C-145-2H Engine Overhaul

[Bruce Fenstermacher]

You must have gotten the last Millennium cylinders available. No one has any in stock and they don't know when they will be available again. I've heard all sorts of stories one being Superior is having quality control issues. I think the most logical though is the same Chinese company that owns Continental (who can't seem to sell a cylinder) owns Superior (the better alternative to Superior). Why would a company produce a product in one subsidiary that undersells another of theirs. I wouldn't be surprise with Superior isn't in the process of discontinuing all Continental parts that Continental produces.

[nippaero]

Bruce, I bought my cylinders back in May of last year. Aircraft Specialties had me on a waiting list while orders trickled in. I finally had all six of them in July. At the time, they had a few Continental cylinders in stock but I wanted Millenium. It sounds like the inventory has dried up again. You might have to source one at a time until you can get all six?

[sfarringer]

I'm curious, if you get cylinders one at a time, do you end up with matching weight pistons?

[nippaero]

I'm curious, if you get cylinders one at a time, do you end up with matching weight pistons?

I don't think it matters. The pistons are packaged separately and are included in the box. Four of my pistons were 704 grams and two were 701.

[Bruce Fenstermacher]

The only 3 Millenium cyl. thought to be in inventory are in Alaska. Everyone has plenty of Continental made and they try to sell them. Putting 6 Continental made cyl will cost $600 more total. When I asked those trying to sell me Continental if they were $600 better they admitted they didn't think they were even as good as Superior.

[170C]

New engine looking super! It will run even better after it gets some oil
spread over it

[GAHorn]

Things are winding down and this motor is almost done. It is going to get set aside while work continues on the plane. I won't hang the engine until after the plane is painted.

I installed a new generator, new plugs and two new long exhaust risers from AWI.

You probably know this... but sometimes people don't.... that generator blast-tube is pointed down....as if it's an exit for hot air to escape. But it's NOT so.
That is intended for cooling air to ENTER, and is ordinarily connected via sceet hose to the high pressure side of the upper, rear, engine baffling so that cool air can blast into the generator...which exits at the forward exits. (I also notice it's a 20A gen. Now is an excellent time to convert to a 35A and 35A regulator, should you so desire.)
Did your assemblyman know if your existing electrical harness will accommodate the gen terminals at the 6-o'clock position?

[nippaero]

George. That is great information. I did not know that. I just installed it the same way the old one was facing (down). Maybe when I install my new baffling, I can accommodate the scat tube to the generator. Thanks for pointing that out.

[GAHorn]

The blast tube is normally connected to a 1" sceet or scat hose to ram air pressure obtained from the rear baffle.

I installed a 1" flange (Aircraft Spruce) on my aft baffle and routed my scat hose down alongside the oil cooler blast tube with Adel clamps.

See also: http://www.cessna170.org/forums/viewtop ... ose#p29863

Flange with bug screen

GenBlast1.JPG (17.81 KiB) Viewed 9048 times

In the pic above, notice the screen placed inside the flange prior to the hose installation to preclude bugs, etc..
The hose pictured below is SCEET hose, which has an inner lining to prevent the wire reinforcement from rusting, breaking off and passing thru the generator.

SCEET hose

GenBlast2.jpg (27.87 KiB) Viewed 9048 times

Be certain that your blast tube is positioned on your generator so that the cooling tube is not blocked by the web of the brush-end of the generator.

SCEET to GEN BlastTube

GenBlast3.jpg (32.14 KiB) Viewed 9048 times

[KS170A]

The blast tube is normally connected to a 1" sceet or scat hose to ram air pressure obtained from the rear baffle.

I installed a 1" flange (Aircraft Spruce) on my aft baffle and routed my scat hose down alongside the oil cooler blast tube with Adel clamps.

See also: viewtopic.php?f=2&t=3469&p=29863&hilit=blast+tube+flange+hose#p29863

GenBlast1.JPG

In the pic above, notice the screen placed inside the flange prior to the hose installation to preclude bugs, etc..
The hose pictured below is SCEET hose, which has an inner lining to prevent the wire reinforcement from rusting, breaking off and passing thru the generator.

GenBlast2.jpg

Be certain that your blast tube is positioned on your generator so that the cooling tube is not blocked by the web of the brush-end of the generator.

GenBlast3.jpg

Thanks George! It's this kind of information that makes being a member so worth it! I've had a 35A gen on my bird since we bought it almost 20 years ago. You guessed it...no blast cooling! Been following this thread because I will likely overhaul the engine this or next year.

[Bruce Fenstermacher]

You know, funny thing. The IPC, A or B, does not show that 1" SCAAT tube or the flange George has pictured in his baffle. It's no wonder so many 170 don't have cooling air blasting into the generator.

