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525efi reversion need help?

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Old 08-03-2011, 10:56 AM
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Default 525efi reversion need help?

I have a fresh built 525efi its been boared 30 over to 509 ci. it also had this cam in it when i got it Teague marine 236/234 duration, 610/632 lift, LSA 112. The cam is almost identical to the stock 525 cam except the LSA is 112 vs merc. 114. Boat has brand new Gen X headers and new stock wet tailpipes. Ran the motor, the looked up tailpipes it had some water drops on top side of tailpipe and water drops forming at the header collector. Took headers of and found water in all of the header ports, about a teaspoon full. I have called several people and they say that cam should not cause reversion. Could it be condensation, I have run out of options?
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Old 08-09-2011, 09:02 AM
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where is cam installed at? The lobe separation is 112. When degreeing the cam, it needs to be in at 107 or 108 intake center atdc. If installed with intake centerline at 112 atdc you may have more reversion because the exhaust valve is open further past tdc on the overlap. It will usually make more power with cam advanced about 4 degrees as well. Just my experience with these cams.
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Old 08-10-2011, 09:44 PM
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The builder had the cam card, originally it was advanced 4 deg. But I told him to put the cam back to the stock position because I thought thats what was causing the reversion. Unless he's blowing smoke up my a$$ its set back to the cam card specs. The motor is back in the boat.
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Old 08-10-2011, 09:46 PM
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Is there any way to see if the cam is in the stock position by checking the timing?
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Old 08-10-2011, 09:56 PM
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Ignition timing? No cam timing yes pull the front cover and see what timing marks were used
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Old 08-11-2011, 02:20 AM
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Seems strange that the camshaft specs you are giving are showing 2 degrees less exhaust duration than intake duration. Not very common or really ideal on that engine package.
Yes, if the camshaft is installed straight up with a 112 degree LSA on that spec. in such an efi engine with the short exhaust duration it would have some uneeded overlap which could cause addtional exhaust moisture to travel back into the headers and obviously possibly into the engine. If the camshaft is actually installed slightly retarded this condition would be even more of a problem.
Have those CMI stock headers been pressure tested and checked for leaks? The problem here could be leakage and not reversion.

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Old 08-11-2011, 09:51 AM
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raylar CHECK YOU HEADERS CHECK YOUR HEADERS your leaking
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Old 08-11-2011, 12:06 PM
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Headers and tailpipes are brand new only have 5 min of idle time on them.
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Old 08-11-2011, 12:19 PM
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My brain is always leaking at my age and daily grind!
When we cam doctored the stock HP525efi camshaft for a new profile we came up with for our HP675efi package I don't remember the stock 525efi camshaft having a shorter exhaust duration than the intake and yes it did have a 114 lobe center and about 2 degrees of advance ground into the camshaft we measured does help and in that engine, that does help lessen the chance of exhaust reversion. I'll check our measurements but I believe we found intake @[email protected]" and the exhaust I believe was [email protected]".

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Old 08-11-2011, 12:56 PM
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Checked my cam card and made a typo. 236intake 244exhaust @50. Lift 610/632. LSA 112

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