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Post by Milkman on Dec 8, 2007 17:49:19 GMT -5
Ok, I've got one here that has me totally stumped. Not a bus, but I've been trying to help a friend out with this one. I'll start with a little back story 1st. Helping a friend work on his 1972 beetle with a 1600cc dual port. 009 distributor PICT 34 carb. He started to have some bad oil leaks, a rattle & some tune issues. He pulled the engine out & brought it over to my house. Replaced the rear main seal, end play good. Found both intake end castings leaking, re-sealed those. Rattle noise was a loose fan nut. Put a dab of lock tight on & tightened the nut back up. Adjusted the valves, found 3 cylinders had tight valve settings. Set point gap, set static timing. Put on my cut bell housing, a fuel line & fuel, started the engine up. Set the timing at 28 degrees total advance at 3000RPM. Engine ran like a champ, no more oil leaks, vacuum leaks or rattles from the fan.
After a few minutes of running the engine started to run REAL bad. Back firing & popping out the carb. Played with the timing, no change. Shut the engine off & checked the valve adjustments. Found the valves on cylinders #3 & #4 tight again?!?! The valves are being held open slightly. Adjusted the valves on that side again to .006" while hot (just to try) & started the engine back up. Ran good for about 15 minutes while I set the timing & adjusted the carb. Then it started to back fire & pop again. Pulled the Left valve cover off. Valves were tight again.
I'm at a loss on this one & need some advice here. I'm suspecting the head/valves are bad, but just want to see if anyone else has encountered this issues before.
Greg
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Post by Milkman on Dec 12, 2007 0:28:40 GMT -5
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Post by riffraff on Dec 12, 2007 10:18:46 GMT -5
Those tubes don't look good. The boat anchor (engine I used to have in my 15 window)had tubes that looked like that when I bought it. It would do just the opposite though. It would chew off the adjusting studs such that the valves would get loose inside of a couple hundred miles. I finally retired the engine after one season because I spent more time changing adjusting studs than driving. I have not torn that engine down yet to see what may have been causing that - although I doubt I will ever know the reason. I wonder if, on that engine, the pushrods are bent a little? Even if they are, I can't see how that would cause the valves to tighten up. Are you sure the lock nuts are good and tight on the studs?? (I know, that's the first thing you checked, but I had to ask) I remember a few years ago we were having issues with Cat 3406 and 3408 natural gas engines. We were getting significant valve recession after only 10,000 hours. That is a far cry from 15 minutes of run time though! I can't imagine the valves are actually recessing into the heads at that rate, but ........  ? It will be most interesting to see what the culprit actually is! Sorry I can't be of more help . |
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Post by Milkman on Dec 13, 2007 1:58:01 GMT -5
I checked & rechecked the locknuts just for my own peace of mind Keith. Wouldn't be the 1st time something simple has bit me!  Marc has pulled the rockers & pushrods, but not sent me any pictures yet. I advised him to roll the pushrods on a sheet of glass to see if there is any wobble. They will be replaced if there is. He did send me some pictures of the heads though. #4 combustion chamber looks like something went through it at one point, but he says the top of the piston looks fine. No picture of the piston though at this time. These heads ARE going to get re-built, it is cheap enough to do. I'll keep posted on what is found with the pushrods.  |
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Post by Milkman on Jan 6, 2008 14:48:23 GMT -5
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Post by Milkman on Jan 6, 2008 20:08:20 GMT -5
Looks like we located a used cylinder. (Thanks Robin!) So I continued on with what I could while we wait for the cylinder & for the heads to be completed. My only worry (as stated in my last post) is the excessive end play. No matter how many times or ways I tried, I always got .009"  Clearances: #1 #2 #3 #4 Piston/cylinder clearance .002" .0025" .002" .002" Ring end gap (Top rings) .013" .012" .013" .015" Ring gap (2nd rings) .018" .015" .019" .015" Ring/groove clearance (top) .0025" .003" .0025" .002" Ring/groove clearance (2nd) .002" .0015" .0025" .002" Rod bearings .003" .003" .0035" .003" Crank end play (this bugs me) .009"  Next will be deck height & to cc the heads when they come back, just to see where this engine sits with compression ratio. |
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Post by dpeters81westy on Jan 6, 2008 23:37:29 GMT -5
Dished Pistons Optimize Compression Ratio.... ;D
Thanks for the details and the numbers. I'll be glad to see the blue paint disappear as well.
