Inliners International Forums General Discussion Engines 261 full flow oil

I'm still working to rebuild my 262. I now think I have an understanding as to how the full flow conversion should be done. But, Im wondering - when the full flow is used if the oil filter fails the motor will be toast in a short time. The way the filter is set up now (by pass oil filter) I would still have oil to the motor if the filter fails. So then, the full flow set up cleans all of the oil as it passes through the filter, but if you loose a hose or the filter plugs up- good bye motor. If I change oil at 3000 miles and use the by-pass filter will the motor last and the potential for an engine loss be less or am I making to much out of this?

yes - I meant to say 261

Modern filters don't fail very often and changing the oil and filter every 3000 miles should limit the potential for damage.

Make sure that you get an oil filter with a built-in bypass valve. This way when the oil is cold or the filter is plugged up, the oil can bypass the filter. Generally, this means not using a gm style filter (GM has the bypass valve in the block). A commonly used filter for conversions is the 1515 or the 1773 (2 quart). These are ford/ chrysler using the 3/4-16 thread size.

Also, your lines to the 'new' filter should be top quality braded. You should be able to purchase these lines and the remote spin on adaptor as a kit from Speedway Motors or similar vendor. As mentioned it's a must to have a filter with a by-pass valve to eliminate the chance of the filter pluging.

Also, make sure to drive in the by-pass plug on your 261. This can be stubborn so be carefull to not damage or break your engine block. Some have had to drill out this pin and replace vs bashing with the biggest hammar. May even need to have your machine shop tackle this job.

Thank you all for the info. This is a father son project. My dad is the brains and I.. well I talk alot about what I have learned here. I'm just leaving to go over to his house to take some parts I've cleaned up. I'll print this and take it with me. We have never found the by-pass plug. I don't think this year block had one. The block has been cleaned so it should be easy to see if it were there. Thanks again will keep all posted. Hope to have a new digital camera for X-mass to post some photos.

The pin that gets pushed in for full flow is located next to the forward oil line on the 59-62 blocks. If you have an earlier block with the smaller oil lines, then there is no option to go full flow unless you modify the block.

One thing that you can do (which the factory also did) is to put in either an oil pressure gauge or warning light in a tee right where the return line from the filter goes back into the block. This will let you monitor what the pressure is on the downstream side of the oil filter and tell you if it has failed or not.

What year 261 block do you have? Is it from the US or from Canada?

I use the factory cartridge filter on mine. It has a bypass built into it along with a huge paper cartridge filter that lasts a long time. It is a little messy to change but I like that I can check out what it has picked up without having to cut up a spin-on filter.

We have decided to build the motor without full flow. I will use a spin on filter though. And I think your suggestion 4onthefloor is a good one. The block is a '55-'57 based upon the casting number (3837012). How do you tell if it is from U.S. or Canada? I found one source that said it could also be a '58, but since no other sites had that info I think it must be wrong. Also, if I'm correct the '58 is when full flow motors were available and that leaves me out. I'm just going to change the oil more often and place a couple of magnets in the pan. It will hopefully last a long time. I'm planning for this to be my daily driver.