Valve adjustment today

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David W

David W

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Jun 1, 2004
412
Catalina 22 Victoria BC
On our 2QM15. First time since we bought her in 2004. Yes, I'm a bad owner. Clearances were a bit tight with all four at under .005 on a spec of ,008.

Notionally, that 3 thou' shouldn't make much difference but it did seem to smooth out the idle and she runs right up to max rpm with out a problem.

I'm a happy guy ( albeit with slightly dirtier hands)
 
B

Benny17441

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May 24, 2004
7,173
CC 30 South Florida
Valve lash varies with engine temperature as metals expand and contract. The manufacturer's recommended valve lash specs take into consideration a variety of engine operating loads and conditions. The prevalent school of thought is that the manufacturer specs be utilized but that in case of error it is better to err in the opposite direction. I believe the difference may rest in the adequacy of the margin of safety to prevent damage. I have in the past inadvertedly ran engines with tight valves over hundreds of hours with no ill consequences but there is really no good reason for knowingly tempting fate.
 
anchorclanker

anchorclanker

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May 27, 2012
1,152
Oday 222 Beaver Lake, Arkansas
Good to see this getting done, its that kind of work that will keep these little engines alive.

Just to add a data point, as the valve stems and push rods get slightly longer due to expansion, once at operating temperature that .005 could have disappeared entirely. I dont know what that particular engine calls for, are they to be checked hot or cold?

For example, a cold clearance of .008 could give a running clearance of .004. Seeing that yours got tighter over time, not looser, everyone should be made aware of how critical this is, or could be. Loose is mainly just noisy, tight can be a killer.
 
anchorclanker

anchorclanker

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May 27, 2012
1,152
Oday 222 Beaver Lake, Arkansas
I found the manual online, valve check cold.

I did find it humorous that the manual suggests disassembly and cleaning of piston rings and check engine bearings at 1000 hour intervals. Its ridiculousness like that that makes people give up maintenance entirely.
 
David W

David W

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Jun 1, 2004
412
Catalina 22 Victoria BC
anchorclanker said:
I found the manual online, valve check cold.

I did find it humorous that the manual suggests disassembly and cleaning of piston rings and check engine bearings at 1000 hour intervals. Its ridiculousness like that that makes people give up maintenance entirely.
Click to expand
Likewise on the intervals. As far as I can tell the 1000 hr mark essentially a minorteardown: combustion chamber cleaning, valve lapping, piston ring replacement and the aforementioned bearing and rod bolt inspection.
 
Charles Erwin

Charles Erwin

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Jan 30, 2012
1,142
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
Anchor

Can you please provide a link to the manual that says one should perform disassembly/inspection at 1000 hours?
 
anchorclanker

anchorclanker

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May 27, 2012
1,152
Oday 222 Beaver Lake, Arkansas
Okay I tried uploading the manual twice and it gets some error.

If anyone wants it I could PM it to you. At 300 hours you check Valve clearance. 500 hours you check and clean injectors, and check injection timing.

At 1000 yours, you not only supposed to remove the pistons to clean the rings, and check the crank and rod bearings, but your also supposed to lap the valves, disassemble and clean the injection pump, and disassemble the gear reduction and clean it.

Granted it would probably run like new forever, but I think you could stretch some of that work out a ways.

I had an MGB when I was a kid, the manuals service interval was about as bad as this. But we have to remember how cheap labor was back then. Big difference between $15 hour and $125. And they worked faster back then.
 
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