- DP
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Post by Milkman on Jan 7, 2008 0:01:34 GMT -5
That blue paint is nasty isn't it Doug? ;D
The more I look into this engine the worse it gets. I just finished pulling the oil pump out to reseal & found the driven gear is just about worn right off where it fits into the cam. (sigh)
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Post by dpeters81westy on Jan 7, 2008 8:01:37 GMT -5
That blue paint is nasty isn't it Doug? ;D The more I look into this engine the worse it gets. I just finished pulling the oil pump out to reseal & found the driven gear is just about worn right off where it fits into the cam. (sigh) I don't know if you've been following my build on CVD or not...but here are the links to my "simple" clean and re-build effort.. :-) www.clubveedub.ca/forums/viewtopic.php?t=23440www.clubveedub.ca/forums/viewtopic.php?t=25683 - DP |
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Post by Milkman on Jan 8, 2008 0:48:16 GMT -5
Been following since day 1 Doug! ;D Just waiting on your PC issues so we can see some more pictures. I have to compliment you on that post, it is a really good one to follow. I'm always looking forward to the updates.
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Post by Milkman on Jan 12, 2008 21:50:09 GMT -5
Well Marc & I finished up his engine today. Removed 1 crank shim & replaced with one .004" thicker, end play now at .0045" Didn't want to peen the thrust bearing, but thank you for the not advised tip Vinnie. Good thing to know, but you are right, something I hope to never have to do!  Honed the last cylinder (Supplied by Robin. Again, thank you!) Measured up the last cylinder to piston clearance, everything within specs. Cleaned everything. Installed the pistons, put the cylinders on with a little RTV on the bottoms. Checked Deck height, .060" all 4. CC'd the heads, 55cc 3 chambers, 57cc on the pounded #3 chamber. Install the new push rod tubes, put the heads on & torqued to specs. Push rods in, adjusted valves. Removed oil pump, measured & cleaned. Installed with new gaskets. Resealed everything else that was resealable & assembled the engine. Gaskatech is your friend! Took her off the stand, re-torqued the flywheel & put the exhaust on. Hook every thing up, filled with oil & fired it up. We ran it for about an hour with no hookups while I tuned & fiddled. No tightening valves, no oil leaks, good to go! Will still need a little fine tuning, but that can be done in-car as my timing light is currently out of comishion. A little priming for good measure.  Bead blasted & painted cover.  .0045" end play now. Should last until he can o/h the bottom end.  Right head. New Ex valves. New guides. Re-built.  Left head. Same repairs as right. I don't like the look of the #3 chamber, but my head guy assured us it will be ok for a stock application. He has never lead me wrong before. That was the chamber that was losing the valve adjustment before the teardown. You should have seen it before they were re-built! Sort of explains why that cylinder/piston was newer than the others!  Starting to look like an engine again.  All the bits & pieces slowly making their way back on.  And now running! Sort of a techno-colored nightmare, but color does not affect how it runs right? Marc is well aware of the issues with paint & has been advised to get some stripper & get it over to the car wash. The second I dropped the engine off, he started to put it into his car! Ah, then enthusiasm of youth..... www.youtube.com/watch?v=wPf__wJdhzYI want to take the time to thank everyone who posted & PM'd their advice for this budget repair job, as well as thank those who offered up cylinders (there were numerous offers!) and to thank Robin (buginu) for dropping off the one he supplied. Hope to see everyone at the events this summer & now we have one more enthusiest with a running car who should be joining us in some of our adventures! Greg |
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Honed the last cylinder (Supplied by Robin. Again, thank you!) Measured up the last cylinder to piston clearance, everything within specs. Cleaned everything. Installed the pistons, put the cylinders on with a little RTV on the bottoms. Checked Deck height, .060" all 4. CC'd the heads, 55cc 3 chambers, 57cc on the pounded #3 chamber. Install the new push rod tubes, put the heads on & torqued to specs. Push rods in, adjusted valves. Removed oil pump, measured & cleaned. Installed with new gaskets. Resealed everything else that was resealable & assembled the engine. Gaskatech is your friend! Took her off the stand, re-torqued the flywheel & put the exhaust on. Hook every thing up, filled with oil & fired it up. We ran it for about an hour with no hookups while I tuned & fiddled. No tightening valves, no oil leaks, good to go! Will still need a little fine tuning, but that can be done in-car as my timing light is currently out of comishion.