Cross Flow Info

[FCnLA]

rude235,
Mine is a '80 235 Evin. I brought to XP spec, which is machined the inside of the block/cylinders just foward of the bypass covers. The pistons also require machining if you use regular pistons. XP,GT(same dif) are twice as high($) as regular pistons, so I had mine machined. This was the largest HP increase that I have done. More punch and better midrange. Fiber reeds, best mod for the money. Smoother idle and all around better running, way quiter! Velocity stacks,
can't tell a whole lot, has to help some,but I can change my jets without pulling the carbs off,way cool. I afraid we are limited on HP parts because of the age of our engines. I got all of my parts from Land&Sea including solid motor mounts and nose cone. I have heard that the 2.6 XP was 245HP. Is your motor an XP? Mine runs pretty good for a dinosaur. Turned a 29 pitch SRX 6800 before I hit a log, OUCH! I'm considering a light wheel if I can find one.
FCnLa

[rude235]

thanx for the info. it's hard to find someone who for one has something besides a merc, and for another who has a 235. mine is not an xp/gt. unfortunately, i can't really tell you much about what kind of numbers mine will run. i've had the boat for a couple of seasons but the jack plate does not work properly and the local guy has no idea how to fix it.

[FCnLA]

Hey rude235,
What's a matter with your jack plate that it can't be fixed?
FCnLa

[rude235]

the plate will move up but will slide back down on it's own. i've taken it to the local mech. and he has no idea who made the plate or where to look for parts for it. he said he's never seen a jack plate like it. most likely the company that made it went out of business according to him. can't find a name or number on the thing. the boat is an '83 nordic viking, if that helps any.

[FCnLA]

OK, I take it that it's hydrolic?
FC

[rude235]

yes, it is hydraulic. so i would think any hydraulic shop should be able to fix but the local shops dont want to touch it because it is a boat. i'm still looking and doing some calling though.

[rude235]

yes, it is hydraulic. so i would think any hydraulic shop should be able to fix but the local shops dont want to touch it because it is a boat. i'm still looking and doing some calling though.

[FCnLA]

Sounds like a leaking seal or spool valve (internal leak). Is the pump assembly in the boat or on the jackplate itself? Does the pump assembly have a data tag on it, with manufacturer's name, etc? If you took the pump assembly out they might work on it. If it's a decent sized shop, they ought to have the seals. There several shops around that make new ones, but they are high dollar!
FC.

[rude235]

the pump is inside the boat. i've tried looking for a tag with some numbers on it or a name or something but haven't found one. i haven't taken the pump off yet though. that will be my next step. i would rather get this one fixed instead of spending a grand on a new one. thanx for the advice.

[BW1969]

hey rude235,
You might want to start looking for a CCC front half and intake for that old cross-flow in addition to the lightweight flywheel. It will allow you to add a second bank of carbs to your motor to really let it breathe.

[FCnLA]

Hey BW1969,
What's different about the front half? I have seen the intakes, too many carbs for me. I heard that the light flywheels are rare and expensive (how much) and what does this do with the charging system. I thought about taking some of weight off of my stock one (buddy has a lathe). I appreciate any input, as rude235 said, It's hard finding some one that knows any thing about an OMC especially an old crossflow.
Thanks, FC

[BW1969]

The intake for a CCC will only bolt to the front half of a CCC engine. Those extra carbs can add as much as 500 rpm (thats a whole lot with a 28-32in. prop). Those lightweight flywheels are a hard find, I just got an original aluminum OMC racing flywheel(from a CCC engine) this summer. You really need one if you are turning those higher rpms (apparently these motors can reach 8000 if set up right). I have seen the cranks break just above the top bearing. You should be able to find a used one for around $300-$500, I don't know if that is too much and I may know where one is. The way I look at it if I can find a crossflow for a few hundred dollars and put a few hundred more into it to make it perfect I'm way ahead of the game. I like them because they are so easy to work on. Good to talk to you.

[FCnLA]

BW1969,
Crank breaking above the top bearing? OUCH! What did the wheel do? Boy, talk about a frizbee with an attitude! What RPM do they go away? I've been told to not spin mine more than 7000. Had it to 6800 w/29"SRX, want more (speed). Price on wheel does not sound bad compared to decapitation. Will it charge enough though? Don't want to be stuck on the sandbar with a dead battery, like our friends with the black efi motors. Like I said, I got access to a lathe. I agree, they are easy to work on. This my first V6 to rebuild, but I've done several 2 and 3 cylinders. Ran the piss out of it, and it hasn't scattered yet. More on it than the 100 hr limit for the Mercs. The parts are also resonable (knowing the parts guy helps). I got a little over a grand in parts and machine work and spared no expense, new pistons, coils, carb kits, starter parts, reeds, cylinoid, etc. I appreciate the info.
Oh yea, what kind of rig do you have? I have an 18' Youngblood picklefork (OB not a converted jet) tunnel and love it!
Good day! FC

