Transmission ID in Fish |
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BMo
Newbie Joined: July-14-2016 Location: Seattle Status: Offline Points: 14 |
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Posted: August-08-2017 at 2:28pm |
I need some help identifying the transmission in my 1987 Fish. The boat was repowered in 2004 with a Kodiak marine Chevy 350 and the prop rotation is now left hand. The transmission seems to be operating fine but I am not seeing the speeds I expect to see from the boat. The engine runs excellent and only has 280 hours on it, so I don't think it is a power issue (it is rated at 290hp). The prop is an OJ 4 blade LH 13x13 and I am only getting about 17-18mph at 3000 rpm. I suspect it is the original transmission in the boat simply because it is covered in rust (it was in saltwater for most of the last decade). There is a tag on the top port side of the transmission but I am not able to make out what it says because of the rust. Unfortunately, I don't have any pics of the transmission to post right now, but maybe someone can give me clues as to what to look for to determine what it is?
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Dreaming
Platinum Member Joined: May-21-2010 Location: Tacoma, WA Status: Offline Points: 1870 |
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There have been a couple of Fish Restorations on this site, most were a few years back IIRC. They might have some photos of their engine/trans setups if you do a google search. I suspect if the original was a RR engine and the replacement was a SR engine, you might have a 1:1 transmission that has the pump indexed for the SR direction. I believe this also reverses the output direction, but I am not completely sure, thus the LH prop.
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3359 |
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Behaving overpropped, but not enough to explain everything.
Needs rpms to make the rated power, you are probably receiving only 180 hp at that rpm To clarify, Rotating the pump housing itself doesn't change the output direction, it simply makes the transmission actually shift when one chooses an alternate input direction I think you have some compounding issue with state-of-tune as well Is the boat dry, or is flotation foam possibly saturated? Is the boat loaded heavy with stuff? You could be looking in the range 14x10 or 13x11, depending if you run light or heavy, but i think a 13x13 doesn't entirely explain your numbers yet Mechanical advance stuck? see if it operates freely |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole |
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BMo
Newbie Joined: July-14-2016 Location: Seattle Status: Offline Points: 14 |
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Thanks GottaSki. The Fish is a fully optioned boat with swim platform, new aluminum tower, full electronics, dual battery, bow sprit, windlass and 85 gallon fuel tank. The boat is dry with no saturated flotation. In the couple times I had it out, the numbers didn't seem to change much from having only two persons in the boat to having four persons, full cooler and gear. That said, I probably tend to run heavier rather than light. Engine is a newer engine with full electronic ignition and fuel injection. Couldn't hurt to give it a full tune, but I really think it is running quite nicely. The power curve from the engine manufacturer shows I should have approximately 230hp at 3000 rpm. It is actually rated at just over 310hp at 4500. Haven't yet taken it up to WOT due to a shaft log corrosion issue I have been dealing with. I am considering going to a 13x11 but didn't want to do so until I have identified the transmission.
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JoeinNY
Grand Poobah Joined: October-19-2005 Location: United States Status: Offline Points: 5698 |
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Well that's a horse of a different color all together. The assumption was that you were giving us WOT performance numbers. If you are limiting the performance to 3000 rpm then there isn't much to be learned from your speed at that point. Its likely a 1:1 borg - no reason to think different. Its rusty so its not a 1.23:1. It doesn't have a big block so its probably just the plain ol garden variety transmission. See how much it will pull the 13x13 at WOT then come back with that information for a propeller recommendation. If it were a 1.5:1 it would be long and heavy. Google borg warner velvet drive 71c and see if you find a picture of your transmission.
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11061 |
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Here are a couple of pictures to go along with what Joe said
The one on the left is a 1 to 1 Borg Warner and the other is a reduction gear version, longer and heavier like he mentioned |
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BMo
Newbie Joined: July-14-2016 Location: Seattle Status: Offline Points: 14 |
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Thanks all. After looking at your pictures and some research on the web, I am pretty sure it is a standard Borg Warner Velvet Drive 1:1. I am curious if there is any good test to determine any transmission slippage I may be experiencing and/or condition of the transmission? The fluid doesn't seem to be burnt but they could have changed it before I bought it. I haven't taken it up to WOT just yet as I made a temporary fix to the shaft log that I intend to fully repair this winter. The alignment of the engine was off enough that the shaft was touching the log and apparently caused the log to corrode (the weaker metal), causing a leak condition. I think my sluggish performance at lower rpms is either the propeller or a slipping transmission, or a combination of both. Your recommendations are much appreciated!
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baitkiller
Platinum Member Joined: October-11-2011 Location: SW Florida Status: Offline Points: 1693 |
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You can get a laser tach on Amazon for $13. Tape the balancer and propeller shaft. They should be the same in gear (fwd) at any given RPM on a 1:1 or different by the ratio of the reduction gear if so equipped.
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Jesus was a bare-footer.............
