J

joeboisselle

Well Known Member
Ok, I've been gathering parts together to build an o-360-a1a, for the last several months, and I think I've got everything. Crank was overhauled, ground .003, renitrided, cad plated etc. So I bought oversized bearings and attached the connecting rods last night and everything worked fine. Tonight I closed up the case with cam, crank and tappets inside. As I started to tighten up the bolts on the top and bottom of the case, I noticed the crank would no longer move. My first thought was perhaps the crank wasn't ground .003 and the oversize bearings were the cause. But why would the case bearings be tight and the rod bearings be fine if both were .003 over???

Next, I see small holes inside the case, pointing out twards each cylinder. I assume these are supposed to be for piston cooling oil jets. The only -360 model I can find with these jets is the vo-360-b1a. Should I find and install the jets, or can I just plug them off? :confused:
Thanks in advance for any help.
 
That's what I'm seein'! I'm always up for good lubrication inside an engine and more is better in my opinion... where'd you find your nozzles at?
I don't recall what diameter the thread was, but it was fairly thin. Hard to imagine that, or even .003 oversize bearings would seize it up as tight as it was.
 
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Ordered them from Mattituck. Part number is: 73772 -- and they're about 18 bucks a piece..


PS. Did you check if your main front bearing moved during assembly? Was it lined up properly and engaged dowel pins?
 
who did your case, was it lined bored? Is the cam tight? If your mains are binding, and the mains and bearing measure out then could it be your deck height?
 
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Thanks for the number. And it looks like everything is set in place, the bearing didn't appear to be sitting on top of the dowel pins.
 
c177tx said:
who did your case, was it lined bored? Is the cam tight? If your mains are binding, and the mains and bearing measure out then could it be your deck height?
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Aircraft Specialties did the case, crank and cam according to Dana Overall, whom I bought it from. I don't recall the case being lined bored, the cam isn't tight. I'm not sure about deck height, I havn't anything to measure it with. :(
 
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Make sure you have torqued all thru bolts and all case backbone bolts properly and to spec. That includes all on the thru bolts on the cylinder decks. If it is still tight, then try to turn the case around the crank or the crank in the engine, whichever your build up stand will allow. If a bearing is tight it may leave a signature on the effected bearing surface. I assume you physically checked all journal dimensions and also did the math to confirm bearing clearance or used plastigauge to find clearance..right? Also assume you checked end play and thrust clearance during assembly? If this turns up nothing, disassemble and check all bearing bores especially the nose bore for size at several locations and planes and check with dial gauge for straightness vertically and horizontally. Double check, that there was nothing behind any of the bearing shells.
If that turns up nothing, try a different crankcase for starters it may be deformed when torqued and if that doesn't work try a different shaft it may have some whip to it.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."
 
tight crankshaft

Also, verify that the dowel pins in the bottom of the main bearing bores are set deep enough. They need to be a finished driven depth .070-.090. If they are too high they will hold the bearing off the case, making it tight when assembling. Deck height is not a factor, yet. Practice proper torque procedure. Verify that no burrs exist on the thrust suffaces (Mahlon mentioned the correct thrust clearance), and slinger clearance. Check bearing size. The bearing size is marked on the back side of the bearing. Wouldn't be the first time bearings have been packaged wrong.

AND, once again verify that the front bearings were not pinched on the pins. This is critical. Ask me how I know.. :eek:

Allen
BPE, Inc
 
Front bearing

Hi Joe,
The same thing happened to us with our 0-360 first time around. The front bearing slipped and the locating pin pressed it against the crank, ruining the bearing and locking up the crank.

The safest way to assemble the case is to lay it down on its side. Place the bearing halves in the case without the crank. Then make a pencil line along the bearings at the case. Make another mark perpendicular to the first one and a corresponding mark on the case toward the outside. These marks will tell you if the bearing is in the same location when you lower the crank and rod assembly into the case half. You now have two marks that will tell you if the bearings have shifted fore and aft and also rotated.

Put the lifters in the case and lay down the cam. Then grab the two rods that will be in the other case half and lower the whole assembly into the case with the bearings on. Position the bearings with the pencil marks aligned and visually inspect the seating of the crank in the proper position and also that both bearing shells are aligned with the pencil marks. It's easy to slightly lift the crank and position the front bearings if they're not in place.

It takes four hands to lower the other case half because the lifters will fall out unless you tie them in place.

Regards,
 
should you use a graphite pencil? I have been told that the graphite will cause a crack after time due to uneven heating caused by the graphite?
 
What a cool thread!

I'm printing this off for overhaul time in about 1900 hours from now..:)

I think this illustrates the point that while assembling an engine is not particularly difficult, each engine is unique and there are a lot of little things that can turn into big issues unless you know about them ahead of time.

Thanks for all the experts who gladly dispense this knowledge!

