Just put rebuilt heads on the motor and fired it up... what's that sound?

[hayward6]

Re: Just put rebuilt heads on the motor and fired it up... what's that sound?

I agree with checkmate. If you replaced the head gasket properly it really wouldn't just blow out like that. And if it is a gasket problem again, you have something else going on in there... Head gaskets usually fail because of some other factor like water in the cylinder, warpage, or not properly torqued... Check everything before you take that head off or all you'll accomplish is spending more money on a new gasket set. Check the heads good too. I've seen water passages rot all the way through to the valves! Start with the basics, and check everything.

 

[Lyle29464]

Re: Just put rebuilt heads on the motor and fired it up... what's that sound?

Maybe just compair the amount of threads showing above the adjustment nut. Left side to right side?

 

[boatinjoe]

Re: Just put rebuilt heads on the motor and fired it up... what's that sound?

Thanks all for the support. I dug in this evening and found that i, in fact,did have an exhaust leak on #7. Visual proof showed up after i pulled the exhaust manifold off... unfortunately i had already lifted the intake at that point so i had committed to the gasket set purchase...

anyway, the head gasket looked pretty good. but my torque was a bit hit and miss. i'm going to re-run the threads with a tap tomorrow and make sure i get oil under the head of the bolts before assembly. (i didn't oil last time, and i think that the bolts bound before reaching the proper torque value.)

im going to throw the manifold on a mill and try to get the flange nice and true before re-assembly and with any luck she will be back together in a couple days.



mystery sound identified.

 

[southkogs]

Re: Just put rebuilt heads on the motor and fired it up... what's that sound?

Glad you found it ... sorry it was all the way back in.

 

[boatinjoe]

Re: Just put rebuilt heads on the motor and fired it up... what's that sound?

Update:

Got the manifold on the mill tonight. Not exactly a tool I use every day, but man is it handy sometimes.



took at least .050" of each flange to get it true enough to get a good seal. even then the #7 flange still had a soft edge to it.



but it'll seal just fine.

 

[Silvertip]

Re: Just put rebuilt heads on the motor and fired it up... what's that sound?

An exhaust manifold leak does not cause low compression numbers. You need to investigate farther and don't forget sealant on the bolt threads that pass into the water jacket.

 

[boatinjoe]

Re: Just put rebuilt heads on the motor and fired it up... what's that sound?

update:

Head re-installed, valves adjusted, intake and exhaust manifolds installed. She's back together and ready for action.

 

[JasonGS]

Re: Just put rebuilt heads on the motor and fired it up... what's that sound?

Sounds good.. Glad you solved your problem..

 

[southkogs]

Re: Just put rebuilt heads on the motor and fired it up... what's that sound?

... and looks "perty" too!

Glad ya' got it worked out.

 

[81 Checkmate]

Re: Just put rebuilt heads on the motor and fired it up... what's that sound?

Nice... you got it purrrrrrring!


Happy Boating!