v6 crossflow heads

[jy118lfd]

Re: v6 crossflow heads

They are probably the original heads from this motor as the powerhead is an 83. Were they any good and will I see a difference with the gt heads? I know it will be pure speculation till I test.

 

[jy118lfd]

Re: v6 crossflow heads

Well after a long time I got my heads today. They were shipped to the wrong person.<br /><br />I have a couple of questions though.<br /><br />The chambers look very different than the ones that are on the motor. The chamber on the 332545 and 332544 heads is a match for the piston the old ones are just pretty much open. <br />What is the timing I should run with the new heads and are these more prone to detonation. Will it hurt to run these on a non gt 150 block?<br />Can I use the 1" carbs on this motor for economy or should I run the 1 5/16 gt carbs. <br /><br /><br />It runs really good just is rpm limited to about 5150 with the gt carbs and about 4900 with the 1 inch carbs. No carbon buildup in the chambers of the old heads. I will try to post a pic if I can

 

[jy118lfd]

Re: v6 crossflow heads

bump

 

[jy118lfd]

Re: v6 crossflow heads

Well I put the heads on. I ran the motor at 28 degrees. With the 1 inch carbs.<br /><br />First My cranking compression went from 80 to 85 with the old heads and gaskets to 90 to 95 with the new.<br /><br />Previous best with 1 inch carbs was 38 mph @4800 <br />now it is 5100 and 43.<br /><br />I am going to put the 1 5/16 carbs back on and run it again<br /><br />Is there a way to change the shift rod on a 78 gearcase to the 79 and later model. My shift linkage has slop in the conection of the bellcrank to shift rod. I have the intake with later style bellcrank an think it looks like a better design

 

[Dhadley]

Re: v6 crossflow heads

28* is a safe bet. When you get the other carbs on take a look in the XP/GT service manual and double check the timing. It may be more than 28.

 

[jy118lfd]

Re: v6 crossflow heads

Dhadley run my slip numbers if you could. I have 5100 rpm 41 mph (above is a typo) 1.86 gear and come up with 7% I don't feel that is possible <br />This all run with a 14 3/4 17 viper prop<br /><br />Can I change the shift rod to the newer style in the gearcase?

 

[Dhadley]

Re: v6 crossflow heads

I come up with about 8-9% so we're close. Thats very good for a Viper. Is the speed via GPS? What tach is it?<br /><br />The shift rods cant be changed easily. The old style with the barrel slides in to the shift mechanisim and the new style (bent top) screws in. Look at the two on ishopmarine.com and youll see. <br /><br />You could cut the two shafts and reweld them but youd have no adjustment. It can be done if your shift rod ended up at exactly the right height but thats why I said not easily.

 

[jy118lfd]

Re: v6 crossflow heads

Speed is with gps and a paddlewheel both within 1 mph at top speed. Tach is j/e and also doubled up with a tinytach. Only about 50 to 100 rpm difference.<br /><br />The motor has approx 450hrs 125 of which are this year. The carbon on the pistons is just a light tan coloring and is almost nonexistant on the old heads. It does have a small amount of carbon on the deflector of the piston inbetween where the ports are in the block. Is this normal?<br />When I changed the heads I was able to wipe it away with my finger maybe the size of a nickel, stickey and gooey<br /><br />Thanks for the reply on the shift rods. I will have to replace the top of the rod and the bellcrank cause there is some slop there that just erks me if you know what I mean

 

[Dhadley]

Re: v6 crossflow heads

Thats pretty good. Nice job of verifying the numbers. Everything else sounds like its doing well. Obviously we'd like to see the rpm higher. That will get rid of the sticky, gooey stuff (coking). If we stick with the same prop and rpm you gain thru set up will yield speed and holeshot.<br /><br />That old bellcrank system can have a lot of slop. Its usually cured with new bushings in the barrel and the bolt for the levers.

 

[Dhadley]

Re: v6 crossflow heads

Thats pretty good. Nice job of verifying the numbers. Everything else sounds like its doing well. Obviously we'd like to see the rpm higher. That will get rid of the sticky, gooey stuff (coking). If we stick with the same prop and rpm you gain thru set up will yield speed and holeshot.<br /><br />That old bellcrank system can have a lot of slop. Its usually cured with new bushings in the barrel and the bolt for the levers.

 

[walleyehed]

Re: v6 crossflow heads

My manual says if the stator leads are in a "RED" sleeve, timing can be run at 32 degs.<br />I also found some info telling me 30 degrees.<br />I run my '82 V6 w/ XP/GT heads at 29-30*, but I am 3500 ft elevation. I think I would stay at 28 if it were me...I notice very little difference at 30 vs 28 other than it seems to have a bit more kick in the pants in mid-range.

