3208T CAT's; 1W5900 Arrangment

banispeter · Post by **banispeter** » Sat Mar 25, 2006 5:35 am

Sean: Never got to the props last year but this year the funded plan is: 1. Walnut blast the bottom (instead of sand) as it keeps the barrier coat intact. Gotta give me speed. That is this Wednesday. 2. Have ordered 21 x 23 #3 cups and will stick them on the 1 3/8" shafts and pray the 3.82 rating holds up. A Bertram retrofitter in FL said that is the MAX you can put on. CAT may have to fool with the rack but wil let you know. 3. Remember I "lost" the exterior exhaust vents that are screwed to the hull sides aft and pull the interior upper fiberglass high rise of the exhaust system tight to the hull? Well, I was in Miami recently on biz and dropped by Glasstech, explained what I needed and whatzhisname said "funny you should ask, we made a pair for a guy in MASSACHUSETTS last fall but he called up and said he didn't need them anymore. Here they are". I now own them. Lucky for that guy Glasstech can't find his paperwork. 4. See you out there. Peter

banispeter · Post by **banispeter** » Thu Jun 01, 2006 5:16 pm

OK. Put on the new 21 x 23 3 blade nibrals #3 cup with no adjustment to the fuel rack and on the 1 3/8" shafts and here are the results: 1. It tops out at only 2300 RPM and both CAT and the Bertram guy in Florida say that is fine considering the shafts ought to be 1 1/2 for a 5 safety rating. Turning up the fuel rack to get to 2800 and I stand a good chance of snapping them off. 2. At 2300 I am turning 24.5 knots or so. Got up to almost 25 on a flat sea slack tide. 3. At 2100 I am turning 20.5 to 21 knots. 4. I think I am going to leave it alone and run it this way. Peter L. Banis KNOT AGAIN Boston, MA

Sean B · Post by **Sean B** » Fri Jun 02, 2006 1:28 am

You may want to rethink that. If you search around on boatdiesel.com, you will find a mountain of evidence that any setup that does not allow the 3208 to reach 2800 RPM at WOT will severely reduce the life of your engines. You can find it in the CAT manual. Anything less than 2800 WOT is an overload, and 2300 WOT indicates a severe one. Whoever the prop guy is that gave you the advice that 2300 RPM WOT is okay should probably be shot for it. I can't even fathom that a CAT guy said that was okay too, WOT tests for overload are pretty common knowledge. Sure maybe your shafts will live, but keep running that way and it won't be too long before your engines melt down and there will be nothing to turn them. On the other hand, I'm not sure why you have such a low WOT with those props because they are not too terribly big. Something else must be slowing you down, I would check all the usual culprits. But you do have a big problem there and I would definitely not run around like that and think it is okay. Don't take my word for it, do some research on boatdiesel. The $25 you'll have to spend there to peruse the old posts will pay big dividends. Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com

smanni · Post by **smanni** » Mon Jun 05, 2006 12:09 pm

I'm no diesel expert, but I agree with Sean. I have been playing with props for a couple of years and both the local CAT and my other general Diesel mechanic say that wide open throttle RPM's reaching the correct number are extremely important in the grand scheme of engine life! - There are dozens of threads on Boatdiesel that ALL say the same thing -I'd be cautious about leaving them the way they are!

smanni · Post by **smanni** » Mon Jun 05, 2006 12:11 pm

Do you have any black smoke at 2300 RPM?

