mercruiser 4.3 overhauling

[ste80]

if you are running a carb, I would go for a slightly more aggressive cam than the stock ones.

:O thanks; wich one is one more agrssive?
yes i will go for carbs, that part of lx wont change, mine is 4 bar carbs (200cv)

 

[ste80]

Te later one replaces the earlier part number so it is the same. If you look up mercruiser lifter part numbers they are the same i think, one supersedes the other.
Given you got it as a pile of parts , Not sure how you tell if they are ok. Even in the US from summit racing they are about $300 a set.
risk is if the engine had water in the oil or something if they are ok.

thanks; actually the lifter are still available for both of them, i didn't find as per the came or other components the voice replace number xxxx.
in this case the numeber are same but with ine (1) as suffix 811844 and 8118441, tomorrow i will check dimension with caliber but looking just like that it seems same so maybe spring inside is different or other small things. but as said maybe better not risk so better to keep original lx one in place. Alalso if the purpose of the lifter is jut keep the road in touch with the came so it should not be a big difference i think

 

[Scott Danforth]

:O thanks; wich one is one more agrssive?
yes i will go for carbs, that part of lx wont change, mine is 4 bar carbs (200cv)

the mercruiser cam has a valve lift at .290 @ 0.050 and an exhaust lift of .296 @ .050 per manual #25

To get a more aggressive cam, you are looking at a custom grind.

 

[ste80]

the mercruiser cam has a valve lift at .290 @ 0.050 and an exhaust lift of .296 @ .050 per manual #25

To get a more aggressive cam, you are looking at a custom grind.

Thanks, when i rebuilt my fiat 500 i did the same, i replace the cam i improve valves diameter and machined the head for rc improvement but for that care i had a lot of came to choose between .
For mercruiser i don't really have any idea where to check for this.
At the beginning i was thinking that EFI one in my hand could be little bit more aggressive but i don't think that much or any actually

 

[ste80]

One more things, (more a surprise)
Why in the manual for my motor they put 88 Nm the head bolts torque and for 4.3 gen+ they put 30 nm (or similar) and other pass in degrease if the block and screw is the same? (88Nm) Is same value that also garage gave me
I think that if you just set 88 you may have to recheck them after some running hours, instead with angular tourque it should not be necessary.

 

[ste80]

the mercruiser cam has a valve lift at .290 @ 0.050 and an exhaust lift of .296 @ .050 per manual #25

To get a more aggressive cam, you are looking at a custom grind.

In this days i was looking the manual (18 and 25)
Accordingly to that it seems that lx (manual 18) has lobe lifter 0.269/0.273 @0.05.
Instead efi #25 as you said 0.290/0.296 as you said.
Is what you meen more agressive? So this is what i should use?
Tks