The Stovebolt Site Forums The Shop Area Engine Shop Do I need an oil filter on my 235?

As I assess how to approach rebuilding my red 54 GMC 1/2 ton, and I am inclined to keep the 235 inline 6, as I don't see myself logging huge miles on it, so gas mileage is not really an issue, even if it hits $3 gallon by year's end. One of the first things I noticed when I got my truck home to Seattle from Oregon was that it has not oil filter. Heck, even a 54 Plymouth, Savoy I had in high school had one of the external types. So do I need one? If so, what is the best way to go about it? I'm looking to connect with some of you guys and get serious about bringing my truck back to its glory days. It has a rock solid body, very little rust, but I have found a little bondo in places. I'd love to hear back from a few of you. I really need to get a conversation going to figure out how to approach redoing the engine and running gear. Thanks. By the way, I chose GMC baseball, because my truck is my current passion, and I am a high school baseball coach (24 years now). I view both as rewarding ventures. Thanks, and hope to hear from some of you soon.

Your GMC should have a 248 GMC engine and it came with a filter. Sadly, too many of them have been replaced by 235s over the years.
Your engine will of course run without it but it will probably run longer with one.
You need to determine if your 235 is a full oiler or not to determine how to rig a filter. There is a tech tip on this site that tells how to convert to full pressure oiling. Also use the "search" feature in the forums to learn how to install one.

There was once a TV commercial that had a mechanic holding an oil filter. He said "Pay me now or pay me later".

Kels

Thanks Guys,

I assumed it has a 235, but it could be the 248, guess I'll find out soon.

My 235 has a big canister-style filter on the drivers side of the engine. Not sure if it was factory stock or not... but I know it's a full-pressure engine. Maybe you have a splasher, which wouldn't have an oil filter?

I run a full-pressure 235 without a filter. I am just sure to change the oil regularly. There have been some discussions on this board in the past about the external filters only filtering 10% of the oil, so I haven't bothered with it.

I have a one owner 1959 Chevy truck that we bought new with a 235 that came new without an oil filter and has never had one installed. Just change your oil at regular intervals.

Thanks to all of you,

I am a rookie, had my truck 3 years, usually just to go to the dump, or my son uses it when the other two cars are being used. Everyone has been really kind, I'm realizing that many of the answers to my questions can be found by searching, but it sure is great to talk to people who have been there.

I have a oil filter cannister off a 54 GMC 1/2 ton with a 248 CID engine if your interested. It is the cannister for a drop in filter.

I want some clarification on this issue only so that someone doesn't get the wrong idea and burn up a perfectly good engine. Didn't the later model (57 up?) 235/261 go to a full filter oil system which was not a bypass system? I know with a bypass engine you can just remove the filter, plug the lines and be fine. However, I remember reading that if you tried this with a full filter system you would cut off the flow of oil and say goodbye to your engine. (However you could route the oil line back to the block.) Or is this only the later model 261 that I am thinking of? I just want put out a caution for some folks that may not know there is a difference.
Steve O

You are correct about the 261. The later models do have full pressure oil filtering, and you must at least run a bypass hose if you remove the filter. The 235 remained a by-pass system until the last year it was made(62). Although it is referred to as a "full pressure engine", the later 235 did not have a full pressure oil filtration set-up like the 261.

Nifty,

Your second query is correct. The full-flow oil system is on the 1958-1962 Chevrolet USA truck 261 engine (easily identified by the 1/2 NPT oil filter lines - they are much wider diameter than the 3/8" lines used on the by-pass oil filter systems).

Tim

My 38 1.5 ton has an oil filter and it is still a splasher so that would make no difference as one of the previous post had suggested. as to whether it's a full pressure engine just look at the oil pressure gauge. if it only reads to 30lbs set up is likely not full pressure if it reads to 60lb you proably have full pressure motor. oil filters were an option at that time. cheap insuance it would seem.

I have had several Chevys-both truck and cars- some with oil filters and some without. The vehicles had either 216 c.i. or 235 engines. In the past oil filters were an extra cost option but in later years most 235 cars and trucks had the filters installed at the factory. On the cars or trucks without filters I always changed the oil every 1000 miles-of course that was before all this modern oil was invented. Even with filters I change both oil and filters after 3000 miles and have never had a problem-getting well over 100K miles out of all my engines. I would drive my truck and just change the oil every 1000 miles- using a best grade 30 wt. oil!

First go to the tech tips section for the details on converting your 235 to full filtered oiling, you should already have full press. in 1954.
Other issue is that the GMC heads seam to be prone to cracking. All the old time mechanics around used to give me the same story, go get a 235 for that GMC.