The Stovebolt Site Forums The Shop Area Engine Shop By-Pass Oil Filter on 261 Full Flow

Hello All,

I am getting closer to installing a 261 into my 51 6400 and I have a question bout the oil system.

I know that I have a 61 261 Chevy that is of course a full flow oil pressure engine. I was wondering if I could use my original by-pass oil filter canister from my 235?

At first I thought that it couldn't work, but a freind tells me that I should be able to use it. I was planning on using a universal oil filter relocation kit and plumming the system with stainless tubing, so that I can use a fram ph8a spin on filter.

But if I don't need to spend money on this and can leave everything looking original, that would be nice.

Thanks in advance,
Elias

You can use the old bypass filter ONLY if you convert the engine oiling system to a bypass setup by moving the small plunger/plug in the left side of the block near the oil galley. (search on the subject for the details, Cosmo will have some thoughts also).

If you already have it setup for full flow then you must have a filter with large enough lines and that flows enough to allow the "full flow" of oil to pass and then go to the engine. To use the old bypass filter on the full flow setup would starve the engine for oil very quickly.

Grigg

Grigg is right. For comparison look at the diameter of the out/in ports on your '61 and the diameter of the older style bypass ports. The '61's are much larger, so it's easy to reason the oil flow starvation Grigg talks about.

Thanks Guys,

I will stick with the full flow set-up. I would rather have fully filtered oil flowing into the engine, than partially filtered. Besides, converting the block back to a bypass system would be somewhat of a step back as far as functionality as well as extra time.

I'll just live with a remote spin on filter that doesn't look original. I mean the engine is not original anyways, so it is really hard to be that finicky originality.

Thanks for quick replies, Much Appreciated,
Elias

There's another reason that you shouldn't use a bypass filter- the stock oil filter designed for the full flow 261 has a bypass relief valve in case the oil filter plugs up or can't flow enough when the oil is cold. This is not present in a bypass filter. Your engine will starve for oil when cold. There is no filter bypass built into the block. Modern engines with spin on filters either have a bypass built into the block or into the filter.


The nice thing about the full flow 261 is that the remote spin on kits for V8's work with no modification- just plumb the 1/2" NPT hoses right into the block. However, you need the ford version that has the bypass built into the filter.

You could use the bypass filter in addition to your full flow filter if you wish. I personally don't think it would be worth the effort but it is interesting to note many heavy duty trucks have a bypass filter as well as a full flow filter.

You would need to find a source of pressurized oil somewhere on the engine and return it to the pan somehow. Again, I believe the work involved would be more than the benefit you will get from it.

Different engine, but here is a picture of just that:
http://rides.webshots.com/photo/2582718360080251109SqwKSM
The large white filter on the left is full flow, and has 1" lines to and from it. The black filter on the far right is a bypass filter, it gets pressure from the outlet of the full flow filter, and returns very clean oil to the engine via an extra dipstick hole.

Grigg

Just bought a summit remote oil filter kit with the built in bypass. Should be in by Monday. I'm hoping to get the engine running by next week.

Thanks for all your input,
Elias

This particular discussion is also on Inliners site mostly relating to filter quality. I read on the FRAM site they are recalling HP4,HP8 filters and it is suggested by some to use another brand filter such as WIX or an MP1 for Ford.