pros and cons of adjusting valves...

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dave_and_dd

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Apr 13, 2015
156
Catalina 309 Port Charlotte
Hey All, I'm approaching 1000 hrs on my 3ym20 (2007 Catalina 309). I do all the typical routine maintenance (oil and filter, fuel and air filters, coolant changes, impellor, changed mixing elbow, etc.) Manual says I ought to be doing a valve adjustment.

Question: Is there any issue with putting off or not doing valve adjustments if engine is running really fine? In other words, does it actually cause any damage...or just a possible slight loss of performance?

Seems to me as valve train wears, valves might not be opening quite as fully, and I might lose a small bit of performance. But I don't think wear tends to make valves too tight (which of course might cause one to burn a valve)? I hate to tear down into the engine when things run so well, giving me an opportunity to cause issues....

thanks for any insight, Dave in Charlotte Harbor.
 
Ralph Johnstone

Ralph Johnstone

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Jan 4, 2006
6,509
Hunter 310 West Vancouver, B.C.
dave_and_dd said:
Question: Is there any issue with putting off or not doing valve adjustments if engine is running really fine?
Click to expand
What have you got against removing the valve cover and adjusting the valves ? It's one of the simpler maintenance tasks for your engine. A piece of cake compared to replacing the %^$&*@# mixing elbow or repacking the shaft gland. I believe your service manual will have a detailed procedure of how to do it. I'm not sure if the current service manual for a 3YM has the procedure but the Yanmar shop manual for my @GM20F has it and it's left foot, right foot, left foot all the way. All it really requires is a grade four reform school education and that's an exaggerated requirement.
 
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kloudie1

kloudie1

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Nov 6, 2006
9,898
Hunter 34 Mandeville Louisiana
The problem with not checking the clearance is that you won’t know before a valve burns and you won’t have an opportunity to avoid a costly head rebuild. It is an easy job but if you are not familiar with it, get a friend who is to walk you through the process. Using a feeler gauge is a little tricky the first time. People don’t think about valve setting much any more since most cars use hydraulic devices to automatically set the valves.
 
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Hayden Watson

Hayden Watson

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Apr 5, 2009
2,819
Catalina '88 C30 tr/bs Oak Harbor, WA
The valve will burn if the gap is too small which causes the valve to not be against the seat long enough to cool it. If the gap is too big, you will lose performance, it will be harder to start and it will increase the wear on stem, lifters, pushrods and cam due to the impact of the system caused by excessive gap.

What Are Symptoms Of Valves Needing Adjustment? - Honda The Other Side
 
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D

dave_and_dd

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Apr 13, 2015
156
Catalina 309 Port Charlotte
Hey, thanks guys for the comments. Yep, I know it's recommended and I know it isn't all that difficult, but some health issues are making me need to put it off a (short) bit. But the insight that helped the most is Hayden above. The idea if it is too loose, it will increase wear on the various parts of the valve linkage. I know if it's too tight it could burn a valve, but they rarely wear and become too tight (maybe you all can let me know if you have seen such a thing as that - i've only experienced valve lash becoming looser with wear).

Anyway, good info, I will put it on my "to do" list for as soon as I can when I get to the 'magic' 1000 hrs.

Thanks, Dave in Charlotte Harbor
 
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Davidasailor26

Davidasailor26

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May 17, 2004
5,086
Beneteau Oceanis 37 Havre de Grace
dave_and_dd said:
The F---ing Manual
Click to expand
You spelled Funny wrong. ;)

Glad you asked the question. My 3YM30 will be coming up to 1000 hours in the next few years, and based on these answers I’ll keep valve adjustment on my schedule.
 
jviss

jviss

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Feb 5, 2004
6,748
Tartan 3800 20 Westport, MA
@Hayden Watson really did nail it. I agree with everything he said, in particular how too-loose valve trains can lead to excessive wear, in particular, peening of of the tops of the valve stems; this makes them super difficult to remove when you have to replace the burnt valves due to loose valve trains!
 
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danstanford

danstanford

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Aug 2, 2010
502
J-Boat J/88 Cobourg
The bigger risk in my opinion is that something will be done wrong during the adjustment process leading to a problem. Follow the process carefully!
 
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jviss

jviss

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Feb 5, 2004
6,748
Tartan 3800 20 Westport, MA
danstanford said:
The bigger risk in my opinion is that something will be done wrong during the adjustment process leading to a problem. Follow the process carefully!
Click to expand
Well, then he should have a pro do it. It's really not hard, and it's also easy to check the valve clearances, before and after the adjustment.
 