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Brian,
WOT RPM will tell lots about what's up and if a prop change is needed. You mention the engine wasn't aligned with the prop shaft but what about the strut? Alignment starts at the strut first so the shaft is roughly centered in the log. Then the engine is aligned to the shaft. |
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BMo
Newbie Joined: July-14-2016 Location: Seattle Status: Offline Points: 14 |
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An additional thought: The Kodiak 350 marine engine is a manufacturer who primarily sells to jet boat providers. They usually don't sell for direct drive applications. A powerful and reliable engine but the power curve on this engine is pretty low end with HP peaking at only 4500 rpm. I think most other direct drive engines are designed for 5000ish rpm. Is it possible this is impacting my performance? That said though, I should be getting at least the same speeds as others at 3000 rpm (most are getting 22-25mph)?
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BMo
Newbie Joined: July-14-2016 Location: Seattle Status: Offline Points: 14 |
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Baitkiller, excellent idea regarding electronic tach. I will pick one up.
PBrainard - my first thought was a bent strut but I quickly found out that finding a new strut for this boat is next to impossible. I have another post in the want ads looking for a strut. I believe it is an SA-20 if I recall correctly. I was able to get the engine positioned such that it no longer touches the shaft log and the transmission to shaft alignment is within .003. It was about .012 when I started aligning. I now don't appear to have any vibration at the lower rpms. Cutlass bearing is still in good shape as well. I decided not to do anything more with it this summer because of several short cruises and fishing trips planned and likely will address it futher this fall/winter. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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It's common to straighten struts. Slight elongation of strut mounting holes pluss washers between the strut base and hull are used for strut aligning.
Contrary to what some believe, no vibration is not a indication of proper alignment. Misalignment can actually bind the shaft to a point of snubbing vibration. |
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3359 |
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Ok, thats 'splains a lot. We thought you were wot at 3000rpms.
I suspect your trans is not slipping at all. If it were, you would have other symptoms real fast because that power loss would manifest into big heat, smells, glazed friction disks, and warped plates causing dirty neutral. I run the exact same same prop in my light tourney boat, nibral oj 4-force. 13x13 , so i can add some relevance to this scenario. When i mash it, i get instant 3000 - 3200 rpm and rising, almost a slingshot . Its not cavitation, just high slip. Like a high-stall converter would do. Its a kick in the pants. However, its in a much smaller boat, so the effect is, well, exhilarating. Now, I can extrapolate what this prop would do pushing that large mass you have, and thats a substantial amount of slip, especially at the lower speeds. hmmmm. This oj prop spead the propwash into a wide flat spread, that almost eliminated roost and flattened wake, so it am very happy with it being a slalom junkie, not getting hit with a glob of 36 mph water to the blsack i got with the acme. I think a 4 blade ACME 13x12.5 like the #209 would suit your situation well. It has much less slip at slow speeds, less aggressive cup, and a more linear 1:1 krpm-mph curve, regardless of loading, where the 4-force looks increasing hyperbolic with more loading. I observed this acme would create a comparatively narrow propwash and likely a higher roost, but that is not a factor for you. I may have some terms wrong, and I agree its a bit soon to choose a pitch without WOT knowledge. However, that said, even WOT numbers with that particular OJ, will be almost worthless to choose a pitch from the acme line. I will stick my neck out there and may be the first to advise, in this situation, get a different prop sooner than later. you have a good prop, just not for that application. You can also get the 3-blade in 1/2" less pitch increments, |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole |
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3359 |
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did some checking... 290hp at 4400 rpm sounded not accurate, or possible
. it should be a 4800 rpm engine, and these numbers suggest it is from Kodiak Type: 5.7L V-8 (Gen 1e Small Block) Displacement: 350 cid (5736 cc) Engine Orientation: Longitudinal Compression Ratio: 9.4:1 Valve Configuration: Overhead Valves (2 valves per cylinder) Assembly Site: Toluca, Mexico Valve Lifters: Hydraulic Roller Firing Order: 1-8-4-3-6-5-7-2 Bore x Stroke: 101.60 x 88.39 mm Bore Center: 111.76 mm Bore Area: 648.59 cm2 Fuel System: N/A or Port Fuel Injection with Electronic Throttle Body Unit Fuel Type: Regular Unleaded Horsepower: 292 hp (218 kW) @ 4800 rpm Torque: 370 lb-ft (502 Nm) @ 3200 rpm don't be afraid to spin it, it won't go boom. Lugging it will Given the 4800 rpm sustained, and your somewhat heavy loading, perhaps consider the 13x 11.5 and 12" pitch 3- blades. they have big blade area and not giving much up, even less parasitics. |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
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The 13x12 and 13x11.5 Acme's are common replacements for the 13x13 hand finished props on 18-19' ski boats... i would suspect that a 23' fish could drop down even more in pitch... 13x10.5 maybe? Like you said, need some baseline performance numbers with the current prop to be sure.
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