420 DA Thread

Blueone said:
I agree on propping like the 450C... just for comparison I am propped perfect with Ni-Bral four blade 22"x 25"pitch and a "L" cup
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And so you are getting the parameters without overstepping them?
 
swaterhouse said:
I wouldn't go by the manual anyway, first the boat was likely over propped from day one as sea ray (along with most other manufacturers) prop for light weights and perfect conditions - makes for good boat tests and reviews!

Second, the 480CE can be easily overloaded and has been known to eat valves, Tony Athens at sbmar.com recommends propping the 480CE like the 450C for long term durability.

Its best to do on the water testing with a clean(ish) bottom and fairly loaded up. You want to make sure the engine gets to up to max RPM easily. You should do that using photo tachs not relying on you gauges as they may be off.

Pretty sure on the 480CE you have fuel flow meters, if you do you also want to check fuel flow at WOT and cruising rpm's to make sure your burning the same or less fuel than the Cummins spec for the 450.
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Are your QSC’s perhaps the nearest equivalent to the 480’s?
 
So, on the subject of propellers......what have you guys been charged by your prop shop to recondition/tune a set of props? Tuckerton Propeller: $550.00 for the set
 
Last Fall, I paid $545 PER prop. $1090. "Refurb", tuning, report.

Jaybeaux
 
Blueone said:
I agree on propping like the 450C... just for comparison I am propped perfect with Ni-Bral four blade 22"x 25"pitch and a "L" cup
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If you bought these props, would you kindly share cost? I just trashed a factory 22X27 prop so I need to find the best solution. Thanks!
 
Buyajet said:
If you bought these props, would you kindly share cost? I just trashed a factory 22X27 prop so I need to find the best solution. Thanks!
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How bad is it damaged? I hit some boulders a couple years ago. Props were actually torn and folded over, looked bad to me but the prop shop said no problem....the worst one cost a couple hundred more than the other but the total was about $1,300. That's about half the price of one new prop to repair both of them.
 
Woody said:
How bad is it damaged? I hit some boulders a couple years ago. Props were actually torn and folded over, looked bad to me but the prop shop said no problem....the worst one cost a couple hundred more than the other but the total was about $1,300. That's about half the price of one new prop to repair both of them.
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Bad. When you fold a blade, the way they get it back is to heat the fold, then bend it. This causes a rearrangement of the build molecular structure which sets a different strength pattern under load. It may be perfect on the bench but when in use with a load on it, it will not be right more than 30% of the time according to my prop experts who do not sell them. No way to test it under load without being on the boat so the cost to pull the boat another time and block it and then wait for a new prop if the refinished one fails is near the cost (here anyway) to just buy one. If I'm buying another 27 and there are issues, I might as well bite the bullet and buy 2) 25's based on the excellent response here. It is $790/prop here to refinish (min.).
 
Blueone said:
Yes ...with medium load 2,700rpm at WOT...cruise at 2,200rpm
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At 2200 rpm, what is your speed? With the 27's I am at 22.4 kts in dead calm. I don't mind giving up a little for the trade off so just trying to dial in knowledge. Thanks
 
I had an 05 420 with 480CEs like yours. After some experience with dropped valve seats on a friends boat I was very cautious with my boat. With the boat loaded like we would use it and full of fuel, the gal/hr were way off. I also installed egt/boost gauges and recorded 900- 1000 deg exhaust temps at CRUISE. This boat had factory props that were 22x27. After much discussion with the local prop shop we reduced the pitch to 25. The boat lost a little on the top end but ran better in the cruise range and the egt lowered to the low 700 range. What matters on prop pitch is how you load your boat not what someone else uses or what some book says. With a clean bottom, full of fuel, and loaded how you will normally run, you should easily hit 2650 RPM and have the gal/hr hit cummin's fuel curve at the rpm where you normally cruise.
 
becnme said:
I had an 05 420 with 480CEs like yours. After some experience with dropped valve seats on a friends boat I was very cautious with my boat. With the boat loaded like we would use it and full of fuel, the gal/hr were way off. I also installed egt/boost gauges and recorded 900- 1000 deg exhaust temps at CRUISE. This boat had factory props that were 22x27. After much discussion with the local prop shop we reduced the pitch to 25. The boat lost a little on the top end but ran better in the cruise range and the egt lowered to the low 700 range. What matters on prop pitch is how you load your boat not what someone else uses or what some book says. With a clean bottom, full of fuel, and loaded how you will normally run, you should easily hit 2650 RPM and have the gal/hr hit cummin's fuel curve at the rpm where you normally cruise.
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Great insight and that makes perfect sense. Generally its two of us, maybe 4, full of fuel and I never break 2200 rpm, usually at 1950-2000 depending on water temp harmonics. I would probably be fine with the 27's but I think it's stupid to buy one 27 knowing that if I buy 2) 25's I will be a lot better off in the long run. Again, thanks
 
Buyajet said:
Are your QSC’s perhaps the nearest equivalent to the 480’s?
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The 480CE's are basically the 450 "CTA" with electronically controlled fuel, 99% of the rest of the engine is the same AFAIK.

The QSC is a totally different animal, everything is electronically controlled, and I think almost all the engine is a redesign. If there are parts that cross between the QSC and 450/480 its a very short list of small components.
 
Buyajet said:
Great insight and that makes perfect sense. Generally its two of us, maybe 4, full of fuel and I never break 2200 rpm, usually at 1950-2000 depending on water temp harmonics. I would probably be fine with the 27's but I think it's stupid to buy one 27 knowing that if I buy 2) 25's I will be a lot better off in the long run. Again, thanks
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Based on the fact the 450 had the 25's that is where I would start, but you should still do full load WOT runs to confirm you can hit your 2650 rpm, again using photo tachs not your gauges.
 
swaterhouse said:
Based on the fact the 450 had the 25's that is where I would start, but you should still do full load WOT runs to confirm you can hit your 2650 rpm, again using photo tachs not your gauges.
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Can't thank you enough and everyone else who commented.
 
Buyajet said:
Great insight and that makes perfect sense. Generally its two of us, maybe 4, full of fuel and I never break 2200 rpm, usually at 1950-2000 depending on water temp harmonics. I would probably be fine with the 27's but I think it's stupid to buy one 27 knowing that if I buy 2) 25's I will be a lot better off in the long run. Again, thanks
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You can pitch the good prop down to 25 and just buy the one new. Running your boat at 1900-2000 rpm on your current pitch will hurt your engines if you are out of your fuel curve. Even after I re-pitched if I ran under 2050 the exhaust temps ran over 900. These boats and engines do not like that speed. I ran 2150-2300 rpm at speeds of 24-28+ mph and exhaust temps between 700-750 and around 1 mpg.
 
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