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My First Onan is a 5CCK Dec 1962

zuhnc

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Last Subscription Date
12/08/2019
Sounds like you have a great running set. I use a Group 31 battery, 4' long, 1/0 welding cable with crimped-on copper terminals and bolted connections to the generator AND battery. None of the lead (?) connectors at the battery end. My battery has 5/16" threaded posts for the cable connection. Slight delay on the first compression stroke, but good after that. High compression heads. Square end. Clean connections and star washers go a long way to good cranking. Vacuum booster should have no tension on the external spring when adjusted properly; slightly loose. The internal spring pulls the throttle open when intake manifold vacuum falls when taking a load. Complete adjustment procedure in the service manual. Yes, it is easier to adjust the valves with the intake off. There are gaskets, but thin, about 1/64", I think. Could be thicker, nothing precision about sealing. Don't forget the copper washers on the bolts holding them on; you can anneal them, if needed. The covers will also fit properly only one way. zuhnc
 

Motorhead

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Age
67
Last Subscription Date
07/09/2019
BT, Yes you do need to remove the intake/exhaust manifold to set the valves. You just remove the two big bolts and leave all the exhaust and carb attached. Loosen the bolts first and tap around the two ports on each side to separate the gasket without tearing it. Same with the valve access covers, loosen the bolt a few turns and tap around the cover. Those gaskets for the covers are available but you can cut them out of flat, .015" gasket paper.
If you don't know how to find TDC where the valves are ready to adjust, here's how to do it.
Pull both spark plugs, both valve access covers. Pull the IGNITION TIMING plug on the cooling fan housing. Turn the engine in the direction of travel until the timing mark on the flywheel comes up to the Top Dead Center mark on the engine timing cover. Now look at each valve galley and find the cylinder side where both valves have some clearance between the cam follower and the bottom of the valve stem. Adjust those valves according to the specs for EACH valve. Make sure that the exhaust valve, the one closest to the engine cooling blower is set the specs for the exhaust valve. MOST engines with adjustable valves, the exhaust valve is set with MORE clearance that the intake valve due to more expansion.
So, NOW turn the engine the same direction of travel, one full revolution and then adjust the other cylinder. I set the valves on my engines at a snug measurement with the feeler gauge. You need TWO slim open end wrenches to adjust the valves. One wrench holds the cam follower and the other holds the adjuster bolt on the cam follower. To lessen the clearance gap, you turn the bolt out. To add clearance, you turn the bolt in.
PAY ATTENTION to the clearances in the book and make sure you adjust the clearances according to the fuel you are running and the clearances listed for the different fuels.
 

Vanman

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Last Subscription Date
07/10/2019
Of course a solid lifter cam is going to have some valve noise, but I think it sounds like excessive clearance, going by ear. Not sure how well it comes through in the video, but I can hear it with my gun mufflers on in person. Setting the valve clearance is on the list.

Keith
 

Tracy T

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Last Subscription Date
07/16/2019
yeah i herd it in the video, sounds a little loose but i rather be a bit loose as a bit tight here!
 

Motorhead

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Age
67
Last Subscription Date
07/09/2019
Tracy, The valve being too loose can cause faster valve seat and valve face wear. The CAMSHAFT, when you look at it, has two sides or profiles. The back side of the cam is designed to allow the valve to close somewhat softly instead of slamming closed. So too much clearance can allow the valve to slam closed.
 

Vanman

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Last Subscription Date
07/10/2019
Yes, and in an aluminum engine it can actually pound the seats further into the block! It also hammers the cam, lifter and valve at opening. But agreed we don’t want too tight, risking a burned valve. We want just right.
 

Tracy T

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Last Subscription Date
07/16/2019
But agreed we don’t want too tight, risking a burned valve. We want just right.
LOL watch it! Do you remember how deep that rabbit hole is!?? I dont think you have much to worry about, these engines dont have the strongest valve springs to begin with.
 

