Engine sync for mechanical engines....

[bayview]

My 6C engines with geldenning and Aetna tachs worked perfectly for 15 years. Never had any indication of problems.

 

[Baker]

"So that engine gradually lost rpm and the sync age was making up fuel to match the rpm's."

THat would have happened regardless of "who" was managing power. ANd in the end, the power manager is the governor...not the synchronizer. The syncro sets the spring tension on the governor just like you did via the power lever.


"Your tachs tell you nothing about the load on the engines - the most important thing you can know.
Any variation in props as tuned, growth on the props or anything you pick up along the way will unbalance the load between the engines.
The engine which becomes overloaded will be subject to damage much sooner then you might think."

You proved my point. Boost/pyro gauges are reference gauges to determine what is going on with the engine...not a gauge to set power to. I have boost/pyro gauges on my current boat and I will have them on the new one. I am a huge fan. I just don't set power by reference to them. I look at them to make sure everything is copacetic. If not, then investigate further.

"You cannot set power with a tach especially on a twin engine application - if you have ever down that you likely know from the unbalanced fuel usage."

I always set power by tachs. And I am willing to bet 99% of people on here do. I think you are a pilot, right? Think about "primary" instruments versus seconday. When you are powering up in a planing boat, the absolute number one gauges you are looking at is tachs....and I guess that would ring true in any boat...twin engine or otherwise. Hell when I am powering up the jet I fly, the N1 gauges are the primary instrument when bringing the engines up for takeoff....and THEN look at other instruments to make sure everything is ok.
Nothing wrong with fine tuning with references to other instruments. But in the end, this thread is about WAH WAH WAH WAH WAAAAH WAAAAH WAAAAAAAAH WAAAAAAAAH WAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHH.
That last letter grouping is what I am looking for.

 

[ranger58sb]

The tachs are not accurate. I dont sync to the tachs...I sync it by ear....wah wah wah waaaaaaaaaaaaahhhhhh. Well aware of Aetna digital tachs as I have them on my current boat. Likely the first mod I will do on this boat. I will have to redo my panel though as the tachs are huge on this boat so I would need something to fill that hole. Anyway, maybe digital tachs and some tension adjustment might be all I need.

I always set power by tachs. And I am willing to bet 99% of people on here do. I think you are a pilot, right? Think about "primary" instruments versus seconday. When you are powering up in a planing boat, the absolute number one gauges you are looking at is tachs....and I guess that would ring true in any boat...twin engine or otherwise.

I expected to look at Glendinnings when we bought our boat, but... the original analog tachs weren't great and I replaced those with Aetna tachs... before I got around to thinking more about syncs... and it turned out the digital tachs have been sufficient.

CruzPro also makes digital tachs, smaller 2" format. Happens I've also replaced all the other engine gauges with CP models, but that was after changing the tachs... and the 4" Aetnas fit my existing holes with no mods.

If your existing holes are larger than a 4", you could maybe just make up a custom bezel for a short-term fix... and maybe (or not) do a complete rework at your leisure?

-Chris

 

[catalinajack]

Our boat has a Glendinning synchronizer. A while back it began malfunctionaling. One engine would periodically drop 200 RPM and then come back up. It drove me crazy so I stopped using it. Instead, I use the tachs to match RPM. I had been using the alternator as a signal generator to run my replacement pprogrammable tachs which worked quite well (but not perfect) as to accuracy. Knowing true RPM via a phototac, I was able to synchronize quite well. Just a few days ago I removed the Glendinning drive cables from the engines and installed signal generators which have no variability at any RPM. I can report that, based on phototach readings at various RPM, my tachs are dead-on. I see no reason to spend money on having my Glendinning repaired/adjusted to make it useful again. It will stay in place for the next owner to use if s/he wishes.

The signal generators I used have a take-off at the top that enables a drive cable to be installed so, theoretically, I can use the Glendinning. However, my engines are Lehman 120s and there is a metal raw water tube directly above the engine drive port in the way. Some day I may substitute a length of flexible hose to get around the Glendinning drive cable. I could have used the two take-offs on the Glendinning control box but that would have required more wiring than I was willing to do at the moment.

As for all those who commented here about their concern for disparate loads on the engines, I just don't get what all the fuss is about. Rarely do any of us run at WOT or even close to that such that engine loads might be a concern. That would be true for even the few who chose to run over-propped. In my case, the port engine has the additional drag from running the hydraulic pump for the stabilizers. Glendinning or not, I will always have differing engine loads. This, in my opinion, is a non-issue.

I expected to look at Glendinnings when we bought our boat, but... the original analog tachs weren't great and I replaced those with Aetna tachs... before I got around to thinking more about syncs... and it turned out the digital tachs have been sufficient.

CruzPro also makes digital tachs, smaller 2" format. Happens I've also replaced all the other engine gauges with CP models, but that was after changing the tachs... and the 4" Aetnas fit my existing holes with no mods.

If your existing holes are larger than a 4", you could maybe just make up a custom bezel for a short-term fix... and maybe (or not) do a complete rework at your leisure?

-Chris

 

[smitty477]

"So that engine gradually lost rpm and the sync age was making up fuel to match the rpm's."