banispeter · Post by **banispeter** » Mon Jun 05, 2006 3:53 pm

Thank you all for your concern. I COMPLETELY misread and thus misunderstood the email from my CAT friends. They said I could run the boat at the 2400 for NOW until they can get down there and fool with the fuel rack, etc. (which is this week). They said they could and would adjust the rack, etc. but ONLY to the extent that in their judgment they would go no further by making upward adjustment to fuel flow considering my old kitty cats have not been ramped up before. To the extent they ramp them up to what they in their judgment believe is as far as they consider prudent I will then begin to reduce prop pitch until I can get to 2850 WOT. I hope they can bring the power up to get me to 2850 and I will consider shafting up to 1 1/2" if I have to. The gears current will handle up to a 1 1/2" shaft. My CAT friends have warned me that increasing the power and thus the load will cause the weakest link in the propulsion chain stress since so many years have gone by with the motors operating under their current settings. I trust that they will do the right thing and if that requires a much smaller pitch and thus top end then so be it. If speed cannot be obtained to my satisafcation (I cannot sufficiently express to you the exhiliration in going 24+ knots in that boat whereas 20 used to be the top end with the 20x22's) I will rethink this matter. There was no smoke and operating temperature was normal. But, as I have been told by CAT, those are not indications of anything and if those symptoms appear it is then too late. Again, I thank all of you for your concern, especailly you, Sean. I will let you know what happens. Peter L. Banis KNOT AGAIN Boston, MA

Post by **dougl33** » Mon Jun 05, 2006 4:32 pm

Peter, I seriously doubt there's anything wrong with your shafts or your motors. You're getting the same speed as everyone else is with this combo, you're just getting it at the wrong rpms. Refresh my memory, what do your motors turn up at wide open no load throttle? If you're getting 3K then you still have a prop issue and not a motor issue. Also, I don't think the shafts are your weakest link. I think its the MG TD 502's. Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth Marblehead, MA [img]http://www.bertram33.com/photogallery/p ... sabeth.jpg[/img]

banispeter · Post by **banispeter** » Mon Jun 05, 2006 4:41 pm

Doug: No load WOT is 3200. It is a prop issue I agree. I do want to spin the motors up a bit and then prop down a little (probably). What speed do you get at 2500 and with what props? I was turning 20x22's and would do 18 knots on a good day which drove me absolutely crazy. Peter L. Banis KNOT AGAIN Boston, MA

Post by **dougl33** » Mon Jun 05, 2006 4:51 pm

Peter, I don't have Cats, I have Mercs, but I spend a lot of time on boatdiesel.com and I was close to pulling the trigger on a pair of low hour 3208T's in an old Sea Ray. This is what your boat should be doing according to the 1984 Bertram spec sheet I have: With the MG502 1.54:1 and 20x22 3 blade with cup: Max speed 26 knots @2800rpm, Cruise 23.48 knots @2500 burning 22 gph. Of course this is for a brand new boat right from the factory with little or no extra weight. Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth Marblehead, MA [img]http://www.bertram33.com/photogallery/p ... sabeth.jpg[/img]

banispeter · Post by **banispeter** » Mon Jun 05, 2006 5:00 pm

Doug: Have the 1983 FBC. Ran the 20x22's. Same gears. Not sure about cup. Never got close to those numbers. Peter L. Banis KNOT AGAIN Boston, MA

smanni · Post by **smanni** » Mon Jun 05, 2006 5:17 pm

that is the exact set up that I just switched my props to and I am very close to those numbers -(still not sure about the fuel burn yet) but the speeds and RPMs are real close!

smanni · Post by **smanni** » Mon Jun 05, 2006 5:22 pm

also I have the SF not the FBC - but I dont think that makes a difference. I have to play with the tabs a bit but the last two weekends and 10 hours of engine use have had me about 21-22 kn cruise between 2400 and just shy of 2500 rpms.

banispeter · Post by **banispeter** » Tue Jun 06, 2006 1:26 am

smanni: You switched TO 20x22's? From what?

smanni · Post by **smanni** » Tue Jun 06, 2006 4:55 am

I had 20x21 no cup and switched to 20x22 (slightly over 22 - I think it was like 22.125 - I have the scan report on the boat) with a #5 cup - I just did this about 3 weeks ago

sbeer · Post by **sbeer** » Wed Jun 07, 2006 12:53 am

Pete, I am running the exact set-up you are. I do not have any problem hitting the #'s that cat requires. When I had the tech down to adjust the valve clearances, we took it out and he told me with the boat at full throttle hitting 2850, I still could go alittle larger on the props if I wanted more speed. When he found out that I had 1 3/8 shafts that idea was crushed. As a matter of fact, he said had he noticed the shaft size before I openned it up he would never have let me do it. Smallest shaft that he recommended was 1 1/2 preferred 1 3/4. Mike