Stovebolt.com Forums The Shop Area The Engine Shop Oil Filter yes or no 235?

So on my 261 with full flow, and there is a way to make the 235's do the same thing, I put a spin-on adapter as low as possible on the engine and I fully expect it to keep the contaminants (metal shavings, crud, etc) out of the system. I have no real enthusiasm for the standard bypass filter as I have seen many of them completely plugged up and totally useless due to lack of proper maintenance. Good comments in this thread for sure!

the really best easy way to determine when a filter will bypass is to simply ask the manufacturer. Generally I would think they are given quite a wide margin to allow for accumulation of contaminants, and the aforementioned cold starts. But you would need to install at least a gauge before and after the filter,
the best would be an actual differential pressure gauge, to determine what exactly is going on in YOUR filter. However without actually installing said gauge(s) This is purely speculation, on all of our parts. I have taken thousands of readings on probably a hundred different pieces of equipment with differential pressure gauges, most of them run around 3-8 psid. (We would change the filters at around 8, or what ever that particular piece of equipment specified) True they were large diesel engines for maritime use, steam/gas turbines, reduction gears, hydraulic systems, things of that nature (I have never seen an automotive engine with a differential pressure gauge) and yes I will concede it does vary with pump RPM. but not to the extent that it will exceed the bypass setting. Certainly not to the degree that you could say "at 4-5000 RPM." With any sort of authority. I have also watched the differential on way too many filters climb as time went on, to NOT use a filter. They are catching something, not anything you can see, but they are clogging up nonetheless. They never really approached the bypass setting, but did rise appreciably.

Yes, at approximately 3-4k RPM most engines will have sufficient flow out of the oil pump to lift the filter bypass. I know it, I have read the manuals and the spec sheets on filters (bobistheoilguy.com is only place that is bat-crap crazy about filters and oil).

A stock SBC oil pump will move 2-5gpm dep on RPM.

Here's a graph of some modern filters and at what GPM they create the specified differential pressure:

Oil dp chart

Save ONE filter all are at or above 10psid with only 2gpm flow. This is COLD oil... but at 5W its pretty darn thin even for 32F.

Yes, I can post bypass numbers for warm oil... but I think its clear that YES, oil filters bypass all the time based on GPM, dirty media, or cold oil.

I would still run any filter (by-pass/full flow) over no filter. Just change the oil more frequently (maybe every 1000 miles) depending on conditions.

can't argue with proof like that, ONE chart with some filters for what application no one knows. Two days ago filters bypassed at 60 PSI, and 4-5000 RPM, now they bypass at 10 PSI, and 3-4000 RPM. Every 1000 miles? Water is wet.

If you really need me to post the info I can. But typically that means that even if I did, you wouldn't read it anyways.

The RPM numbers are valid for *most* motors. Again, I can post the information, or you can google it. Either way its correct.

If you were NOT using any oil filter I would definitely change it much sooner as the oil can only hold so much crud in suspension. Oh, wait... now that's wrong to... I guess you run all your cars with no filters and never change the oil? Yeah....

I could go into media flow rates, or oil pump GPM... but is that really necessary? I mean your position is simply that 'you are right' vs discussion.

If I am wrong, please correct me.

those numbers make no sense because at 10 or 12 psid, (or in the case of a factory subaru filter, 24 psid) the bypass would open and the differential would no longer increase. There are so many variables that you aren't considering. Yes it is very clear that at 34 degrees those particular filters (for what application I still don't know) would probably bypass at over 2 gpm. But what about 50 degrees, or 150 degrees? I have never heard anyone but you decree that at whatever RPM you have decided it should be today, that a filter will bypass. But apparently you read another article over the weekend. No one is arguing that the bypass may open with 34 degree oil. However at operating temperature I don't buy it. But as I said I have never seen a car engine with a differential pressure gauge, and I am pretty sure you haven't either. Basically you have produced no conclusive evidence other than you saying so. water is wet.

So i recently picked up a bypass filter fairly cheap. My thoughts are, it cant hurt, even though it may not help. But it was an option, and I have one, so I'm going to install it. My question is does anyone have a photo of a correct color scheme, decals, and how it was mounted. I've seen the installation instructions, but would like to see some more photos of paint, plumbing, and mounting. thanks!

The colors and the label were different, depending on a variety of factors: (have you looked at the Tech Tip?)

If you have a Chevrolet/GM AC filter:
- year of filter
- size of filter
- installed as an accessory or as an RPO

I've looked at the tech tip, just hoping for a more visual representation than "yellow/black". lots of gray area there. would like to Have a pic from one of our experts so I can try and match it close to right.

Unless someone has documentation for your year, use the Black & Yellow for your year?