The Stovebolt Site Forums The Shop Area Engine Shop Adding an oil filter to a 235

I read through a few threads on adding an oil filter to a 235 engine, as well as the website [url=http://devestechnet.com/Home/FullFlowOil][/url]. My engine has the three pads on the left side of the engine just behind the generator (the option 5 layout in the above link), but they're not drilled and tapped. I have yet to find any information on whether these can be drilled out, or how far they can be drilled if it's possible and advisable. What can you tell me?

Thanks,
Chuck

Why not do it the way the factory did, with U bolts on the intake manifold attaching a bypass filter? Full flow filtration on a stovebolt is a solution to a nonexistent problem. Take that other website with a big grain of salt- - - -it's mostly plagiarized info from other sources with little or no attribution.
Jerry

I suppose that the idea of not filtering the oil is so foreign to me, that a full flow oil filter seems a necessity rather than a factory "option". Having changed the oil for the first time yesterday, and watching the last bits of sludge drip out of the oil pan in globs (in a beautiful tan color), I cringe at the thought of what may be moving across the bearing surfaces. From what I read, the addition of an oil filter would be after the fact filtration anyway, but my outlook is that it is filtration nonetheless.
Why is filtration a "nonexistent problem"?

Thanks for your response,
Chuck

I understand where you are coming from , watching the goops drip out .

But you have already started the process of cleaning that up. Next follow up oil drain at 1000 miles (or earlier if you like) . I did do a flush on mine , 1/2 gal of diesel fuel added to the oil already in the sump . IDLE for 10 mins and drain.

I have nursed a well used 216 for 80,000 miles , cracked block , loose mains , fuming at speed . for 20 yrs . All that time and all those oil changes , I used 15w40 diesel engine oil . A High detergent product that flows well at all temps we get here .

I guess the only reason I never fitted a filter was because of the difficulty of getting the necessary components here .

I like the info given on Deves site . It seems quite comprehensive and if you cannot do without a filter , I think that should work well for you.

Chuck,

About that sludge you watched drain out .... When was the last time that oil was changed? And the tan color tells me that you had a little moisture contamination (condensation maybe?) -- an oil filter won't help that. If that engine was run long and hard, and then left to sit for a long time, it's no wonder the oil looked like that. It would look like that even if the engine had ten full flow oil filters hooked to it.

I'm running 15W40 in my 261 (that Jerry rebuilt in my garage read all about that in the 261 Rebuild Tech Tip. Sure, its not a 235, but the info in it will help explain just what's going on with all your bearing surfaces.

As long as you are in the Tech Tips section, you will want to read our Tech Tip on Bringing a dead engine back to life -- Or how to correctly start an engine that hasn't run in a long time.

Good luck with your project!

Keep us updated.

John

If you're going to add a full flow filter, you're going to have to remove the engine or have a bunch of metal shavings running around in there after you drill & tap a hole going into the oil galley. However, depending on whether you want to use the stock type fuel pump or an electric pump, you do have at least one other option. If you plan on changing to an electric fuel pump, you don't need to drill any holes or remove the engine. You only need to remove the oil pan. Just make a blank-out plate for the spot where the oil pump used to be and run your oil lines over and out that side. It will look like this when you've finished and will work the same way:

I have studied these oil filter setups on the stovebolt. I am in the middle of a engine R&R right now and the plan is to install the bypass oil filter system for startup and break in. Then after I drop the break in oil, remove the filter all together. Truck will get its oil changed every year and get about a 1000 miles/year on it maximum. No need to fuss with canister bypass filters in my opinion. I think the majority of filth that gets in these engines comes in by way of vented valve covers and valve cover caps, anyway. Ever see the valve cover on a 1954 chev car or truck 235?
If one is serious about keeping the crud out of the engine, they will first address and consider a adequate PCV and or filtered breather system. Just my .02
Steve

Check out this website, some good reading here for sure:

http://chev235guy.blogspot.com/search/label/Oil%20Filter%20Myth

Here is my experience with adding an oil filter to my 54 235 and what I learned. Mostly from this site and feedback from this group.

In 1954 oil filters were a dealer option. When I bought my truck 3 years ago it had never had an oil filter on it. It is the original 235 and is still running strong.

I purchase an original oil filter from someone on Facebook. I cleaned it up, painted it, and added to my engine.

All I did was bolt it to the manifold (as they use to).