Bent Trigger

Subscriber
Last Subscription Date
10/03/2019
Any good suppliers for these gaskets. This should have been in the last post. Sheesh sorry!:p
 

Vanman

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Last Subscription Date
07/10/2019
I have a pretty good feeling that the generator bearing is good, based on the evidently low operating hours, but the original grease in it may well not be so good. I’ve read on here of the seal being removed to allow cleaning and regreasing. What tool would you use to do that that won’t damage the seal?

Also, I have been having a hard time finding a match for this barrier strip, but with three terminals. Any suggestions of where I might find one? The screws are #10-32.
Keith 02266795-3A3D-4EAD-9AB8-04B9C114BD1A.jpeg7B808F97-AAA1-456A-BD2B-C9A8B71718B7.jpeg
 

Motorhead

Subscriber
Age
67
Last Subscription Date
07/09/2019
Keith, Take a pick tool and remove the seal from the OUTSIDE lip, not around the center. Remove it directly opposite of the anti rotation tab on the bearing. Pack some good grade grease back in there and carefully replace the seal. If you have to, you can bend that tab up a bit out of the way. Just don't pry against the seal. I just repacked the bearing on the high hour JB yesterday. Takes but a few minutes.

On that terminal strip, Could you get a NUT on the back side OR retap the hole to the next bigger size and put in a new screw? If the good hole is a #8-32 thread then you can re-tap to a #10-32. If you don't have any taps, send it to me and I'll repair it for you and send it back.
 
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Vanman

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Last Subscription Date
07/10/2019
Yes, they are there in general, but evidently “they don’t make them like they used to”. I’ve painstakingly sifted through them looking for one of the same style and dimensions, but have come up dry. I had wanted to use the original mounting holes, but the new ones are much smaller. This one has zero identification on it, making it hard to search for lol.

Keith
 

Tracy T

Subscriber
Last Subscription Date
07/16/2019
Keith i wish i could recall where / what brand we used at the transformer shop i worked at, they were setup where you cut it as long as you wanted it with a bandsaw and then drilled the mounting holes.
 

zuhnc

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Last Subscription Date
12/08/2019
I have taken longer ones, removed those strips I don't want, and sawed off at the proper length. If necessary, carefully ream out the holes to fit your fasteners. Drilling, unless you are very careful, will break the bakelite or plastic material. zuhnc
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
That makes sense. Indeed the ends look sawed off. If only I could find this original style. But at least now I can look for 3 terminal and larger instead of just 3.

Keith
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
Did a little more work on my Onan today. Was able to get the intake / exhaust manifold off without injury to the gaskets, so that was nice.

Only bolt that gave trouble was the little one that secures the air cleaner. It was laughing at my impact driver, which was just hogging out the slot. I went forwards and backwards several times, but no go.

Then I worked on it with a chisel, making the slot deeper and squeezing it back closed some. I was fully prepared to just chisel it’s head clean off, but it must have read my mind because the impact driver got it after I worked it over with that chisel.

Tough to wiggle that manifold out of there!

Then I was able to remove the valve covers, also without injury to the gaskets, so happy about that.

Next session I’ll set the valve lash and put it back together.

Oh yeah, forgot. I need to decide what to do about the fuel pump. Either go with an electric pump, or rebuild the mechanical one. Either way it has to stay in place since the governor spring support bolts to it, and I’m not going to fabricate a new spring support just to be able to use a block off plate.

Keith A30EF6AA-36CD-4EF1-9D87-5E57D0B61682.jpeg3C979015-5764-472E-ABFE-E52E4A3580BD.jpeg
 
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Tracy T

Subscriber
Last Subscription Date
07/16/2019
You think that manifold was tough? :rotfl: Try it still in the motor home!:spew: Now that was tough! and had to be done to get the set out!
 

brianh

Registered
I have a pretty good feeling that the generator bearing is good, based on the evidently low operating hours, but the original grease in it may well not be so good. I’ve read on here of the seal being removed to allow cleaning and regreasing. What tool would you use to do that that won’t damage the seal?

Also, I have been having a hard time finding a match for this barrier strip, but with three terminals. Any suggestions of where I might find one? The screws are #10-32.
Keith View attachment 371719View attachment 371720
Get a hypodermic needle attachment for your grease gun, then you can easily slide the needle in around the edges of the seal and grease away!
 
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