Time for an engine alignment?

[akintosyali]

I was looking at some pictures of my transmission, and I realized something weird, and I am wondering if this could be the cause of the vibration on the boat or not..

I am attaching links to 2 different images of the engine mounts. (Chrysler 426 gas engines) The view if from rear of the engine.

left mount:
http://www.tosyali.com/2006/Hatterasconstruction/IMG_2145.jpg
right mount
http://www.tosyali.com/2006/Hatterasconstruction/IMG_2146.jpg

If you look at the right mount, you'll see that between underneath the arm (from the engine) and the mount, there is a metal washer pressing hard on a plastic disc washer, so there are 2 washers.

If you look at the left mount, you'll see that there is only one washer, and it looks as if the arm is not even touching that washer.

I also realize that the arms seem to be sitting on a bolt, equal distance from the mount base, so maybe I just have a missing washer but not a problem. I am not too sure, so I have decided to bring this to your attention.

What do you suggest?

 

[Liquid Asset]

It is hard to tell from your picture, but if I am looking correctly, those nuts should be tight on the engine mount bolt threads. I think I would definetly give it a check and see what is going on.

 

[Trojan]

You need to check your alignment. The fact that the adjustment lock nuts are not tight, the motor COULD be anywhere. Those mounts are very easy to adjust and could have moved on there own. Usually they don't move on there own, locked or not but they could have. The washers you refer to are not washers at all, but a special rubber shock bushings top and bottom. The banjo bolt which supports the motor is threaded. You just need to rotate the vertical through bolt to raise the motor up or down. The half nuts lock the adjustment once the correct alignment has been reached. Your system is a whole lot easier than the old pry, shim and check method. The fact that the one adjustment is almost or is on bottom side of the adjustment. Leads me to believe that the motor may be way out of adjustment. Manufactures usually build the stringers so the adjustment is near center to start with on a new boat.

BILL

 

[REBrueckner]

First of all, if you have vibration, you should disconnect your shaft flange from the transmission and see how the face plates match up using feeler gauges as discussed on this forum elsewhere. Then you'll know for sure if your engine and shaft are in alignment or not:the mounts could appear perfect and the engine be out of alignment. Or vice versa. You will have to disconnect anyway to adjust the engine mounts for proper alignment.

In this case, from the pictures, I agree with Trojan's comments.....something appears improper....but I have a slightly different diagnosis: it appears to me the right mount bushing may be overly compressed ...hence the rubber bushing is compressed rather flat....perhaps overly compressed...from engine weight and from the support bolt being overly tightened against the engine mount above the bushing; The left mount washer does not appear compressed, hence it appears this engine mount is not holding much weight. But it is possible that these were never really balanced well from the last adjustment...check the shaft flange for alignment...that will give you the feedback for sure.

My guess is that the right side engine will be found to be low from washer compression. These ARE nice mounts. They prevent athwartship movement and make raising and lowering adjustment a neat affair.

 

[akintosyali]

If the engine was misaligned, wouldn't the shaft be bent after some use? The reason why I ask is because if the shaft is even slightly bent, then unhooking the shaft to check for alignment would be a lost cause -right?

 

[Trojan]

If the shaft was bent it would vibrate like hell and move around at any rpm. If it was out of alignment it would vibrate more as the RMS increased. It takes a lot to bend a shaft. But it can be done though. Like REBrueckner said get your feeler gauges out and check.
REBrueckner you cannot compress the bushing very much they are shaped like a top hat and molded in rubber. The vertical bolt is just tighten against the bottom of the lower bushing and is secured with a cotter pin through the castle nut. It floats within the yolk. It does appear that the adjuster is bottomed out against the lower bushing. That is why I think the motor is out of alignment. That would not be good engineering on the boat builders part to design it that close to the bottom of the adjustment. Once you unhook the shaft flanges and rotate the shaft you will know if its bent. Hopefully its just a miss alignment.

BILL

 

[REBrueckner]

Akin,
A shaft out of alignment usually means by perhaps 1/4" of height or so (engine height needs to be changed) and perhaps a few thousanths of actual alignment (engine orientation relative to the shaft coupling)...the shaft is rarely bent under these conditions...it usually sags over its length from the shaft log more than these amounts...

Another way to look at it: you can pull the shaft up or push it down when disconnected.... it deforms without damage due to it being a non perfectly rigid body...and it's still just fine...shafts usually get bent when the prop or strut bangs into a hard object and is permanently deformed..at the aft end.

 

[OVERSPRAY]

I recently delt with a similar alignment issue with my engines, Though they are small blocks, they have the same type of mount. I couldn't figure out why one engine had the mounts adjusted slammed all the way to one side, no vibration, just way to one side compared to the other motor. upon thouroghly inspecting the entire drive line I noticesd that I had a bent strut!! aparently P/O hit something or ran aground and bent the starboard strut. Not enough to warrant replacing at the time but it changed the alignment considerably. However, my understanding of this system is if those lock nuts are loose, and have been for some time. theris no telling, As with other comments, the first and easy step is to diss-couple and check coupler alignment. That will tell the tale at least for starters. I just wanted to point out that the strut is where the driveline alignment begins. and the whole system can be off if there is a problem in that area.