Inliners International Forums General Discussion Engines 261

I've started work on the53COE.........I am swaping the 235 for a 261 I've read the article on oiling....will the drill mod. require a high presssure oil filter or can I use stock canister?? what is the procedure for drilling steam holes in my 848 head?/what can i expect for preformance when all is done?? thanks for any help or advice on the 261 rebuild

I just finished building a 261 and elected to not run a filter and just change the oil every couple of thousahd miles. Drilling the head is pretty simple. I just tacked the head gasket to the head with a little silicone, marked the holes between the combustion chambers and drille into the water jacket. Performance wise you'll get a small horespower increase (approximately 10% per the manual). The torque increase is only about 4% per the manual; however, the torque curve is flatter and of longer duration. I did the Offy intake, 2 Carter/Webbers, mild cam and Fenton headers with dual exhaust. Difference over the stock 235 is daylight and dark.

That's about it unless you want to get into a lot of 'trick' machine work and parts.

John M...

http://www.speedprint.com/Deves50/oilfilterinstall.php
Here is an address to a place that deals with Oil Filters on 261. I did not have to drill a thing on my 261 for the Oil Filter. I add one to the side down on the block screw on type works finner than a frog's hire.

There are 3 types of 261s. none are like the photo in the article except the 1954 which is best run W/O a filter.

The later 261 60-62 have two large holes which can be 'plumbed' like the pictures unless your using that for a motor mount.

The 55-60 models can be run with or W/O. There is an article here about that.

No matter which one you have the 'by-pass' canister won't work as the fitings are to small for 'full flow' operations.

Good luck, John M.....

John M,

I thought all 261s had full flow oil fitering.

Why is it better to run a 54 261 without filter? Babbet rods? But why?

Just curious.

Luis

That model is basicaly the same as 235 with small oil gallery.

Even a "235 conversion" like the one in the picture must use the small oil lines. It will work but you restrict the oil flow right out of the pump.

Its a 'whole lot of work' & puts oil lines right next to the exhaust system creating fuel for a massave fire/explosion.

The later 261s had filters on the firewall. That's dificult to do in a 'street rod'. It can be done using a spin on adapter like the one shown IF your NOT using that part of the block for a mount etc.

It's really just better and a lot safer to use commercial oil & change regular.

The 'later' Chevy 6 has the filter on the right side (away from exhaust)and a 2 Qt. unit fits most.

John M., #3370....

PS: Oil filters were a option even on the 261s until around 1960 on the big trucks and busses.

Just yesterday I drilled and tapped the holes in my 1954 261 block for installing a full-flow oil filter. I followed the steps in the Inliners Tech Tips and in the Stovebolt Page, and all went well. Then, this morning I stumbled into this thread where John M. advises against using the filter on the 54 261. I do not quite see the problem. The ID of the two 3/8" NPT nipples is about 0.438", which is enough larger than the 0.366" ID passage between the oil pump and the main oil gallery. I plan on using 1/2" braided hose for the filter connection. My Crane handbook indicates that there should be little, if any, additional pressure drop, other than that due to the filter and its adapter, which is there for all 261 installations. I am using a GMC oil pump, so I should have plenty of oil pressure and flow. Am I missing something?

At least I think that I have a 1954 block. That is what I was told it was when I bought it in 1958. However, there seems to be some confusion on the casting numbers. It is a 3733950 casting. Some of the casting number links indicate a 1954-1955 block, but there is one link in the Inliners page that says 1955-1957 for the 3733950. Any insight?

By the way, the tapping for the 3/8" NPT threads went a lot better when I used a tapered reamer on the 27/64" drilled holes before tapping. The Stovebolt page said to use a 9/16" tap drill, and I could not get my tap started.

This engine has sat since 1962, but it has been great to get back int the six cylinder business. These Inliners posts and threads have been been a a great help.

Hoyt, II # 922

Hoyt,
Don't fret, you're doing fine.

Whether or not to run a filter has to do with the bypass filtration setups with the 1/4" lines that just dump what little goes through the filter back into the oil pan, not full flow filtration. Not taking advantage of full flow filtration when it's available doesn't make alot of sense to me...

The 261's with the factory full flow filtration setups are from 59-62 (and some '63 4X4's) and use 1/2" NPT fittings. They were always mounted to the intake manifold, just like the earlier bypass versions.

I see no real need in worrying about a fire, the factory did it without any problems, and all you're doing is basically replicating what the factory did, so don't sweat it. Just use some common sense and make sure all your connections are done right. Running hard line from the motor to a filter mounted somewhere other than on the motor would be an example of what not to do, as it wouldn't take into account chassis flexing.

Another thing to keep in mind is that even on full flow systems, there needs to be a way for the oil to bypass the filter when the oil pressure/volume becomes greater that what the filter can handle. Most engines have a bypass/relief valve somewhere in the block, but some have it in the filter itself. The factory had one in the filter head for the 59-62 261's. If you decide to run a spin-on type filter, and you do not have a way for the oil to bypass the filter, then you need to use a Ford filter which has the bypass built in. I don't know the filter number, but I know someone posted it on this site a couple months back. If any of this is unclear, let me know and I'll try to explain it better.

