• Mobile App For Android Now Online!

    Download it here. The app is searchable in the Google Play Store under Sailboat Owners.

    Sorry iPhone/iPad users, we are still waiting on Apple. :(

    Click the X in the upper right corner to make this go away

3GM30F Cam shaft cover?

Oct 26, 2008
4,570
Catalina 320 Barnegat, NJ
Hello engine gurus! I'm not pleased about the appearance of my engine and I want to remove, clean and re-assemble various parts, at least so I can monitor what's going on inside the engine compartment a bit more easily. I have a little oil leakage, I'm afraid, and I want to at least isolate the source if I can. It's hard to do with all of the grime. That said, I'll start with changing out hoses as well. It's hard to know where to start. I changed out the sea water pump belt and the alternator belt looked fair enough to leave.

During that episode, I was curious about that cover right behind the belt. It appears to be a cover over the cam shaft and I tried to remove it, mostly out of curiosity. I got the top screw off with an impact driver, but the bottom screw got buggered and won't budge, Is it worthwhile to remove this? It leads to my question about what is behind the timing gear case. Service manual shows removal to inspect and service the oil pump. I guess my question is ... is it worthwhile to pull off the pulleys, remove the case and service the entire system, including crankshaft, camshaft & oil pump? Is it something I could tackle?

The engine is 20 years old but new to me this year. I know that it has been serviced every year, but I haven't read the service tickets in detail to know what has been done exactly aside from oil changes. It just looks like it needs some service to me, but I didn't experience any performance issues since I brought the boat home in early July. I did have to add oil, though, following our trip home from Massachusetts, mostly under power. Wanting to be proactive ...

IMG_3141.jpg


Am considering changing to a serpentine pulley system for the high-output alternator, btw.
IMG_3140.jpg
 
Last edited:
Jun 8, 2004
2,437
Catalina 320 Dana Point
Yeah, no it's not worth removing anything you don't have to, oil leaks are probably valve cover. Mine looked almost as bad before I recently cleaned and repainted. I took out the wood panel in back for better access and to varnish anyway. Remove hoses, cables etc. in the way, cleaned corrosion with brass wire wheels and dremel with polishing heads for the nooks and crannies. Engine block paint touched up with $25 spray can of Yanmar silver. The rusty SB engine mount (That one always rusts) primed with Rusty metal primer and gloss black with a brush.
engine.jpg
 
  • Helpful
Likes: Scott T-Bird
Nov 6, 2006
8,861
Hunter 34 Mandeville Louisiana
Hey, Scott.. Lots of that grime looks to be belt dust.. That will come off easily with spray 409 and a parts brush.. Put a bag over the alternator or remove it and blow it out to get the dust out of it so as not to wet it with detergent.. There is a lot of stuff behind that cover.. The injection pump has to come off with its timing shims and the governor has to be disconnected from the injection rack of the pump. I wouldn't try to service the oil pump unless you see evidence of low oil pressure .. something like the pressure warning light blinking on at idle speed.. The cover right behind the belt is a cover for the old manual hand crank.. There is an oil seal right inside.. so you'd see the tip of the camshaft and a cross pin where the crank handle engaged.. From the picture, it does not look to be leaking there..
 
Oct 26, 2008
4,570
Catalina 320 Barnegat, NJ
I took out the wood panel in back for better access and to varnish anyway. Remove hoses, cables etc. in the way, cleaned corrosion with brass wire wheels and dremel with polishing heads for the nooks and crannies.
I was wondering if that panel comes out easily. I removed that trim at the upper right and the screws across the top. It loosened but wouldn't give on the left side. I figured that block on the floor had to come off, but it wasn't in the program for the afternoon so I put everything back together without going any further.
 
Oct 26, 2008
4,570
Catalina 320 Barnegat, NJ
There is a lot of stuff behind that cover.. The injection pump has to come off with its timing shims and the governor has to be disconnected from the injection rack of the pump. I wouldn't try to service the oil pump unless you see evidence of low oil pressure .. something like the pressure warning light blinking on at idle speed..
Thanks for that input. You are talking about the timing gear case, right? I figured it would be pretty involved and I don't have a performance issue like you describe … yet. I am wondering what should be (should have been) done for servicing this engine with close to 2000 hours. I'll spend the money to take care of it if I can avoid a replacement down the road.
 
Jun 8, 2004
2,437
Catalina 320 Dana Point
On the corner in the aft cabin there are screws under the corner trim going into the piece behind the engine. That part comes out fairly easy once you find the screws on backside. I also removed door and wall panel for aft cabin, that was a PITA and required I take just enough off the corner to get it in and out.
 
  • Helpful
Likes: Scott T-Bird
Nov 6, 2006
8,861
Hunter 34 Mandeville Louisiana
I was talking about the little cap directly behind the belt, the one with the buggered screws.. The first part is about the timing case.. I was not clear on that..
Servicing... The only thing that should be serviced is the valve clearance.. Pull the valve cover and check per the service manual (interval is 500 hours).. The other thing is occasionally cleaning the heat exchanger bundle, and changing the oil and filter at regular intervals.. belts ands water pump impeller.. That is pretty much it..
 
Nov 26, 2012
1,388
Hunter 34 Berkeley
That actually doesn't look bad to me. I recommend repairing any leaks and, of course, keeping the engine clean helps in spotting leaks and belt dust. One thing that I am super uptight about is leaks in the raw water system. Salt water leaking down onto the engine always creates corrosion issues.
 
