Eng Sync - how do they work?

[EKM]

yes, stupid question....
My 6CTA eng sync does not seem to be working correctly and trying to figure out why.
So at cruise if I turn the sync on it works. My port tach isn't working correctly and reading high so what signal does the eng sync get to work? Sync appears to be working when set at speed. If I put the sync on at idle and push up the port throttle, the starboard engine doesn't come up to speed. Boat is out for the winter so can't really troubleshoot. Just trying to understand where it get rpm signal from and how it works.
Thanks in advance to you SME's.

 

[Skip Boyer]

Your boat, engines, year model are a good bit different than what I have but, when I was trying to figure out how mine worked it took a while. Basically with the detroits, engines running at idle speed, transmissions must be in gear, turn sync switch on, push stbd throttle to wide open, then control speed with port throttle. I don't think my system gets any signal from the tach head unit. In the engine room I have a "sync" sytem that consists of a control box, a hyd reservoir, couple cylinders, some hoses and wires that run to each engine. Just food for thought when you get to troubleshooting again.

 

[Jaybeaux]

I assume it is a Glenn-Denning (sp) engine synchronizer. There are a couple of schools of thought on how to operate them. Sort of like a Ford vs Chevy argument. Neither is right, neither is wrong. It is a preference thing. I will start with the way "I" operate my engine synchronizer:

First, I don't like to make my synchronizer "work too hard" so what I do is manually move the throttles to where I want to go....usually 2200 rpm. At this point, the engines don't have to be exactly in sync, just close. Use the sync gauge to judge. I then "activate" the Engine Sync switch on the helm; followed by advancing the Starboard throttle all the way forward. This is the visual reminder that the Starboard is the slave throttle and that both engines are being controlled by the Port throttle. I then use the Port throttle to make any adjustments to speed and both engines are kept in sync. When it is time to bring the boat back to idle---and this is the key point---bring the Starboard throttle back to "even" with the Port throttle, then bring it back just a bit more (maybe an inch) until you feel it stop. Don't put a lot of pressure on it, just feel the stop. Then, disengage the Engine Sync switch, and now you are back to individual control of each engine. You will immediately see that the Starboard engine is lagging the Port, because of the way the system works, and you will need to advance the Starboard engine slightly. I then bring the engines back to idle in a four step process. I don't just slam the sticks back to idle. This procedure puts very little "demand" on your engine sync. With regard to your port tach reading incorrectly, I think that the engine sync has it's own engine speed pick up. The tach at your helm has no bearing on the sync, as I understand it.

The "other way" to operate the engine sync is to bring both engines up to just above idle. I was told like 900 rpm. Activate the Engine Sync swithc; advance the throttle on the Starboard engine to full forward; then control the engines with the Port Throttle only. Do this all the way up and down through the power range. When done, bring Port throttle to idle (Starboard will follow); then return Starboard Throttle to idle, disengage the Engine Sync switch.

My personal preference is for the first procedure described. The reason is in the second method, the engine synchronizer is working its ass off to go up from idle to 2200 rpm, and then back down. Why put that wear and tear on the device? Sort of like cruise control in your car: Do you set the cruise at 25 mph then use the "+" to increase the speed to 70 mph and converserely the "-" key to reduce speed? No, you only use those for small adjustments. That's the way I look at it.

Hope this helps,

Jaybeaux

 

[fwebster]

Perhaps someone else has better information th at I , but Glendenning typically uses one of 3 sources for rpm input. 1.) a Glendenning sensor mounted on the nose of the crankshaft that sends actual rpm info to the Glendenning control box the nGelenenning uses that data to match the rpms of the 2 engines. 2.) an electronic pulse counter (tooth counter) that matches the pulses counted on the primary engine to the slave engine. The tooth counter is installed at the factory by Sea Ray and it also drives OEM tachs. 3.) an electronic signal from the factory OEM gauge package.

If I were guessing, your tach and synchronizer issues are not related. You probably have a Glendenning synchronizer and your flaky tachs are probably Teleflex Sea Ray OEM tachs whic are known to be flaky. The easiest fix is to replace the Tachs either with new ones from Sea Ray or with Aetna digital tachs. Aetna's are plug and play on Sea Rays and the biggest challenge is fitting the different diameter Aetnas into the SR dash.

 

[dtfeld]

Glendinning makes a mechanical and Hynautic (hydraulic) system based off the same control box.. I attached a picture below for reference. I have the mechanical version in my boat, and I operate it just like Jaybeaux's first option. Here is the operating manual. There is a troubleshooting guide in the back.

https://www.glendinningprods.com/wp...12/Synchronizer_-_Manual.v1.pdf?4cf23d&4cf23d

The basic operation of this is there are rotary cables attached to the flywheel of each engine leading back to the control box. Inside the control box, a little differential gear pulls on the throttle cable of the slave engine to match the lead. Its all mechanical. There is a lag between the lead and slave engine, especially with large RPM changes that is normal ( as in trying to power up from idle). It sounds to me like yours is working correctly, but may (maybe) need the clutch cable adjusted. I would wait til next year, get a a few more hours with it. Try the recommended procedure, and if still not satisfied, look into it further.

 

[EKM]

Thank you so much for the explanation. I have the Glendinning Mechanical in mine in looking at dtfelds picture. So sound like the system is really working ok, my port tach is probably off. Boat ran very well at WOT and was hitting over 30mph and before going back to cruise speed.
Thanks again for the help!
Ed

 

[Woody]

yes, stupid question....
My 6CTA eng sync does not seem to be working correctly and trying to figure out why.
So at cruise if I turn the sync on it works. My port tach isn't working correctly and reading high so what signal does the eng sync get to work? Sync appears to be working when set at speed. If I put the sync on at idle and push up the port throttle, the starboard engine doesn't come up to speed. Boat is out for the winter so can't really troubleshoot. Just trying to understand where it get rpm signal from and how it works.
Thanks in advance to you SME's.

If you have a mechanical tach drive the drive cable will be coming off the belt end of the engine, not the flywheel end. If you think your sync isn't working correctly call them, they're really friendly, helpful folks.

 

[EKM]

If you have a mechanical tach drive the drive cable will be coming off the belt end of the engine, not the flywheel end. If you think your sync isn't working correctly call them, they're really friendly, helpful folks.
View attachment 93076

Yes....have a mechanical tach drive cable of the belt end. I painted the cowling before launch this summer so I know its there.

 

[EKM]

If you have a mechanical tach drive the drive cable will be coming off the belt end of the engine, not the flywheel end. If you think your sync isn't working correctly call them, they're really friendly, helpful folks.
View attachment 93076

What is the piece coming between the cable and engine??

 

[Woody]

What is the piece coming between the cable and engine??

I'm no expert on the subject but it's an adapter of some type. Look around on the Glendinning site, there is a ton of info there plus they like to talk about their products if you call them. FWIW the cables are often the problem, sharp bends, kinks, worn or broken ends.

 

[dtfeld]

If you have a mechanical tach drive the drive cable will be coming off the belt end of the engine, not the flywheel end. If you think your sync isn't working correctly call them, they're really friendly, helpful folks.
View attachment 93076

Sorry, thanks for correcting. I guess that’s a balancer? Either way, it’s on the belt end of things.