timming table

[ony]

hi, I know most guys use v8;s, I rebuilt a 92 4.3 v6 put a mercruiser cam in it talk about changing the ve and timming tables. anyway how many degrezz timming is safe without damaging the engine to start with? is it normal to have to lower the ve table after installing a little better cam? I had to lower 50 kpa at 2000 rpms from 50 to 40.2 inorder to achive 128 blm

[Fast355]

hi, I know most guys use v8;s, I rebuilt a 92 4.3 v6 put a mercruiser cam in it talk about changing the ve and timming tables. anyway how many degrezz timming is safe without damaging the engine to start with? is it normal to have to lower the ve table after installing a little better cam? I had to lower 50 kpa at 2000 rpms from 50 to 40.2 inorder to achive 128 blm

It is very common for an engine with a cam to run rich in the idle and lower throttle range. In the higher RPM range it will be running lean though. The idle vacuum is often less with the bigger cam, putting you in an area of the fuel map that has higher values than the normal idle area. If the Mercruiser cam for the 4.3 is anything like the 395' marine cam for the 350 you will be seeing it running rich at lower speeds and lean at higher speeds and loads. My express went from nearly perfect to about 8-10% rich down low and about the same 8-10% lean at higher rpms with the MAF used on the Vortec engines disabled.

[ony]

thank fast,getting it tune in pretty good except when first started and after a hot soak restart idle ruff tell it gets to closed loop.

[ony]

the cam I put in my engine cam out of a boat, the man said base timming sat at 6-8 degrezz, if I set it to 6 and set the bin to 6 initial timming will it affect any things except the injectors fireing sooner?

[ony]

it runs with this table with out any knocks, I don't have any thing to compare it with. if the sensor don't show knock and you cant here pinging how much more could I run in degrezz with out engine damage?