New Paint

After an incredible weekend sailing I was back at the cleaning and painting of all the parts to be re-assembled.  Matter of fact I had to order another can of Yanmar Gray paint.  Didn't think I would go through a whole can on one tiny engine but this thing is going to sparkle when I'm done.  I will begin the final assembly this week.

When I was at the boat this weekend I soaked the mounting bolts in PB Blaster so I stand a chance of getting them off.  My hopes of re-using the engine mounts went up in smoke.  I had a close inspection of the mounts and looked past the rust to find the rubber crushed and compromised.  There goes $400.

I also attempted to un-stick the coupling bolts.  The nut size seems to have shrunk.  It is now somewhere between a 16mm and 17mm.  There is not enough room to get a socket on the head so I have to use an open ended wrench in a very hard to access area.  This will not be fun.  I soaked in PB and will try again in a couple of weeks.  Unfortunately it may involve vice grips.

Honing In

I have spent the last week continuing to take apart and clean up parts.  I ordered all the replacement parts that I need and they arrived so I have had a chance to evaluate further.  As previously mentioned the cylinder was measuring within specs so I decided to just hone.  I borrowed a hone and did that on the drill press.  The hone was larger than I would have liked but it fit in once it was spinning and only required 30 seconds with maybe 6 plunges.  The before and after photos don't do it justice.  It did highlight the slight ridge at TDC that was almost imperceptible before.  Still not enough to worry about.  So I am told.

Before Hone

After Hone

I spent the rest of the time wire brushing and cleaning all the parts I want to repaint; which is darn near everything.  I primed and painted about half over the weekend.  Don't know if one can of Yanmar Gray will be enough.

I ran into a problem when removing the valve guides. I put the new valves in the old guides and felt a lot of wiggle.  I slid on the new guides and no wiggle. I tried to drive the old ones out with a rod and split the back sides so I stopped.  There is a special step tool you are supposed to use.  I will try to turn one on the lathe sometime this week so I can continue to rebuild the cylinder head.  I have read where heat and cold are also used to loosen them up for removal or setting.

Parts

I am feeling very manly as I now have the motor all apart, in about 75 individual pieces.  All neatly laid out and cleaned on the bench.  I have determined that I will not re-bore the cylinder.  I have measured it a dozen times and can't duplicate the widest measurement that I had the first time.  All measurements are falling within the specifications.  So I will hone and re-ring the existing piston, re-valve the head and rebuild the motor.  I will paint all the exterior in Yanmar Gray and replace rusted out components as I go.  Replace all gaskets, seals and filters.  My only real disappointment is I can not get a good serial number off the block.  The name plate is missing and without the serial number I can not identify the year.  My Proud Parts and Pieces.

Sunk

As I continue to break this motor apart, some things are becoming quit apparent.  1.) This motor has been half submerged in salt water.  2.) Someone tried to get it apart and failed, with damage.  The biggest fight was to get the Transmission separated from the bell housing.  Someone had tried to do this before and there is evidence that they sawed their way in through the vents in the tranny case and beat the dickens out of the damper disk trying to get it to let go of the input shaft.  The damage is cosmetic and I can clean it up because the cost of a new housing was over $200 so that will be the course of action.  As evidenced in the photos you can see the water/rust line.  All of the bolts on the oil pan and the lower bolts on the timing gear case were corroded beyond saving.

The V-Pulley on the front for the motor I believe was also compromised by water.  It kept breaking as I was using the puller to get it off. I finally had to thru bolt it as the grooves were crumbling.  It did finally come off but will need to be replaced.  $60.

 The next biggest fight was getting the timing gear case off.  It was never supposed to be that difficult.  The manual just says remove the v-pulley, remove the pin on the camshaft manual starter and extract all the mounting bolts.  It was definitely trickier than that.  It was very difficult to get off.  It appears that the governor pin must be finessed at the same time you are pulling.  I was using so much force that the crankshaft bearing was coming out of the case and jamming the governor pin even more. The more I pulled the more it jammed until I finally pounded it all back together to start all over. After much finesse and help from an expert I was able to get it off with out breaking it.  A little amendment to the manual would be very helpful.

