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502 Head Gasket (I think)

Rcenter1

Rcenter1

Well-known member
A bad day
image_zpsc4c5aac3.jpg
I am starting this thread to give Jeff a break (Slingblade)

All year we have been chasing with your help why my boat was running great and then acting like it ran out of gas when it dies at high rpm and then acting flooded when trying to restart it. With Jeff's help I tracked it down Saturday. It was steam coming out of my crankcase vents attached to an undersized flame arrestor. Once the boat warmed up, the steam flowed and then displaced the oxygen inside the carb causing to to stall out and not restart until it subsided until Saturday when I took off the vents to the arrestor and it fired right back up. I took it easy and brough her in, during all this time there was no water in the oil at any point all year! I check it every time I take it out. Until Saturday. The above picture is what I found.

Steps taken
1. took out spark plugs, inspected them for evidence of burning in water. they all looked good and all were identical to each other.
2. looked for evidence of water in cylinders. There was none.
3. Unhooked ignition and had fiancé turn over engine looking for water to come out of a cylinder. There was none.
4. Took off headers looking for a sign off cracking, I am getting 4 plugs from work tomorrow to do a pressure test but I see no visible evidence of cracking or that one of them was dumping water in a cylinder.
5. Took off valve cover gaskets, I thought,,,might as well, I knew it wouldn't tell me much but they are going to have to come off anyway.lol

At this point obviously I am praying for an intake gasket problem but realistically I know I am probably gonna have to dig deeper to the head gasket and pray its not a crack in the block. The purpose of this thread as everyone knows I got 2 weeks to fix this is to prepare myself with knowledge so I don't have to hurry with the wrench. I want to plan the work and work the plan and kick this things ass. The reason I am so calm is because at least now I know where all my problems are coming from, I finally know. I don't know why it waited so long to mix with the oil, that sure would have spread up this hole knowledge process.

Some questions,

What gasket set to buy?
It is a 502 big block with aluminum heads. The rockers are a cool ass orange color. Are they all the same? I don't see very many different sets out there.
If I need serial numbers, where do I look for them at?
Should I just get the set at the local speed shop or buy marine? (Hawkins Speed Shop) in Richmond, indiana is where I usually buy performance stuff.
I have an offer on the table for a $2000 cash buy for this engine the way it sits, it seems like my engine is worth more but as we all know I'm pretty frustrated with it. I could buy a small block 350 with 365 horse plug and play everything included with 16 hours on it for like $4500. I am considering as I know the boat it came out of.. Just a thought, maybe a dumb one....

Guys thanks for all the help and if there is any more tests I can do let me know. Jeff has already educated me on what to do to clean out the engine so I am prepared for that mess.
 
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I would stick with the 502 if it can be saved. I am a smallblock fan but not over a 502. It will only push your 24 about 60 or so.The fuel economy would be a plus but probably devalue your rig.I hope it gets better for your luck because your a cool guy and you deserve to enjoy that cool boat.
 
Keep in mind I am not the best mechanic which is why the small block was appetizing.lol

Also will need to know where to go for torque requirements. Forgot to ask that in the original post.

Thanks for the encouragement.
 
Factory or ARP head bolts? It varies by bolt maker and assembly lube used. Intake bolts i believe are 35 ft lbs. Btw your orange roller rockers are probably Harland-Sharp brand and are pretty good rockers. I run the same.
 
Gimme Fuel said:
Factory or ARP head bolts? It varies by bolt maker and assembly lube used. Intake bolts i believe are 35 ft lbs. Btw your orange roller rockers are probably Harland-Sharp brand and are pretty good rockers. I run the same.
Click to expand...

They don't look like factory bolts to me but I have never took apart a big block. I will give you a call tomorrow morning. I may try to sneak another picture of the heads, it was dark by the time I got off the valve covers.
 
Head gasket change is actually not too bad at all. I have always had good luck with Cometic gaskets. The bad thing is, trying to track down WHY the head gasket blew. I rememeber hearing that your distributor was loose down at Cumberland. That could be tthe reason behind blowing the gasket. With the timing moving all around you could have gotten some detonation which will eat head gaskets all day long. I read you have replaced the ignition system, which is a good start.
 
