Black Baja

iTrader: (2)

Ask the builder where he installed the cam. I bet it was put in to far advanced. Those stock cams go in at something ridiculous like 116* or 118*

SB

iTrader: (1)

If it's the hyd roller 502 Mag:
If flat tappet

Tidewater757

UPDATE: I was told by another engine builder in our area that if the block had been decked and the heads shaved you must install adjustable rocker arms to make up for the difference, sounded pretty legit to me so I had my engine builder do that yesterday when I started the motor with the vacuum gauge on the motor it had 14 inches of pressure, I thought it was fixed so I took the gauge off and waited for the engine to warm up so that I could double check the timing, the engine was surging and started to run real rich so I put the vacuum gauge back on and we are back down to only 7 inches. Any ideas??

drumerjb

Sounds like a valve seating issue. Seating when cold & loosing tappet clearance as temps rise. It will burn rich depending on how much compression is lost due to incorrect tappet clearances. Hear any vacuum leaks?

articfriends

iTrader: (1)

If your engine builder assembled a motor w non adjustable valve train without checking lifter preload /valve lift and was actually too tight then you need a new engine builder! Did you flow injectors? Any chance someone installed a 2 bar map sensor?

Griff

Possibly still valves adjusted too tight. Once the lifters fill with oil pressure and are pumped up, they might not be allowing the valves to close all the way.

SB

iTrader: (1)

Tidewater - I just did a OSO forum post search of you to see if any history on this that you have not presented in this thread, and I found a lot.

http://www.offshoreonly.com/forums/s...archid=3356677

For us to help, we need this history 'cleaned up' and presented on this current thread so we can be more knowledgeable on this issue and past issues that are probably interrelated to each other.

Also, please include things like if this engine was the previous one you had issues with, what they where, new boat to you, if ECU's are original or have been replaced by you or prevous owner, if any reprogramming has been done by you or previous owners, if superchargers or etc had been previously installed, etc, etc

Tidewater757

Yes the fuel injectors were rebuilt and flowed. The MAP sensor was swapped with the known good running motor with no effect.

Tidewater757

No this is a new rebuild so that the previous issue with the port motor. The ECU is the same one that the boat came with and presumed to be stock, and has been swapped with the port motor to rule that out. Never had a super charger.