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-   -   Vacuum pump and maximum "safe" vacuum (https://www.offshoreonly.com/forums/general-q/375606-vacuum-pump-maximum-safe-vacuum.html)

underpsi68 05-04-2022 06:26 PM


Originally Posted by Smitty275 (Post 4830935)
If your just racing it you can 10-15 no issues. If it's gonna be ran for long duration keep it around 10 max. 7 is safer. Gotta say I've never seen an oil filter crumple. Biggest issue with running them long duration seems to be the wrist pins dry out and top ring wear. Being in a vacuum the oil drops back to the pan very efficiently and there is next to zero oil mist that would otherwise be there. Crank seals don't last as long either.
As for the bearing issues he had previously, I doubt that had anything to do with the vac pump.

I have been wondering what appears to be a rear main seal leak on my engine. Was thinking if it was the pump sucking the oil out? I never had a rear main seal leak ever!!

One of the great things about a vac pump is the engine doesn't leak any oil, when running. I get a drop or 2 after I turn it off now.

articfriends 05-04-2022 08:44 PM


Originally Posted by SB (Post 4830948)
I’ve collapsed a few filters with jaw and/or band type filter wrenches trying to take off filters some knumb nutz installed way too tight. :) :wink You know, when you should have stuck a big flat screwdriver thru it 15 minutes before hand. Lol.

i can’t see any either way a filter would crush in. It’s not from a vacuum pump. Oil psi inside at 50psi -100psi. Maybe vacuum of -150 psi ? Don’t think so.


https://cimg6.ibsrv.net/gimg/www.off...47646b48aa.jpg

https://cimg8.ibsrv.net/gimg/www.off...fd44c96ae.jpeg

I know what your saying, i saw the filter they had that collapsed, didnt have a scratch on the paint till I put a tool to it to get it off, my reasoning is same, 50 to 100 psi inside, idk what sucks a pressurized filter enough to collapse it

SB 05-04-2022 09:21 PM


Originally Posted by articfriends (Post 4831082)
I know what your saying, i saw the filter they had that collapsed, didnt have a scratch on the paint till I put a tool to it to get it off, my reasoning is same, 50 to 100 psi inside, idk what sucks a pressurized filter enough to collapse it

I just googled it and found a reasonable article on what can collapse a oil filter:

https://knowhow.napaonline.com/what-...lter-collapse/

articfriends 05-05-2022 07:04 AM


Originally Posted by Rookie (Post 4830955)
Glad to see you got it running with the Holley Terminator. Nice numbers!

I wish you lived closer , trying to figure out how to create a low oil pressure safety into the tune , configure a custom 12v triggerd out map and rpm based output to trigger his shifter relay and finish developing his nitrous stages (cant figure out how to assign a pin to output to define it), set targets real low, rev it on dyno once to see them send out their signal then I can tear it off so I can get next motor on. The other jason you met who helped us with your holley is coming over hopefully!

hogie roll 05-05-2022 07:26 AM


Originally Posted by SB (Post 4830948)
I’ve collapsed a few filters with jaw and/or band type filter wrenches trying to take off filters some knumb nutz installed way too tight. :) :wink You know, when you should have stuck a big flat screwdriver thru it 15 minutes before hand. Lol.

i can’t see any either way a filter would crush in. It’s not from a vacuum pump. Oil psi inside at 50psi -100psi. Maybe vacuum of -150 psi ? Don’t think so.


https://cimg6.ibsrv.net/gimg/www.off...47646b48aa.jpg

https://cimg8.ibsrv.net/gimg/www.off...fd44c96ae.jpeg

The circular steel thin wall is great in tension (pressure). Terrible in compression (vacuum)

mcollinstn 05-05-2022 09:34 PM

The only way the "Outside" of the filter can could be crushed inwards is if they ran the oil pump dry at high sump vacuum. Leaking pump pickup tube or pickup was not submerged - either of those would do it.
That would also explain bearings into the copper.

Smitty275 05-08-2022 07:24 AM


Originally Posted by mcollinstn (Post 4831223)
The only way the "Outside" of the filter can could be crushed inwards is if they ran the oil pump dry at high sump vacuum. Leaking pump pickup tube or pickup was not submerged - either of those would do it.
That would also explain bearings into the copper.

Could also explain the collapsed piston skirts. Wonder if someone got in a rush and forgot to put oil in. Or they flushed the motor between pulls with ice water and forgot to put water back in the cooling system.

articfriends 05-08-2022 03:39 PM


Originally Posted by Smitty275 (Post 4831420)
Could also explain the collapsed piston skirts. Wonder if someone got in a rush and forgot to put oil in. Or they flushed the motor between pulls with ice water and forgot to put water back in the cooling system.

Hard to know, they ran a carb with jet extensions in the FRONT and didnt know better, they revved engine '8200" even though the 280/800 lift roller cam is done by 7000, they set motor on pan. I built them 4 th-400s for there 4 trucks, 2 were for low hp 500-700 range so they didnt get ultrabells or aftermarket cases. They already brought one back with the bellhousing broke and asked if I missed that when I was rebuilding it as they say they never bolted it on a engine , LMFAO, there was a huge gouge in dowel hole where they rammed it on not lined up so ANYTHING is possible! I sent owner a picture of a titanium retainer in my lathe that I was doing a tiny cut on inner step, his answer back was "those new lifters look really nice"

sutphen 30 05-09-2022 06:35 AM


Originally Posted by articfriends (Post 4831467)
ANYTHING is possible! I sent owner a picture of a titanium retainer in my lathe that I was doing a tiny cut on inner step, his answer back was "those new lifters look really nice"

wow,,thats almost like talking to cfm.:D

SB 05-09-2022 06:39 AM


Originally Posted by sutphen 30 (Post 4831507)
wow,,thats almost like talking to cfm.:D

Yup. :lolhit:


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