I added a T fitting where the oil pressure gauge enters the engine block and connected one side of my oil filter.


I removed the square headed "pipe plug" and connected the other oil filter line.


20 minutes and done. (the 20 minutes does not count the time I spent tracking down the oil filter lines. I originally bought a set of rubber lines from Classic Parts but only one fit. The other one was too short. I went to my local parts store and purchased a copper/nickel brake line the correct length and a few fittings to adapt to the proper connection.

As a side note: I also read somewhere, maybe hear that a mistake some people have made is when bringing a true barn find (a truck that has not run in decades and still has the old non-detergent oil in it) back to life is they fail to drop the oil pan and clean all the sludge out it.
This will end up in the oil with new detergent oil breaking up the sludge (detergent) and re-introducing it into the oil.

Just adding a bypass filter is pretty straight forward, you either use the stock style canister type filter which clamps onto the intake manifold (which is perfectly fine to use and the easiest option), or cobble together a spin on after market filter with the appropriate small size hoses (or use fittings that you can solder closed and drill the appropriate restriction), also a perfectly fine solution.

The reason that is so important to use the proper size lines or restriction is that with a bypass system, the oil filtration system is designed to tap off one of the main oil galleys, then bleeds a little pressure off the main, filters it (using very small inner diameter hoses so no large particles will filter out anyhow), and then dumps the clean oil directly into the pan where the now clean oil is instantly diluted with dirty oil. Lines with too large inner diameter bleed too much pressure from the main and you run the risk, especially with an older more worn motor (read that oil pressure bleeding past the larger bearing clearances generally found in a worn motor), of starving the bearings of the oil and pressure needed for continued service, potentially leading to a bearing failure. Its not a particularly efficient system but it does provide some, albeit, limited, measure of filtration. The thing is, if you are driving your truck every day and putting thousands of miles on each year, it may be helpful. But if you are like me, my motors don't go more then 1000 miles, usually less, before I change the oil. A regular oil rotation back in the day would be like every 3000 (except for the fussy) and a lot of the time longer then that. So regular oil changes in my view are more beneficial then adding a bypass filter.

But you are right, its a hard habit to get away from. I generally ran filters for years with my motors, but on this last 261 build, I decided to forgo a filter and it was strange in the beginning but in the end, no issues whatsoever and I am not easy on my motors.

dgrinnan: I'd love to have an air filter like yours!

I added the oil filter to mine more for the look than a concern out of needing the oil filtered.


The air filter is a little easier to keep clean than the oil bath. It was on the truck when I got it. I just cleaned and painted it.

That's a really good point, Dave!

My 235 was overhauled in 2006 and I have run without a filter ever since. I change the oil every 3000 miles. I did put an aftermarket remote filter but could not get a pressure reading so I took it off and run without ever since.

There are a lot of different thins you can do. I actually mounted my oil filter setup on my inner fender of my 51 2 door sdn. Its not a truck, but you get the idea. I had the extended length oil hoses made at the same place I get hoses made for my tow truck when a failure occurs. I didn't want the oil filter hanging on intake and the truth of the matter was that the split exhaust manifolds I used were going to touch the filter. That couldn't be good I thought, so relocation was my only option at that point. Pics are from a few yrs ago when I 1st put together and aint great but if you can see what I did.. Its a 261 with a 235 head, same concept tho.. Food for thought..

Glenn, that's a clean looking set up under the hood. Original but neat and clean.

Thanks. I appreciate that. Definitely not Original tho. But has the similar look of it.

The only reason I run an oil filter is because it came with the truck and I think that it looks cool. After looking into how little it does in terms of filtering the oil and hearing about catastrophic engine failures caused by a broken rubber line, I am not married to the idea of going out of my way to purchase one for a truck which did not come with one.
An old timer mechanic friend of mine who worked on these vehicles when they were new told me that the first thing that he did when one came in for service was to remove the oil filter because of the risk of flexible line failure. He said, though uncommon, catastrophic is catastrophic.
Furthermore, he said that in all of the years which he worked on these engines, when he dropped the oil pan to remove crank and rod shims (a recommended regularly scheduled service), it did not matter if it had an oil filter or not, there was the same amount of sludge in the pan. He was talking about engines which he was the guy who changed the oil every 3,000 miles.
BTW, I have the utmost confidence in this guy's knowledge and character. They don't make many, if any, mechanics like him anymore.
Carl

Make hard lines for it then if the soft lines are an issue for you. If you want the filter, there are many ways to get what you want with out the risk of catastrophic failure. Or take your friends advise and dont do it. What ever you choose is ultimately the right decision for you. We are only giving you options to think about. And like my outlook on choices I make when at a crossroad, I like to hear other opinions. And that's what you got from people, who also besides your mechanic friend, learned from experience.

