Oil Filter Bypass Hole,Plug Or Not Plug? - Team Camaro Tech
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post #1 of 6 (permalink) Old Mar 15th, 03, 08:19 PM Thread Starter
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Has anybody ever heard of removing the bypass spring and install a plug?I wish that I never did.On initial start up the hyd.roller cam 350 w/a m55a melling pump w/a short fram filter showed to have about 50psi.As the engine warmed up it slowly decreased to about 25psi and never really wanted to build upon increasing the rpm.But it did have oil pr.so I took off down the road.About 50 miles later it has about between 15 to 20psi at idle and only builds to a max.of maybe 25psi.I new there was a problem so I removed the plugged oil filter adapter and installed another one from another 350 that I had,and installed a new filter of the same kind.Problem is fixed.It was to my understanding that roller cam motors should plug the bypass hole,and the machinist I used agreed.Has anybody else ever experienced the same problem?If not I hope I can help somebody out that is thinking of doing this,and just dont do it.
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post #2 of 6 (permalink) Old Mar 16th, 03, 03:40 AM
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The filter isn't big enough. When you started it initually there is always going to stuff get trapped in the filter (moly etc.) and it partually plugged an already too small a filter. In one of Bill Jenkins books he stated that after much testing he came to the conclusion that even a small block Chev. must run the 2 quart truck filter to have enough flow with the bypass blocked. Leave it the way Chev designed it. You will have no problems.
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post #3 of 6 (permalink) Old Mar 16th, 03, 04:18 AM
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I do block them. Always have.

The molly paste assembly lube used for cam break in will plug the filter soon after you fired up the new engine. You should follow the directions regarding the cam break in procedure then change the oil and filter after about 1 hour while still warm. That gets the metal crud and molly paste out of there. The rings will not like the molly paste while trying to break them in so it needs to come out as soon as possible after the cam is broken it. After that, you should not have problems with low oil pressure. If it does affect your oil pressure after the first change, your oil was not being filtered anyway [img]graemlins/clonk.gif[/img]

Think about it another way. If you leave it alone you will still quickly plug the filter with the molly paste and the bypass will do its job and open. Now you are breaking in a brand spanking new engine using no oil filter at all. All those metal particles are just being pumped right back into the oiling system and continuously recirculated. That can't be good.

If you plug it, you will always have filterd oil. During the break-in process you may see lower pressure on the gauge but at least the oil is still getting filtered. After the initial oil change, you should not have low pressure issues any more. If you see low pressure on the gauge after the initial break-in, you need to check the filter as it may be dirty. If not, you have other problems. The engine is not under load during cam break in and the pressure is not in the danger zone.

Loose that Fram filter. They are not the best. Try a Wix or Purolator. They are much better.

Just my opinion. [img]smile.gif[/img] Your results may vary but I want you to have both sides of the story.

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post #4 of 6 (permalink) Old Mar 16th, 03, 07:04 AM Thread Starter
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I used the BG assembly lube when I assembled my motor which I could be wrong but I dont think it is a moly type lube.At least it doesnt appear to be,and the roller cam and lifters had already been broke in before.So I used the same assembly lube as the bearings when I installed it.And I lubed it real good.I cant use a larger filter because it hits the hooker comp.headers.I assume because the heads have been angle milled.So I guess I will try it again now that the break in oil is out and use maybe a different filter.I thought the fram filters was the best.Is there more opinions about the filters.And should I reposition the headers in your opinion to accept a larger filter?Thanks for the replys. [img]graemlins/sad.gif[/img]
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post #5 of 6 (permalink) Old Mar 16th, 03, 07:10 AM
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Here is some interesting reading on filters. The largest filter you can fit in is always better for the engine.
The Frams seem to be the cheapest to buy and not the best in filtration either. Follow what others are saying when they have the rollers, experience is better than an overhaul.



Click..is Jim..former owner of a 69RS-LM1 350/255 - 700r
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post #6 of 6 (permalink) Old Mar 16th, 03, 08:16 AM
David Pozzi
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Fram and others make a racing filter that is higher flow.
The higher flow is gained by using filtering media that is more porous. The disadvantage is they usually don't filter as fine a particle out.

[ 03-16-2003, 10:50 AM: Message edited by: davidpozzi ]

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