I do not know about the Merlin block but good timing on bringing this thread back to the top. Too many people forget the oiling system, I did, now mine is set up correctly.

After market blocks do not have a bypass hole/spring at filter adapter area. It is a MUST to run a high flowing filter preferably with a built in bypass relief valve,large enough lines,fittings etc other wise you can shear off distributer pin,wear cam gear out fast or at a minimum the pump bypass relief will open too much causing your oil to become aereated,Smitty

ttt

Link to KN HP6002
http://www.knfilters.com/search/prod...x?Prod=HP-6002

According to their website this filter doesn't have a PSI Relief Valve. Are you still using the 6002 or have you changed? I am about to block off my bypass and thought this was important to clarify. Is the filter's PSI Relief Valve the same as a bypass?

You are correct,after researching this briefly tonight I see what your saying. The fram hp-4 has a built in relief valve,the k/n series of filters DON'T,at most they have a anti-drainback valve and the hp-6002 doesn't even have that. What they do have though is a flow rating that far exceeds the output of the oil pump and alot of filter media area which will give you very little restriction and makes a bypass valve un-necessary,Smitty

Regarding the 30Lb. relief valve in the block. How come this valve isn't open all the time when oil pressure is above 30psi which it frequently is? I am just getting around to purchasing the filter adapters etc. and need to verify what I am doing. Articfriends- you seem to be the resident expert on these issues. I have a few questions if you don't mind.

As far as the block bypass valve it's a 30lb differential in pressure,not 30 lbs.Lets say you had some really restrictive hoses and a low flowing oil filter,3/8's id hoses and you were running 70 weight oil (it's like honey when cold). Your pump is putting out 10 gallons per minute but this junk hardware will only flow 7 gallons per minute. You have so much excess oil that has nowhere to go it builds up 100 psi of static pressure. The hardware can only flow about 60 psi worth with all this resistance so the excess oil pressure differential is enough to lift the bypass valves. I will tell you,you would have to really have a cobbled up mess to lift a 30 lb bypass valve. You can easily lift the relief valve on a pump though when the oil is cold,Smitty

Thank you. I would like to take this one step at a time for a clear understanding. As far as identifying the passages in the mounting pad on the block: I see the one hole on the edge that is either blocked or has the relief valve depending on which way you choose to go. What is the other hole next to it on the edge that is always open and seems (from the pics) to be drilled at an angle? What is the large hole in the center and what is the fitting that I see in there sometimes? Thanks for your patience, I dont have access to the blocks so I have to identify everything through your pics and description. Not only do I need to make sure I get the correct parts and install them correctly, but I would also like to increase my knowledge of how the system works.

The angled hole is the 'Oil out of engine' from the oil gallery. This hole sends hot used oil into the filter element or is pumped out via a hose to the filter remote mount inlet or oil cooler then filter (however you have it set up). The Big center hole is where the filtered (clean) oil gets pushed back into the motor where it goes to the sump and sucked back up by the oil pump. It then gets used, dirty and hot, flows back through the outlet to get cleaned again by the filter.

Such is the life cycle of oil. Pretty boring if you ask me! No porn, no internet, no football. Nothing! Just get all hot, dirty and used, then get screened cooled and cleaned to have it happen all over again! :lolhit:

Smitty, I have to disagree with you on running a filter with an internal bypass. I have been running with plugged bypasses in my blocks and no bypass in the filters for 5 years now and my dist. gears show no abnormal wear. I do use the large truck style 2 quart filters now. I have read that the bypasses have a tendency to open a good portion of the time the engine is running so you are running partially filtered oil. After the time I had a lifter break and seeing the damage all of that metal did to the engine, I don't want to run any unfiltered oil.