Hello Below

Hello Below

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May 7, 2012
1,354
Hunter e33 Maple Bay, BC
1. Read over the procedure on 2.2.2(5) - page 23 of the 3YM30 Serivce Manual.
2. Prepare the engine for valve adjust by removing rocker arm cover. Access the front end of the engine and set aside a long socket wrench with appropriate sized socket for large nut on crankshaft.
3. Dig out a bill with Ulysses S. Grant on the front of it.
4. Stop the first competent marine mechanic going by with his tool box.
5. Watch, ask questions and learn.
6. At 2,000 hrs carry out adjustments on your own
Edited: “arm rocker” to read rocker arm cover.
 
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Ralph Johnstone

Ralph Johnstone

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Jan 4, 2006
6,509
Hunter 310 West Vancouver, B.C.
danstanford said:
The bigger risk in my opinion is that something will be done wrong during the adjustment process leading to a problem.
Click to expand
The OP has done all the typical routine maintenance (oil and filter, fuel and air filters, coolant changes, impellor, changed mixing elbow, etc.) If he's done that, he's prepared to adjust the valves blind folded, with one hand tied behind his back, after a wild night of heavy drugs.

Leaving his dock and motoring out into open water to raise the sails is far, far, faaaar more complicated than adjusting the gap on the inlet and exhaust valves.
 
D

dave_and_dd

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Apr 13, 2015
156
Catalina 309 Port Charlotte
Ralph Johnstone said:
The OP has done all the typical routine maintenance (oil and filter, fuel and air filters, coolant changes, impellor, changed mixing elbow, etc.) If he's done that, he's prepared to adjust the valves blind folded, with one hand tied behind his back, after a wild night of heavy drugs.

Leaving his dock and motoring out into open water to raise the sails is far, far, faaaar more complicated than adjusting the gap on the inlet and exhaust valves.
Click to expand
In addition to the above quoted by Ralph, in my "youth" - (50 yrs ago) I have dismantled VW engines and rebuilt them including adjust valves, and also did a ring and head rebuild on my first car (a 1960's Plymouth Belvedere with a Slant 6).

On a practical note, what could I screw up on this job?
  • adjust valves too tight - yeah, that would burn them. but unless you are cramming a feeler gauge in it should be pretty easy to tell if you are doing it too tight.
  • adjust valves too loose - ok, but hopefully don't do that - slight drag on a feeler gauge.
  • I don't know: forget to tighten the locking nuts on the adjustment screws? Yeah that would be bad
  • not replace valve cover correctly? maybe leak oil?
what else could I do wrong?

Finding TDC on each cyl can be a pain, but is usually pretty evident when you get it.

other thoughts??

thanks, Dave in Charlotte Harbor
 
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jviss

jviss

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Feb 5, 2004
6,748
Tartan 3800 20 Westport, MA
Biggest beginner risks:
* not being able to precisely measure the gap with a feeler gauge. This requires practice, and "touch." Measure the existing clearances (turning the crank as appropriate), record them, then do it again, and again, and see if you are repeating the same measurements.
* risk of not properly tightening the lock nut. This also requires "touch," or a torque wrench and a set of small, crowfoot wrenches.
*causing a valve cover oil leak. Not the end of the world. Maybe have a new gasket on hand.
 
jviss

jviss

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Feb 5, 2004
6,748
Tartan 3800 20 Westport, MA
dave_and_dd said:
In addition to the above quoted by Ralph, in my "youth" - (50 yrs ago) I have dismantled VW engines and rebuilt them including adjust valves, and also did a ring and head rebuild on my first car (a 1960's Plymouth Belvedere with a Slant 6).

On a practical note, what could I screw up on this job?
  • adjust valves too tight - yeah, that would burn them. but unless you are cramming a feeler gauge in it should be pretty easy to tell if you are doing it too tight.
  • adjust valves too loose - ok, but hopefully don't do that - slight drag on a feeler gauge.
  • I don't know: forget to tighten the locking nuts on the adjustment screws? Yeah that would be bad
  • not replace valve cover correctly? maybe leak oil?
what else could I do wrong?

Finding TDC on each cyl can be a pain, but is usually pretty evident when you get it.

other thoughts??

thanks, Dave in Charlotte Harbor
Click to expand
Wow, I was typing my reply as you wrote this. I think we mentioned a few of the same things.
 
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