[n2582d]

George,
The TCDS, on page 12 lists item 301, the 12 amp. generator, item 305, the 25 amp. generator, and item 307, the 35 amp. generator which requires a dampened crankshaft. Item 307 also comes with an asterisk.

The asterisk denotes that approval has been obtained by someone other than the aircraft manufacturer. An item marked with an asterisk may not have been manufactured under a FAA monitored or approved quality control system, and therefore conformity must be determined if the item is not identified by a Form ACA-186, PMA, or other evidence of FAA production approval.

What is your basis of approval for installing the 35 amp. generator? Here I said that only a logbook entry is required but based on what you've said about this asterisk (on the Javelin tank, etc.) I'm thinking I may be incorrect there. AK172-6A is for the early 172's. I could see it being used as "acceptable data" but not "approved data".

I've been looking for documentation that shows that the 35 amp. generator requires blast tube cooling. AK172-6A doesn't show it. It only says that "the air inlet on the band at the rear of the generator must be down". My guess is that Cessna wanted the hole down to prevent water or solvent ingress. Fig. 91 in the 170 IPC shows the installation for the 25 amp. generator without any mention of a blast tube. The '56-'62 172-175 IPC doesn't show, but lists, a blast tube with optional 35 amp. generator with fig. 88. Just above this listing it lists the 25 amp. generator with no mention of a blast tube. I'm guessing this is how you decided that only the 35 amp. generator requires a blast tube on the C-170.

TCM contradicts this on page 54 of the O-300 overhaul manual.

So, according to TCM, even the 12 amp. generator should have a blast tube.

Finally, I found it interesting that the 100 series service manual (17-21) says that, "if additional power is needed on the 172 or 175 a 50 amp. heavy duty system is available." I haven't yet found any other documentation for this 50 amp. installation.

[GAHorn]

You asked what is MY approval basis for installing a 35A generator. I didn't install it. Cessna installed the 35A system when my airplane was built. (SN25713 left the factory with factory camera and agricultural kits installed, which included the 35A gen system. It is listed in the original Equipt List.)

You address a question implying that the change from a 12 or 20 or 25 ampere system to a 35 A system is a minor alteration requiring only a log book entry, but FAR 43, Appdx A states under para (a)(1)(xii) that the change of the electrical system design is a MAJOR ALTERATION, so it would require a Form 337. However, no need for Field Approval (Block 3) is req'd.

The IPC is not an approved document so that corresponds with Bruce's comment as well as may explain why you found no IPC illustration to support gen cooling or blast tubes. But, you might find it interesting to view Fig 60 in the 172/175 IPC which clearly shows the cooling hose, blast tube generator cooling installation. Here it is in PDF format.

CCF03012017_0001.pdf

Gen Cooling Hose/Blast Tube

(806.1 KiB) Downloaded 462 times

The TCM X30013 Ovhl Manual, Pg 54 paragraph you posted states a cooling blast tube "must be connected to a source which will maintain a minimum of 1.5" (cooling air ) across the generator. The Service Manual instructions for removing the generator states (para 17-28 (b) "loosen the clip securing the blast tube and pull the tube clear of the generator." This can be done without disconnecting the cooling-air supply-hose...a plausible explanation for why they did not mention the cooling hose.

Yes, there are a lot of details which require familiarity with aircraft service and repair which are not perfectly documented. This is why FAA has minimum experience requirements for repairman certificates.

An example of the need for such experience is found in the AK172-6A Instructions you mention. If you read it closely, you will notice that the instructions have the workman remove the lesser-rated generator and replace it with a higher-rated generator....but make NO MENTION of increasing the wiring gage/capacity to accommodate that upgraded system. This is likely because the 172 (in the serial range applicable for that kit) left the factory with a standardized wiring harness which already had the capability to handle the "optional" 35A generator/regulator. All that would then be necessary would be to also upgrade the fuse/c.b., which the AK172-6A does instruct.

