The Ford Barn

30ratrodder · 01-04-2011, 10:24 PM

Hi. Is it OK to run a flathead without an oil filter?
Thanks

bobscogin · 01-04-2011, 10:36 PM

No more or no less OK than any other engine. I wouldn't, but you may get differing opinions.

Bob

Fibber Mcgee · 01-05-2011, 06:48 AM

I think if you use Fords stock filter you pretty much are running it without one ,being a partial filtration system.I use the stock filter and just change my oil every 1500 miles and oil still looks pretty clean.

Terry,OH · 01-05-2011, 07:36 AM

Fords of 32-35 did not have an oil filter and Ford did not offer one as an accessory until 1936. From 36 until the war the filter was not installed on the car unless the accessory filter was purchased. Many flatheads have never seen a filter and the filters are only a "partial flow" design which means that Not all the oil was passed through the filter every time around. Go ahead and run without the filter.

Steves46 · 01-05-2011, 08:13 AM

My 46 doesn't use a filter and she has done just fine however I do change the oil every 1000-1500 miles. You should be ok. Steve

Brendan · 01-05-2011, 09:04 AM

Sponsored Links (Register now to hide all advertisements)

i don't run one on my 35 21 stud motor

JM 35 Sedan · 01-05-2011, 09:12 AM

If you feel you must run a filter, my suggestion would be the method shown in the attached picture. This is usually best done during a rebuild. Otherwise, I would go filter-less and change oil frequently. Today's oils do a good job of keeping the inside of an engine clean. JMO

This larger picture may help those who can't see the attachment that well.

36tbird · 01-05-2011, 09:26 AM

I think Ford offered the oil filter as a marketing ploy because as others have stated here, it is a bypass/partial oil system that returns the filtered oil to the pan, not into the system to be used right away. I'm wondering now if a PCV is more important than an oil filter because apparently Ford's breather system without one is what allows sludge build up from moisture condensation. Frequent oil changes will prevent that, too, of course.

19Fordy · 01-05-2011, 09:30 AM

Quote:

Originally Posted by JM 35 Sedan

If you feel you must run a filter, my suggestion would be the method shown in the attached picture. This is usually best done during a rebuild. Otherwise, I would go filter-less and change oil frequently. Today's oils do a good job of keeping the inside of an engine clean. JMO

I can't read what the "thing" is that is inserted into the "connecting "oil passage. Please let me know. Thanks, JIM

Ol' Ron · 01-05-2011, 10:06 AM

The oil filter shown in the sketch above is payyerned after the filter system used in WWII and kept by the Canadian engines after the war. I started using this system back in the 60's on the stockcar to save barings from flaking. The oil comes out of the pump where the oil pressure sending unit is and is 1/4" pipe. I redrill this to 3/8. Then about 2" up the rear of the block I drill another hole (3/8NPT) for the return oil. the passage way between them is plug usually with a 7/16 set screw. Every eng that leaves my shop has this mod. This filters 2/3 of the oil going to the main bearings and 3/4 of the oil to the rods. If you use a dual remote filter with cooling fins it will reduce the oil temp. I'm using this system on my grand sons engine with 5-20 synthetic oil. The thinner oil runs cooler. Hope it works.

JM 35 Sedan · 01-05-2011, 10:16 AM

Quote:

Originally Posted by 19Fordy

I can't read what the "thing" is that is inserted into the "connecting "oil passage. Please let me know. Thanks, JIM

I can't read that either but as Ol' Ron said, it is a plug (set screw) that is threaded in place between the two passageways.

Labold · 01-05-2011, 10:22 AM

I've been running my '40 without a filter but am planning to try what Ol'Ron is describing asap.
Even though I change my oil regularly and am probably ok, I still feel weird not running a filter of some sort. ...not that good kind of weird either...

