Buick Spin-On Oil Filter Conversions
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Up until 1958, all Buick engines were equipped with the old-style canister oil filters. They are messy, hard to change, and even harder to find when you do need to change them. This page tells you how to convert your 1953-1958 Buick Nailhead V8 from a canister style oil filter to a modern spin-on style oil filter. I had originally thought that the information here was somewhat applicable to the older "Straight Eight" engines as well, but I can't seem to find anyone who makes adaptors for them. In theory, you could have one made, but I've never seen a straight-8 oil filter mount, so I can't say for sure. If you know of a place that makes these, let me know. Anyways, the general details about the aftermarket conversion kits will also be applicable to doing this conversion on any make or model of car, so long as it originally used a similar style of canister filter. Also, for reference, my project car for this article was my 1958 Buick Special with a 364 cid Nailhead engine in it, so that's what the pictures are from. I have to scan in some great pictures in the factory 1958 and 1959 Buick manuals when I get a chance; they show the on-car mounting in great detail.

As with any of my web pages, this information is strictly for informational purposes only. If you decide to use this information to work on your car, you do so at your own risk. If you get oil stains on your driveway, mess up your engine, or have any of the other many possible bad results of doing any work on your car happen to you or your car - it's not my fault. Use common sense, think about what you are doing, and stay safe so you can enjoy your car for years to come.


The Factory Knows Best

If you have a 1953-1958 Nailhead engine, you can take the factory way and do the conversion with all Buick parts. The oil filter on these engines is not directly mounted to the engine block (like a Chevy V8), but is instead mounted to a small adaptor that is in turn bolted to the engine block. The engine block for a 1959 or 1960 Nailhead is close enough to the earlier engines that the factory oil filter adaptor from those two years can be used to mount a spin on filter to the earlier engines. Your original adaptor will be a 4-bolt unit and the 1959/60 adaptor will be a 3-bolt unit, but this is fine. The lower rear bolt hole is not used if you take this route, and it appears to work just fine. Note that I can only confirm this works on a 1958 364 engine, but I have been told that the same swap will work on the earlier Nailhead engines as well. (If you have firsthand experience and/or pictures that confirm/deny this, please let me know so I can update this page.) After the conversion, the new spin-on filter will be positioned at approximately a 45 degree angle pointing down and towards the front of the car.

The new unit uses shorter bolts than the original, so you may need to procure some. They're standard pieces. The gasket is readily available from various restorers - in my case the yard I bought the new adaptor from (Buick World, IIRC) tossed in the gasket with the adaptor for no extra charge. CARS sells them for about $3. The mounting position can be hard to understand at first, so once I figured mine out, I took some side-by-side pictures to show you how it will mount.

Once you have the adaptor, gasket, bolts, and new filter in-hand, the swap itself is only moderately harder than a full oil and filter change. Remove the old filter, then wipe off as much grim as possible from the adaptor. Unbolt the adaptor and remove it from the engine. Clean the mounting surfaces completely, install the new adaptor, and tighten down the bolts. I couldn't find a torque spec in the 1959 manual I have, so I opted for something in the range of 30-40 ft-lbs. The bolts could take more, but I was concerned about the aluminum adaptor warping, so I snugged the bolts and called it good. Installing the new filter is just like any other filter change. Fill up the filter part-way with oil so the oil pressure comes up faster when you start the car again, wipe some oil on the filter gasket, then spin the filter on and hand-snug it.

Note that the adaptor has the bypass valve in it - at least according to the 1959 Buick manual I have. (I did not take the adaptor I got apart to find out for sure, and I did not see where the valve was located either.) If you decide to do any cleaning and detailing on it, take it apart if possible, clean it, then reassemble it to make sure you do not leave any grit/grime/junk/solvents inside the adaptor when you put it on your engine - if you don't clean it completely, it could have a very bad effect on the longevity of your engine. :-(

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The Aftermarket Answer

If you don't want to change out your oil filter adaptor, or if you have an pre-1957 Nailhead engine that the 1959/60 adaptor will not work for, then you need to go the aftermarket route. At least one company custom makes oil filter adaptors for early engines - the one I got from Oil Filter Adaptor Enterprises for my early Nailhead is pictured here. It has a center bolt that threads into the original canister adaptor with a small "shield" to ensure the oil goes where it's supposed to, and a large aluminum base that threads over the center bolt and provides a base for the new spin-on oil filter to mount to. The center bolt has two different threads on it - the "top" portion has the right threads to go into the adaptor and the "lower" portion has the right threads for whatever oil filter they say you need to use with that adaptor kit - in this case, it used the same filter as a Buick V8, see notes above about what filter you can/should use. After the conversion, the spin-on oil filter will be positioned in the exact same way that the canister filter was - in my case vertically.

Note that the pieces will only fit together and work one way - your kit should come with instructions, but in my case, I lost them while the car was in hibernation waiting for me to get back to working on it and I had to figure out how it was supposed to work on my own. In my case the three key things I found out via trial and error assembly were not earth shattering, but they are important.

First, the inner shield is not a simple washer - it is slightly cone shaped. The bottom/center of the cone goes "on top of" a small shoulder on the new center bolt and the top/outer edge goes against a small circular lip the surrounds the threads on the original canister adaptor. This piece keeps the incoming and outgoing oil separated and makes sure oil actually goes through the filter.

Second, the large aluminum base has a top and a bottom. The "top" in my case has a small groove machined around the center hole that allows the shoulder on the center bolt to be recessed a little bit. This in turn allows the new base piece to be tightened down far enough to seal with the outer lip area of the original canister adaptor.

