Possible blown head gasket on olds.

« **on:** August 22, 2016, 02:34:29 PM »

My boat recently started running bad (missing/ running on 7 cylinders) and running hotter. Full disclosure; I have a Hardin bypass thermostat kit that has worked great. I also have a regulator with overboard dump. I know right off the bat some of you would tell me to ditch those items but they have been working flawlessly for a while previous to this problem. So I pulled the plugs and found the right side middle two fouled with fuel - but one slightly rusty and had what looked like water on it. So....head gasket most likely right? Just wanted to ask for any pro tips on doing the head gaskets; or, what brand and type work best for this application. Copper spray? Also, it looks like it has a one piece turkey tray intake gasket in it now. Does anyone reuse the valley pan section (cutting off the gasket part) and install composite gaskets? I've done this with a previous olds powered boat but didn't own it for too long after I did the work to know if there were any issues. Also what about exhaust port block offs?

« **Reply #1 on:** August 23, 2016, 09:04:10 PM »

Quote from: evilb on August 22, 2016, 02:34:29 PM

My boat recently started running bad (missing/ running on 7 cylinders) and running hotter. Full disclosure; I have a Hardin bypass thermostat kit that has worked great. I also have a regulator with overboard dump. I know right off the bat some of you would tell me to ditch those items but they have been working flawlessly for a while previous to this problem. So I pulled the plugs and found the right side middle two fouled with fuel - but one slightly rusty and had what looked like water on it. So....head gasket most likely right? Just wanted to ask for any pro tips on doing the head gaskets; or, what brand and type work best for this application. Copper spray? Also, it looks like it has a one piece turkey tray intake gasket in it now. Does anyone reuse the valley pan section (cutting off the gasket part) and install composite gaskets? I've done this with a previous olds powered boat but didn't own it for too long after I did the work to know if there were any issues. Also what about exhaust port block offs?

Recheck your engine water pressures. 10 to 15 pounds maximum or you will "seep" all kinds of gaskets.
Any good head gasket will do okay. I use cometic gaskets torqued to 95 pounds.
Ditch the turkey tray. Use a good quality intake gasket. Mondello sells a small tray you install in the lifter Valley to replace that big tray. It helps control oil spray under your intake manifold.
That exhaust port block off is a completely different animal. Some intake gaskets have a plate you can use however they don't seem to work very well or the last very long. Factory Oldsmobile heads have a "Siamesed" exhaust port arrangement in the 3 4 5 + 6 ports. To properly address that situation you should talk to someone at Modello or purchase aftermarket heads all.
Good luck.

« **Reply #2 on:** August 23, 2016, 10:18:55 PM »

What's the oil look like? Any water? Is it milky?

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« **Reply #3 on:** August 24, 2016, 06:53:31 PM »

It should be noted that the Cometic and other MLS gaskets require a different surface roughness finish than composite gaskets, in order to seal properly. The type of gaskets were determined when the block and heads were decked.

You really should do a compression test before proceeding. That will give you an idea of the condition of your engine. If you don't have a compression tester, AutoZone and O'reilly have loaner tools. Just beware that the loaner tools are pretty abused. Don't look so much at the actual numbers so much as comparing PSI from cylinder to cylinder, unless you are using a trusted compression tester.

If the two suspect cylinders are down on compression, you could do a leakdown test. Air leaking from the valve cover breathers could be rings or a blown head gasket. Air leaking from from the cooling system would be a blown head gasket. Air leaking from the carb or exhaust would indicate valves not sealing.

Good luck,

Joe

« **Reply #4 on:** August 24, 2016, 07:00:19 PM »

Some of the older heads had issues with water jackets around valves cracking... One of my G heads cracked between valves after gate valve being opened all the way... didnt realize it till afterwards. Just took one trip back from sandbar...

« **Reply #5 on:** August 25, 2016, 04:46:09 AM »

Thanks for the replies guys. I've been busy so haven't gotten the compression test done yet. Will do soon. Maybe a tiny bit of water in oil. But at the same time it started missing it seemed to start running hotter too. up to 200 degrees. before it was right around 160.

I don't think the pressure was too high but I'll recheck the regulator. I did milkshake it before. That's why I got the regulator. I'll report back after the compression/leak down.

evilb

Possible blown head gasket on olds.

vwagon13

Re: Possible blown head gasket on olds.

trido

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Flusher

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Your Mom

Re: Possible blown head gasket on olds.

evilb

Re: Possible blown head gasket on olds.