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Cam and valvetrain longevity....??? low duration high lift...

Old 09-18-2016, 04:30 PM
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Originally Posted by Full Force View Post
My buddy Bill degreed them, looking for that a paperwork but I know things were checked

Just thought I'd throw it out there as much of us here are racking our brains trying to figure this out as you are. My advice on pull or wait til refresh time is wait. If it were a 5 mph gain then I'd think twice. Well actually I'd be pulling but another couple mph just enjoy the reliability and and time boating. Just more cost and time effective it would seem. I'd like to see some post with 325 partially CNCd heads on 540 combos. We seem to see many results with the 305 and 315 CNCd heads and combos making good power but just not much with the 325's and there has to be plenty of them out there. I think I asked about if you port matched or not but regardless the engines would still pull 6k. What's getting me is the lack of power between 5,500 and 6k. There is no reason those cams should not pull to 6k. I double checked mine today that were from Gellners 540 packages and they are 244/248-647/641. They made peak hp at 6,200 however on my builds I advanced them 4 deg to bring them in at 5,800. If you were to do anything like I mentioned before I'd install 1.8's on the intakes on one engine just to see if there is any gains or not. I will ship you a brand new set to try for nothing. Your only looking at a few hours of time. Nothing ventured nothing gained. Up to you! That would give you 720 gross lift and more duration as well.

I read a post in regards to possible valvetrain instability and I don't believe that's an issue or you would have noticed your BSFC numbers out of whack when you dyno'd. I've had that happen before and it shows up big time.

At this point I'm not convinced it's the cam unless somehow they simply weren't ground to specs on card which is highly unlikely and would have been caught during installation and degreeing. I'm certain there is more power to be had with your heads however again not the real issue. We discussed the intake and carb combo and all pretty much agree as you did they should be inspected and flowed along with your heads. Has anybody here used the intake your using? Just curious.

Up to you but if you want I'd be happy to send the rockers to try.
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Old 09-18-2016, 04:42 PM
  #132  
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We will see, trying to not re invent the wheel financially here, thought I did that once lol

Originally Posted by vintage chromoly View Post
Good move Tim!
Maximize what you already have.
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Old 09-18-2016, 05:47 PM
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Originally Posted by getrdunn View Post
I double checked mine today that were from Gellners 540 packages and they are 244/248-647/641. They made peak hp at 6,200 however on my builds I advanced them 4 deg to bring them in at 5,800. If you were to do anything like I mentioned before I'd install 1.8's on the intakes on one engine just to see if there is any gains or not.
What heads were on those packages? How much did they make at 6200 and then at 5800 after advancing them? How much advance did the cams have ground into them ?
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Old 09-18-2016, 06:02 PM
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Tim I hope you get to your hp goals, but a 10.000 pound boat and hopefully 700hp will =unhappy TRS drives
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Old 09-18-2016, 07:09 PM
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Heres a 548ci build by another oso member. Dart 310 heads. Victor JR, 850 carb.

Comp 235/243 114 LSA 623 lift. Fairly close to the 741 and 525 EFI cam.

Safe to say, there'd be no point propping for anything over 5200? peak torque around 4100rpm. Why is it surprising that tims cams, with 6* more intake, and 3* more exhaust duration, is pulling maybe 300RPM higher?
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Old 09-18-2016, 07:47 PM
  #136  
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I have a barn full of drives, how you throttle helps a ton... At 630 hp and lots of big water beatings I made almost 2 seasons the one I broke last year 3 times in 10 hours was the case messed up, since last July and all this season all good and I beat it weekly... But yes at limits, after engines run where I want them the boat gets 3's or 4's conversion that's next step... Then boost

Originally Posted by Craney View Post
Tim I hope you get to your hp goals, but a 10.000 pound boat and hopefully 700hp will =unhappy TRS drives
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Old 09-18-2016, 09:23 PM
  #137  
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Originally Posted by getrdunn View Post
Did you ever check cams to confirm lift and duration? Also did you install straight up and degree them? Something is not right? This is obvious as we all have come to the conclusion but need to get to the root of the problem. Those cams should easily make power over 6k.
Those cam sheets FF has of his cams are from Cam Doctor. Cam Motion and a few others, do this after cam is ground and send sheet with cam.
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Old 09-18-2016, 10:06 PM
  #138  
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Originally Posted by MILD THUNDER View Post
Heres a 548ci build by another oso member. Dart 310 heads. Victor JR, 850 carb.

Comp 235/243 114 LSA 623 lift. Fairly close to the 741 and 525 EFI cam.

Safe to say, there'd be no point propping for anything over 5200? peak torque around 4100rpm. Why is it surprising that tims cams, with 6* more intake, and 3* more exhaust duration, is pulling maybe 300RPM higher?
What was the CR on this engine? A 741 cam should make power past 5200, now if that engine is around 9:1 cr then that makes sense that it's done making power at that RPM.
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Old 09-19-2016, 05:19 AM
  #139  
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Ok, still no cam specs from the couple that had "success" also how they were dynode? was it with no accessories and dyno headers? or was it with Alt, Sea pump, and the boats exhaust like stainless marine or GIL..?? makes a difference in numbers...

Also how much time is on the successful engines in the boat being used? I logged 65 or 67 hours, cant remember... clearly I can build engines and proved a few wrong there, thye are fine, besides making good power and with them being 3hp apart and .3 ftlbs apart I don't see my building being the issue...

I would love to see that info I asked for, also seems only 2 guys have similar builds? why did they make power and I did not?
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Old 09-19-2016, 06:10 AM
  #140  
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my engines had 10.3-1 comp,,wilson single plane and a dom(may have been a 1250) on it.and the biggy,,afr 335 cnc'd heads.only the alt was running,cross overs and stelling long tubes.as for hours,,alot and still going.
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