Are guys still blocking off the bypass oil filter housing like H-O used to say to do
 

I'm building a stroker 462ci for someone and I'm not sure if I should block off the oil filter housing bypass like HO had in there book back in the day. I always have done it, but over this pasted summer, with my own motor I had my Wix filters clasping one after the other. So, I'm just wondering if anyone else has had this happen to them with or without it blocked off?

Thanks

Used to, but stopped that, and not gonna block em. Sick a magnet oil plug in and feel better about it.

2 rules of thought on this, one, you don't ever want to have unfiltered oil pass thru the engine. Two, in most cases if it does bypass the filter, it won't make enough of a diff to matter and the bypass is a level of safety.

Most oil filters do have some type of bypass built in, so...

Obviously, if the filter collapses, that's not good, and it would be better to have a bypass in that case.

You have to be mindful of you filter choice(s) and warm up procedures, especially if you block it off. Your oil psi needs to be kept in mind too.

When an engine is cold, without a bypass, you could potentially starve the engine for oil for a period of time before it reaches where it needs to be, longer than if the bypass were to open.

Filters need to have a higher burst rate rating if you block it. Or should. So it's good to know what that rating is for a filter you choose.

If the filter media filters to a refined level, it can clog faster and that would decrease oil flow, hence increase back pressure/decrease oil psi. This is one reason I don't use K&N filters, they need to be changed more frequently or they restrict flow and increase risk of blow-offs/collapse. I think the HP line does have a bypass, can't recall at the moment though.

Oil filters don't universally have a bypass valve, it can be dependent if the application is known to have a built in bypass valve or not. If you pick one for an app that is known to have a OE built in bypass, and you block the OE bypass, then you run the risk of collapse/blow-off.

This can be the case when people switch to remote filter setups, eliminating the OE bypass.

Long story short, in general, leave the OE bypass in place. IF you do choose to block it, be mindful of the filters you use.

I generally don't block them, the risk comparison to me is a wash. I do though have it blocked on my 535, but that's only because the builder chose to do so. I might change it back, but haven't gotten to that thought yet.

What's the part number on the Wix that you are using, and what are your oil change intervals?


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HO racing at that time sold the Lee Maxi filter ,
This was a two stage filter and had a section in it to still filter the oil and feed the engine when the bypass opened.

If you want to block the bypass you need to run either a 2 quart filter that can handle the highest volume of oil that the pump can move, or a screen type supplement filter.

That's great, all filters should have that, but it would compromise the life of the element.

A larger body filter would overcome the limitations of flow, but with headers it would be a task to fit without going remote.

O-Berg or screen type is an option, no worry of collapse, but the small filter area makes it to where you would have to clean it fairly regularly.


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Are you sure that's how they worked? Trying to figure that one out. Do you mean if the bypass in the filter opened if would still be filtered?

https://www.youtube.com/watch?v=Z9DAp4DXsQY

https://www.hotrod.com/features/oil-...-982-1046-98-1

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I’ve collapsed quite a few Wix filters even with a factory bypass on different platforms. Cold weather really tests them. We use Wix a lot, but these days there are often better made filters, they seem like they are cheaper made all the time.

My preference is to pick a filter that has a higher built in bypass pressure with the external GM bypass blocked. The original external bypass pressure on a lot of GM stuff was in my opinion to low. The low bypasss was ok for flat tappets, but causes a more issues with roller cams. I have mine blocked with roller cams, unblocked with flat tappets. I see a lot more bearing scars when running a stock external 3 to 5 low pressure bypass. The internal filter bypasses generally have higher differential pressures for better filtration.

Which filters do you use now?

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I run Baldwin filers and never have blocked the bypass.Tom

The B39?


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Ok thanks, that clears up a lot of what I was thinking about on this. Ever since this past summer having had my motor spin a bearing, I've been trying to figure out what actually made this happen, so I didn't make the same mistake again on the rebuild. So, after seeing the collapsed filter I started thinking back to the day before. I was beating on the car quite a bit and was noticing that the oil pressure was going really high thinking "this is odd" and was also thinking that it can't be a bad thing, so I continued and never thought anything more about it. Then I realized that the provision on the oil filter housing for the oil gauge is before the oil gets filtered through the pleats. So, if the filter collapses the oil is going to have a harder time getting through which is going to show higher oil pressure at the gauge. So, I can only imagine how low it must have been on the other side in the middle as it was getting fed into the motor. Yikes! lol So now I drilled and tapped a new location on the top of the housing where it will read after the filter. Now the oil pressure over all is different. It seems lazier not in a bad way but in a way that I understand why its acting different. That probably sounds stupid but it's hard to explain. ha-ha

Thanks for your theory on this it really helped me decide what to do for this build. It's for someone else so I want to get this build right with no problems

It was wix 51258

Would you ever use a non-blocked off filter housing or do you always block them?

Yeah I don't think that one has a built in bypass. And suspect you have the filter housing bypass blocked too. Which would give you erratic oil psi if the filter collapsed.

You should just put the oil psi sender by the distributor, which is at the end of the oil passage, giving you a more accurate reading of what the engine is seeing. If anything gets out of whack in the engine, many times you would see it from an oil psi reading from the end.




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FWIW, the KRE oil filter housings appear to not have a bypass: https://www.kauffmanracing.com/Ponti...%20Housing.htm

I leave the factory bypass in place. Its better to have enough unfiltered oil than to have not enough filtered oil. The factory engineers do things for a reason. I remember an article that was written by a well known engine builder that calculated that you would need 4 filters in parallel to run your engine safely without a bypass.

I used to block all of my filter adapters, never had any problems whatsoever with blowing or collapsing filters. I always used lighter weight oils usually 10w-30.

At first I used the the Lee Maxi 2-stage filters per H-O Racing recommendation. Later when the Lee filters went out of production I switched to NAPA Gold / Wix all without issues.

On my 421 HO build which is essentially a restored factory performance engine I opted to leave the bypass functioning as it was intended.

All of my engines would be considered stock to moderate builds. I always tapped into the port next to the distributor for my oil pressure readings.

B39 and B9 as I remember.Tom

I am not afraid of the stock filter housings with the external bypass on mild flat tappets on mild builds, but that is about it. What I have noticed is the better filter like a Baldwin (it generally has more filter element in it than the Wix) with the stock GM external bypass will often end up providing less filtration, or a very least, make no difference at all. With the better filter, the bypass opens more and it takes longer for debre to be caught in the filters.

When possible, I prefer plugging external bypass’s and switching to the in filter bypass that has a higher bypass pressure between 9 and 15 psi. I have no issues with blocking bypasses on street and strip stuff as long as the oil pressure is read after the filter so it reads the actual filtered galley pressure. That is what I do on Pontiacs with headers. But when blocking the bypass with no bypass in the filter the pressure needs to be read after the filter.

So, am I understanding this right. When you use a roller cam and lifters you will not use a bypass in the housing and you will block it off? I'm asking because I'm using a roller cam in the build I'm doing now, and I'd like to know what's the best way to go.
Thanks