Frank 7a TMX IO360
 
Any time you are overhauling an aircraft engine, you should have experience looking over your shoulder. Even an A&P mechanic is not allowed to do an unsupervised overhaul unless he has done that particular model before.
 
I had a similar problem after assembling mine. After taking a few minutes to think about it, a few more for the handful of Valium to kick in..... :D

I loosened up all the bolts (didn't seem to take much before things loosened up), and then started tightening again, in the proper sequence, but only about one turn of each bolt at a time, all the while checking for binding, bearing slippage, etc. Finally finished, case spun easily on the crank.

Not to dismiss anything anyone has said previously, all applies. I apparently cranked either out of sequence, or got the crank in some kind of a bind before checking for free rotation.

We'll see in the next week or so if I actually did it right!
 
The verdict is in! I opened the case back up this morning, and sure enough, the front main bearing was sitting on the dowls. I was off by maby 1/16th an inch! So a new bearing is in order and I'll get back to it next week. While in a&p school, six years ago, I overhauled a continental o-470 and it was quite different than this. I agree with you Mel, an experienced mechanic over my shoulder would be nice, but living in the boondox I don't think there's more than a hand full of people in my county that have much if any lycoming overhauling experience. Thanks for your help everyone!
 
leaking bearing pins

Okay Joe, now that you have found out the bearing was pinched, get an air nozzle with a rubber end on it. One that you can seal off the air from escaping and blow air through each of the front bearing pins. Put your finger on the under side of the pin boss. Sometimes, when a bearing is pinched on the front main it will push the pin downward and bust the pin boss, (it's not very thick under there). If you don't feel air, you dodged a bullet, but if you do feel air, you'll have to get another pin and weld the bottom of the hole up. If you don't, you could possibly experience low pressure at your front bearing.


Allen
BPE, Inc.
 
Allen----------

Even though I am not doing any engine work (at least not now), I sure do pay attention to the "Nuggets" of knowledge you are willing to share with the members of this forum.

This goes equally out to Mahlon also, and I apologize if I missed anyone else.

It is very refreshing to see experts in technical fields share their info here, I am so tired of the usual "just send it in, and we will fix it" attitude that is so much a part of modern life.

Ditto to Stein, Walter (engine guy), and others in specialized fields who post helpful items here.

Mike
 
Aircraft Specialities does not do cases.

Aircraft Specialties does not do cases. If you sent it to them, it was subcontracted out, probably to Crankcase Services, in Sand Springs, OK. Check the paperwork that was returned with your components very carefully. The data on that should tell you if the case was altered.
 
Hard Knox said:
Aircraft Specialties does not do cases. If you sent it to them, it was subcontracted out, probably to Crankcase Services,
Click to expand...

I didn't see this post, or hear anything about this, until this morning as tax season is more than a little bit busy. Glad it turned out to be the dowel issue. Hard Knox, that particular case was bought from Aircraft Specialties and came tagged.
 
Nuggets

Mike and all, I enjoy the vast amount of knowledge gained on this forum. The day will come (soon I hope) that I will have to rely on your experiences of building an airplane. I'm just laying the ground work ;)

Allen
 
There can be 3 styles of cases for this engine. Newest style takes a think bearing & case will not have dowels. Straight dowels take brg. P/N LW11020 or LW16047. Real early styles had collared dowels and take brg. P/N LW10124 ( mainly narrow deck). Make sure you have the right combination. With the crank in one side of case check end play and see if it rotates smooth. Agree on checking for burrs and front main bearing pinch. I have seen a lot of people pinch the front main bearing. I always assemle my engines with the case down on the table so I can seat the front main easily. I tape it & mark it & have someone lower crank down slowly while I position the bearing. Mark bearing along parting half & diagonal lines so you can see fore & aft position. Marks are made with bearing in the half & taped on the top. Also the 160 HP, 180 HP & 200 Hp cases are the same today. Only difference is cooling nozzles & rear drive governor vs. front drive governor. Agree with bearings not also being marked correctly for size.
 
BlackRV7 said:
I didn't see this post, or hear anything about this, until this morning as tax season is more than a little bit busy. Glad it turned out to be the dowel issue. Hard Knox, that particular case was bought from Aircraft Specialties and came tagged.
Click to expand...

Hey Dana! Haven't seen you around here much lately, or maby it's just me. First thing I thought of when the crank wouldn't turn the other day was "hmmm, I wonder if Dana has another one of these... and if he'd take this one back?" :D I think just the cam I bought from you was yellow taged, the case and the crank were just overhauled. (I didn't want to pay extra for the tag) I'll send you some pictures sometime when I get it together so you can appreciate what we went through to get it. :rolleyes:

Ron, my parts book is telling me lw-13884 and that's what I bought from aero, it fit into the dowls real nice... when you could see 'em.
 
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