Offshoreonly.com

Offshoreonly.com (https://www.offshoreonly.com/forums/)
-   General Q & A (https://www.offshoreonly.com/forums/general-q-20/)
-   -   Big Block Oiling Question / by-pass valves (https://www.offshoreonly.com/forums/general-q/252956-big-block-oiling-question-pass-valves.html)

doctor_ratz 05-05-2011 06:34 PM

Big Block Oiling Question / by-pass valves
 
I just put in a new 540 cube big block to replace one of a pair that was blown. I bought a new block w/o any plugs or bypass valves installed. After assembly, and install, I noticed on another engine that there are two by-pass valves. One under the filter, and one up under the threaded nipple for the filter. That's when the panic set in. I did not install that bypass valve under the nipple, only the one in the filter area. I have oil pressure on the gauge. Do I need to pull the engine and install the second bypass ?????
I have been told that this second bypass is only for truck type oil coolers. Which is correct ?????

getrdunn 05-05-2011 06:56 PM


Originally Posted by doctor_ratz (Post 3395876)
I just put in a new 540 cube big block to replace one of a pair that was blown. I bought a new block w/o any plugs or bypass valves installed. After assembly, and install, I noticed on another engine that there are two by-pass valves. One under the filter, and one up under the threaded nipple for the filter. That's when the panic set in. I did not install that bypass valve under the nipple, only the one in the filter area. I have oil pressure on the gauge. Do I need to pull the engine and install the second bypass ?????
I have been told that this second bypass is only for truck type oil coolers. Which is correct ?????

I'm not running any in my 496's. I know things have changed over the years however I never recall ever seeing any there. Will be interesting to see what others have or are doing. If you don't get a response do a quick google search. I can't understand why there would be two. What kind of block is it?

dennis r 05-05-2011 07:49 PM

you should block off the one under the filter housing so all the oil goes thru the filter and cooler

getrdunn 05-05-2011 07:57 PM


Originally Posted by dennis r (Post 3395940)
you should block off the one under the filter housing so all the oil goes thru the filter and cooler

Seems like a nickel works perfect for that if I remember right.

Rockfish71 05-05-2011 08:21 PM

Sure if it is worth 5 cents to you :) me I would tap it to 3/8 and plug it

doctor_ratz 05-05-2011 08:51 PM

These are 502 genVI blocks.
I just checked the damaged block and it does not have the second bypass valve under the nipple.
The reason you should not completely plug the bypass under the filter is for possible oil stavation if your cooler or filter get plugged. There is a 30 PSI bypass available from GM performance to replace the standard 15 psi automotive unit. I am an old drag racer and have had trouble in the past losing oil pressure with a blocked bypass on small blocks.

doctor_ratz 05-05-2011 09:02 PM

Did a search, and you guys were right. Seems like the correct answer is no by pass in the nipple, and plug the one on the oil filter pad. If I can do it in the boat, that is what I am going to do, other wise it will have to wait till winter.
Thanks guys !!!!!!!!!!!!!

jeffswav 05-05-2011 09:13 PM

Yea, remove the center valve and plug or install a 30psi vave in the one on the side.

dogturd21 05-05-2011 10:47 PM

I am only slightly familier with this issue, but the question in my mind is: if the valves are incorrect, can this be fixed without removing the engine ?

getrdunn 05-05-2011 10:55 PM


Originally Posted by Rockfish71 (Post 3395972)
Sure if it is worth 5 cents to you :) me I would tap it to 3/8 and plug it

I had to look twice and chuckle a bit when I saw a reputable speed shop doing it downstate.


All times are GMT -5. The time now is 11:20 AM.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.