merc 44 questions

[outboardjetboater]

great site

thanks for the info. great site. i feel like i missed my opportunity because i spent $1800 to put my 4 cyl back to stock, and i could have spent a little more and got some performance increases.

thanks again

[outboardjetboater]

exhaust baffle plate

crank,

i have a 92 4 cyl 44 ci merc that has been bored 15 over. did the bore have any affect on port size and height?

thanks
outboardjetboater

[Tim Weber]

It shouldn't effect the port timing at all. The wrist pin location on the piston is adjusted for this very concern.

It was thought in some circles that you had to bore a block 30 over to get it go but we never found this true with a D. I think this was more so for the old KG-4 and 30H.

Tim

[crankbearing]

port height

Hi,

Tims right, it should not effect your ports at all - BUT - I think I know what you are talking about the later 4 cyl blocks after 1990 I believe were lifted .050" on the exhaust side. These are not legal for DSH anyhow.. They should be I think that it would be the same in the rule book as the 55 - 55H block difference..

What skirt clearance did you leave and what pistons are you running.

Regards,

[outboardjetboater]

pistons were american marine 3-ring. skirt clearance, i don't know. the rebuild was done by local merc mechanic. i wanted to add some horsepower, but nobody around here said that it could be done.

[Fast Freddie]

Added Power

Too late, but the two-ring pistons would have been a noticeable improvement!

[crankbearing]

yes 2 ring

Fred is correct you would have noticed a lot with the two ring pistons change. Wiseco would have also been an alternative. I hope your mechanic at least loosened things up a little around the crank..

Regards,

[outboardjetboater]

i asked about wiseco and he said they were great for high performance, but had no longevity. anyone have experinece with this.

[mike ross]

I thought from the national meeting we only approved aftermarket pistons from Sierra and Vertex. I thought Weisco was not approved for some reason. Dave Scott or Mark Wheeler can probably correct me if I am wrong. Just looked it up and that was what we approved. I know Weisco makes pistons for the 44xs but maybee its just the oversized pistons that need to be Sierra or Vertex brands. Mike

[mike ross]

This is a stock rule for the 44xs and if your doing a d mod then the pistons might be interchangsable.

[Mark.Wheeler]

Mike,

The SORC approved Vertex and Sierra pistons for the merc 44XS. These pistons, and Wisco, are fine for D mod.

Mark