F & M oil filter adapter (Now Tempest)

How to keep the Cessna 170 flying and airworthy.

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snellbob
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Joined: Thu Sep 23, 2010 8:49 pm

F & M oil filter adapter (Now Tempest)

Post by snellbob »

I have read several past postings about the F & M oil filter adapters. Sounds like the gasket and thread issues have been resolved. Does anyone out there have recent pictures of the unit installed on an 0-300? Particularly a pic of the blast tube modification. Install document that I read requires oil temp bulb to be installed into the oil filter adapter and blast tube air to be routed to that area.
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GAHorn
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Re: F & M oil filter adapter (Now Tempest)

Post by GAHorn »

Here's a solution one Member used:

(Click on pic to enlarge... Click on enlargment to ENLARGE.)
Attachments
1/2-inch aluminum flexible electrical-conduit from Home Depot aircraft division.
1/2-inch aluminum flexible electrical-conduit from Home Depot aircraft division.
1/2-inch aluminum flexible conduit, held inside orig tube, drilled-thru, with cotter or safety-wire and directed against gen with Adel clamps.
1/2-inch aluminum flexible conduit, held inside orig tube, drilled-thru, with cotter or safety-wire and directed against gen with Adel clamps.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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snellbob
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Re: F & M oil filter adapter (Now Tempest)

Post by snellbob »

Thx George. Hope all is well.
As I recall, I think you have one on your bird. Still happy with it?
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GAHorn
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Re: F & M oil filter adapter (Now Tempest)

Post by GAHorn »

snellbob wrote:Thx George. Hope all is well.
As I recall, I think you have one on your bird. Still happy with it?
Yes. I could never be happy with the original screens and I don't like extra hoses/fittings and firewall mounted filters.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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n2582d
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Joined: Mon Apr 29, 2002 4:58 am

Re: F & M oil filter adapter (Now Tempest)

Post by n2582d »

Bob,
Thanks for bringing this up because those of us that installed these years ago may not have the blast tubes correctly mounted. The instructions that came with my filter adapter, dated 10-26-98, made no mention of realigning the blast tubes. The current instructions to modify the blast tube can be seen on page 4 here. It's unfortunate the instructions are so ambiguous: "Extend, reposition and/or modify the blast air tube as necessary." George's example proves that the instructions should be more precise.

In comparison with using standard aircraft ducting at between $2.85-$4.80/ft. that roll of conduit costs $22 at Home Depot. It's also heavier than aircraft ducting. Finally, it provides much less air flow. With a cross sectional area of 0.32 square inches it's less than half the cross section of a 1" diameter ducting which is 0.785 square inches. The spiralling ribs are not conducive to low resistance either. If I were to annual an aircraft with a conduit blast tube that modification would be on the discrepancy list.

I think the ideal solution is to make a new tube from 5052-O. The original tube is 1" O.D. with 0.049" wall. Lacking the tools to do that one could cut the minimum length necessary from the end of the existing blast tube and attach CAT, CEET, SCAT, or SCEET ducting with a hose clamp. My preference would be the SCAT or SCEET. If one didn't want to cut up the old blast tube then install the ducting to the baffling with a 1" aluminum flange which is riveted to the rear baffling. Use a 1-2" section of 1" diameter tubing at the downstream exit to provide an anchor point for the ducting to slip onto.

Many times I've seen ducting incorrectly mounted. The duct will last a lot longer if it is not supported just by the impregnated fabric. Pull the wire out a little ways and then cut it. Now bend the last 1/2" 90º so it is parallel with the duct. Clamp this bent stub of wire and the outer string under the hose clamp. The wire will now help support the duct and the wire end will not be free inside the duct to poke a hole through the fabric.
Gary
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GAHorn
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Re: F & M oil filter adapter (Now Tempest)

Post by GAHorn »

I agree with Gary that using soft aluminum tubing in similar size to the OEM is always preferable. (I disagree that the one previously depicted is an inspection "discrepancy".... depending upon how the modification was documented. Either the flexible conduit OR the aluminum tubing would be a discrepancy unless documented as a minor alteration.... and if so documented, either method would be airworthy, IMO.)

The weight difference is true...but negligible. The airflow difference is also true and negligible. So is the method using aluminum tubing...which will be less than OEM due to length and additional bending. The use of SCEET/SCAT could also be argued that it is more restrictive than the OEM blast tube due to it's corrugations. In other words, any change will likely adversely affect cooling airflow. (I thought the other Member's method was humorous...but he said it was necessary because the OEM blast tube was totally destroyed by the previous-owner's attempts at bending it. The automotive rubber heater-hose used instead was unacceptable to his IA...but the aluminum elect. conduit satisfied the man as a "minor alteration".)

The point I feel that should be considered is that any modification should meet "the rule" by using acceptable materials and techniques and documentation.

In my own airplane I did not alter the blast tubes at all. My own blast tubes are just like Cessna originally placed them... and I have not experienced any abnormal oil temp indications due to that FM Enterprises oil filter adapter installation. (My OEM blast tubes were modified in accordance with the instructions... "as necessary". I found it UN-necessary.) :wink:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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