[C38] Head Gasket

Mon Sep 19 17:54:54 EDT 2011

Hello again Jay,
The original Universal thermostats are not magic but they are a size not used in automobiles.  I couldn't stand the idea of paying $20 for a $3 part so I bought an automotive thermostat and ground the edge down until it was the same diameter as the original Universal thermostat.

My engine ran exactly 19f for 16 yrs after that, which was when I sold the boat.  I expect that thermostat is still working fine.

The reason you have to bring your engine up to maximum temperature is because all stop leaks are thermally set. Bars uses a fiber from some kind of nut shell that clogs up any small leaks and then combined with a glue in their formula, it makes a very hard almost ceramic plug after extreme heat.  Unless the water gets really hot, the plug will never harden like it should.

Diesels hate to run cold.  I would give your boat a new thermostat, regardless of if it is one of the gold plated, super duper Universal ones or an off the shelf automotive thermostat.  You mentioned partially closing the raw water inlet.  This is probably a really bad idea but if you get your thermostat corrected, you should be fine.  

Most people have just the opposite problem, running too hot under a full load.  Our heat exchangers were a bit small for the application and a larger upgrade is a great investment if you ever decide on it but I would fix this problem first.

One other cooling Achilles heel on our boats is the exhaust riser. Unless yours has been replaced, it is probably cast iron. The inner cooling passages of the water from your heat exchanger is routed through the riser to cool the exhaust.  The cast iron rusts causing scale in the passages to stop the water flow.  We make it a rule to always look overboard to visually check the water flow every time we crank up.  This will tell if your system has clogged up as well as any loss of flow from any other reason, like a bad raw water impeller.  We once had a total loss of flow while warming the engine at the dock  Our raw water inlet had tried to suck up a plastic shopping bag.  Had I not checked the flow, we would have overheated.  We probably get more engine overheating comments here than on any other mechanical subject.

If you had a flow problem, your engine would overheat under load even with a bad thermostat running too cold.  I just mentioned these things to make you aware and also to give you something else to worry about just in case you run out of things.

TomTroncalli

----- Original Message ----- 
From: Jay Sorensen 
To: tdtron at earthlink.net;Catalina 38 Listserve
Sent: 9/19/2011 3:56:46 PM 
Subject: RE: [C38] Head Gasket

Thanks for the ideas Tom!

The complete top end gasket set was only $109 from Yacht Supply Depot.  It’s part 07916-24345 for the 1985 Kubota block and manifold that make up our Universal M-30.  Just the head gasket would have run about $45.  If your idea works then I’ll keep the kit as a spare when we cruise Mexico.

Do you happen to know how warm the engine has to be for the Bar’s to set up?  Our engine seems to run very cool (140 degrees) even at max speed and I have been wondering how to safely increase the operating temp to the 160-190 as specified.  I was hoping this would minimized carbon build up in our exhaust system.  I’ve heard an automotive thermostat may work but would like to discuss with someone with more experience.  Maybe I just need to partially close the raw water inlet valve! 

So I’ll figure out a way to re-torque the bolts in place and try the Bar’s.  And I completely agree with you on the resurface and valve grind.  My Dad was a German car mechanic and always did it to our cars when pulling a head for any reason.  Believed it was “false economy” not to.

Thanks!..............Jay  

From: listserve-bounces at catalina38.org [mailto:listserve-bounces at catalina38.org] On Behalf Of tdtron at earthlink.net
Sent: Monday, September 19, 2011 11:14 AM
To: Catalina 38 Listserve
Subject: Re: [C38] Head Gasket

Hello Jay,

Before you tear down that engine, I would try some Bar's Leak first.  Bars doesn't use aluminum which makes it a bad choice for the more modern type leak products but it is wonderful for our engines because almost none of our leaks are with aluminum components.

The Bars will not work until you have had the engine up to running temperature for at least 10 minutes.  You have indicated you have already ordered the top end gasket set.  Expensive?  Wow!  I think the head gasket alone is something like $150 if I remember correctly.

I worked in an automotive shop most of my adult life and I've seen miracles from Bar's and other stop leak products. They only work if you catch the leak while it is still small.  Adding water and putting off adding the stop leak will only allow the situation to get worse.

If the head gasket blew, it is usually from distortion of the head and stretching of the head bolts while in an overheated condition.  With cast iron heads, they usually don't stay warped like aluminum heads will but I would still re-torque the head just to be safe.  Do this before you use the stop leak product.

Anyway, that's my opinion.  If the stop leak product works, they are actually permanent repairs to the gasket.

I don't know if they still do, but the former "Big Three," GM, Ford and Chrysler, used to put a bottle of Bar's in every new vehicle they built as insurance against any small leaks. They figured it was cheaper to put in a bottle of stop leak and potentially reduce their chances of major problems with any gasket failures.

If you do decide to pull the head, I would recommend a resurfacing and valve grind while the head is out. These two operations are fairly cheap and would bring the head back to factory new condition.  Any machine shop can test the head to tell you if it needs resurfacing. if you can trust them.  Any obvious warpage can be checked by a straight edge ruler tested in several angles across the machined surface of the head.  Unless you had a nuclear meltdown, I would bet the head is OK.  To test to see if you need a valve grind, pour some mineral spirits in each cylinder with the head laying up side down. If the mineral spirits leaks out, you need a grind.  If it takes an hour or more to leak down, your head is OK.  

Tom Troncalli

----- Original Message ----- 
From: Jay Sorensen 
To: listserve at catalina38.org
Sent: 9/19/2011 12:07:11 PM 
Subject: [C38] Head Gasket

Good Morning All,

Looking for some advice here. Our beloved 5424 overheated last weekend (failed belt, during an anniversary trip!) and now there is the smallest of coolant leaks from the head gasket near the F/W pump housing.  Oil seems unaffected but I’m not sure about coolant entering the cylinders.  Any leak must be very small as after the trip the coolant level was imperceptibly lower.  I presume that at least the head gasket needs replacement and a probable machining of the head, correct??  Or does anyone on the list have any good experience with a gasket leak sealer?  I’ve never tried them and I don’t think I trust them unless I hear glowing reviews.  

So I currently plan to move the engine into the galley to remove the head and have it checked.  Doesn’t seem reasonable to try to remove it in place, correct??  Any recommendations on how to easily move 350 lbs of engine out of the engine bay??  I’ve seen videos of hoisting it out once it’s on the galley floor, but not the initial removal phase.   I’m sure someone out there has done it a few times!  I’ve ordered a complete top end gasket kit and hope to start this week.  

So far this has been a tough little motor that has always done its best by us.  We just want it to be perfect again.

Thanks for any suggestions, including why the high temp audio alarm did not work!

Jay Sorensen
C-38 Broad Reach, #311
San Diego, CA 
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