Bruce Lancaster · 01-05-2011, 10:39 AM

And I too suspect that PCV is about as important as a filter...how many gallons of sludge have all of us dipped and scraped out of flatheads?? PCV plus thermostats to keep engine warm enough to cook off the combustion water and mystery chemicals.
Remember, Ford put PCV's on the same military engines that got the filter arrangement shown above. They were used in armored Bren carriers, artillery tractors, and severe use applications like that.
Lots of people worry about the "3/4 filtering" not passing the oil to the rear main.
This is the way oil is routed in all small block Chevys that have the built in full flow filter, all made since '57 or '59 or so. See lots of them sitting by the road with smoked rear mains, don't we??
Interestingly, the SBC oil system is virtually identical to the system shown here except for having the passages cast into the block and having extra galleries to feed those hydraulic lifters and rockers we don't need to worry about here.
If you don't think Knudsen had a few flatheads sitting on the workbench when designing the SBC, have a look at the way the pump/dist drive seals the oil gallery and look at the top of a flathead or Lincoln pump...coincidence?? Yeah.

By the way, the stock filters used '40-53 bypass systems allow finer filtering than is practical in full flow...and expensive heavy duty engines, big $$ large stuff, puts this idea to work by running 2 filters, a full flow plus a bypass one that gives the oil a good screening for the finer crud. Might be interesting to try.

Mart · 01-05-2011, 11:27 AM

It says "Grub Screw".

I have the by-pass filter on mine, and I was surprised at how much oil does flow through it. I could see the return squirting back into the fuel pump stand and the beehive filter was quite hot - that means to me that the hot oil was flowing through at a decent rate to make it heat up like that.. If there was no flow it would be cold, so the hotter the better - and the fins act like an oil cooler when the car is moving along.
It does have the 1/16" restrictor.

My other engine has no filter. Don't do enough miles for it to be a problem.

I might try the setup above on my next build.

One important point to make - I know this has caught someone out because I read it on one of the forums - If you are not running a filter, make sure a previous owner has not modified the block like above - likewise double check if it has any military history, because the passage where the grub screw has been fitted needs to be open to run filterless.

Mart.

Mike51Merc · 01-05-2011, 11:29 AM

Something to beware of regarding the "full flow" modification--- as the filter clogs up the flow will be reduced and eventually becomes a "no flow" oil system.

Bruce Lancaster · 01-05-2011, 12:18 PM

Grub screw is British and Commonwealth speak for set screw in American...
Modern engines have a bypass valve either in the filter itself or as in SBC in its attachment to bypass the filter whenever there is too much pressure differential across the thing.
According to various small block gurus: Modern disposable single filters are often running in the bypass mode because they lack sufficient flow capacity...SBC tests show bypass when cold and at high RPM, not just when dirty. Racers hence run dual filters in parallel or the gigantic truck version, and hotrod builders used to recommend swapping in the pre-1969 (also used later on Police, heavy duty applications) filter with the separate can...this actually flowed more than the nice convenient late one.

bobscogin · 01-05-2011, 12:20 PM

Quote:

Originally Posted by Mike51Merc

Something to beware of regarding the "full flow" modification--- as the filter clogs up the flow will be reduced and eventually becomes a "no flow" oil system.

Quality filters will have a by pass built in that prevents such an occurrence.

Bob

Mike51Merc · 01-05-2011, 04:33 PM

Quote:

Originally Posted by bobscogin

Quality filters will have a by pass built in that prevents such an occurrence.

Bob

Yes. I'm also reminded of a sad story that may have been posted on the HAMB, of a freshly rebuilt flattie with a full flow modification that they guy decided to "test run" without the filter (he capped or blocked off the filter lines). He filled it with oil and proceeded to cook his bearings & such.

Jack E/NJ · 01-05-2011, 05:25 PM

Jack E/NJ

36tbird · 01-05-2011, 05:52 PM

Mike, if you are going to modify a system, you need to know the system, right? Don't mean to be harsh, but c'mon. For all the others talking about bypasses not working or plugging, is anybody on these forums really talking about running an engine so long that we might plug everything up with contaminates? We go from guys not running a filter and changing their oil every 1000 to 1500 miles to guys that run filters but then worry about plugging them up but they probably do not run their oils any longer than those without filters. Am I right! WE ARE ALL MOTHER HENS OVER THESE OLD MOTORS! IT IS WHO WE ARE! RECOGNIZE IT, DEAL WITH IT!