[BW1969]

FCnLA,
As near as I can tell my lightweight flywheel will charge at 9 or 10 amps (that's what my book tells me). I have a buddy (also the person who has taught me everything I know about tweaking a 2.6 crossflow) who can crank 235 up to 7800 rpms and his motors last for years. I have had a couple of others tell me 8400 is the magic number. They won't go any faster they just come apart. Right now I'm running a 1979 19ft Boston Whaler Revenge with a 1983 235 that has had the ports squared, bottom of the cylinder walls cut, and the pistons scalloped. The intake has also been ground to open it a little to let it breathe better. I'm still playing with the timing and jetting. I can already tell it is a case of diminishing returns and won't go as fast as I want. I also have a 1969 BW center console that I am tweaking a 1981 140 for. But what the plan is is to put together my CCC engine (using a 1981 235 I have apart in the garage) and find an Allison bass boat. I even got my hands on a custom set of CCC intakes that already have the plumbing for nitrous if I'm feeling really daring. However, I think I'll wait for that.
Have you ever considered finger-porting your 235?
Talk to you soon.

[FCnLA]

BW1969,
I'm familiar with the Boston Whalers, except for the Revenge part, nice boats. Whats a BW look like? I'll bet that Whaler will move! I was told that the finger ports were for the looper motors. Or the guy did not know, or he did not want to do them (mercguy). I said something to him about squaring the ports up on mine, but he pointed out how thin the cylinders are (big bore) and squaring corners may cause a crack. This leads another question about finger porting (thick enough?). He scared me off from doing that. I did flatten the bumps out in the ports, where the factory drilled them, though. I'm considering a looper 225 (found one locked up). But until I get it together, I'm going to see how deep in the 90's I can get with my 235. I'm having a chining problem right now, about 88ish and it wets the sponsons out and drops speed. Going to blueprint my hull this winter and look for a cleaver in the 30's. I know of a guy south of here that used to race V4's. He had all the cool stuff (four carb intakes etc), but he's gone to loopers. I can get his # if you're interested.
What are your jet sizes? Mine are 4 circuit carbs: high speed pull over:16, main:62C, mid:36, idle 20. Have any problem with midrange lean out? I noticed a "pinging" at a mid range cruise,timing@21 . Went up 5 sizes and cured it. If it's a little rich, I figure it's good for a cool down after a high speed run. What do you have your timing set at? Mine's at 22. I have been going to move it up but I need to get the hull right first. Will 2 degrees make a difference? Scared of going more than 24 because of the gas and the 80 model heads. Allison bass boats are very nice and fast, and I have seen some used ones at fairly reasonble prices for the year model. When you're ready let me know and I'll keep my ears open.
Take care, FC
[This message has been edited by FCnLA (edited December 04, 2000).]
[This message has been edited by FCnLA (edited December 04, 2000).]

[BW1969]

FC,
The couple of guys that I know that raced these engines had them finger-ported (without any problems). Also, as far as I know the 2.6 GT and XP had the ports squared at the factory. I'm just now putting together a 1988 225 looper, and I'm going to sell it. I don't like them, too big and heavy and the carbs and intake system seem like a real mess. Too much plumbing. Plus, the guys I know that raced the cross-flows never had to worry about the OMC looper V-6's, just the merc 2.5's.
I've got my 235 jetted at 65 and timed at 27 degrees and after a high speed run my plugs are black, however I don't have the older style heads on right now, I just found a set I liked this year and haven't installed them yet. When I put them in I've been told to move the timing to 25 and the jets should be fine. How does your boat do coming out of the hole? I would think it would be a little slow with such a low timing setting.
I might want to talk to that guy that raced the v-4's. You could e-mail me his # at "cytoman1@aol.com" I would appreciate it. Talk to you later.

[gbmmirage]

Guys I have some Crossflow parts that will help you. also have OMC flexplate flywheel for 235 for sale. I have a cross cut intake and front half that has been cut pretty good. would take $300 for the flywheel paid over $800 for it in like new shape. I had several 235 modified them myself. I have done several 140s also. I found that the 235s run good at 28 degrees timing and 71 -72 mains. I'm at sea level and int he houston area where it's hot and hummid all the time. I have changed to Mercury but still have some modified part for the crossflow v-6s the flywheel I have will charge up to 12 amps. the stators come in 9 and 12 amp. you can e-mail me about anything you want to know about those motors I ran them for 15year....Mossboats@aol.com
[This message has been edited by gbmmirage (edited December 08, 2000).]