  • Like
Likes: kloudie1
Jan 22, 2008
1,539
Hunter 34 Alameda CA
It's the old adage, If it ain't broke, don't fix it. However in my case I had a pretty significant oil leak around the timing gear cover due to a failing gasket. I found this procedure on-line and pulled the cover from the engine. It wasn't too bad. It took me 4 hours. I'll include the procedure for reference in case something changes.
 

Attachments

May 24, 2004
6,539
CC 30 South Florida
My take on oil leaks is that the difficulty of fixing it is directly proportional to how large it will get.
 
Oct 26, 2008
4,570
Catalina 320 Barnegat, NJ
It's the old adage, If it ain't broke, don't fix it. However in my case I had a pretty significant oil leak around the timing gear cover due to a failing gasket. I found this procedure on-line and pulled the cover from the engine. It wasn't too bad. It took me 4 hours. I'll include the procedure for reference in case something changes.
Ok, so that is a great source of information and my engine number starts with E and is in a 1999 boat. That seemed to be pretty specific to the gasket problem described. I find that the oil drips are black and seem to collect on the port side in the pan underneath the engine. When I reach under to clean it up, I usually find black spots on the back of my hand, which usually brushes the underside of the oil pan. Now that I know where to look for a damaged gasket, did you actually see the damage before you removed the timing case?

As an aside, I suspected leakage at the connection between the engine block and the oil pan. I suppose there is a gasket there, but the only way to possibly change it would be to yank the entire engine, so I don't imagine that is going to be an option even if the leak is there.

The procedure does not sound bad at all, to me, to replace the timing case gasket! I'm guessing that the linkage at the fuel rack pin / governor is tricky and that makes me uncertain. Also, the timing shims are completely foreign to me and I would be very concerned about damage or displacement … it just sounds particularly concerning to me. Aside from those 2 issues, I would be pretty enthused about replacing the gasket if I knew for sure that it is damaged. How can you tell before disassembly?

I could manage the leak and top off as necessary, but I would prefer to eliminate the leak if all it takes is replacing a damaged gasket. It is particularly helpful to know that it is a known problem for my particular engine!
 
Oct 29, 2005
2,108
Hunter Marine 326 303 Singapore
Scott, I've repaired this leaking timing gear cover gasket back in 2013. You probably have to remove the high pressure pump before re-installing the timing gear cover. Do put back all timing shims in same order. Hope these photos helps.

Ken Y
 

Attachments

  • Like
Likes: Scott T-Bird
Oct 26, 2008
4,570
Catalina 320 Barnegat, NJ
Scott, I've repaired this leaking timing gear cover gasket back in 2013. You probably have to remove the high pressure pump before re-installing the timing gear cover. Do put back all timing shims in same order. Hope these photos helps.

Ken Y
Thanks everybody! This has been hugely helpful!
 
Jan 27, 2008
2,963
ODay 35 Beaufort, NC
Scott, nothing worse than phillips head screws, except slotted head screws. I'd replace those screws with either a socket head cap screw (so you need an allen wrench to remove) or I'd put in a stud with a lock nut so you can remove with a socket wrench. The one you got buggered up you could try to cut a slot with a dremel and use a flat screwdriver, or tack weld a bolt on it so you can use a wrench, or cut flats on the sides and try to use a wrench or vice grips on it.
 

jerry

.
Jun 9, 2004
61
Catalina 320 500 Stockton, Mo.
Yanmar 3gm30f camshaft cover
To be clear, the small cover behind the belt is a camshaft cover. IF it is leaking oil, remove the cover and using a needle nose plyers pull out the seal. Install the new seal using a socket and tap it in flush. Very easy. Just did mine this summer. I don't remember the part number, I ordered from Toad Marine online. Cost was less than $10. Getting that screw out will be the biggest issue. Those cover screws do not need to be tight. I tried to make a gasket for the cover which did not fix the leak. Lessen learned - Do it right, do it once.
 
Oct 26, 2008
4,570
Catalina 320 Barnegat, NJ
Yanmar 3gm30f camshaft cover
To be clear, the small cover behind the belt is a camshaft cover. IF it is leaking oil, remove the cover and using a needle nose plyers pull out the seal. Install the new seal using a socket and tap it in flush. Very easy. Just did mine this summer. I don't remember the part number, I ordered from Toad Marine online. Cost was less than $10. Getting that screw out will be the biggest issue. Those cover screws do not need to be tight. I tried to make a gasket for the cover which did not fix the leak. Lessen learned - Do it right, do it once.
Hello @jerry ,

The camshaft cover doesn't leak, although I will be annoyed until I can get that screw out. On Sunday, I went sailing and ran the engine for half hour going out and half hour coming back in. I didn't run the engine hard, but just hard enough to warm her up. I wiped down the engine block all around the timing gear case, particularly at the lower end before going out, to start with a clean finish. I also put a pad down to see where the oil drips might originate.

So, I didn't have any drips because I didn't really heat it up, but there was a significant amount of oil oozing from the bottom edge of the gear case. I can't see any of the gasket but it is pretty clear that the gasket leaks. There wasn't a lot of oil, just enough to get a pretty good slick on my finger as I ran it across the bottom of the case. Just like in @Ken13559 's 1st photo!

That pretty much concludes my investigation on that front! I think I will replace the gasket this winter. What more to do is yet to be determined!