Maybe the worst thing in a flathead to worry about is sludge buildup in the valley oil tube. Other than that, the old gals will run forever.

01-04-2011, 10:24 PM	#1
30ratrodder Junior Member Join Date: May 2010 Posts: 11	Flathead filter Hi. Is it OK to run a flathead without an oil filter? Thanks

01-04-2011, 10:36 PM	#2
bobscogin Senior Member Join Date: May 2010 Posts: 248	Re: Flathead filter No more or no less OK than any other engine. I wouldn't, but you may get differing opinions. Bob

01-05-2011, 06:48 AM	#3
Fibber Mcgee Senior Member Join Date: Oct 2010 Location: Callahan Fla Posts: 1,149	Re: Flathead filter I think if you use Fords stock filter you pretty much are running it without one ,being a partial filtration system.I use the stock filter and just change my oil every 1500 miles and oil still looks pretty clean. __________________ Wanted, a car with a " Dynaflex Superflowing Unijet Turbovasculator which is Syncromeshed to the Multicoil Hydrotensioned Dual vacuum Dynomometer. "

01-05-2011, 07:36 AM	#4
Terry,OH Senior Member Join Date: May 2010 Posts: 4,743	Re: Flathead filter Fords of 32-35 did not have an oil filter and Ford did not offer one as an accessory until 1936. From 36 until the war the filter was not installed on the car unless the accessory filter was purchased. Many flatheads have never seen a filter and the filters are only a "partial flow" design which means that Not all the oil was passed through the filter every time around. Go ahead and run without the filter.

01-05-2011, 08:13 AM	#5
Steves46 Senior Member Join Date: May 2010 Location: Lithia, FL Posts: 1,050	Re: Flathead filter My 46 doesn't use a filter and she has done just fine however I do change the oil every 1000-1500 miles. You should be ok. Steve __________________ If it aint broke, don't fix it!

01-05-2011, 09:04 AM	#6
Brendan Senior Member Join Date: May 2010 Location: At my kitchen table in Santa Rosa, Ca Posts: 2,903	Re: Flathead filter Sponsored Links (Register now to hide all advertisements) i don't run one on my 35 21 stud motor __________________ If it would have been a snake it would have bit ya! i can't spell my way out of a paper bag!

01-05-2011, 09:26 AM	#8
36tbird Senior Member Join Date: May 2010 Location: nw SanAntonio, TX Posts: 939	Re: Flathead filter I think Ford offered the oil filter as a marketing ploy because as others have stated here, it is a bypass/partial oil system that returns the filtered oil to the pan, not into the system to be used right away. I'm wondering now if a PCV is more important than an oil filter because apparently Ford's breather system without one is what allows sludge build up from moisture condensation. Frequent oil changes will prevent that, too, of course.

01-05-2011, 10:06 AM	#10
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,857	Re: Flathead filter The oil filter shown in the sketch above is payyerned after the filter system used in WWII and kept by the Canadian engines after the war. I started using this system back in the 60's on the stockcar to save barings from flaking. The oil comes out of the pump where the oil pressure sending unit is and is 1/4" pipe. I redrill this to 3/8. Then about 2" up the rear of the block I drill another hole (3/8NPT) for the return oil. the passage way between them is plug usually with a 7/16 set screw. Every eng that leaves my shop has this mod. This filters 2/3 of the oil going to the main bearings and 3/4 of the oil to the rods. If you use a dual remote filter with cooling fins it will reduce the oil temp. I'm using this system on my grand sons engine with 5-20 synthetic oil. The thinner oil runs cooler. Hope it works.

01-05-2011, 10:22 AM	#12
Labold Senior Member Join Date: Jun 2010 Location: Bowling Green, Ky Posts: 109	Re: Flathead filter I've been running my '40 without a filter but am planning to try what Ol'Ron is describing asap. Even though I change my oil regularly and am probably ok, I still feel weird not running a filter of some sort. ...not that good kind of weird either...