Third, the seal between the outer edge of the new base and the outer lip area of the original canister adaptor is critical to get right - if you do not do this, it will leak oil at a frightening rate because this seal is all that keeps high pressure oil inside the engine and not on your driveway. (You can guess why I know this... :-) The original seal for the oil filter canister was fitted into a recess just inside the outer edge of the adaptor and was designed to seal the canister. The new base will probably not seal properly to this old seal, and you should discard it in favor of the new seal that came with your adaptor unless it tells you otherwise. The new base will screw down over the new center screw and the outer edge of it will end up slightly recessed in the canister adaptor. This seal must be tight!

Remember that the aftermarket oil filter adaptor will mount to the existing oil filter adaptor and essentially become part of it - once installed you will not remove it while doing routine oil changes. It is a part of the engine. As such, it should be installed very firmly and you should ensure it does not come loose - I would recommend some Loctite on the upper part of the new center bolt that threads into the original canister adaptor. Also, in my case, I found out that doing this work with the original canister adaptor mounted on the car was basically impossible - especially getting the base seal installed and tightened. Removing it from the car, cleaning it, and doing the assembly on the workbench is much, much easier and much more likely to result in it working right without leaking. You'll be able to work with clean part, with plenty of working room, and most importantly, you will not be working upside down while laying underneath the car.

NOTE: I have received email telling me that I managed to completely mess up this install and it really does install quite easily in the car. I'd love to post the revised instructions here if I had them, but I don't. However, the person emailing me said they have done this conversion on two separate cars and that it worked great and went in easily. Based on looking at the parts, it seems like it ought to be really simple and work great, so I would chalk up my experiences to 1) bad luck and 2) losing the all-important instruction sheet. If someone has the instruction sheet and they could scan it in and send it to me, I'd love to post it here for reference. I'd also like to read it to figure out what I did not get correct what I tried this install.

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Canister Oil Filter Adaptor

The original canister oil filter adaptor is a pretty big piece, at least on my car it was. It mounted with four bolts and used a steel shim gasket between it and the block. The canister filter itself is a pretty hefty piece, and it has to clear the block, so the adaptor has to be thick enough to space the "centerline" of the canister filter mounting point out away from the block far enough to make stuff clear. Even with that added width compared to the factory spin-on adaptor, the canister actually sits right next to the block where it goes into the adaptor and the adaptor edge virtually touches the block in that area. It's a a real popular area to get filled with crud too - lots of oil in the area (you always get some seepage at any gasket) and stuff is very close together. When I first went to disassemble stuff on my car, I thought the canister adaptor was part of the block - and then I scraped about an inch thick of sludge off of a few areas and realized it was actually a separate piece... Yuck.

Note that the adaptor contains the factory by-pass valve - in consists of what looks like an oversize ball-bearing, a spring, a gasket, and what looks like an oil drain plug with a hollowed out center area for the spring to ride in. If you intend on cleaning the adaptor (to paint or detail it, for example), you should remove these items so that the adaptor can be completely flushed out before putting it back on the car. Leaving any grit/grim/junk/solvents inside the adaptor when you put it back on the engine is a really bad idea...

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A Word About Oil Filters

Pretty much every Buick V8 engine from the 1959 364/401 Nailheads, through the 400/430/455 engines, and to the last Buick 350 engines in 1981 uses the same oil filter mounting. Right now, they all cross-reference to a Fram PH-25 if you look it up in the parts store books. This is pretty bogus, though - this is a somewhat miniature filter compared with the original AC Delco PF-5 filter my 1959 Buick manual calls for, and I know it's smaller the filters I have used on my 1973 Buick in the past. A bigger oil filter is generally a better thing - it allows for more surface area to filter more oil (it can trap more crud before clogging) and it adds more oil to the system which is better for engine temperature (the oil is the only thing that cools the bottom end of the motor). The original part number for the 1959 Buick was AC Delco PF-5, which now cross-references to a Fram PH-11, which is the normal size you would expect to find here - see pictures below. The mounting thread is the same, and the gasket is in approximately the same place, but the outer shell is about 1/8" larger in diameter - you can see this in the photo of the gasket ends if you look closely. So, the morale here is not to trust the parts store book all the time. The original filter specified for the older cars was the larger one, and that's what I'm using.

Note that some cars had more clearance around the filter, some had less. Check the clearance around your filter to be sure if you try this swap. In some cases, the smaller oil filter may be a good thing.

Note that you can even step up to some gargantuan 2-quart filters with the same base as the Fram PH-11. I failed to write down the part number when I was at the parts store, but some later parts-number searching on Google says that a Fram PH-373 might be the right number. Be aware that they might have more clearance problems, as well as the fact that they would be twice as heavy when full and as a result could put too much strain on the filter adaptor. Feel free to experiment if you want to go this route, but don't say I didn't warn you. :-)

Lastly, lots of folks hate Fram filters - for what seems to be good reasons. This page is not about that debate and I don't want to get into that debate here. (Google for something like "oil filter comparison" if you want to read up on this area - it's actually rather interesting.) The pictures used the filters I was easily able to obtain at my local parts store at the time I wrote this page. They were pushing Fram at that time, and so all the part numbers and pictures are Fram. The key point is to make sure you get the size filter you decide it right for your situation. The Fram numbers will cross-reference to pretty much any brand you care to use.

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Page last updated 12/27/2011 10:23:21 AM