Prop suggestions new 351w
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Category: General Correct Craft Discussion
Forum Name: General Discussion
Forum Discription: Anything Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=30371
Printed Date: May-04-2024 at 7:36am
Topic: Prop suggestions new 351w
Posted By: svxwilson
Subject: Prop suggestions new 351w
Date Posted: June-21-2013 at 3:09pm
| I am looking for some prop recommendations. I have a freshly rebuilt 351 with 300hp and a 1.23/1 ratio. I currently have a ACME 543 but at 4000rpm I am just barely over 30mph. I want to get a prop that will get me close to 50 for a top end. I mostly slalom ski with it. Boat is a 1991 20ft Ski Brendella super comp. |
Replies:
Posted By: phatsat67
Date Posted: June-21-2013 at 3:25pm
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I don't imagine a lot of guys have info on hull performance numbers on this site for that boat. Just as a reference most 240 HP 351W engines in 1982-1988 Ski Nautique 2001's (2400 dry weight) run between 4400 and 4600 RPM with an Acme 540. With an Acme 542 (equivalent opposite rotation to the 543) these boats would run between 4600 and 4800 rpms. ------------- |
Posted By: svxwilson
Date Posted: June-21-2013 at 3:36pm
| What ratio is the tranny on the Ski Nautiques? |
Posted By: svxwilson
Date Posted: June-21-2013 at 3:37pm
| What ratio is the tranny on the Ski Nautiques? |
Posted By: KRoundy
Date Posted: June-21-2013 at 6:08pm
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Ski Nautique boats have had the 1.23/1 transmission since the late '80s. Where about in Montana are you located? I have a ton of relatives that live in the Flathead Lake area. ------------- Previous: 1993 Electric Blue/Charcoal Ski Nautique Current: 2016 Ski Nautique 200 Open Bow |
Posted By: svxwilson
Date Posted: June-21-2013 at 9:11pm
| Billings area. Wish I was in the flathead area. |
Posted By: TRBenj
Date Posted: June-25-2013 at 12:23pm
Well thats certainly not going to make you many friends here. You seem to have a very oddball combination if I understand you correctly- a reverse rotation (RH) engine combined with a 1.23 tranny and a LH prop. Is that correct? I am not sure why anyone would have gone to all the trouble of building a reverse rotation motor if they were going to go with the less desireable LH prop in the end. The whole reason CC went to the 1.23 was so that they could use a standard rotation (LH) engine and still keep the RH prop. Regardless, you need a prop in the 13x16 range. If you needed a RH prop, the Acme model numbers I would suggest would be 422, 1442 or 470. You might try the LH version of one of those to start, and then come back with your testing results to see if you need to go larger or smaller. A 13x12 is just way too far off to get an accurate baseline. If you describe your engine configuration (modifications?) in more detail, we could perhaps figure out what WOT RPM you should be targeting with your prop choice. The 50mph mark can be a tough one to take down. ------------- |
svxwilson wrote:Posted By: svxwilson
Date Posted: June-25-2013 at 3:16pm
Well thats certainly not going to make you many friends here. I was frustrated i apologize. I will repost on that mastercraft forum my apology Was not trying to piss anyone off I posted here and people basically told me to find another forum. Got no help. I know I have a low production boat. I have had a hard time finding info on it. But thank YOU for your reply. Yes I have a reverse motor with a 1.23/1pcm and a left hand prop. I do not know enough about Ski Brendella to tell you if that was the original config or not. But it's what I am working with. US MARINE ENGINES www.usmarineengine.com Is where I got the long block from. They explained the extra HP came from the cam and higher compression. Please forgive my engine ignorance. I can turn a wrench and replace parts but by no means am I a mechanic. From their webpage "High quality components that equal high quality rebuilt marine engines. All of our marine engines come with new rings, new springs, new pistons, new valves, new push rods, new timing set, new rockers, new brass freeze plugs, new push rods, new bearings, and new lifters. Head castings, crankshafts, camshafts, and rods are all machined back to marine engine specifications and blocks are bored oversize." I reused the holly carb and intake