2.5 Fronthalf fishin Motor Question 4 pedal or 7 pedal ?

[Germansaleen]

Hi All,
i am in the progress of building a nice 2.5 out of an 1997 fishing Motor Block OG 569428 bored to .030 or .020 on all 6 and a nice moderate portmap and light chestcut, Small 644-818141 rods ,all with hp bearings, Vertex pistons,Non oiler crank from a 1996 260,light fly ,16 amp elektrics, wh15 carbs ,ported intake ,4 pedal rubber reed cages with carbon boisons and 1 inch intake spacer if the guy in south florida will build one for me instead of going fishin in the keys .


My question is ..

if i go with a 4 pedal front half it looks to me,
it will have less crankcase volume then a 7 pedal front half with the big openings in the crank case area.

ok...... the reed cages will stick in the openings and close them a little but all together the 4 pedal 2.5 stock efi or carb fishing motor front half looks to me better and will have more low and mid punch if it has a smaller crank volume.

It will loose some Fuel/Air Flow at higher rpm's troug the smaller openings but it will have more velocity if the chape is right and i think the advantage will be better ,instead of going in to the big is better theory.
I am not planing to go to 9 or 10k Rpm's.

max rpm should be 7.8 to 8k on this fishing motor

anyway i will cut the front .050

my thoughts are right ore wrong ?


the pics are just to show the different openings,the first front will fit and that's the one what i can get for a couple of bugs the second is a big bearing 260 and will not fit.


Have a nice Weekend
Michael

[patchesII]

No brainer, 4 petal on a 7-8000 rpm motor

[HStream1]

with Erik!! But trash the Boyesens and go with a good set of TDR's. Some like CCMS reeds. I personally can't speak for them, never tried em.

No brainer, 4 petal on a 7-8000 rpm motor

[Germansaleen]

Erik,
what means , No Brainer ? will work fine and revs easy to to 7 to 8 k ?

Sorry..... i am a Sauerkraut German with only 8 year South Florida Language experience and you know, its mostly Hispanic down south . No Brainer has translated different meanings to me.

thanks for help !!

[HStream1]

I'll Translate for Erik sense he is not online right now. He means it's no contest between the 4 and 7 peddle. The 4 will be the better choice on a motor that is not going to turn more than 8k.

He wasn't trying to be a smart arzz or anything like that. "no brainer" is just slang for it's not hard to figure out, or there is no comparing the two, refering to the 4 peddle being the better choice over the 7 for the application you described.

Did I do Good Erik

[Germansaleen]

Hi Bud,
i know Boisens are not the best, but i bought the reed cages in like new condition and they came with a new set of the two stage carbon boisens. They are very stiff and the second stage will open hardly by hand.Looks to me that all the time or mostly the smaller openings will get open under vacuum and that will be a 20-30% flow restriction.

I heard only good things about the TDR's and jay smith loves them to.


The Boisens are 100$ to 150$ value and are new in Box , i give them a try the first hours on my other 2.0 liter powerhead next month .


thanks for your help
michael

[Germansaleen]

Thanks for the translation

if you need something translated into German let me know

[HStream1]

Kein problem

[Germansaleen]

How about the crankcase volume ?

what fronthalf will have less volume the 4 or the 7 ?

would be interesting to cc a rod slot and compare the two, has annybody done that before ?.

michael

[jay j]

I just went thru this and a 7 petal is by far going to be better in all out performance. the 4 petal will run out of breath approaching 8k, but if the squish is right with the fuel map and good fuel they will keep spinning, but the 7 petal will go past 8k easily and pull hard all the way thru. Heavier boat there may not be a huge difference. I am putting a prostock motor together to ride ride the river and I am gonna use the 4 petal. Btw my other 4 petal motor would turn a little over 9k but struggled to do so. They are very good dependable motors, good luck.

[patchesII]

Lol. You nailed it Bud

[Germansaleen]

Thanks for all your input and help

i will go with the 4 pedal fronthalf for the 2.5 and the 8000 to 8500 max rpm.
it is a back up motor and should be reliable and i wont not spend lots of $ into the rebuild . I will get the vertex pistons for that block with the steel liners and build like like a pro stock motor and i think 8k to 8.5k on carbs is save for the vertex without trouble.

my other drag project nic powehead with a smilin jacks slider is for higher rpm and i have to deal more carefull with that "investment" to make it reliable and save ,but thats the next story.
the top pinned pisons and gold rings alone do have a price tag like the total rebuild of the 2.5 fishin motor .Crazy Price tag .....

the best available set of custom made JE forged blower pistons for a 1500hp 632ci has cost me 1500$ racer net and that was a set of 8 and build to my spects out of a chunk of nice aluminum.

thats how merc racing squeeze the $ out of our pockets and thats not nice for our sport and hobby.
because..... we are not all poker run guys with a 50foot cat and four 1275 SC merc racing engines and a million at the bank.
i think.... most outboard guys have to work real hard to get the cash for that hobby like me.

and i don't have four nice chicks in g strings on my rear sun pad , because my boat doesn't have a rear sun pad

michael