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-   -   HP 500 EFI head gasket failure (https://www.offshoreonly.com/forums/general-q/385867-hp-500-efi-head-gasket-failure.html)

Tartilla 07-14-2025 05:15 PM

Aluminum heads on BBCs have many benefits...

Be grateful you have the room to do some surgery...I would have to pull the engine to pull the heads. Even get the exh manifolds off.

Glad you were able to get more data on how the stb head gasket failed.

As Brad said...worth just having a look at rhe rollers on the lifters and the cam lobes.

Brad Christy 07-14-2025 05:22 PM


Originally Posted by Tartilla (Post 4930362)
Aluminum heads on BBCs have many benefits...

Be grateful you have the room to do some surgery...I would have to pull the engine to pull the heads. Even get the exh manifolds off.

Glad you were able to get more data on how the stb head gasket failed.

As Brad said...worth just having a look at rhe rollers on the lifters and the cam lobes.

Tartilla,

I’d love to take credit, but that was JayTee.

But I do stand my my Cometic recommendation.

Thanks. Brad.

Shotgunn 07-14-2025 07:34 PM


Originally Posted by Tartilla (Post 4930362)
Aluminum heads on BBCs have many benefits...

Be grateful you have the room to do some surgery...I would have to pull the engine to pull the heads. Even get the exh manifolds off.

Glad you were able to get more data on how the stb head gasket failed.

As Brad said...worth just having a look at rhe rollers on the lifters and the cam lobes.

I did peek at the rollers. The main reason I bought this boat was the HUGE engine room, but I never planned on pulling the heads in there. I have extension boxes so I dont even need to pull the drives to get the engines out. Im gonna try to remember to fix the float switch before I put the exhaust back on. I dropped 2 bolts(stainless of course) and was able to simply reach down and retrieve them. I sure hope this works out, I really do prefer being on the lake rather than being in this engine room.

Tartilla 07-14-2025 09:25 PM

I bought a telescoping magnetic pick-up tool to keep on the boat....but .ost of my hardware is stainless....lol...so it mostly gets used for the odd socket that migrates to the bilge.

SB 07-15-2025 02:11 AM

I have two of these.(they fo make a much longer one too ) . Super soft aluminium. Will bend into any shape.
I broke off the magnet off one. I bend the end into a U. Size depending on objectvtrying to get. It lets me pull things forward on floor of boat under engine without getting stuck on other metal things .




JaayTeee 07-15-2025 05:31 AM

Now that you’ve schooled in doing these, you should probably plan on doing
its neighbor to the right….. I’ll bet they’re in the same condition as the head you last removed

Shotgunn 07-15-2025 07:35 AM


Originally Posted by JaayTeee (Post 4930391)
Now that you’ve schooled in doing these, you should probably plan on doing
its neighbor to the right….. I’ll bet they’re in the same condition as the head you last removed

Next time they are getting pulled lol. The other one had a top end done before I got it. The little wire lock through the intake bolt is missing and the head gasket looks different. I am unsure exactly when but was told it was recent(by the salesman, so you know its true). I am planning to yank them this winter and turn them into 509s. The boat runs plenty good so maybe just a bit of head and intake work and a better tune, and hopefully all set for another 600hrs. Maybe my next life I'll get my staggered Top Gun with some serious power, but this go round I'm a Baja baby. I really do like these HP500EFIs, the boat is pretty solid with all the luxuries you could ever want, a pretty good starter boat into a realm I wish I'd gotten into years ago.

liberator221 07-15-2025 10:42 AM

How’s the block deck under that really bad gasket?

Shotgunn 07-15-2025 10:55 AM


Originally Posted by liberator221 (Post 4930420)
How’s the block deck under that really bad gasket?

it was fine, cleaned it up and put a straight edge on it. I will work on it in the evenings and hopefully find out by this weekend.

Markus 07-15-2025 12:21 PM

2 down. 2 to go.


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