They know how to make soft lines to hold pressure these days, especially 30lbs of oil pressure, so the argument of catastrophic failure is not legitimate these days IMHO. One could even rig up an oil pressure switch to shut the ignition off if oil pressure dropped below a set pressure, if one was really worried about soft lines.

So many great replies sharing a wealth of experience - I love this site.

The sludge was a little disconcerting, and I worry a bit about what's moving through the oil, but I also recognize that this is an old engine that sat for a long time (I don't know how long) since it last ran. The tan colored oil immediately screamed "water" to me, but I figured (hoped) it was merely condensation, and the few minutes of running since the oil change seems to confirm that, the oil is now so clean that it's difficult to read on the dipstick. Nonetheless, I'll still change the oil in very short order (I considered adding diesel too, Dusty, but figured a short-order oil change (slowly cleaning it up) would be more appropriate until I have a feel about how much sludge is really in there). I may very well just drop the oil pan, it looks so darn simple (i.e., accessible) on this engine. For now, though, it's so cool to see that old engine run, which I will let it do a few more times to see what happens to this clean oil, then change it at the first sign of a color change.

Y'all are making me feel a little better about not having a filter on the engine, but, still, it feels so friggin' odd.

Thanks,
Chuck

It is an odd idea to not run a filter, especially on an old engine that you wouldn't think would run clean and efficient, however....

I pulled the pan among other items to replace seals and gaskets last spring. The oil wasn't terrible, truck had been run on an off over the years, but there was white/grey sludge at the bottom of the pan trapped between the baffles. Some speculated on here it could be lead from leaded gas back in the day or lead from the bearings, depending on the type of bearings that may be installed. Just an idea where some discoloration could come from. Now, we've only ran about a tank of gas through it on the new oil, and ours does have a filter, but I'm surprised that the oil still looks brand new, I would have expected it to get dark rather quickly.

Good convo. I just recently retired a 49 216 that had approx 123k miles on it. I got it when it had 99k on it, pulled the head and had it rebuilt and put 23K miles on it before retiring it. I knew the original owner and know that the dealer installed bypass oil filter was installed before he took delivery of it when it was brand new.

The bottom end looks exactly like you'd expect an old engine that primarily ran non-detergent oil to look. In the attached pic you can see the difference in condition and oil deposits between the original bottom end and the rebuilt and refinished original head. Non-detergent oil doesn't suspend the debris it deposits it onto the stationary parts of the internals, namely the side walls and the bottom of the oil pan. Thats why crud builds up and you want to drain the oil when it's hot inorder to get as much of the debris out as possible.

Long story short, when you observe the pic you'll see the blocks pushrod gallery sidewall is coated with old oil debris/crud/ byproducts even tho the engine ran a bypass oil filter since new. After I got it running I ran detergent 15w40 oil and thats primarily why the head looks so clean when compared to the block.

So will a bypass oil filter keep a stovebolt engine from developing sludge? In my scenerio it didn't.
Oil gallery pic with pan removed

Good luck
Dave
P.S. I forgot to add that the pic is when I removed the side pan last year with approx 22K miles on it to change out the leaking gasket. So the head coloration in the pic is after approx 22K miles.

To add to the no filter side, I have a 1997 Blazer. From the factory it had a remote oil filter.
I had nothing but problems with the lines running to the filter leaking.
So at about 200,000 miles I removed the filter and hoses and installed a block off plate on the engine. That was 190,000 miles ago. I now have 390,000 miles on the engine with nothing ever been done to it.
I change the oil at 7000 miles, as the owners manual recommends.
This engine still runs strong with very little oil consumption.

Oil filter, oil schmilter, I say.

Yeah, what Carl said!