 

[Melvin Hatcher]

Re: v6 crossflow heads

Originally posted by Dhadley:<br /> The 332544 & 322545 are good XP/GT heads. The 1 5/16" carbs are an overkill but it will clearly flow enough fuel at wot to see if the small carbs are holding you back. It'll burn a lot of fuel and the holeshot may suffer but remember youre testing for top rpm.<br /><br />Whatever heads you use, set the timing for those heads.

Which are the better set of heads to use on on 150 or 235 cross flow,the 332544 & 322545 or the 329772 & 329773 . . . and how do you determine the correct timing for either head?

 

[Melvin Hatcher]

Re: v6 crossflow heads

Originally posted by Dhadley:<br /> 28* is a safe bet. When you get the other carbs on take a look in the XP/GT service manual and double check the timing. It may be more than 28.

I have never seen a XP/GT service manual. The only thing I can find for my engine 1985 XP 150 is for the standard V6 of that era. If the XP/GT manuals are available, Please tell me where I can purchase one.<br /><br />Regards,

 

[jy118lfd]

Re: v6 crossflow heads

I have not checked the timer base yet but I have read what you have read wally. I will stick with 28 for now. <br /><br />Dhadley If you remember I was the one with the 150 possibly like yours that an omc engineer told you the front half of the block is porous and makes the signal weak. I have seen pistons from motors that were lugged and this looks nothing like them. the goo was very small and thin. I do not think I will get anymore rpm out of this. I have tried a 15 1/2 15 and still only got 5100. That was about 4 months ago with the old heads and 1 inch carbs.<br /><br />I am running the boat tomorrow but I will swap the carbs soon to the gt's and test. <br /><br />Ain't this fun!!! <br />I kinda like this, I just wish I would find something stupid that is holding it back. <br />5800 sure would be nice.<br />I have come along way as the motor is now 1hle from the top and I tried the top hole It would not allow any trim and would blow out the prop often so down it went 1 hole from the top.<br />Sure wish I had a jack plate 1/4 inch would probably be just right<br /><br />When I started the motor would only run 4200 rpm now a little of this and that and I am only about 650 rpm shy of my target<br /><br />Unlike others I will keep you all informed to help everyone

 

[jy118lfd]

Re: v6 crossflow heads

Bump

 

[Dhadley]

Re: v6 crossflow heads

Sounds like a plan! Keep coming with updates. Like you said -- aint this fun?

 

[jy118lfd]

Re: v6 crossflow heads

I ran it with the gt carbs yesturday. Top speed is 42.5 @ 5250 rpm. It idles so much better with the gt carbs. I took apart and checked the 1 inch carbs for blockages but there are none. With the 1 inch carbs it still idles at 650 in gear but it is noticably more rough than with the 1 5/16 carbs. It seems that it will idle at 600 rpm or lower with the gt carbs.<br /><br />With the gt carbs it jumps on plane and the midrange is outstanding. From 3000 up to 5250 It is nothing short of amazing the difference from the 1 inch carbs<br /><br />I have a gph meter and the results are:<br />1 inch carbs<br />15 gph wot 5100 41 <br />10 gph 4000 30 mph<br />8.8 gph 3500 25 mph <br />.8 gph 650 rpm in gear<br /><br /><br />18 gph 5250 42.5<br />11.4 gph 4000 30mph<br />9.5 gph 3500 25 mph<br />.9 gph 650 rpm in gear<br /><br />The 1 inch carbs are the older three circut carbs and the gt's are the ones with the top plate that is removable with the plastic bowels as well.<br /><br />Dhadley I am at an impass now, I have changed many parts and am unable to get this motor to rpm up higher than where it is now. I need a new direction for this. Everything I do seems to help a little so it is improving but I do not know where to go from here.

 

[Dhadley]

Re: v6 crossflow heads

You have done everything we did except switch motors on boats. At one point with mine I became convinced it was the boat. I switched with a buddy and the low rpm followed the motor. His motor ran fine on my boat and mine wouldnt turn up on his.<br /><br />Your numbers (excellent) show us that the hull is responding to the small increases in torque. 1.5 mph for 150 rpm is good.

 

[jy118lfd]

Re: v6 crossflow heads

Did you ever notice a difference with the idle on the older carbs vs the newer ones Like I have. Just wondering if it is in the design, cause I feel the smaller carbs would have had the better idle.<br /><br />Could the 78 electronics have any bearing on the rpm or power? <br /><br />I have a 15 1/2 15 alumnium that I am going to try next time out I will be in touch

 

[Dhadley]

Re: v6 crossflow heads

Actually I thought the 1" carbs I had idled better than the big ones. The best starting & idleing ones I found were the 1 1/4" off a Sea Drive. But I have a early 90's 150 cf that has the original carbs and will idle at 450-500 all day.