[FCnLA]

Thanks for your posts, gmmirage and BW1969. Boats are my greatest passion. Had a 3hp Johnson and a 14' ArkansasTraveler (aluminium) as a first boat at the age of 8, and have loved them ever since. I am new in the high performance aspect of them though, and I appreciate any help. Emailed you both hope you receive it.
My rig is anything but doggie out of the hole. It will plane in under 2 seconds, no kiddin', with a 26" Powertech over hub semi cleaver, or what ever they call it. Not long after that I'm turnin' it 6700 before it get's squirrelly. If more timing will make it leave harder, then I'm in there! Who knows, I might get froggy enough to tear it down, port it some more and rering it. I just want to be consevative enough to not turn my motor in to a boat anchor. One last question though, when setting the timing, once the lever attached to the timerbase has fully bottomed against the advance screw (full advance), will the timing change in relation to RPM. I've heard some say yes, some no. I don't like hanging of the back of my boat with a timing light doing about 60 to 70 mph. I do not have a test wheel or access to a dyno, and would like to do it at the ramp.
Thanks, good day. FC.

[D. Ulrich]

Alan Stoker is now writing the Outboard Tec column in HOT BOAT! Alan ran OMC V-6 motors in the MOD-VP class for a long time. Look him up for all your OMC mods. Originally posted by FCnLA:
Thanks for your posts, gmmirage and BW1969. Boats are my greatest passion. Had a 3hp Johnson and a 14' ArkansasTraveler (aluminium) as a first boat at the age of 8, and have loved them ever since. I am new in the high performance aspect of them though, and I appreciate any help. Emailed you both hope you receive it.
My rig is anything but doggie out of the hole. It will plane in under 2 seconds, no kiddin', with a 26" Powertech over hub semi cleaver, or what ever they call it. Not long after that I'm turnin' it 6700 before it get's squirrelly. If more timing will make it leave harder, then I'm in there! Who knows, I might get froggy enough to tear it down, port it some more and rering it. I just want to be consevative enough to not turn my motor in to a boat anchor. One last question though, when setting the timing, once the lever attached to the timerbase has fully bottomed against the advance screw (full advance), will the timing change in relation to RPM. I've heard some say yes, some no. I don't like hanging of the back of my boat with a timing light doing about 60 to 70 mph. I do not have a test wheel or access to a dyno, and would like to do it at the ramp.
Thanks, good day. FC.

[drewvir]

drewvir ,yes omc's second effort fingerported the 235 in the early 80's.i've got a johnson 2.6 gt 1985 with the original owners book,if you want to see anything in it,just e-mail me.the motor runs well with 72 mains@28 degs.total timing.i run the motor on 93 pump gas,but you can't use anything less or boom!i set the timing on the trailer in the water,w/o a test wheel,just set the propshaft level in the water,make sure the boat is straped down well,and the truck is chocked.then just warm it up,run it in gear at atleast 5000 and set the timing there.it's a lot safer than hanging over the boat at 70 mph!oh,by the way all the gt&xp motors had rev limiters in the power packs,change them to a stock 235 pack,they didn't have them
i hope this helped
drew

[FCnLA]

Thanks, Drew.
That's what I plan on the jets and timing. Setting it too. Got the old 235 packs. Also a light wheel thanks to Greg @ Mossboats. Now if the weather would cooperate. FC.

[thumper]

Hi Guys -
Better late than never! Can I join in? I have a Vector with a modified 2.6XP on it. Does that qualify?
I'm also looking for the light flywheel if anyone knows where one is that the guy doesn't need to make his retirement on the sale.
also an update on one of the prior questions, I ran the 10 amp system all last year and had no trouble keeping the battery good and I was also running a full time fuel pump. i think it won't keep up if you have a killer stereo though.
thumper

[drewvir]

thumper,
in the back of last months h/b a guy is selling one for $250 i think.all the omc guys i know say you don't need it/waste of $$.i was going to buy it but they changed my mind.
Drew

[thumper]

I was told pretty much the same thing other than it might make a difference at over 7k as far as chopping the throttle and breaking the crank plus they look neat if it's the same one I saw about 2 yrs ago.
Thanks for the opinion and info. What month HB did you see it in?
thumper

[FCnLA]

Hey Thumper,
Someone else with a crossfly, COOL! I was told there was a harmonic vibration at about 6100 rpms which caused the crank to break above the upper bearing. Sounds scary! I put one on mine. I'll bet it weighed at least 3# lighter. It really should spool up faster. Noticable difference in just picking them up. CCC gold anodized. Also with the solid mounts I did notice a little more vibration, oh well, if your gonna play, ya gotta pay! FC

[thumper]

Who's coming to firewater?
Who's coming to pre - firewater?
don't make me stomp all those mercs by myself and have all the fun!!
If no one else shows up all those mercs are gonna take their bikini women and go home early out of embarassment.
I've got limited room in the house and plenty of space in the backyard if hoteling it is too much. I sit about 1/2hr from pre and 2 hrs from firewater.
thumper