from old engine. The engine builders had to search for the reverse parts because they are harder to find. I talked with Greg at ACME and he recommended a 4 blade 13.5x14.25 model 1793. So I ordered that, he was convincing about their customer service that they would exchange until I found the prop that works best with my boat. I know 50mph is something I won't get to. But close is what I am aiming for. I do mostly slalom skiing and cruising up and down a very large lake. So lower rpm at higher speed is the desired result. I have never been pulled out of the water as fast as it can do right now with the current prop ACME 543. But 4000rpm was 31-32 mph. I never took it to wot with that prop and current engine only had it out once after install so I was breaking it in and I wasn't sure if wot would be a good idea first break in trip out. The engine builders said the desired rpm was 4200 and not to exceed 4600. Once again thank you for your help. I will happily listen to anything you have to say or recommend. If there is a better forum for my peticular brand boat then let me know. |
Posted By: TRBenj
Date Posted: June-25-2013 at 6:14pm
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The oddball combination I was referring to was the mix of the RH rotation engine and the 1.23 trans in a direct drive. Correct Craft started using the transmission (which obviously reverses the direction of engine rotation) so that they could start using LH engines and still turn the desired RH prop. LH (standard rotation) engines are cheaper to build and have more parts readily available for them- its more of a PITA to build a righty, but CC did that just about exclusively prior to 1989, just so they could keep their RH prop. What Im saying is that either that engine and tranny is a non-original combination, or Brendella went through all the trouble of sourcing a RH engine and failed to reap the benefits by matching it to a LH prop. Backwards logic... follow me? The 13x12 and 13x11.5 Acmes (540/541, 542/543) are great ski boat props... for 1:1 boats. They are way too small for a gear reduction powertrain like your 1.23. All of the Ski Nautiques that are of similar size and weight as your Brendella (1989-2009) used 13x16 props with that transmission (replaced by 12.5x15.5 Acmes in 2001). Its no wonder it has a ridiculous holeshot and overturns (speed vs. RPM) by 1k RPM- it has 4" less pitch than it should for good all around performance. Thats a lot. 4200-4600 is a very conservative RPM being supplied by the builder. The stock engine is generally spec'd at 4400, and Ive found it runs best if propped to turn 4400-4600. By raising compression and flow to the tune of 60 extra hp, the RPM at which peak hp occurs surely moved up, probably to the 5k RPM range. Tough to be sure without info on the heads, cam or intake, but thats probably a pretty safe target to shoot for. The bottom end of any old 351w is plenty strong for 5500rpm, so the extra revs wouldnt bother me a bit. I would try the Acme 1443 (13.25x15) as a starting point if youre buying new. ------------- |
Posted By: svxwilson
Date Posted: June-25-2013 at 8:14pm
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EJ OJPROP who works for OJ said "We supplied Brendella with 14 X 16's as original equipment with that ratio. I would offer a 13.7 X 15.5 XMP for that set up" Do you think the 4 blade 13.5x14.25 is a poor choice? I should have it Friday. I ordered a prop pulling kit and the 1793 Monday. I ordered it new from acme so I can return and exchange till I get the one I like. Can you explain the logic between the 3-4 blade prop choice. I understand how size and pitch affect I don't understand how the extra blade affects everything? |
Posted By: TRBenj
Date Posted: June-25-2013 at 8:30pm