Talking about filters.

Last week I took of the oil pan of my 235.

When I assembled it about 2 years ago I thought it would be a good idea to put 15 extreme strong mini neodym magnets all over the inside of the pan.

You won`t belive how much they catched.

They look like 15 little hedgehogs sitting in the pan.

Though the bearings and the rings show no wear at all (after 2 years)I was surprised how much metal dust my little friends collected.

I have to say that this engine was drilled for fullflow with a modern filter (spin on conversion) and had regular filter and oil changes.

The Toilet Paper bypass filter on the other 235 seemed to filter much better, since I have the same magnets in the oilpan and what they collected is minimal but still enough to put them in every engine I have.

Frank

and, NO I don`t sale TP filters

I am a member of the TDR, and have posted a lot on that board, and guys over there suggest placing a strong magnet on the outside of the oil filter. I have never done it, but now that I've read your post I'm going to do it on both my engines!

I was putting them inside the pan.
I belive that works even better.

I got those mini Magnets neodym (0.2 inch diameter)from Ebay. I think it was 50 for 15 bucks.

Frank

Dear Mr Hoyt;

Don't believe it! There's a big difference.

The early engines (pre 54) had 'low oil pressure' systems, running 15# normal pressure. Later (54-62) they ran double that and more in some conditions.

The filter options on trucks with the 261 had the filters mounted on the firewall using 1/2" lines. This is how the factory did it. Passenger cars had the same as pre 54 until 1963 when the filters were mounted on the right side away from the hot exhaust.

I am told that 4X4 vehicles with the 261 engine were mounted on the manifold from the factory but this was an "option" or 'special order' etc.

Back in 'those days' commercial oils had not been developed yet and 'full flow' filters were new too, with Ford V-8 engines having some of the first in 1953.

Today; It's a totally different ball game.

Commercial oils keep their detergent active for about 4000 miles. Changing oil then negates the need for a filter in non-commercial usage.

The "don't sweat it" attitude toward fire safty is foolish advice.

High power magnets on the bottom of the pan work well except with 4X4s.

Good luck.

every full flow 261 i have ever seen the filter was mounted on the intake manifold. that includes the 62 3/4 ton i had right out of high school to the 261 that was given me last out of a c60 dump truck. even the 270 gmc i have out of a 59 panel is mounted on the manifold.

The early engines (pre 54) had 'low oil pressure' systems, running 15# normal pressure. Later (54-62) they ran double that and more in some conditions.

What does that have to do with the issue at hand? A '54 engine is full pressure, and he has converted it over to full flow as well.


The filter options on trucks with the 261 had the filters mounted on the firewall using 1/2" lines. This is how the factory did it. Passenger cars had the same as pre 54 until 1963 when the filters were mounted on the right side away from the hot exhaust.

I don't know what filter you're refering to, but I have never seen a "factory" type filter mounted on the firewall, that goes for bypass and full flow. I have always seen them mounted on the intake. Even my official Chevy parts and accessories manual shows them on the intake.


I am told that 4X4 vehicles with the 261 engine were mounted on the manifold from the factory but this was an "option" or 'special order' etc.

Starting in '59, all 261's had the engine block that would take the 1/2" lines and could be setup to be either full flow or bypass depending on whether you left the pin out flush with the block or pushed it in. Whether or the filter was "optional" has nothing to do with the issue.


Back in 'those days' commercial oils had not been developed yet and 'full flow' filters were new too, with Ford V-8 engines having some of the first in 1953.

Today; It's a totally different ball game.

Commercial oils keep their detergent active for about 4000 miles. Changing oil then negates the need for a filter in non-commercial usage.

My understanding of what detergents do is to help keep all the crap suspended in the oil so that the FILTER can remove them. Which would mean that the longer you run unfiltered oil, the more crap is floating around in it that can get embeded into the bearings, etc...


The "don't sweat it" attitude toward fire safty is foolish advice.

Obviously you don't get it, I was refering to the fact that you CAN run a filter without causing a fire. You take one incident of somebody not doing it right and paint everything with the same broad brush.
I run a '60 261 with fentons and a trans-dapt remote filter setup and the lines miss the exhaust by a couple inches. Been that way for years without an issue.


High power magnets on the bottom of the pan work well except with 4X4s.

Why not, it's not like there rolling around loose in the pan. You can always go with the filter mounted magnets, assuming you ran a filter...

Gentlemen;

The ones I've seen (large trucks) in California had the filter on the firewall except for the low pres/by pass(cars/light trucks) which were on the manifold. Perhaps the trucks were built differently on the east coast. Here big trucks had 2 1/2" steel lines that ran to the frame where rubber ones turned up connecting to another set of steel lines that connected to the filter canister.

The "issue at hand" is running flamable liquids near a 900+ degree heat source. There is NO engineering school or theory in the world that subscribes to this nonsense. It is not done on aircraft, watercraft, motorcycles or other land based vehicles as a result.

Here however, you see (aftermarket)fuel filters mounted right above the exhaust with rubber hose/clamps and this type of (home brew)oil filter commonly advised etc.

