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-   -   Aluminum cyl head question???? (https://www.offshoreonly.com/forums/general-q/286356-aluminum-cyl-head-question.html)

prostockcat 10-13-2012 02:48 PM

Aluminum cyl head question????
 
I HAVE CANNFIELD ALUMINUM HEADS ON MY 540s. JUST HAD THEM REDONE WITH NEW GUIDES ON BOTH SETS,VALVE JOB ETC. BOAT WENT GREAT AT THE BEGINNING OF THE YEAR AND HAS SLIGHTY FELL OFF ON TOP SPEED. I DID A COMPRESSION TEST AND LEAKDOWN TESTON BOTH MOTORS ONLY TO FIND I HAVE 7 WEAK CYLS BETWEEN THE TWO MOTORS. ALL LEAKING OUT EXHAUST VALVES. QUESTION IS ARE THE EXHAUST GUIDES PUSHED THROUGH WATERPORTS? IT LOOKS ALL WET AROUND THE BOTTOM OF THE GUIDE THAT STICKS INTO THE EXHAUST PORT.

Full Force 10-13-2012 04:12 PM

Do yopu have INCONEL valves??? you can tulip valves and start to lose sealing ability...

MILD THUNDER 10-13-2012 04:25 PM

If you tulip the exhaust valves, and they dont seal well, it can suck water back in from the exhaust when the piston goes down. Thats probably where your water is coming from.

Full Force 10-13-2012 04:31 PM


Originally Posted by MILD THUNDER (Post 3795309)
If you tulip the exhaust valves, and they dont seal well, it can suck water back in from the exhaust when the piston goes down. Thats probably where your water is coming from.

I would start there for sure......been there..!

prostockcat 10-13-2012 06:00 PM

They r inconnel. I have a cam with 110 centerline. I'm just trying to see if the guides didn't seal properly. That's why I'm wondering if they go through watterports

Unlimited jd 10-13-2012 06:18 PM

Yes they do and guides can rot through

Full Force 10-13-2012 06:23 PM

Yea...but even with messed up guide....should still seal....look for tuliping

MILD THUNDER 10-13-2012 06:24 PM

Inconel valves can tulip also.

What did you have timing set at? Considering both engines are showing issues, Im gonna rule out exhaust problems, cracked head, etc. .

I believe your heads have the guides thru the water jacket, but not sure with a canfield head.

Full Force 10-13-2012 06:32 PM


Originally Posted by MILD THUNDER (Post 3795351)
Inconel valves can tulip also.

What did you have timing set at? Considering both engines are showing issues, Im gonna rule out exhaust problems, cracked head, etc. .

I believe your heads have the guides thru the water jacket, but not sure with a canfield head.

Yes they do!!!! I had inconel tulip this summer......got lucky it didn't break....

mike tkach 10-13-2012 06:33 PM

my guess is timing set to low and egt,s are sky high,i have seen this happen even with inconel valves.


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