly will always be there. You can radius and port/enlarge the oil drain holes in the center of the valley so there is virtually no oil sitting in the valley but virtually every source I have read says that (for our roller cam engines) it is best to block or greatly restrict those holes via pipe plugs/restrictors/standoffs.

Tibo

iTrader: (15)

You can also extensively enlarge and put a liberal radius on the front oil drain holes. The stock holes are positioned with nearly 1/2" between the bottom of the drain hole and the lifter valley floor, allowing oil to pool a bit before any draining occurs. I'm sure you could enlarge the holes even more than I do but I don't know enough about block strength to go bigger.

t-top havoc

iTrader: (3)

Looks great Tibo!!
I like the dizzy end returns-- attention to detail!!

Dyno Don

iTrader: (7)

HV pump has been known to be the cause of a spun bearing.
Worn cam bearings, worn timing gears and worn out dist. gears.

The only reason to ever run one is if you have a bleed off like a turbo or a supercharger.

It all came to pass in the old days when we ran excessive bearing clearances, but soon learned that was not a good idea.

Tibo

iTrader: (15)

I believe that Apeiron was referencing this thread ( https://www.thirdgen.org/forums/tech...e-vs-high.html ) that was referencing this article ( http://www.carcraft.com/techarticles...s/viewall.html ) by Car Craft. It seems to be a worth while article that really calls into question the whole high volume or pressure pump wiping out bearings.

project89

iTrader: (1)

hi volume high presure pumps will no wipe out bearings

the engine in my turbo v6 camaro runs 65#'s op at idle hot and over 105# at redline hot
that engine has over 100k on it and is abused daily, bearings still look as good as the day i put them in

LilJayV10

iTrader: (5)

I had always heard about a HV pump sucking the pan dry and never believed it till I put one in a 93 Z28 I build for a friend. Top of second gear @ WOT it would loose oil pressure everytime. Put in a standard pump and never had a problem since.

t-top havoc

iTrader: (3)

I had a HV in my bigblock & never had a problem...
This is interesting...

TTOP350

iTrader: (8)

Way better answers to this over on speedtalk.com

HV pumps, poor drain back and stock size pans are a good idea on high rpm quick rev'n SBC and SBF motors.
There is a need for HV pumps on older motors with larger bearing clearances but todays motors not so much.

Waaaay to many variables to just say one pump is the best for everything.