THE PROBLEM WITH USING SUCH KITS on other models aircraft...SUCH AS OUR 170 MODELS... is that our airplanes left the factory with wiring appropriate for the generator system installed AT THE TIME OF PRODUCTION. This means that if the AK172-6A is used to change a 12 or 20A generator in a C-170 to a 35A system...the wiring will likely be TOO SMALL gage. Therefore additional changes must be made to safety convert our 170s. While I am relying upon memory in making the next statement, ... it is my belief that the smaller gens in the 170 were not originally equipped with cooling-air supply, and that the upgrade to a 35A gen made 3 mandatory changes in the upgrade: Increased wiring and fusing capacity, cooling-air/blast tube system, and dampered crankshafts.
As those items became standardized in later aircraft like the 172... they were simpler upgrades. Your mention (regarding the TCM paragraph quoted) that TCM required the 12A gen to be cooled overlooks the date of publication of the TCM X30013 manual. The paragraph was found in the June 1982 manual and perhaps some earlier versions, but will not be binding to airframe items installed separately. TCM is not the certificate holder for Delco-Remy generators. TCM, under a marketing-system known as "specification", in which "spec numbers" were assigned to engines PRE-configured for particular airframe installations, may have included generators AS WELL AS GEN COOLING SYSTEMS to the customer's order. In such cases they might offer instructions for engines so-equipped.
However, generators, pumps, regulators, and many other accessories are usually considered AIRFRAME items... not powerplant items. Therefore the Airframe mfr's manuals apply in those instances. I would not consider TCM's manual binding with regard to generator installations, however helpful the info might be.

You ask about the 50A generator option. It is not possible in a 170 because the 50A generator is too long... the firewall is too close to allow the installation. The later 172/175 firewalls were "stepped" and could accommodate the longer 50A generator.

[n2582d]

Interesting trivia. I agree that equipment such as the generator is an airframe rather than an engine item. So Cessna rather than TCM would dictate whether to run a blast hose to the generator. George, do you think you plane had a generator blast tube from the factory? I seriously doubt it because, according to AK 180-6, "model 180 airplanes prior to s/n 50106 and model 182 airplanes prior to s/n 34754 did not have a generator blast tube installed" on their 35 or 50 amp. generators. This would correspond to the 1958 model year, the same year as the 175 s/n engine in the PDF you linked above shows a blast tube. It was four years after your plane was produced, on Nov. 14, 1957, that Cessna decided that maybe TCM was right and developed Service Kit 180-10, "50 Amp Generator Blast Tube - Model 180 and Model 182" to retrofit these earlier aircraft that did not have blast tubes to "improve end bearing life".

THE PROBLEM WITH USING SUCH KITS on other models aircraft...SUCH AS OUR 170 MODELS... is that our airplanes left the factory with wiring appropriate for the generator system installed AT THE TIME OF PRODUCTION. This means that if the AK172-6A is used to change a 12 or 20A generator in a C-170 to a 35A system...the wiring will likely be TOO SMALL gage. Therefore additional changes must be made to safety convert our 170s

My '52 had a 60 amp alternator installed by field approval using Cessna 172 wiring diagrams as data. What these later wiring diagrams - and 170 diagrams prior to the 170B - omit is wire gauge. One has to use AC 43.13 to determine appropriate wire size when doing conversions to larger alternators or generators. A cursory check of the 170B diagrams found an increase from #14 to #10 wire from the "A" terminal of the regulator to the generator and from the "B" terminal to the bus. Aircraft after s/n 26995 - 1956 models - utilize this larger gauge wire. I don't understand how Bruce could have missed that here!

[GAHorn]

Well, don't blame Bruce... that was posting of "data" from the "170 Book", a composition gathered from many unnamed sources.

The Electrical System Service Manual documented the typical 170B electrical schematics and that indicates the generator circuits were comprised of 14 ga and 10 ga generator circuits. According to Mil-W-22759 (admittedly a later spec.) offers that 10 ga wire is suitable for only 20 amps continuous in lengths less than 25 ft.
The conversion to a 35A gen/reg requires 8 ga wire to replace the original 10 ga.

Since my airplane "lost" it's engine while stationed in El Salvador/Ecuador area, the person importing it to the U.S. in the early 1970s installed an O-300-C engine which the FAA Airworthiness Inspector ...APPROVED! (This made it "legal" even tho' the "C" engine was not on the TCDS.)
The 35A gen was listed on the original equipt list from Cessna so it's only a presumption that the correct gage wire existed in the airframe.

The restorer of N146YS completely re-wired the aircraft in accordance with MIL-W-22759/16 wiring and AC43.13-1B/2B using Cessna dwgs and existing wiring. (He was well-equipped/connected to Cessna I suppose, since he worked for Textron.) He used 8 ga. wire in the generator Arm/Reg/Buss circuit. He also converted the aircraft to Klixon Circuit Breakers. The 337 he completed states:
"Electrical Installation in accordance with the following sections of AC43.13-1B, Chapter 11:
Section 4-Circuit Protection Devices
Section 5-Electrical Wire Rating
Section 11-Clamping
Section 15-Grounding"

As for the blast-tube question... I have no idea if it "left the factory" so-equipped. I'd guess not. (I discovered the blast tube un-connected and the lack of cooling when I acquired the airplane and made the addition.)