rust spots in exhaust ports of head
#21
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When I was removing the manifold bolts some weren't tight. I never heard any leak noises though. Why would a leaky gasket cause this?
#23
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Looking at these photos I would think if it was reversion the rust would be a lot worse than the pictures show. The rust would be more concentrated .I would thinks its condensation on cool down or running it on a garden hose. Last November 2014 It was cool outside 50's and I ran it on a hose to fog it. After fogging the engines I put the boat away for the winter inside my garage. The engines were close to operating temps of 150-160. Cold water in the manifolds and risers and heat from the cylinders during cool down has to condensate IMO. I'm not going to worry about it..Back together it goes today... Its been this way for years and runs great
Thanks for everyone's input
Thanks for everyone's input
Last edited by 35fountain; 03-22-2015 at 08:31 AM.
#24
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Have you looked at your bores with a borescope. If not try an borrow one or purchase or pull a head on the worst side. Something just seems strange. I just can't imagine your cams causing any issues but then again....
Now that your aware of it you'll more than likely isolate the problem.
Or you'll put it back together and try and forget you ever pulled exhaust,
Or put dry pipes and and once again solve one problem and create another.
Good luck and keep us posted on any new findings. Call emi or Hardin marine tomorrow and see what they say.
Could very well be reversion issue but my gosh I would have to go back and look however if I recall they looked similar to 454/420 hp cams.
Now that your aware of it you'll more than likely isolate the problem.
Or you'll put it back together and try and forget you ever pulled exhaust,
Or put dry pipes and and once again solve one problem and create another.
Good luck and keep us posted on any new findings. Call emi or Hardin marine tomorrow and see what they say.
Could very well be reversion issue but my gosh I would have to go back and look however if I recall they looked similar to 454/420 hp cams.
#26
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Have you looked at your bores with a borescope. If not try an borrow one or purchase or pull a head on the worst side. Something just seems strange. I just can't imagine your cams causing any issues but then again....
Now that your aware of it you'll more than likely isolate the problem.
Or you'll put it back together and try and forget you ever pulled exhaust,
Or put dry pipes and and once again solve one problem and create another.
Good luck and keep us posted on any new findings. Call emi or Hardin marine tomorrow and see what they say.
Could very well be reversion issue but my gosh I would have to go back and look however if I recall they looked similar to 454/420 hp cams.
Now that your aware of it you'll more than likely isolate the problem.
Or you'll put it back together and try and forget you ever pulled exhaust,
Or put dry pipes and and once again solve one problem and create another.
Good luck and keep us posted on any new findings. Call emi or Hardin marine tomorrow and see what they say.
Could very well be reversion issue but my gosh I would have to go back and look however if I recall they looked similar to 454/420 hp cams.
#28
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#29
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Took my exhaust manifolds off today to replace my port engine starter and noticed some rust spots in the exhaust ports of the head. I pulled all the plugs and they are dark tan with no signs of rust. Twin 509 500 HP
Boat ran great last year. Could it be condensation on cool down or slight reversion? EMI exhaust with short ss risers and silent choice. My cam is a crane 551/534 lift 226/234 duration and a 112 LSA. I know the 112 LSA is borderline with short ss risers but that's how it was built years ago.
Thanks
Boat ran great last year. Could it be condensation on cool down or slight reversion? EMI exhaust with short ss risers and silent choice. My cam is a crane 551/534 lift 226/234 duration and a 112 LSA. I know the 112 LSA is borderline with short ss risers but that's how it was built years ago.
Thanks
Bumping up the idle about 100 rpms will help some.
#30
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Crane Cams 134241 - Crane Cams Hydraulic Flat Tappet Camshafts Details
Big Block Chevy 396-454ci 1967-95
Notes:
1980 and later engines should use 271-96801 springs and 271-99957 retainers at an assembly height of 1.800".
Good mid range torque & HP, fair idle, moderate performance usage, mild bracket racing, auto trans w/2500+ converter, good w/plate or manifold nitrous system, marine applications; primarily used in 350+ HP mildly modified engines with free- flowing above water exhaust systems for performance applications, responds well to improved cylinder heads. 3200-3600 cruise RPM, 9.5 to 11.5 compression ratio advised. Good w/centrifugal or Roots supercharger, 10 lbs. max. boost w/8.5 max. compression ratio advised.
Grind Number H-286-2 (Replaces CCH-286-2)
Operating Range 2400-6200 RPM
Duration Advertised .286°/.296°
Duration @ .050" Lift 226° Intake/236° Exhaust
Valve Lift with 1.7 Rockers .534" Intake/.553" Exhaust
Lobe Separation Angle 112°
Max Lift Angle Intake: 107° ATDC
Exhaust: 117° BTDC
Open/Close @ .050" Cam Lift Intake: 6° BTDC (opens)
40° ABDC (closes)
Exhaust: 55° BBDC (opens)
1° ATDC (closes)
Last edited by 35fountain; 03-22-2015 at 07:50 PM.