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Yes, I think the 13.5x14.25 1793 is a poor choice for a light ski boat trying to maximize top end and trying to keep the revs in check. I think you will spin it at least 5300 if that 300hp number is accurate. Try it and find out though- the more data, the better! I disagree with Eric on the 13.7x15.5 being a good choice as well... its going to be too darn big for your boat. Ive tried a few of their XMP 13x15.5 props and they act much larger than a comparable sized Acme... to the tune of running nearly 400rpm lower. I dont know what it is about thier design, but top end suffered tremendously with them. Theyre even putting 13x14.5 props on the new 6.0L Mastercraft 197's and supposedly they arent spinning to the moon, which amazes me. Dad's 6.0L 196 on the other hand, can pull a 13x15.5 Acme north of 5600 all day long. It would pull a 13x14.5 Acme over 6k. Blade count has little effect on RPM vs. speed, so dont give it much thought. Just remember that the fewer the blades, the more efficient the prop is (and thus faster), all things being equal. 4's will come out of the hole slightly better then 3's, more noticeably when heavily loaded, but blade surface area on the new CNC 3's has narrowed that gap a lot. Just match the size of the prop to your boat and RPM's that you want to run. If you have the choice between 2 identical props that run the same RPM, one being a 3-blade and one being a 4-blade, then go with the 3 if your boat is generally lightly loaded and you value top end speed. ------------- |
Posted By: svxwilson
Date Posted: June-25-2013 at 8:51pm
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So let me get this straight.... Put the new prop on and take it to wot? Take note of rpm and mph at wot? I would not mind having more than one prop also. One that is better for pulling a large mammal like 250lbs up and one that is for top end and slalom skiing. I can get up behind a old tired 86 bay liner with a 2stroke that topped out at 20'ishmph with me on a slalom. I am sure I can get up with a top end prop behind my 351. So ultimately I will be looking for 2 props eventually after I sell my 543. |
Posted By: svxwilson
Date Posted: June-25-2013 at 8:54pm
| Boat came with a 13x13 4 blade that is damaged but repairable. it looks like the acme as far as what it is made out of but it doesnt have a brand name on it. Do you think it would be worth it to repair that one or should I just put that money towards a better 2nd prop |
Posted By: TRBenj
Date Posted: June-25-2013 at 9:00pm
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There is no need for 2 props with that powertrain. A slightly modified 351w and 1.23 in a fairly light ski boat, propped for all around use will come out of the hole better than 95% of tournament inboards. Including most Chevy powered boats made in the last 10 years. The only boats I can think of that might have an advantage are the ones with greater reductions (like the 1.5:1 MC Powerslots). Yes, WOT RPM and speed are the numbers we need. If you can verify theyre accurate, that would be ideal. Get a shop tach and verify the one in the boat is accurate and bring a GPS along with you that can capture your max speed. ------------- |
Posted By: 89Martinique
Date Posted: June-25-2013 at 11:11pm
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TRBenj, What gives MC a bigger advantage? How does the 1.52:1 Power-Slot perform better than a 1.23:1 or 1:1? Our friend has a blue Stars and Stripes. And even though my comp has more power, I think his MC may come out of the hole a little better. (He upgraded his prop from factory to large and less pitch) Thanks, Joe ------------- Current Boats: 1992 Supra Comp-TS6M PCM 351w HO Pro Boss Pro-Tec Ignition - Full Composite (no wood stingers!) 1989 (3rd Gen) Correct Craft Martinique B/R PCM 351w Power Plus 1984 E-Scow Keuka Lake, |
Posted By: svxwilson
Date Posted: June-25-2013 at 11:34pm
| The only GPS I have is through my smart phone. I have a app I use for the truck to know how far off my speedo is with big tires. It seems accurate. The lake I go to has service good enough to run the app. As far as the tach I believe it's accurate but have never actually tested it. My speedos in the boat froze up the last trip out. They are both stuck on 20mph. I will be looking into how to fix that next. Might even do a GPS speedo then I won't have to worry about it..... Ever. I can't remember riding on a boat that actually had functioning speedos, they always seem to have issues and I was excited when I bought mine because it had 2 functioning speedos. |
Posted By: TRBenj
Date Posted: June-26-2013 at 11:23am
