Finding Valves

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dancrosswis
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Joined: 6/6/19
Posts: 11
Finding Valves

My 1995 Universal M-35A(C) has deferred scheduled maintenance I will tackle this winter. That includes checking my valve clearances. I rebuilt a couple of motorcycle engines in my teens, but that was (ahem) awhile ago and, any way, one of them was a two-stroke.

Envisioning the task, I was brought up short by two simple questions. Which valve to adjust? And, when? When I pull off my valve cover, I want a diagram in hand to answer those questions. I have developed one.

The diagram and its explanation are in the attached .pdf.  I hope others find this useful.  I welcome comments and encourage corrections.

Dan Cross
sv Hiatus
1995 C36 MKII  TR/SK M-35A(C)

Dan Cross
sv Hiatus
Sailing from Menominee, MI
1995 C36 MKII TR/SK M-35A(C)

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pkeyser
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Joined: 5/18/13
Posts: 585

Dan-

Here are some dumb questions.

My first car was a 1970 Plymouth with a  225 cubic Inch "slant six". It became apparent that the valves needed adjustment when the car engine assumed the sound of a Sherman Tank clattering down the road. They had no preventative maintenance manuals in those days. The procedure was relatively simple, remove the valve cover, insert the correct feeler gauge, and with the engine running, adjust the rocker arm nut to the feeler gauge gap and then replace the valve cover on a noticeably quieter engine. There was no particular valve sequence other than starting with the noisiest tappet 1st.

I know a diesel engine is a much different animal than a gas engine.

-It appears that the valve adjustment would be performed with the engine not running?
-Should the engine be warm?
-Is there a recommended engine hour interval where this should be done? 
-If the valves needed adjustment, would there will be a drop in performance? Are there other indicators? Smoke? Starting difficulty? Burned valve seats? 

I've had three sailboats with diesels and I've never adjusted the valves.

You bring up an interesting topic.
 

Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B

dancrosswis
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Joined: 6/6/19
Posts: 11

Paul,

Warning:  some of your questions are above my pay grade.  And, I'm just repeating what I've read.  I wouldn't say that I'm knowledgeable.  But, here goes:

  • The adjustments are made with the engine off.
  • The engine must be cold.
  • The recommended interval for my M-35A(C) is every 500 hours.  It's covered in the Owners Manual.  My engine has over 1500 hours and I doubt the valves have ever been checked. 
  • Your last (and best) question is well above my pay grade.  Here is what Steve D'Antonio has to say:

If the clearance between the valve stem and the rocker is not within the engine manufacturer’s tolerance, then the valve will either open too far, or not far enough, and it may stay open too long, or not long enough. Any of these scenarios plays havoc with an engine’s operation, upsetting efficiency, power output and fuel economy as well potentially damaging components, and making starting more difficult, and/or producing excess smoke.

I'm not experiencing any symptoms.  It's the hours that worry me.  And, I'm babying Hiatus this winter here in Wisconsin.  I'm making it up to her after exposing her to the harshness of a couple seasons in saltwater in the Bahamas and the East Coast.  I've spent the last 3 days removing rust from her stainless fittings.  That's unheard of along the Fresh Coast.

Dan
 

Dan Cross
sv Hiatus
Sailing from Menominee, MI
1995 C36 MKII TR/SK M-35A(C)

dhickmanii
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Joined: 7/27/18
Posts: 26

I have the heads off my M-25 now. Here is a pic without the valve cover. 

 

David
Mobile, AL
S/V Beach Belle
1983 Catalina 36 Mk I #154

Std. Rig, Fin Keel, M25

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pkeyser
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Joined: 5/18/13
Posts: 585

Thanks for bring the topic up Dan. My manual is on the boat and I'll give it a look next visit. 

Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B

dancrosswis
Offline
Joined: 6/6/19
Posts: 11

Update:  it worked.

I can report that the valve adjustment sequence I pulled together from the literature works in the real world.  It was fun to see those valves "rock."

Dan Cross
sv Hiatus
1995 C-36 MKII  TF/SK M-35A(C)

Dan Cross
sv Hiatus
Sailing from Menominee, MI
1995 C36 MKII TR/SK M-35A(C)

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