In my admittedly biased opinion, if a stovebolt engine needed full flow filtration, some GM engineer would have figured out how to do it from the factory. They managed to do just that on the later 261's. All a full flow system does is strain out the chunks big enough to damage bearings and score cylinders- - - - -most of the nasty stuff passes right on through until the bypass filter with much finer pores in the filter media can grab it. A best-case scenario would be to have two filters, one full flow for the big chunks, and an ultra-fine strainer for the small stuff. Some spin-on filters intended for hydraulic fluid have 1-micron media- - - -which catches particles 1/10 the size of a full flow motor oil filter. One of those filters with a 1/16" bypass orfice to control the flow rate, plus a second spin-on plumbed as a full flow on an engine with the oil galleries modified would be ideal- - - -but unnecessary.
Jerry

With wide open valve covers with a crankcase under vacuum from the downdraft tube, and driving on dirt roads before the interstate highway system was created, an oil filter which barely sips a little oil at a time, couldn't possibly keep up with the amount of dirt entering the engine.
Most of the crud ends up in the bottom of the oil pan where it stays put. Back when these trucks were originally in service, this was all cleaned out when the regularly scheduled crank and rod bearing service was performed.

I just got done cleaning a full flow canister, just pulled it the other day. The filter was heavier than any I could remember and there is about an inch of thick crud in the bottom of the canister. It is soaking right now to get the sludge out of the canister. I haven't got to the oil pan yet. The rocker shafts were open and there was not an excessive amount of junk on the head or rockers. My thinking is that these filters may not be to space shuttle standards, but they appear to do some good and collect a lot of sludge.

MikeE,

Are you referring to an original full flow canister on a 261, or, a some king of full-flow conversion on a 235?

If a conversion, how did you accom0lish this?

Thanks,

How many miles since the last oil change? That sounds like a lot of sludge. I will bet there is just as much sludge in the oil pan. The oil pump in these engines is low volume and low pressure compared to more modern engines. This will lead to reduced overall movement of oil in the oil pan, resulting in heavier, dirty oil settling and remaining at the bottom of the pan whether you have an oil filter or not.
Carl

If we can't get on the same page terminology-wise, this discussion is pointless. Bye!
Jerry

Now I'm more curious than ever to pull the oil pan and have a look/see.
Chuck

First mine is a by-pass not a full flow. This is a barn find engine 50 - 53 block and head that I was told ran great when it was taken out. Right. I am in the process of resurrecting it. From what I am seeing so far, this engine may have a previous rebuild on it or has seen some decent care in the past. The head has been fluxed and is a good one, not much ridge in the cylinders and the exterior appears to have been painted by someone other than GM at one time.

MikeE,

If/when you drop the oil pan and remove all the gunk/crud in the pan, thoroughly clean the by-pass oil filter canister and put in a new filter element.

Then, use single grade (30 wt) or multigrade (10-30 to 15-40) detergent/modern engine oil. Detergent oil holds most of the small crud-producing (particles/junk) in suspension - the filter then "catches" that gunk.

It may be that this change in type of oil should not be done with a well-worn engine (or, with a babbetted rod engine)?

If you have moisture in your oil (pan), it is most likely coming from the atmosphere via the "breathing holes" in the valve cover. The road draft tube should draw these "vapors" away before they drop-out as liquid. This process/hope does not work if you drive short distances (no warm-up) at low speeds (the road draft tube does not work below 15 mphs). If/when I go for a short low-speed drive, I try to change the route to be sure I get warm-up and road-draft "suction" (10-15 miles above 40 mph, maybe).

If I am wrong on any of the above advice, we will quickly see corrections.

All that you have said is correct, but this engine is not in a truck right now. The canister is soaking now for a total clean up and paint job. I am tearing this engine down for rebuild, going to replace my other one. When I get that one back out, it too will come apart again. It runs but but not even close to my liking. After that, I am two heads short on two other engines. Other than that, I am not doing much.

For people who prefer the convenience of a spin-on filter instead of the original-type canister with a removable cartridge, do a little research on the Wix, Fram, or other manufacturer's online catalog for a hydraulic oil filter in the 1-micron filtration range instead of a full flow filter designed for a gasoline engine. Plumb in a remote adapter that mounts to the firewall, inner fender, or even to the original location on the intake. I use a Holley carburetor main jet with approximately a 1/16" hole in it for flow control, threaded into one of the adapter fittings for the remote mount. You'll get better filtering than the OEM AC or Fram filter can manage, and also avoid the hassle of cleaning out the housing at every filter change.
Jerry