THat would have happened regardless of "who" was managing power. ANd in the end, the power manager is the governor...not the synchronizer. The syncro sets the spring tension on the governor just like you did via the power lever.


"Your tachs tell you nothing about the load on the engines - the most important thing you can know.
Any variation in props as tuned, growth on the props or anything you pick up along the way will unbalance the load between the engines.
The engine which becomes overloaded will be subject to damage much sooner then you might think."

You proved my point. Boost/pyro gauges are reference gauges to determine what is going on with the engine...not a gauge to set power to. I have boost/pyro gauges on my current boat and I will have them on the new one. I am a huge fan. I just don't set power by reference to them. I look at them to make sure everything is copacetic. If not, then investigate further.

"You cannot set power with a tach especially on a twin engine application - if you have ever down that you likely know from the unbalanced fuel usage."

I always set power by tachs. And I am willing to bet 99% of people on here do. I think you are a pilot, right? Think about "primary" instruments versus seconday. When you are powering up in a planing boat, the absolute number one gauges you are looking at is tachs....and I guess that would ring true in any boat...twin engine or otherwise. Hell when I am powering up the jet I fly, the N1 gauges are the primary instrument when bringing the engines up for takeoff....and THEN look at other instruments to make sure everything is ok.
Nothing wrong with fine tuning with references to other instruments. But in the end, this thread is about WAH WAH WAH WAH WAAAAH WAAAAH WAAAAAAAAH WAAAAAAAAH WAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHH.
That last letter grouping is what I am looking for.

"I always set power by tachs. And I am willing to bet 99% of people on here do. I think you are a pilot, right?"
I am not a pilot - and I think yo are correct that most people set there engines by tach and that is how some get into trouble. If your props are close your rpm will likely be close as well but not exact.

"Nothing wrong with fine tuning with references to other instruments. But in the end, this thread is about WAH WAH WAH WAH WAAAAH WAAAAH WAAAAAAAAH WAAAAAAAAH WAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHH.
That last letter grouping is what I am looking for."
The boats we have do not generate any sort of annoying sound whether the rpm is synced or not - engine room insulation along with exhaust mufflers always left us with the ability for normal conversation on the bridge or pilothouse. Wind noise was the predominant issue dependent upon weather.

 

[sunchaser]

The boats we have do not generate any sort of annoying sound whether the rpm is synced or not - engine room insulation along with exhaust mufflers always left us with the ability for normal conversation on the bridge or pilothouse. Wind noise was the predominant issue dependent upon weather.

I can't hear worth a darn. But I can sure hear twin diesels that are out of sync when at the helm or especially at the stern. Not all of us are concerned about odd engine vibes, but it drives me nuts.

This past summer when cruising on a vessel with twin 16V92s the Glendinnings and digital tachs were spot on to provide that beloved diesel symphony as opposed to new wave vibrations. Ahh, the joy of synchronized big DDs!

 

[Codger2]

I can't hear worth a darn. But I can sure hear twin diesels that are out of sync when at the helm or especially at the stern. Not all of us are concerned about odd engine vibes, but it drives me nuts.

DITTO!

 

[Baker]

The boats we have do not generate any sort of annoying sound whether the rpm is synced or not - engine room insulation along with exhaust mufflers always left us with the ability for normal conversation on the bridge or pilothouse. Wind noise was the predominant issue dependent upon weather.

This whole time you have been driving your guests crazy...hahaha!!! Just kidding. And it doesn't take a loud boat to notice. I think one of the reasons it is difficult on this boat is that it is so quiet. But I can still hear it. My current/old boat and new boat are both very quiet boats. I run on plane so the most noise is generated by the boat moving through the water. Engine noise is minimal to almost non existent. But it is the harmonic vibraton that causes the WAH WAH. Meridian has underwater exhaust(which I do not like). So engine noise is muffled even further.

 

[Baker]

Our boat has a Glendinning synchronizer. A while back it began malfunctionaling. One engine would periodically drop 200 RPM and then come back up. It drove me crazy so I stopped using it. Instead, I use the tachs to match RPM. I had been using the alternator as a signal generator to run my replacement pprogrammable tachs which worked quite well (but not perfect) as to accuracy. Knowing true RPM via a phototac, I was able to synchronize quite well.
Cummins uses a magnetic pickup that counts teeth on the flywheel. SO while not exactly a phototach, it is every bit as accurate. When hooked up to a digital tach, it is absolutely 100% accurate.

 

[tdomenech]

Have 2 3208 CATS with Glendinning. Works great!

 

[RickyD]

My father's Uniflight had a light bulb with two halves. One pulsed with the port engine the other with will the other. With a little adjustment we could get them mostly simultaneous therefore very close in RPM. These were gas engines. I'm just now thinking that might not work for diesels if it was based on spark plug firing.

 

[tdomenech]

Have Glendenning on my 3208's. Works GREAT! Would not go without it. Have only had one problem in 7 years...quickly diagnosed (cable broke?) and repaired by mechanic.

 

[Sangraal]

I installed the Glendinning system on my Lehman 135’s. Probably some of the smartest money I have spent on a boat. The system is unbelievably accurate.