The Stovebolt Site Forums The Shop Area Engine Shop What's in the oil filter

So. I get a call from the machine shop. They ask me if I want to drill the block for full flow oil filter.

The engine is all done. Head is all done. But they have to assemble the short block and put the head on it.

For full flow. They would have to wash the block and do the machine work then re wash/paint the block.

I asked them if changing the oil every 2 to 3 thousand miles would make any difference and is it worth the time and expense to do the work. Machinist said no.

I am having the engine reassembled. I want to drive the truck.

The klingon (attached to the intake manifold) filter will do just fine. I have been waiting 8 years for the other engine. This guy will put me in my truck in less than 3 months. I like this guy. He wants to go get the 8 year project and finish it for me. I like this guy.

Full flow filters are probably better but look at all the thousands of chevs that survived the bad oil of the 50's. If you change your oil regularly and use good oil, I really can't see the point. After waiting this long, I'm sure that you will change your oil oftener than it needs be anyway. Cummins diesel engines have used a full flow and a bypass filter for the past 50 years. Full flow for the bit stuff and bypass for the smaller trash. If you eliminate the bypass filter, have you gained that much?

If you use the right filter element, the bypass filter will do a much better job of keeping the oil clean than a full-flow filter. I used to sell the Frantz filter system for big rigs that replaced the bypass filter cartridge on a LuberFiner 750 canister with one made of toilet tissue. It would trap particles down to 2/10 micron, (0.0002")
A full-flow filter can't restrict that much, because it would drop the oil pressure to virtually nothing.

The full-flow filter traps particles that could score bearings, and lets the small stuff pass through. Ideally, and engine should have both systems, but I don't know of any automobile or light truck engines that have that setup.
Jerry

As soon as I get mine on the road I'll be installing a Franz filter. I had one on my 55 back in the mid 60s and it really does the job.

My OLD 235 has been modified for full pressure and full filtering, the oil now stays clean like a modern engine. The old by-pass filters of any make or brand do almost nothing, may as well leave it off.

Btw I'm using a remote unit with a modern spin on filter.
Best of luck

For these reasons I believe the full flow conversion is overrated and unnecessary. After a Google search of "oil filter testing" I was stunned at how easily most filters will let dirty oil go by. I run an Amsoil bypass filter on my stovebolt and catch particles down to 2 microns absolute.

I have to disagree, even with Tom Langdon, on this one. He told me that, since a bypass filter only filters about 10% of the oil, leaks will be more of a problem than any benefit that a bypass oil filter can provide.

My viewpoint is that any filtering is better than none. Don't plan on extending oil change mileage because you add a bypass filter, but, if the engine doesn't produce more crud than the filter can take out, it may take ten circulation cycles, or more, to get the crud out, but eventually most of it will be filtered out.

I have a '51 4400 and a '50 3800. The 4400 had the add-on bypass filter and the 3800 didn't. One confusing factor is that the 3800 also has the valve cover with vents.

I pulled the valve covers off both and took pictures. The 4400 valve gear looks nearly new, even though it hasn't been run for more than 12 years. The 3800 valve gear is filthy with multiple dirt encrustations. (It has been run for more than an hour since I bought it.)They have nearly the same mileage on them and both odometers work.

So, you decide.

I just pulled apart a 1954 235 with a by-pass filter that has run about 5,000 miles over the past 4 years and has had the filter element changed every two years (whether it was needed or not).

I also just pulled apart a 1960 261 engine with a full-flow spin-on filter (factory full-flow plumbing but after-market spin-on filter unit) that has run about 1,000 with the same spin-on filter).

Both engines look about the same under the valve covers.

I'd say the full-flow set-up is better but the by-pass set-up is quite adequate if you change your oil and filter regularly.

I got a bypass filter on my 235 and a full-flow modern spin-on for my 261.

What I like about the full-flow filter setup is that 100% of the oil gets filtered BEFORE the main bearings.
A filter with bypass may be used for extra protection, like the original 261 full flow plumbing provided.
I use NAPA gold filters with 20 microns and anti-drain back. These are made by Wix !
NEVER use Fram filters! The cheap and thin paper elements inside have widely been reported to collapse very easily.

What I like about the bypass filter setup is that it traps particles as small as fractions of 1 micron AND eventually 100% of the oil gets filtered within minutes.
Also, even a clogged old filter never drops pressure, like full-flow filters without bypass can if not replaced with every oil change.
Frantz toiletpaper filters are the best. The TP element also removes a lot of water from the oil.


The best argument against using any oil filter is to avoid oil leaks and a potential fire hazard since the oil line plumbing on these engines is on the same side as the exhaust manifold !

Personally, I prefer filtering of either kind and going with metal oil lines and clean and good plumbing, inspected regularly.


That said, in the end I probably would be fine without any filter, since I never push my engines too hard, change my oil very frequently, keep the air filters clean, my valve covers and crankcase are filtered and being in the desert also forms less water inside the crankcase.


Btw: Early stovebolts had no oil filtering, because the oil at the time was a non-detergent type, where particles settled at the bottom of the pan as sludge, which required periodic cleaning and sometimes flushing of the motor with kerosene or other harmful solvents or acids.

Later detergent motor oils kept particles suspended in the oil, requiring a filter to trap them, especially when going longer between recommend oil change intervals.

I have the bypass on my 216 and it still purrs after 55 years of use and abuse. No argument here.

One thing I did notice about the 4400 with the optional filter was that I had a lot of crud in the bottom of the oil pan. I had to scrape it out with a gasket scraper.

I think I will refer to this crud as 'inert dirt' because, if I had to scrape it out, it seems unlikely that oil flow would have moved it, unless you went to a kerosene purge, or some additive.

Single-weight, non-detergent oil would drop things (particulates) out into the pan because that type of oil would not hold particulates in suspension (as stated above by On the road again).

That's not really a bad idea. If it falls out of suspension and forms the kind of sludge that I had, its no longer a major problem.

Ok What is a bypass filter and a full flow filter??
My truck is a 1954 3100 has the filter on top I Suspect that's a bypass filter. I change my oil every 2000 miles with Rotella it even looks clean after 2000 miles. Thanks Peter

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