The bigger the reduction (1.5 being greater than 1.23 being greater than 1:1), the more RPM you can spin the engine out of the hole. The higher the engine RPM, the more power it makes, so the reduction trannies allow you to put more power to the water at idle through low speeds. Once the boat is fully planed off and running efficiently (usually mid 20's or so), prop slippage is a much lower number, and the reduction transmission and larger prop size balance out so that all combinations run pretty close to 1:1 speed vs. RPM (ie, 3000rpm = 30mph). Remember that when talking about 19-20' ski boats, 1:1 boats tend to use 13x13 props, 1.23 boats use 13x16 and 1.5 boats use 14x18... Multiply that 13" of pitch by 1.23 or 1.5 and you'll end up pretty darn close to 16" and 18", respectively. Generally speaking, a boat will go faster by spinning a smaller (lower pitched) prop at a higher RPM. If you were to compare 2 MC Skiers or Prostars (80's or 90's vintage) with the same engine and different trannies (one being the 1:1 and 13x13 and the other being a 1.5:1 and 14x18), the Powerslot boat would be faster out of the hole but slower up top by a mph or 2. The difference between 1:1 and 1.23 CC's is barely measurable though, and may be why other manufacturers have gravitated towards the 1.25:1 reduction... you get the best of both worlds. Take a look at some of the fast flat bottomed v-drives on the other hand... they tend to run overdrive transmissions (0.7-0.9 to 1) and small props (11x15). When they turn the engine 5000rpm, the prop can be turning north of 6k rpm. Thats how you go fast. Now, I dont imagine they would pull a skier out of the water like a tournament inboard! ------------- |
Posted By: 89Martinique
Date Posted: June-27-2013 at 1:13am
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TRBenj, Thanks for the explanation. Make a lot of sense. Now who makes the 1.25:1? Supra used the 1.23:1 just as CC did. Only difference is the CC takes ATF and the Supra take 20-20W engine oil. (weird) So that explains why my HO supra (extremely light boat!) has a run for its money when up against a regular 230HP MC from 84 or 85 (one is black other blue, the blue one!) Now did PCM really gain 10hp by leveling off the engine with the new 1.23:1 transmission? They advanced the timing by 4 degrees at base and leveled off the motor and gave it a new paint job. Did that really give the 240HP for the Power Plus that my 89 CC has over the 230HP that an 88 and below Martinique would have? Sorry for hijacking thread! Just some questions that I would like answered! Thanks, Joe ------------- Current Boats: 1992 Supra Comp-TS6M PCM 351w HO Pro Boss Pro-Tec Ignition - Full Composite (no wood stingers!) 1989 (3rd Gen) Correct Craft Martinique B/R PCM 351w Power Plus 1984 E-Scow Keuka Lake, |
Posted By: TRBenj
Date Posted: June-27-2013 at 8:41am
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All early 1.23's (through 1990) used 20w oil instead of ATF to combat buzzing at idle until PCM came up with a fix. If you haven't done so, I would install the kit and switch to ATF. No measurable hp changes came in 1990. Standard marine 351w's from all marinizers varied in ratings from 230-260hp. Those numbers probably had more to do with marketing than anything else, as they were all using the same long blocks with similar ignition and exhaust systems. The TS6M is a great ski boat, but pretty slow up top from what I remember. It would not surprise me if the older mc's ran you door handle to door handle, especially if they're slot boats. I wasn't speaking about a particular transmission when I said "1.25", just that several manufacturers (mc and cc) have gravitated towards it. PCM's power plus tranny is actually being stamped 1.26:1 these days instead of 1.23. That 1.26 ratio matches the powerslot tranny that mc uses primarily (at least in the 350 and 6.0l direct drives). ------------- |
Posted By: 89Martinique
Date Posted: June-27-2013 at 12:27pm
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Hmmm. So I have an 80's PCM 1.23:1 in the 92. Whats the "buzzing" you are referring to? Both of my transmissions are fine. My CC tho very low on ATF when I bought it. I'm not so sure about the slow top end. My rpm and mph are very close in hand. WOT @ 4,400 RPM = 44~45 MPH. I'm not sure what the MC is capable of tho. And yes, my friend's MC and my Supra are nose to nose. When I put the comp in the water last fall for the first time in 2 years, the MC was near. Met up and then had a little "race". We both punched it and he just about beat up and out, after that I started to just barely pull ahead. But it was a very short "race". While he may beat me in speed, I beat him in sound!  ------------- Current Boats: 1992 Supra Comp-TS6M PCM 351w HO Pro Boss Pro-Tec Ignition - Full Composite (no wood stingers!) 1989 (3rd Gen) Correct Craft Martinique B/R PCM 351w Power Plus 1984 E-Scow Keuka Lake, |
