Engine Synchronizer

How important do you think a synchronizer is on gas engines? What is it mostly use for fuel mileage or what? Did a search and could not find a thread.

The best one is just listen. Your ear can get as close as any glendinning. Now, the newer electronic controlled engines with auto synk, thats different.

During our 1,600 mile trip our synchronizer stopped working. I spent the last 5 days of the trip synchronizing by ear. It's a PITA compared to the joy of one throttle for both engines underway, especially when you need to slow down and speed up constantly on the ICW.

When we arrived at our destination, I called Glendinning and they patiently helped me diagnos the problem, sent me the needed parts at a fair price and walked me through the repair. I'm synced again and happy with Glendinning.

My impression is that twin-engine owners, especially pilots of multi-engine aircraft, prefer to manually synchronize the engines.

markpierce said:

My impression is that twin-engine owners, especially pilots of multi-engine aircraft, prefer to manually synchronize the engines.

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Mark, a post without a picture? Shame on you.

hmason said:

Mark, a post without a picture? Shame on you.

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Auxiliary helm on a "real" vessel:

Now I feel better.

Having had to run my boat without the synch working for awhile, I was sure glad to have it back. For long legs, no big deal but for times when a lot of adjustments needed, or dealing with a following sea coming into an inlet, big PITA.

markpierce said:

My impression is that twin-engine owners, especially pilots of multi-engine aircraft, prefer to manually synchronize the engines.

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Truth be told, it's just that real pilots are too cheap to pay for automation if it ain't already there. Besides, we can just hand fly it.

Sitting so close to the engines in a plane it is easy to hear the engines but from the fly bridge it is a lot harder to hear.


Steve
Who is the new to Houma boat in the slip near you?

So on mechanical engines, has anyone installed a sync themselves? Our current 6.3 Volvos do't have them, but I was considering adding one next summer. Is it something that the do-it-yourselfer can do easily? To me, it seems like the install is straight forward enough, but the post install setup would be the bear.

Call Glendinning Tom. They are very helpful. It all depends on how your throttles are set up, including of course hydraulic vs. cable vs electronic, and the method of getting an accurate tach reading, preferably direct from engine. It is actually a pretty simple system.

kartracer said:

How important do you think a synchronizer is on gas engines? What is it mostly use for fuel mileage or what? Did a search and could not find a thread.

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Could impact several things... ride, fuel, noise... all of the above...

At least four ways to sync:
- listen
- analyze your wake
- needle gauge (using tach sender info)
- mechanical or electronic system (e.g, Glendinning)

The inexpensive needle gauge used for syncing is simply taking pulses from the tach output (not the tach readings themselves), comparing, and when the needle is straight up (typically) both engines are running at the same RPMs. That of course depends on how accurate the senders are

We don't have one now, but did on an earlier gas boat... and I found it useful to compare sound and wake to the needle... as I was learning that boat...

-Chris

caltexflanc said:

Having had to run my boat without the synch working for awhile, I was sure glad to have it back. For long legs, no big deal but for times when a lot of adjustments needed, or dealing with a following sea coming into an inlet, big PITA.

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I agree! My Micro Commander throttles are not automatically synching the engines and so far the MC Tech hasn't been able to solve the problem. Luckily, I've had some multi engine time and synching them by ear is not a big deal. (Harder from the fly bridge as was previously noted.)

Syncing by ear is not as easy as you think. For those of you with synchronizers, try synching by ear, then engage the synchronizer. You'll be surprised at the difference. It's kind of like driving a straight line in choppy water and then turning on the AP. You can do it, just not as well.

Tom.B said:

So on mechanical engines, has anyone installed a sync themselves? Our current 6.3 Volvos do't have them, but I was considering adding one next summer. Is it something that the do-it-yourselfer can do easily? To me, it seems like the install is straight forward enough, but the post install setup would be the bear.

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Glendenning syncs are great, robust and pretty fool proof to install. Will also bet they can get closer than all but superman on syncing better than ear.

The hardest thing is finding a good mounting spot where the cable runs are out of the way and compliant.

I was a repair tech for them when I worked for a marine electronics firm.

I believe they also have an adapter for very accurate tachometers...but havent looked at their website in years.

Just recently tossed the manuals and alignment tool making room on the boat.

Just curious, will not a set of digital tachometers like Aetna get you as close as a synchronizer? Where does the synchronizer get its signal in this case?