Patience

Patience is usually something I never have enough of.  On this tear down I forced my self to be patient rather than rush to make things happen, taking time to document and learn.  My tranny was still stuck on the motor bell housing refusing to come off the way the manual says it should.  I left it to soak in penetrating liquid.  The next day I replenished my supply of PB Blaster.  And soaked it again.  I was sure that only rust and 20-30 years of being together was keeping me from my goal.  I used 4 of the 8 bolts and mounted them backwards in the threads from the rear of the bell housing and clocked the tranny about a half inch so they had a flat surface to push on.  I applied heat and more PB as I slowly cranked a round in each.  Because of their position so close the housing, I could not get a socket on the head and had to use an open ended wrench. 1/6 of a turn at a time.  This slowed down the process allowing the heat and PB to work.

During this time I took measurements on the inside bore diameter of the cylinder.  I took dimensions along the center line axis of the crank at the bottom, middle and a 1/2" from the top of the cylinder.  I took the same 3 measurements along an axis perpendicular to the crank.  The center line measurements were as follows (in inches):  2.953, 2.955, 2.955.  The perpendicular measurements were: 2,953, 2.953, 2.956.  As could be expected, the upper dimensions in both directions are out of spec. The measurement should be between 2.9528 and 2.9540. The wear limit is 2.9567.  So I have one dimension that is right at the limit.  Do I just hone and re-ring or re bore to an over sized piston at 2.9626 ?

Back at the tranny; There were 5 distinct pops/cracks as as the transmission finally gave way after an hour of effort.  There was no damage to either housing or the components as far as I can tell.  I will clean up the parts and will look to replace the disk plate for sure.  I will extract the fly wheel and see if that can get cleaned up and has no fractures.  I will remove the housing on the tranny to clean it up and verify that the internal gears and bearings are all still good.  I love PB Blaster.  I sure hope the guy that invented it has retired a wealthy man.

New Project

Since the end of last year the motor has been harder and harder to start.  I chased a fuel air leak for a couple of months and once that was solved I came to the conclusion that we were suffering from low compression making a cold start difficult.  The Yanmar 1GM10 is not a complicated diesel  motor but I have no familiarity with it.  So with lots of research and talking to people I decided to try to fix the low compression my self.  Low compression comes from a leaking valve, bad head gasket or blow by in the cylinder.  Usually the later but I tried the valves and head first.  I removed the cylinder head, did a valve job and re installed with a new gasket.  The valves were tight and there was no leakage from the top end.  However, there was a lot more blow by in the bottom end.  Conclusion: Engine needs to be pulled from boat and rebuilt.

Front

Right Side

Having gained confidence from the head job, I decided I can do this rebuild my self.  However, pulling the motor out of the boat for a couple of months was advised against in case I have to move the boat out of the marina during a hurricane.  And the cessation of any sailing activity over the summer lead me to pursue another route.  I located an old used motor, age and condition unknown.  I negotiated a price and picked up a summer project this past weekend.  I will document the rebuild here with lots of picture and my inevitable mistakes for the world to see.  Or at least me and the 3 followers of this blog.

Left Side

Rear

 These pictures were taken after pressure washing and initial cleanup.  I then began tearing apart all the hoses, wires, etc to see what we had.  The starter was cracked and shot, needing replacement.  The alternator was frozen, needs replacement.  The motor will turn over by hand which indicates low compression.  Thermostat frozen, internal zinc, gone.  Transmission seems to engage in forward and reverse.  I soaked the transmission coupling  and was able to separate the old shaft.  Everything was coming off nicely until It came time to remove the transmission.  The eight bolts came out fine and the bell housing separated from the engine.  It will not come any further.  My manual says it should slide right off.  The input shaft should come out of the clutch plate splines with out any tricks.  I can not budge it.  There is evidence of rust (sever) on the fly wheel and clutch plate.  The shaft seems to be frozen in rust.  I am currently applying pressure and soaking in penetrate to see if it will give..

Carbon build up on exhaust mixing outlet

Underside of cylinder head showing valves

In the mean time I have removed the head.  Valves are as to be expected and piston looks OK.  I will try to use a micrometer to get bore gauges and see what condition he cylinder wall is in and if it needs honing or a re-bore. Once I get the transmission off I can asses the extent of the shafts and if I need new bearings etc. Included with the motor was also the control panel and associated wiring harness and the lift wet muffler.