Posted By: TRBenj
Date Posted: June-27-2013 at 1:22pm
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The early PCM trannies buzzed at low (idle) speed. They specified 20w oil to help quiet them down, and then came out with a kit that basically expanded the fluid reservoir. Looks like a 8" hose coming out of a tranny that has been so retrofitted. It eliminated the buzz and allowed you to return to ATF (my '90 has been converted). I would consider 44-45mph pretty slow for a HO 351w powered 19' boat. Even most of the NWZ SN's (1992-1996) with those motors were good for 47 or so. 44-46 is a pretty typical top end for a non-HO (240hp) early 2001 (82-86) and the MC Skiers and PS190's of the 80's ran about the same. The 'slot boats were towards the slower end of that spectrum though, so what youre seeing makes perfect sense. Your boat would run better if you propped it to turn 4800 or so at WOT, by the way. ------------- |
Posted By: Hollywood
Date Posted: June-27-2013 at 1:28pm
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omfg this thread is still going on??? ------------- |
Posted By: svxwilson
Date Posted: June-27-2013 at 1:51pm
| Lots of good info here. I now understand much more about different boats with the different ratios and props. I am a newb boat owner so I am like a sponge for the info |
Posted By: Hollywood
Date Posted: June-27-2013 at 1:58pm
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understood, tim's being very generous regurgitating it all ------------- |
Posted By: 89Martinique
Date Posted: June-27-2013 at 8:00pm
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Hollywood, calm down. lol TRBenj, Thanks you for shedding light on all of this. Really appreciate it! My HO isn't so much a HO. The GT40P heads got wreaked due to uh.. too much fun.   Now it has the heads that my CC has. Still the 4010 carb, dual 3.5" exhaust, and Pro Tec ignition. But I will be getting a pair of GT40P heads from my uncle. He helps me, I help him, and his junk yard buddies let him know of every GT40P that rolls in! So, will gain a little power back again. Hopefully that should bring my top up a bit more. ------------- Current Boats: 1992 Supra Comp-TS6M PCM 351w HO Pro Boss Pro-Tec Ignition - Full Composite (no wood stingers!) 1989 (3rd Gen) Correct Craft Martinique B/R PCM 351w Power Plus 1984 E-Scow Keuka Lake, |
Posted By: svxwilson
Date Posted: June-29-2013 at 4:35am
| I got 41mph at 4200 rpm. I also started a new thread for the new results. More details there. |
Posted By: Faceplant
Date Posted: October-26-2013 at 11:43pm
Just out of curiosity , why are RH props more desirable than lefties ??
|
Posted By: TRBenj
Date Posted: October-27-2013 at 11:21am
| The torque of the RH prop offsets the weight of the (starboard sitting) driver to some degree. |
Posted By: Faceplant
Date Posted: October-28-2013 at 1:22am
| 1979 Ski Supreme with a 351 and a 1.1 Velvet drive . 13 X 13 Lefty . Only 39 MPH at 5500 Rpm . RPMs seems WAY high for that speed . I wakeboard and slalom . Top speed isn't really that important but do like to go fast on occasion . Would a 543 prop bring the RPMs down at top speed or increase them . Also on a side note - saw a 13 X 11 prop for sale at a good price . Should I even bother considering this or would it be all wrong for my application ? |
Posted By: Gary S
Date Posted: October-28-2013 at 7:44am
Like Tim says are you sure those figures are accurate? Forget the 13x11, less pitch,the 11, will increase your rpm ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Faceplant
Date Posted: October-28-2013 at 9:27pm
| Thank you . I will try that next Summer . Anyone know of a 543 for sale ? |
Posted By: oldscool
Date Posted: October-28-2013 at 11:05pm
| Ok, after reading this thread I'm going out and pull my prop and see what's on there. I'm getting 43 mph WOT with gps speedo. New tachometer says 4600 rpm. I knew the newer nautiques were slower and the carbureted 5.8 doesn't help, but in the right water conditions I can get 50+ out of my 73 with 48-4900 on the tach and that's a carbureted 5.0 with 1-1 velvet drive. Seems to me I can get the speed to rpm a little closer with the right prop. |
