#1
IP: 71.134.240.155
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Mystery sound- solved !
After all the great suggestions, I went after the mystery sound (loud knocking only under load), by attacking the valves as the source of the problem.
I changed the remaining three springs after cutting a new access panel in the engine hatch area of the cabin. That allowed me to really get at the first two cylinder's valves. I had checked the clearances before, and they seemed good. But a more careful measurement showed that while a 0.010 feeler gauge felt snug, I was able to get a 0.012 size in there as well. And for the 0.012 gap, even though a 0.012 feeler felt snug, I was able to get a 0.014 in there too. So, it was pretty easy to adjust the tappet clearance with the new access panel, and using the "feeler-in-place" method, I closed the tappet clearances until the correct size fit snug, but the next size up would not enter the gap. Duh! After re-assembly of everything, the engine started right up (whew!), and after a warm-up period, I gave it full throttle under load, and THE NOISE WAS GONE ! The mystery noise was valve tappet clearance too great in cylinder #1 and #2. A big prize to the member who guessed that possibility. And a Big Thanks to this great community for helping me get a really hard job (1 week!) done. -Rick Last edited by rpowers; 04-23-2011 at 11:35 PM. |
#2
IP: 216.115.121.253
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You must have been working hard today.
Congrats! Now send a video of the boat underway, I can't go sailing yet, so you have to for me Waiting vicariously, rus
__________________
Whiskeyjack a '68 Columbia 36 rebuilt A-4 with 2:1 "Since when is napping doing nothing?" |
#3
IP: 24.224.206.117
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Nice work.
Congrats on the fix there Rick. That was a big job so hopefully no more trouble for a while. Enjoy your season.
__________________
Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. |
#4
IP: 138.88.76.168
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Rick..nice work. I detached my 4# ground cable from the flywheel cover and my 4# (+) cable from starter today. I am still disassembling instead of reassembling.
I did some other stuff too, but the engine is far from running again!
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#5
IP: 70.27.58.76
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Don't keep us in suspense...who guessed it right???
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#6
IP: 130.36.62.223
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Video in production
For Russ,
I am in the process of making another short video showing the engine in action (boat in motion!). Nowdays I'm able to cruise at 2200rpm with lots of excess power. Stay tuned for the next video release! -Rick Last edited by rpowers; 04-26-2011 at 12:27 PM. |
#7
IP: 76.172.41.141
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Hi Rick,
I am in the process of replacing the head gasket on my A4. My question is can you adjust the valve clearance, as you did, without removing the manifold/carb/exhaust connection? Thanks, Bruce |
#8
IP: 24.224.206.117
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Bruce,
You will need to remove the exhaust manifold and carb to do it. I was looking at mine just this morning but luckily I don't have a valve problem...I was contemplating having to haul it apart. Carb: Turn off fuel valve and let go fuel line (have something to catch gasoline dribble). Let go choke cable and throttle cable from carb. Also little copper line at rear of it....let it go from the manifold. 2 bolts then and the carb is off. Exhaust Manifold: Let go the aft end of the hot section. It might be a hose and clamp on it (very likely). Remove the 3 bolts on the manifold and wiggle the manifold and hot section as one piece off over the manifold studs. Then wiggle it out of the space and the valve access cover is there for you to remove. I have a bit of room on my boat to get at the sides and the whole removal would take about 20 minutes tops. It looks worse than it is.
__________________
Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. Last edited by Mo; 07-04-2011 at 02:54 PM. |
#9
IP: 71.134.240.155
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Carb out, manifold in place
Just need the carb out of the way, manifold can be in place for valve adjustment.
-Rick |
#10
IP: 76.172.41.141
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Thanks,
I am just now investigating the valves and am not sure what the need (if anything). One question: does anyone know of a method to test for a leaky valve once the head is removed? Bruce |
#11
IP: 208.54.4.21
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Quote:
I did mine with the manifold in place too. EDIT: (Pic added for Shawn for ID-4th present )
__________________
-Jerry 'Lone Ranger' 1978 RANGER 30 Last edited by roadnsky; 07-04-2011 at 07:01 PM. |
#12
IP: 174.65.54.224
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Bruce,
Compression test should tell you something about the valves. For the most part, compression above 85 in each cylinder should imply that the valves are seating properly. With the head off I would hand crank the engine and watch each valve as it seats. It's not scientific but if you can't see a gap (do a full 360 view of each valve as it seats) you should be ok. Clean up any carbon deposits.
__________________
"Jim" S/V "Ahoi" 1967 Islander 29 Harbor Island, San Diego 2/7/67 A4 Engine Block date |
#13
IP: 167.225.107.17
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Oh man, best thread EVER!
I've been wondering what the valve arrangement of this engine was, and how to adjust them, and observe what's going on. Is it possible to put a crank handle on the flywheel and manually rotate the engine to detect valve problems? Thanks. |
#14
IP: 206.125.176.3
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Ajax, yes..the crank handle is an excellent tool to use for fiddling with the valves.
There is another thread too..check this one out...rigspelt's drawings & stickboy's picture in this thread are invaluable. --> rigs' valve thread
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#15
IP: 155.104.37.18
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Thanks, that second thread is awesome too. This will be a great help this winter.
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#16
IP: 206.125.176.3
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Yeah...I printed it out and took it to the boat with me.
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#17
IP: 167.225.107.17
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Where can I obtain a handcrank for the A-4? Is there something I can fabricate?
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#18
IP: 71.79.244.92
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As I recall, a large spark plug socket fits the nut on the end of the crankshaft but you'll need to cut slots on each side of the socket to go over the roll pin. Cautionary warning-- as with the tuning crank, don't use this to try to start the engine. Of course, you can buy the crank from MMI if you don't want to ruin a socket
__________________
Mark Smith 1977 c&c30 Mk1 hailing from Port Clinton, Ohio |
#19
IP: 206.125.176.3
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Ajax, Mark's got the right idea. You could fabricate one yourself with a spark plug socket. If you don't feel like messing with it, here is what Moyer has available.
MMI sells three different cranks. One is the 'timing' socket, which is simply two slots in a large socket to slip over the roll pin in the front of the flywheel. If you fabricated one, it would mimic this design. It will work great for setting timing, valves, turning the motor over in the winter to keep some oil on the bearings, etc. - item # IGLM_17.1_479 Here is the other one they make - item# IGLM_17_285, complete with handle: MMI also makes a 'starting' crank, which is forged or cast or something quite a bit fancier. It has specially shaped slots so that as you crank fast enough to start the motor, it will 'fall off' the roll pin. This one also does everything the first two do, with the added advantage of being designed to start the engine. - item # MISC_01_74: I've never had to hand crank my motor to start it, but I bought the fancy crank..it is cheaper and lighter than having a spare starter. On my boat, it barely clears the cabin sole, & only if I remove the bilge cover. There are some You Tube videos of guys hand starting their A4's..you should check them out! (blocked at work, so you'll have to do your own searching.)
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) Last edited by sastanley; 12-06-2011 at 09:43 AM. |
#20
IP: 155.104.37.18
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Thanks guys.
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#21
IP: 71.205.93.210
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Last edited by marthur; 12-07-2011 at 08:27 PM. |
#22
IP: 206.125.176.3
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see Ajax?? Around here you don't even have to ask and ye shall receive!
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
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