01-05-2011, 10:39 AM	#13
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: Flathead filter And I too suspect that PCV is about as important as a filter...how many gallons of sludge have all of us dipped and scraped out of flatheads?? PCV plus thermostats to keep engine warm enough to cook off the combustion water and mystery chemicals. Remember, Ford put PCV's on the same military engines that got the filter arrangement shown above. They were used in armored Bren carriers, artillery tractors, and severe use applications like that. Lots of people worry about the "3/4 filtering" not passing the oil to the rear main. This is the way oil is routed in all small block Chevys that have the built in full flow filter, all made since '57 or '59 or so. See lots of them sitting by the road with smoked rear mains, don't we?? Interestingly, the SBC oil system is virtually identical to the system shown here except for having the passages cast into the block and having extra galleries to feed those hydraulic lifters and rockers we don't need to worry about here. If you don't think Knudsen had a few flatheads sitting on the workbench when designing the SBC, have a look at the way the pump/dist drive seals the oil gallery and look at the top of a flathead or Lincoln pump...coincidence?? Yeah. By the way, the stock filters used '40-53 bypass systems allow finer filtering than is practical in full flow...and expensive heavy duty engines, big $$ large stuff, puts this idea to work by running 2 filters, a full flow plus a bypass one that gives the oil a good screening for the finer crud. Might be interesting to try.

01-05-2011, 11:27 AM	#14
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,745	Re: Flathead filter It says "Grub Screw". I have the by-pass filter on mine, and I was surprised at how much oil does flow through it. I could see the return squirting back into the fuel pump stand and the beehive filter was quite hot - that means to me that the hot oil was flowing through at a decent rate to make it heat up like that.. If there was no flow it would be cold, so the hotter the better - and the fins act like an oil cooler when the car is moving along. It does have the 1/16" restrictor. My other engine has no filter. Don't do enough miles for it to be a problem. I might try the setup above on my next build. One important point to make - I know this has caught someone out because I read it on one of the forums - If you are not running a filter, make sure a previous owner has not modified the block like above - likewise double check if it has any military history, because the passage where the grub screw has been fitted needs to be open to run filterless. Mart.

01-05-2011, 11:29 AM	#15
Mike51Merc Senior Member Join Date: May 2010 Location: Northeast Pennsylvania Posts: 1,582	Re: Flathead filter Something to beware of regarding the "full flow" modification--- as the filter clogs up the flow will be reduced and eventually becomes a "no flow" oil system.

01-05-2011, 12:18 PM	#16
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: Flathead filter Grub screw is British and Commonwealth speak for set screw in American... Modern engines have a bypass valve either in the filter itself or as in SBC in its attachment to bypass the filter whenever there is too much pressure differential across the thing. According to various small block gurus: Modern disposable single filters are often running in the bypass mode because they lack sufficient flow capacity...SBC tests show bypass when cold and at high RPM, not just when dirty. Racers hence run dual filters in parallel or the gigantic truck version, and hotrod builders used to recommend swapping in the pre-1969 (also used later on Police, heavy duty applications) filter with the separate can...this actually flowed more than the nice convenient late one.

01-05-2011, 05:52 PM	#20
36tbird Senior Member Join Date: May 2010 Location: nw SanAntonio, TX Posts: 939	Re: Flathead filter Mike, if you are going to modify a system, you need to know the system, right? Don't mean to be harsh, but c'mon. For all the others talking about bypasses not working or plugging, is anybody on these forums really talking about running an engine so long that we might plug everything up with contaminates? We go from guys not running a filter and changing their oil every 1000 to 1500 miles to guys that run filters but then worry about plugging them up but they probably do not run their oils any longer than those without filters. Am I right! WE ARE ALL MOTHER HENS OVER THESE OLD MOTORS! IT IS WHO WE ARE! RECOGNIZE IT, DEAL WITH IT! Maybe the worst thing in a flathead to worry about is sludge buildup in the valley oil tube. Other than that, the old gals will run forever.