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  #1  
Old 02-27-2011, 05:45 PM
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bryanflood bryanflood is offline
 
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Posts: 114
Default Rebuilding an O-320

My engine was due for an overhaul and I thought it might be fun to do it myself. I am going to post some of the pictures and assembly steps here. I will not be able to post everything I did b/c I just didn't document it that carefully. There are many measurements and assembly steps that need to be taken, of which I just didn't take a picture, sorry.

Also, I took all the pictures with my phone, so sorry they are such poor quality. Hopefully you can get an idea of what I did.

My first day I worked on getting the crank shaft seal in place and the gear on the crank shaft. Getting the shaft seal on is a bear, it requires a special tool, for which, I paid $100.

Next is the gear there are lots of instructions in the manual to make sure that it is firmly seated on the crank. Including tapping with a punch and checking with a feeler gage, finally after torquing the screw the saftey is bent.










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  #2  
Old 02-27-2011, 05:57 PM
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Default Rebuilding Lycoming O-320

The rods are put onto the crank shaft in the following pics. I was really curious to try the plastic gage technique of checking the bearing clearances against a dial bore gage and a micrometer. My experience was that the plastic gage was fairly repeatable but not very accurate. The plastic gage seemed to show that the clearances were around .002 smaller than the other gages. Luckily all measurements ended up being within limits so I didn't extensively investigate which was more accurate. I guess however I trust the mic and dial bore gage a bit more as I calibrated them against standards. Finally the journals are oiled and the rods installed, be carefull with the nut orientation.







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  #3  
Old 02-27-2011, 06:05 PM
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bryanflood bryanflood is offline
 
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Default Rebuilding Lycoming O-320

You have to check a bunch of dimensions on the case, this is pretty boring, except that you need to assemble the case and take it back apart again. The shafts for the idler gears need to be installed. Tappets are also oiled and fit at this time.





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  #4  
Old 02-27-2011, 06:14 PM
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bryanflood bryanflood is offline
 
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Default Rebuilding Lycoming O-320

Before the case can be assembled the bearings need to be put in place. The front bearing is a little tricky because it's split is oriented 90 degrees to the case split and it has to be carefully aligned. Marks are made on the bearing BD case during a test fit, then when the crank is installed you can verify that the marks are aligned with those on the case. The cam is also installed in the pics.




Last edited by bryanflood : 02-27-2011 at 06:21 PM.
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  #5  
Old 02-27-2011, 06:19 PM
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Default Rebuilding Lycoming O-320

Before the case is joined the shaft seal has to be prepared with contact cement and the dreaded POB and silk thread installed. This actually went easier than I expected. Next the bolts are tightened in a specific sequence to pull the case halves together. I didn't get allot of pics, things are pretty busy as there is a 1 hour time limit.




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  #6  
Old 02-27-2011, 06:32 PM
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Default Rebuilding Lycoming O-320

The accessory case needs to be assembled with the oil pump and the rod for the fuel pump. The gears also need to be aligned and installed on the back on the case. The tach shaft and seal needs to be installed. Double check that all the pipe plugs for the oil galleries are in place. There are also a bunch of measurements taken at this stage. Finally the oil pump drive shaft and tach shaft are wiggled into place and the assesory case screwed to the engine.














Last edited by bryanflood : 02-27-2011 at 06:47 PM.
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  #7  
Old 02-27-2011, 06:38 PM
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Default Rebuilding lycoming O-320

Next I masked and painted the case, then moved it to my living room (can't carry it up the basement stairs with cylinders installed) for final assembly. I had to build a ventilated paint booth in my basement b/c it's below 0 here. I used a marine engine compartment blower to blow the fumes out of my dryer vent. Worked great and didn't stink up the house.





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  #8  
Old 02-27-2011, 06:44 PM
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Default Rebuilding O-320

The next steps involved populating the accessory case and installing the cylinders. I think I also put the oil return tubes on at this time. I will have to wait for a parts shipment before the next update, which might be a week or more.




Last edited by bryanflood : 02-27-2011 at 06:48 PM.
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  #9  
Old 02-27-2011, 06:49 PM
jrs14855 jrs14855 is offline
 
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Default o 320

I am collecting parts for an 0 320 and intend to assemble it on my own. I have been to two assembly schools. This will be only the second four cyl Lyc I have done, I had help on the bottom end on the first one.
Comments:
If you choose to use the plastigage, DO NOT torque the rod bolts any where near the full torque value. These are stretch bolts, full torque one time and then throw them away.
I am going to put my faith in Divco on the case dimensions. I do not plan to assemble the case to check dimensions.
IIRC correctly, the crank seal is usually done after the engine is fully assembled. The special tool is not necessary. This has been discussed at length on this forum
There are three different style/part number main bearings. Doweled/no dowel and o 235 style four piece front main.
Some shops seem to do the case assembly on the vertical with the crank bolted to the engine stand. I personally don't like this and plan to assemble the case on the horizontal as shown in your pics. If assembling on the horizontal, the cam should be wired in place temporarily to the"upper" case half. This holds the lifters in place while lowering the "upper" case half in place.
The crankshaft end play should be verified after the case halves are joined.
It appears you used some kind of cam lube. Can you address this and other lubes/sealers used??
My VERY OLD Lyc manual calls for a stp/oil mix. Some shops use stp, some don't. I plan to use the stp mix unless someone convinces me differently.
I just found some very interesting info on AVWEB about oils and cam lubes etc. I have always used Aeroshell but will not be using it again.
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  #10  
Old 02-28-2011, 05:17 AM
mahlon_r mahlon_r is offline
 
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Default

The top left nut on the oil pump is safety wired backwards....;-).
Did you get the castle nut under the cam gear installed and saftied? Can't tell from the pictures.
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."
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