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This thread answered pretty well all my questions without having to type a thing :) !!!
I am building up my 86 2.4 with 2.0 rods , non-oiler crank, shaved heads, steel block and 5 petal front end with plastic reeds (even though I have a 7 petal for it) . I will be getting a lightweight flywheel ASAP.
As far as doing any exhaust chest mods...........I'll leave that for another thread :D
GREAT info guys.
dang skip ya beat me to my question - does any one have any pics of a hogged out ext chest.how did that 2.4 get up and out with that much material removed?did it kill a bunch of bottom end?and how much top end did ya pick up?what tuner did you run with it?that should be enough questions to keep this thread going,eh?
I have a set of pormarine pistons being frooze right now I am going to use them in my next motor. After I get them back I will send them to Jay to get lightened and balanced and staked. I have run a lot of cast pistons up to 8000rpm and not had one come apart yet. I do not drag race I like to run long distance WOT that short little burst does nothing to me. If cast pistons were going to fail over 7000 they would of done it to me along time ago. I will try to figure out how to post pictures and post some of my 2.5 porting for you to check out
THAT WAS ONE HELL OF A REED, I MEAN (read) WHAT A FLIPPIN EDUCATION,
That again waz sum good shizamm ...........
Mike
The stock Merc production 200 piston will run up to 7500 but that is when the skirt starts to collapse. I usually say not to go over 7000 because that leaves a safety margin. When the skirt starts collapsing the motor will loose power and eventually the piston will break.
I still want to pull skiiers and have some decent torque so I figured that milling out the chest would get rid of that nice punch that I'm actually building this engine for.
I see the port is smoothed out and larger, what about the teardrop shape ? Is that the difference between a torquey engine and a screamer ? or is it just the overall size increase of the port ?
I was thinking of smoothing everything out without increasing the size much to keep the torque. Is that out to lunch ?
I have some pictures here I was going to e-mail to you but it keeps coming back. E-mail me and I will send you a couple of pictures. I have one that will give good performance and still have good low end for a 2.5 The same chest work should work well on a 2.4. Some day I need to sit down and figure out how to post pictures. [email protected]
Thanks alot. I just hope that I was of some help. I know what it's like to turn a good piece of aluminum into scrap with a grinder. I'm just trying to help save somebody a little money...
It's a long drive from Texas but maybe I will get down there and play with you folks sometime next year. I'll bring my old rag Stream down and see the weather in Fla.
That's a damn good shot of your Talon. Looks like you were really haulin' the mail!
I had my 2.5 200 exhaust chest cut by JSRE for a 1400# boat and I specifically told him I wanted to not loose torque. I'll post a pic of the chest for comparison.
Also,what is the longest thread in S&F history? Are we getting close?
You are #3, but you will need 30 more posts to beat #1
This is sum goooood readin' !!!!! :D
I'm gonna be buildin' a damn good motor by the end of this thread !!!!
why are th 2.0 rods SO much bigger than the higher HP 2.4 rods ?
I expected a bit of difference in size, but not this much !!!!
Are the 2.4 rods made from a better material to keep them lighter ?
No they are not made of a better material. You definitely have the good 2.0L rods there. One big advantage in the big rod is it will take the SPS racing rod bolts, with the little rod you are stuck with the weak bolts. Nice picture
I spoke to Dave at Marine Dynamics, and asked his opinion on my approach to substantial H.P. gains using Hi flow 5 petal cages ( He machines & sells them w/ dual stage or large single reeds.) His response was that I may gain some "snap" but the hi-flow 5 petal are not even close to the sheer volume available from a 7 petal configuration. He also indicated that the real meat & potatos H.P. increases come primarily from "changing the port timing".
The guy spent a long time on the phone w/ me answering my barrage of why & how to questions.....did not blow me off 'cause I wasn't buyin' today, but I will definately deal w/ this guy in the future. The core of the information he gave me indicated that I can make small incremental gains in HP with bolt on parts but until I change the port timing or run nitrous you're not gonna notice any real substantial HP gains. Being that I don't have the talent & knowledge that alot of you guys have, nitrous sounds very appealing to me. Putz around at 80 w/ a reliable 200 then flick a switch and I've got an F-16:eek: How expensive and complicated is a nitrous system and how stressful is it on a relatvely stock 2.4 200. Is this the kind of system where I get 20 thrill rides then have to rebuild or may at any time have to patch the holes in my cowling from where my rods went thru? Hey Skip... I assume that's what these pics are you've been posting, all related to the port timing? I assume port timing is the relation of the port openings size, length, & position to the position pistons in thier cycle? Sounds real complicated, time consuming and expensive, not something I would wanna do with this dinasour I got. Now bolting on a tank, lines, and an "afterburner" switch sounds appealing to a backyarder like me. Come on skip whadda ya know about a bottle of nitrous? B.MAC
Nice after Nitrous picture skip. What the man told you is not entirely right. Port timing is the #1 HP gainer but, if you cut the heads, machine the chest a little, go 7 petal and your other bolt on mods the motor will run a lot better, its not like you wont notice the difference. You should not change the port timing on a chrome or Nicasil cylinder, it will peel. So if you don’t have 6 steel sleeves, that’s out. I don’t like Nitrous because I want the power all the time not just once in a while then the bottle is dead.
I am glad you got to talk to David. He is one of the nicest guys you will ever meet and he is probably one of the most knowledgable you will run across. I would enture to say he is in the Top 2% in the country. He knows what goes on inside these motors. Also, there are few people I will actually deal with in the country and he has my complete trust. I used to work for David on my days off from my regular job and I learned so much when I was over there. Great guy and a great shop to deal with. One thing you need to know about David though...
He is a perfectionist and to some degree a pessimist. I have bought numerous parts since my first dealing with him in about 1989. If he says the parts you are wanting are in good shape, they are most likely in VERY good shape. If he says you will pick-up 10 hp with a particular mod, you will probably get 15 on a hot, humid day in south Texas.
He is completely correct about the fact that you won't get any REAL hp gains without grinding on the ports. But I get the feeling that you are looking for a modest gain, a few hundred RPM and some more punch. If that is the case, for a little labor and not much money you can make a reasonable gain. If you feel like tearing down the motor and buying some gaskets you can help your cause greatly. I am not talking 70 hp but you could probably make 240 total hp pretty inexpensively.