corey331 said:
Head gasket change is actually not too bad at all. I have always had good luck with Cometic gaskets. The bad thing is, trying to track down WHY the head gasket blew. I rememeber hearing that your distributor was loose down at Cumberland. That could be tthe reason behind blowing the gasket. With the timing moving all around you could have gotten some detonation which will eat head gaskets all day long. I read you have replaced the ignition system, which is a good start.
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I also over heated twice this year, both were significant but I think I cut power before they were catastrophic. Also, I believe I was getting small amounts of steam from the crankcase vents when I bought it. But there were no vents to look at, I had to install them. The distributor was loose when I bought it too and I did not notice until my top speed was declining slowly over time. At one time I thought I loosened it but I didn't. Many many reasons it could have blown and yes the entire ignition system is new
 
First thing is to pull intake and inspect gasket surfaces there. You should be able to tell if it was leaking. If all looks good there, time to pull the head. Sounding more and more like a head gasket that may have been compromised even when you bought it. No biggie really though as long as all looks good. Once again you should be able to see where the gasket was leaking.

Cometic gaskets are very good and so are Fel-Pro. I tend to stick with the big names like those. Always had good luck with Fel-Pro.
 
I'm not that knowledgeable on these subjects but wouldn't pulling the heads and shaving them be good insurance for your head gaskets. If you over heated there is a possibility of a tiny amount of warping.
 
Yeah being that you are not running any kind of boost or crazy compression, a Fel Pro would work great too. I'm used to always having boost or large amount of nitrous to deal with in my cars. Thats why I said Cometic. I have also had good luck with Fel Pro's LocWire gaskets, but I doubt you will need anything that serious.

Does your boat have aluminum heads? If so, and you have to take them off, I would have them checked to make sure they didn't get warped a little when the engine overheated. And when you put it back together, I would invest in some ARP head bolts or studs. It sucks spending that kind of money on some bolts, but they are worth it. They won't stretch like the stock bolts and you can reuse them time and time again.
 
I second the ARP bolts if you don't already have them. Good piece of mind. Also get yourself some of their Perma-Torque lube. Very good stuff and a must for head bolts.
 
I thought originally my block had a bow tie stamped on it but i was wrong. the bow tie is stamped on the heads and the block has 8.2 stamped on it under the heads by the spark plugs. dont know if that is good or bad

Heads, bolts, and rockers
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image_zps5ce930e2.jpg


The head bolts are definitely studs with nuts
 
Chevy Big-Block V8 | Cylinder Heads


Important Technical Note: Use of the adjustable Mark IV cylinder head is not recommended with the new "Gen V engine". Changes in the configuration of the "Gen V's" coolant transfer passages allows coolant to seep into the lifter valley when the Mark IV head is used. All Gen VI block will accept Mark IV cylinder heads because the water coolant holes were decreased in size. These cylinder cases all have aluminum front covers with six bolts, not the sheet metal front cover. Mark IV camshafts, water pumps, intake manifold, distributor and clutch housings can be used with the new "Gen V" engines.


What timing cover do you have?
I think those heads are oval port. 2.25/1.88 110 pretty good head I think the came on zz 502 motors. and that may be what you have .
 
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slingblade said:
Chevy Big-Block V8 | Cylinder Heads


Important Technical Note: Use of the adjustable Mark IV cylinder head is not recommended with the new "Gen V engine". Changes in the configuration of the "Gen V's" coolant transfer passages allows coolant to seep into the lifter valley when the Mark IV head is used. All Gen VI block will accept Mark IV cylinder heads because the water coolant holes were decreased in size. These cylinder cases all have aluminum front covers with six bolts, not the sheet metal front cover. Mark IV camshafts, water pumps, intake manifold, distributor and clutch housings can be used with the new "Gen V" engines.


What timing cover do you have?
I think those heads are oval port. 2.25/1.88 110 pretty good head I think the came on zz 502 motors. and that may be what you have .
Click to expand...

I am not home anymore to check timing cover. I found these exact heads on eBay, they were attached to a zz502 motor. I am assuming Jeff that I am not going to have that problem you were talking about since my block is newer and came with these heads.

http://www.ebay.com/itm/GM-Performa...Parts_Accessories&hash=item19e0e687d2&vxp=mtr

Seems like a good price assuming it really does only have 10k on it
 
Rcenter1 said:
I am not home anymore to check timing cover. I found these exact heads on eBay, they were attached to a zz502 motor. I am assuming Jeff that I am not going to have that problem you were talking about since my block is newer and came with these heads.

http://www.ebay.com/itm/GM-Performa...Parts_Accessories&hash=item19e0e687d2&vxp=mtr

Seems like a good price assuming it really does only have 10k on it
Click to expand...

I am sure you are right.should not be a problem since you have 8.2 stamped on the block. I will have the correct intake gaskets with me.
 
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