Posted: Sat Aug 05, 2006 3:02 pm Post subject: Valve adjustment
OK, I'm flumuccussed!!
Try as I might I can not get the valves to run sweetly.
Today I put the head back on, but before I put the head on and the carb etc I turned every piston to t.d.c. of exhaust stroke and set the valves to 0.016 yet when I fired her up she sounds worse than before.
Tickata tickatatickata etc.
Now my French rebuild M201 MB engine runs almost without any valve clater at all, in fact sometimes it's hard to hear that engine running!! But my m38 MC engine............ jeeze........ sounds like an army of gold miners tapping though a vien of quartzite. The big and little ends are fine, I've had the bottom end off and the big end caps and there is no disernable play, the bearings look like new, just gently worn.
Now my old chevy straight 6 I could just let the engine tick over and set those hydraulic tappets by sound, with the valve cover off, perfect every time.
Is there a trick to setting these side valve tappets??
If anybody has been following my recent woes, the lower compression on the rear two cylinders WAS due to the valves being slightly too tight and too little clearance tween the tappet and the stem.
All the best,
Thing is I only sorted the valve/tappets etc about 2000 miles ago and they were in good order then. And to be honest by the standards of other 'restored' jeeps its not too bad, even good!!
I have 4 options either;
1. Hotchkiss have a way of building super smooth engines
2. I'm too picky
3. I just don't have the knack
4. Somethings wrong someplace
However, I've just tonight noticed a weeping of water behind the distributer a horizontal crack about 3 inches long parallel with the top edge so it looks like major rebuild and complete strip of the block for stiching so this is all now immaterial. I run her to the last couple of shows of the season and then pull the engine.
When I replaced the head gasket the engine face was in need of a shaving and a shaving off the head won't hurt either. I can replace the freeze plugs at the same time and pull the cam.
With the engine out I can fit 'Herm's' duel circuit brake kit a lot easier.
Last I looked the crank was fine.
So I guess thats pretty much it for this year.
Joined: Apr 03, 2005 Posts: 256 Location: South East PA
Posted: Sun Aug 06, 2006 5:04 pm Post subject:
Be careful with that crack. If youre going to do any driving with it, the rattling of the engine, especially if it hits resonant frequency, will expand the crack even more.
Tapping is okay. Its better than setting the valves even a little too tight. However, too much tapping is not. While it wont really cause any damage, itll just run like crap at the higher RPMs.
Are the camshaft journals worn out a little bit since they were a little too tight before? Perhaps there is an uneven surface there, so youre getting your measurment from the highpoints, but the valve is still riding on the low points.
Not sure if that made any sense to you. I'm not sure if thats really that plausible. Someone with more engine rebuilding experience than me could tell you for sure. _________________ Bob Collins
1954 M38A1 MD79056
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