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  #11  
Old 05-05-2011, 09:19 AM
KenM KenM is offline
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When I installed the oversized valves I reamed the guides with the proper reamer. I agree with your observation that the valves might be the smoking gun since they were changed during the rebuild. I do not have access to the proper tool to measure the valve guides - a split ball gauge - so I compared the feel of all four valves to the feel of the valves on a sister engine. One felt a little tight, so I helped it a bit with the reamer, and after that it felt OK. Nevertheless, sticky valves could be the bad guy here. I'll have to figure out a way to actually measure the valve guide IDs. Measuring the valve stems is not a problem. Thanks for your input.
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  #12  
Old 05-05-2011, 09:28 AM
KenM KenM is offline
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Yup piston slapper I'm getting pretty skilled at creating my own problems. At least this way my wife isn't the only one that puts things on my 'to-do' list.

I'll be taking a long look at those valves. Hmmm. Wonder if the heads from the sister engine are the same? I'll have to look that up. Maybe I'll swap them...
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  #13  
Old 05-05-2011, 10:27 AM
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piston slapper piston slapper is offline
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The only people that dont make mistakes , dont ever try to do anything. As long as you dont make the same mistake twice, you're going in the right direction.

As far as the heads being compatible from another engine,
18-20-22 hp heads are alike, as long as they came off another verticle shaft engine.
The oil drain hole is drilled on the wrong side on horizontal heads....they wont drain if installed on a verticle engine, It does make them smoke pretty good though.

25-27 hp heads are alike but you cant use horizontal heads on a vertcle engine.
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  #14  
Old 05-05-2011, 05:38 PM
KenM KenM is offline
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Looks like the other heads won't be correct for the CV-22, since they're from a CH25. But, if the only difference is an oil drain hole, maybe they'll be lightened a bit with a drill and tried out just to see what happens. That CH25 also had a thrown rod (not by me, however). In fact, it crashed so bad that the crank is in two pieces.

Or, to evaluate whether or not my oversized valves are sticking in their guides, I could just put the original (normal size) valves in for a quick check to see if it starts. But, I'm a little worried that with about .010 clearance instead of the recommended .0022, I could do a lot of irreparable damage to the aluminum guides in a real short period of time. Waddya think?
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  #15  
Old 05-05-2011, 06:34 PM
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Restrorob Restrorob is offline
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Putting stock size valves in a oversized guide likely won't tell you much, Just like when guides wear the valves rock around and do not seat then compression drops. I've seen many worn guides that the engine would start then immediately die once the valve started bouncing around in the guide.


Quote:
Originally Posted by KenM View Post
When I installed the oversized valves I reamed the guides with the proper reamer.

What size was this "proper reamer" ?

The manual gives the ID spec for a new guide, It also gives the OD spec on a new standard valve stem. You know the spec on the oversized valve stem, Do the math and you will end with the exact size reamer you need to use to maintain factory spec oil clearance with the oversized valves.....
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  #16  
Old 05-05-2011, 09:01 PM
KenM KenM is offline
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The reamer I used is 0.2873, same as the spec on page 1.15 of my service manual. But at the end of the day it comes down to meeting the clearance spec between the valve guide and the valve stem, which according to this same service manual is .0015 to .0030. That's the measurement I want to verify. Maybe there's a number, letter, metric, or fractional drill that will work as a pin gage for the valve guide. Restrorob, thanks to you and others for your continued interest in this puzzle of mine.
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  #17  
Old 05-05-2011, 09:54 PM
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Restrorob Restrorob is offline
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No problem Ken.....


Since you used the specified reamer I'd venture to say the valves should be good to go, This brings something else to mind.

btw, It's always easier having problem childs sitting in front of you.

There's a possibility a piece of metal shaving from the blow-up got into the oil pump and has the pressure relief valve piston stuck, If the oil pump produces too much pressure it would over pressure the lifters as well.

Since you loose compression while cranking to perform the compression test, Hook a oil pressure gauge up and see how many lbs it's pumping.....
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  #18  
Old 05-06-2011, 09:20 AM
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Quote:
Originally Posted by KenM View Post
Looks like the other heads won't be correct for the CV-22, since they're from a CH25. But, if the only difference is an oil drain hole, maybe they'll be lightened a bit with a drill and tried out just to see what happens. That CH25 also had a thrown rod (not by me, however). In fact, it crashed so bad that the crank is in two pieces.

Or, to evaluate whether or not my oversized valves are sticking in their guides, I could just put the original (normal size) valves in for a quick check to see if it starts. But, I'm a little worried that with about .010 clearance instead of the recommended .0022, I could do a lot of irreparable damage to the aluminum guides in a real short period of time. Waddya think?
25 Hp heads wont work on a 22HP engine.
To clarify the earlier post...18-20-22 hp heads will interchange with each other as long as the oil drain hole is in the right place.
25-27 hp heads will interchange with each otheras long as the oil drainhole is in the right place.

The valves are the same in all command twins 18-27HP.
The only times I have seen valve guides wear in a twin is from heavy dirt ingestion. The guides are a very hard and brittle metal, seen alot break, not to many wear out.
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  #19  
Old 05-06-2011, 10:07 AM
KenM KenM is offline
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Restrorob, I was going to hook up an oil pressure gage to the engine to see what the pump is putting out. Do you know the typical oil pressure specs for this engine family? I don't recall seeing it anywhere in my manual. And it's certainly possible that I've got some tramp metal in the oil pump assembly, and right now it's real easy to yank it and look it over.

Piston slapper, I hear you about not being able to put the CH25 heads on the CV22. I know that some of the head components, like the springs, are interchangeable, but the heads themselves are different part numbers.

Next steps: (1) see if I can measure the clearance between the valve stems and the valve guides. I've got some .001 metal shim stock. I should be able to fit a sliver, or two, of this stuff down the guide with the valve installed. (2) measure the oil pressure after looking for a problem with the oil pump pressure relief. Or, measure the oil pressure BEFORE looking at the oil pump, then look for problems there and measure it again. I think I saw someplace that the oil pressure should be 30-40 psi, but that may have been for some other engine. Again, thanks guys for your continued support with this. Maybe someday I will be able to play it forward for somebody else.
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  #20  
Old 05-06-2011, 12:31 PM
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Restrorob Restrorob is offline
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Quote:
Originally Posted by KenM View Post
measure the oil pressure BEFORE looking at the oil pump,

Do just that ^^^^, If you look at the pump first you will never know if it was a over pressure issue.

The manual states a minimum of 20 lbs pressure at idle, Cranking speed is way lower than idle so I would think you wouldn't want over 40 at idle or even less at cranking speed.
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