The factory 'by-pass' ones got away with it because of the low pressure. The factory solid 1/2" steel lines were used here in Calif. to solve the problem from 59-62 as mentioned but it still remained as the rubber ones often leaked from engine/vehicle motion.

'Hot Rod' engines with more compression run faster with higher oil pressure and create much more heat in the process. Most of these have filters away from the exhaust system.

The 261 does not. This is why I build them W/O any chance of an oil fire for my customers/removing the oil filter option.

An 'oil fire' is one of the most devastating events on earth and I sincerly hope that none of you (Inliners Inc.) personaly find out how.

Many thanks for the interest in the filter installation for my 261. As a propulsion engineer in the aircraft industry, I am well aware of the fire hazard associated with fuel and oil lines near an ignition source. I have toyed with the idea of building a manifold that would connect the oil filter adapter to the 3/8” pipe fittings in the block, which would eliminate the need for hoses or tube fittings and connections. However, since the exhaust manifolds and pipes are on the other side of the engine, I think that I will just use good quality, ½” (or3/4”?) OD stainless steel tube with AN fittings on an engine-mounted filter. Are there filter adapters with a built-in bypass valve? I would hate to have to use a Fxxx filter!

I am open to any suggestions from members with more experience. I ran three different 261powered Chevrolets (a 51 and 53) from 1958 through 1966, all without filters. I put over 50,000 miles on one of the engines and the rod bearings were going bad when I sold to a friend for a song. After he tore it down, it was not obvious that the lack of a filter caused the rod bearings to go bad, but it looked as if a filter would have been a good idea.

By the way, does anyone know what was the application for the 3733950 block? My 29-57 master parts catalog does not show it for any of the 54-57 261 blocks.

Hoyt, II # 922

Dear Mr Hoyt;

As it was one of the first, it probably was in a 1 Ton (C-30) or larger. I'm not sure if they were available in busses then or not.

An 'asbestos blanket' from a Welding Supply House wraped around the front head pipe(s) will stop the heat.

It's that with 'Hot Rod' type engines it looks so out of place etc. These too, are maintained much more carefuly than 'normal', so the filter concept is just academic.

I never run a filter on any 'early' Chev 6 because of this. On the 'other side of the coin' I use a 2 Qt. one on later & V-8s which doubles the change interval with commercial oil.

Fram PH-1 has the by-pass valve.

Good luck.

Here's the correct 59-62 261 filter. Notice the u-bolts for clamping it to the intake manifold and the lines that straddle the exhaust.

As for lines, try going down to the local hardware store and buy some 1/2" pipe nipples and some elbows to use to clear the exhaust area, should you be too close to the exhaust. It's not that difficult. You could even get aluminum or stainless steel ones from a place like McMaster-Carr, should you want to polish them for show. Then either continue to run hard line or proper hose material to the filter, depending on where you locate it.

Both Jegs and Summit offer complete kits or just the adapters. Some come with threads for both GM or Ford filters. Summit #SUM-G4985 is one possibility. Just look through the catalogs. I see they also have filter mounted magnets available.

When I spend several thousand dollars rebuilding an engine, and you have an oportunity to run an effective filter arrangement (full flow) which makes a difference in the longevity of an engine regardless of the type of oil or change interval, it would be pretty stupid of me not to use it. The results that Frank got with the magnets should be enough to convince anybody of the need to run a filter. If you won't remove the filter from a newer car, why would you do it on anything else? I can't believe I have to sit here and make a case FOR running a filter. It's rediculous. At least everybody got a chuckle out of it. Your implications that I don't know anything about flamability, etc... are what's nonsense. I deal with these things on a regular basis.

Dear Bryan;

It's because; it only takes a pinhole leak @ 60# pressure to cause a disaster and the 'newer' engine design(s) eliminate that possibility.

Your photo is that of a 40+ year old obsolete design/device.

Remote filters like this are only seen on industrial engines (generators/forklifts) and never near a heat source.

If I were to sell something like that here, today & it caught fire, I would be suied into bankruptcy.

They do filter well, but here on the 'left coast' It's a different world and there liability far outweighs any possible benefit.

Happy trails.

gearhead you and i are saying the samething. you just take longer and say it better. now i have been working on these motors since i was in high school and have never seen a fire or seen a car that had a fire in a junkyard.
now if the oil filter is so much a danger. maybe we better take the carb and fuel line off and plug them because they set right over top of the exhaust and that is a fire waiting to happen.

Yeah yeah yeah... your all right!

I have the hoses of the filter extermly close to my exhaust and never had a problem with them.

Though I will replace the hoses by solid steel lines when I do the new 261 - just for peace of mind.

Probably the hoses would work for an other 10 years close to the exhaust pipes but with the steel lines I just have a good feeling.

So both of you are right. Hoses may work and never give any trouble, steel lines are even better.

my 2 ct.

Frank

John M, gearhead, bob308, Frank, et al.,

Thanks much for the interst in my filter installation in my 261, and for all of the suggestions. I will send in some pics when I get it together.

Hoyt, II # 922