Valve stem clearance

[cgwymp]

Anyone care to hazard a guess as to appropriate valve stem clearance for an 8/1 Listeroid?  Most stuff I've dealt with in the past has used ca. 0.004" and that's what I'd probably use absent other information.  Yea/nay?

[aqmxv]

There's not a lot that is very critical on these engines.  Four thou is probably fine.  I don't think I'd go below about .003" just because of exhaust valve stem swelling.

[cgwymp]

Gary at DES sent me a box of parts (see my "Nice Christmas Present" post) and included a pair of valve guides.  These have a much better fit than the ones that came in the engine.  I haven't made any measurements yet but they feel like the proverbial "slurp" fit....

Cheers!

[oliver90owner]

Remember to check for concentriciy if changing guides.  The seats may need recutting.

Regards, RAB

[cgwymp]

Thanks, RAB.

I'm working from the assumption that they /will/ need recutting!  ;-)

[mbryner]

Speaking of valve clearance, I have a question (not that I expect anyone to be here on Christmas Eve!):

Tonight when I went to shut down my 6/1, I hit the compression release first instead of the fuel rack.   The engine didn't stop or slow down with just the compression release, which was odd.   So I turned off the fuel rack.   After it stopped, I put on the starter handle and turned the engine over.   Even though the compression release was set, there was still compression and I couldn't turn it over.   So I examined the rocker arm mechanism and there was huge amount of valve lash, and the push rods were just flopping around.   The valve lash adjustment nuts were tight and the whole rocker arm assembly was bolted tight against the head.   It seems the rocker arms themselves are loose on their shaft (correct description?).   I adjusted the valve lash to just a tiny little bit (didn't have adjustment gauge with me) and now it all runs OK.    I have been using oil lately on the rocker arm assembly instead of the grease cup when I oil the valve guides daily (but I didn't today).   Is it really bad to use oil instead of grease here?   Is this part of the break-in process?    I'm at almost 200 hours on the engine and getting good fuel efficiency, about 5 hours/gallon red diesel.

Marcus

[bschwartz]

I just use oil on mine.  I have about 475 hours and haven't seen any slop like you are describing.  Maybe there was some dirt in your assemblies when the valves were adjusted?  Hard to say.  As you did start it recently, and then all of a sudden the decompression lever didn't work, I'd have to say something was stuck where it shouldn't be and finally let loose.  Maybe something in the top of the exhaust push rod?  I'd take any parts of the rockers, pushrods etc. apart and give a good cleaning and inspection.  It couldn't take more than a half hour to take it all apart, clean and reassemble.  I'd love to hear your findings.

[BruceM]

Given the sometimes hilarious out of whack parts that come out of Rajkot, I agree with Bshwartz, a close inspection of cups, pushrod ends, and rocker arm assembly would be a good idea.  I would go further and check the exhaust valve tappet an cam, as well, if you haven't done that already. You can't go wrong with a thorough checkout, and you might save yourself some grief down the road.

[mobile_bob]

check the rocker geometry as well, some of these indian engines are terrible in that regard
allowing the rocker to basically shove the valve sideways as it tries to open it.

bob g

[mbryner]

Thanks guys.   I'll definitely take it all apart on Tuesday and report then.   That's the next available free time I can go out to my land where the engine is located.   What I can report is that it affected both the exhaust and intake sides.   Both had too much valve lash.

[JohnF]

It can be something as simple as dirt in the valve cup, eventually it breaks down and you get larger clearances.  Probably not much to worry about, clean everything up, re-set and try again.

[potter]

Yea ide go with globs of green paint in the cups .

[mbryner]

Follow up:  Checked everything out, and after another 30 hours or so of running, I haven't had any more problems.   It must have been the green paint which came out of the push-rod cups.   The valve lash seems to be stable now.   Also, I started using chainsaw oil in the valve guides and rocker arms.   It's stickier and seems to stay longer.   thanks for the advice.