Some get a signal off an alternator. Then a new belt on only one side gets installed, or a new pulley or ---

Also, engine speed, prop RPM, prop HP and fuel burn per side can independently vary. Then mismatched props enter into the equation. What are we really trying to get in sync? And why?

sunchaser said:

Just curious, will not a set of digital tachometers like Aetna get you as close as a synchronizer? Where does the synchronizer get its signal in this case?

Some get a signal off an alternator. Then a new belt on only one side gets installed, or a new pulley or ---

Also, engine speed, prop RPM, prop HP and fuel burn per side can independently vary. Then mismatched props enter into the equation. What are we really trying to get in sync? And why?

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Are you asking about a Glendenning?

My understanding is syncing is all about eliminating vibration in the drive train. Partly for wear and tear....and some people get freaked about the noise.

I have Aetna digital tach's

After four seasons don't see the need for synchronizers but perhaps I am under informed?

Actually I don't try to get them, exactly the same. Close, i.e. Within 10 or so rpm is fine.

What would the real world measure able benefits of tighter rpm sync???? Never thought much about it before this thread

I would always vote yes to synchronizers. However, how much they will benefit you and how necessary they are also depends on your usage of the engines. I'd say the higher the rpm and the greater the speed, the more advantageous they are.

sunchaser said:

Just curious, will not a set of digital tachometers like Aetna get you as close as a synchronizer? Where does the synchronizer get its signal in this case?

Some get a signal off an alternator. Then a new belt on only one side gets installed, or a new pulley or ---

Also, engine speed, prop RPM... per side can independently vary.

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ksanders said:

I have Aetna digital tach's
After four seasons don't see the need for synchronizers.

Actually I don't try to get them, exactly the same. Close, i.e. Within 10 or so rpm is fine.

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I have Aetna digital tachs, too, and I can come close enough so additional sync gauge (needle) or a full-up Glendenning system doesn't seem all that necessary. Under calm conditions, I can usually get the top of the bell curve around 5 RPMs with the Aetnas; rough water, between 5-10 RPMs... differences because the RPMs and props do indeed seem to be impacted by conditions.

The boat came with Faria gauges, and if the helm had included a needle gauge that would have been fed by signal wires from the tachs BUT it would not have been using any info from the tachs themselves. Instead, the sync gauge would have simply been using the input as an easy wiring extension from engine sender to needle. A Faria-like sync gauge would simply take RPMs from the two engine senders and the needle would display when the two are (mostly) equal. IOW, without regard to what the actual RPMs are at any given time; equal = synced. Don't know how other brands do it.

Our senders are magnetic and take info from the flywheel. (There's some magic there I don't fully understand.) The Faria tachs didn't have wonderful adjustments for calibration. The Aetna tachs just want a tooth count, easy.

-Chris

The OP asked about gas engines. On those there is usually no tach cable tap to operate a Glendinning. On gas boats either digital tachs or a needle type sync gauge will be good enough. On lots of gas boats it is really hard to hear the beat frequency of being out of sync. Hard to sync by ear, some of them.

How do you tell where the tach pick ups are an if they are putting out the same? The engine syn. gauge with the needle is much cheaper that buying twin digital tachs. Glendenning looks to me a great set up just out of my budget at this time.

Ski in NC said:

The OP asked about gas engines. On those there is usually no tach cable tap to operate a Glendinning. On gas boats either digital tachs or a needle type sync gauge will be good enough. On lots of gas boats it is really hard to hear the beat frequency of being out of sync. Hard to sync by ear, some of them.

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Not entirely the case, Ski:

Synchronizer - Glendinning Products, LLC.

True, it can be adapted to a gasser, but it is a bunch of hardware right on the front of the crank, and it will prevent you from easily changing a belt. PITA, like a 3116.

I stand by my point that on a gasser, the needle sync gauge is good enough.

Main advantage to the synchronizer in my opinion is the single lever engine control for both engines if having to change change speed often like on the ICW. Our Glendenning setup has a speedometer cable type setup connected to the front engine pulley. Very easy to disconnect when changing belts. No electronics involved in the speed pickup.

Ski in NC said:

True, it can be adapted to a gasser, but it is a bunch of hardware right on the front of the crank, and it will prevent you from easily changing a belt. PITA, like a 3116.

I stand by my point that on a gasser, the needle sync gauge is good enough.

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Pulling the cable off one of their drive adapters is about as easy a task as unscrewing anything, say the cap off a bottle ; so I don't understand the issue here. And, it's not like you are changing belts all that often.

Fair enough. Just remembering the PITA 3116 rig with the drive hardware, but the PITA part was really the belt guard, not the drive hardware.

A full cover belt guard sure would make it a PITA on both counts.