Posted By: 63 Skier
Date Posted: October-29-2013 at 12:39am
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I agree you may see a few more mph with a different prop and a couple hundred more rpm. The '73 is a flat bottom without the hook your newer boat has to plant the bow. They it higher speeds with less HP. Also lighter, narrower boat. ------------- '63 American Skier - '98 Sport Nautique |
Posted By: TRBenj
Date Posted: October-29-2013 at 7:44am
Those numbers sound a little optimistic on the 73... Not doubting your honesty but questioning their accuracy. Unless the engine has had some work done, 47-48mph and 4600rpm are the norm for that hull and power plant (and a stock 12x14 federal, or equivalent). A GPS and a known-accurate tach would tell the real story. Whereas the 1600lb Skier will typically under turn with a stock sized prop (< 1:1 rpm vs speed) a modern hull will overturn by a significant margin due to its increased weight and larger wetted surface area. A 300rpm differential is actually doing really well (my 90 overturns by nearly 500rpm at wot with a stock sized prop). What doesn't seem quite right is the lower numbers- 4800-4900 and 45-46mph would be more typical out of that hull and powertrain (I'm assuming you have the typical gt40). Time for a tuneup maybe? |
Posted By: oldscool
Date Posted: October-29-2013 at 3:56pm
| Tim, The new boat has a 13/16 oj legend. I read somewhere on here that the oj 4 blades sucked. I need a spare prop anyways for traveling, so what acme prop should I try? Also the skier has a worked motor and not sure of the hp.(rebuilt when I bought it ) but the right conditions means millpond glass and only me in the boat. With a little chop and a passenger it will porpoise its way down to 46-48. I trust the tach is very close and set my speedo at 36mph/3600rpm. I know this is close but not exact. I think the skier has a 12/13 oj legend 3 blade, but not sure, my spare is a Michigan same pitch. Now I have to go check LOL. |
Posted By: TRBenj
Date Posted: October-29-2013 at 4:25pm
|
Tom, I went back and re-read your diary and your post... and Im confused, ha. You said you have the carbed 5.8 and 275hp- are you sure? I was only aware of the 260hp (non-HO) and 290hp (HO) carbed 351w's that PCM was offering in the late 90's. Any chance that 275hp is actually a 305 (5.0L) Chevy? http://correctcraftfan.com/reference/2000_brochure/index.asp?page=33" rel="nofollow - 2000 brochure If its a Ford, take a look at the end of the heads and see how many bars are in the casting... should be either 2 or 3. GT40 (HO) heads have 3, the standard heads have 2. I do not care for the 13x16 OJ. An Acme would wake it up quite a bit. If you have the non-HO 351w or the Chevy 305, a 12.5x15 Acme would be my choice (most likely a 470). If you have the HO 351w then I suspect you have a little bit of tuning up to do, and an Acme 422 (12.5x15.5) should work best. In regards to speed, the smaller hulls usually run fastest with a little bit of weight in back that allows them to porpoise. The faster (stock) 16' boats seem to porpoise naturally at WOT without any extra weight in back, and Ive seen a few flirt with the 50mph mark. A slight chop will run faster than glass calm. That 12x13 OJ is a good prop- much better all around than the original Federal (though top speed will be similar). Setting the speedo using the tach is a good way to get you in the ballpark if the tach is accurate- though most from that era were marginal, in my experience. Either way, it could still be off by a few mph, which is pretty common. A GPS would tell the true story. |
Posted By: oldscool
Date Posted: October-29-2013 at 9:22pm
| Thanks for the advise Tim. I will look into the 470 for next year. Definitely need to gps the skier next summer, you can drive. |
Posted By: TRBenj
Date Posted: October-29-2013 at 9:54pm
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Sounds good to me! Let me know if you confirm which engine your '00 has... You've got me curious. Would love to see pics of that skier as well! |
Posted By: oldscool
Date Posted: October-29-2013 at 10:26pm
| Definitely a 5.8 does not say HO so must be 260hp. Was told 275 by the previous owner. Should have checked before posting. |
Posted By: TRBenj
Date Posted: October-30-2013 at 8:32am
| Check the heads just in case- then you'll know for sure. Numbers look pretty good if it's a non-HO. |