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Engine mount doesn't seem to fit

Jeff R

Well Known Member
So I thought I would take a break from pounding on the canopy and get the engine mounted. Taking advice from some locals, I decided to mount the engine to the mount first. It is hard finding people to help this time of year and I thought I could do this alone.

Well, it hardly seems that the Dynafocal mount fits quite right. The only way I can get the screws even barely into the engine is to insert them at a highly skewed angle. It appears the only way to get them in would be to pound them with a hammer, leaving the rubber shock mounts highly distorted from the misalignment, not to mention the screws would be digging into the engine hole.

I tried putting the top bolts in first, but it is like the mount is about 1/2" too short. Then I tried putting them in the bottom first and had the same problem. Then I put one bolt in the upper left and tried to fit one in the lower, opposite corner, but again, I had to skew the bolts at an angle to get it to just barely go in the hole and the bolts were just barely in the holes.

I don't see how the mount could be bad as they make these things in a jig, nor would the engine be mis-drilled, so it has to be me. So, what am I doing wrong? I can't possible see how the bolts could be inserted if I had put the mount to the firewall first.

I suppose I will try to get a local expert to come out, but I thought maybe someone could tell me where I am obviously messing up. Oh, the spark plug wires on the left side were in the way, but I unscrewed them from the plugs and they are no longer a factor.

Thanks.
 
Jeff, now relax a bit

How I did it. Alone. No local advice was available only VAF as major source.
I mounted mount to the firewall first. Two spacers were necessary at both lower middle mounting locations near nosegear.

I used the instructions from this site. Air-assisted engine hoist lifted the engine easy. First and second bolts were easy. Third took about 30 minutes. Then I took a walk through the park. To put forth bolt I needed couple extra tools listed in the instructions and two or three strong words. One hour spent on 4th bolt. Engine mounted. Total time 2 hours. No biggie:)
 
I used drift pins to align everything. Here's how it worked:

I cut the heads off of 4 hardware store bolts the same diameter as those used to mount the engine. Then I tapered one end of each bolt to a point. I put the engine, lord mounts, and motor mount in rough position and used the alignment pins to get things lined up. Then I used one of the engine mount bolts to push the alignment pin all the way through the assembly and added the nut. Repeat 3 more times and you're done. I think the whole process took 30 minutes.

One thing that may help is to use a strap to pull the engine tight to the engine mount. That solves the geometry problem caused by the engine mount bolts being pointed towards the center of the engine. If you don't have the engine pulled tight against the engine mount, you'll never be able to insert more than one or two bolts.

By the way, I found it pretty easy to hang the engine with the engine mount attached to the airframe.
 
Get the Mount Installed First

IMHO, you are fighting a losing battle trying to mount the engine with the engine mount not installed on the airframe.
Install the mount on the plane (even temporarily if you want) and then mount the engine. I forgot what you are building, but if it is a taildragger, then it will also be benificial to get the tail up so as to somewhat level the plane. The following is MHO on how to do it. Your results may vary
Mount the engine by starting with the top bolts first. Snug the bolts up only far enough to keep the rubbers secured in the mount. Let some of the weight off the engine and install the lower fwd mount rubbers and washer(s). Then check alignment and reduce or add the weight of the engine as needed. Install the aft mounts and work the bolts through as you can. Don't worry if the aft mount is not aligned as you will get it there when you get the bolts all the way into the engine mount. It does take patience and it can be like wrestling a bear.
Note: Make sure that you install the shock mounts correctly. Each pair of mounts contains a "firm" and "soft" mount. The stiffer mount goes on the aft on the top and the fwd on the bottom. I am sure that you are fully aware of this, but I had a friend years ago that did not realize that they were different and got two of them wrong! After all the above mentioned drama, I had to remove him from his shop as he would have likely committed hari kari with a screwdriver.
Good Luck
 
ow I did it

I think the mount on the firewall is much easier.

Now unlike most things you get to line up..I.e you leave all the bolts loose until you get them all inserted?...

Well that doesn't work with mounting the engine...Because the rubbers have to be compressed say on the bottom before it will pull the top holes into alignment where you can put the bolts in.

So I would put the bottom bolts in first..Then let the engine down a little so in the hoist so the weight of the engine is pushing down/compresing the lower rubbers a little.

The tighten the lower bolts...You'll notice the more the lower bolts are tightened the more the upper holes will line up...

Thats the key, eventually that will tap in no problem..

Put my motor on in less than an hour by myself
Frank
 
Are you sure you have them arranged correctly? The top and bottom mounts are arranged differently.
 
Mounting Engine

Two things I would suggest. 1) Confirm Dynafocal series of both mount and engine match. i.e. series 1 or 2. 2) Recognizing that dynafocal mounts don't actually match angularly until the donuts are slightly compressed. Should be fairly straight forward at that point unless the motor mount is actually incorrect.
Good luck.
 
........but if it is a taildragger, then it will also be benificial to get the tail up so as to somewhat level the plane.......
Not to be contrary but installing the engine without any help, I found it advantageous to let the tail sit on the ground as it normally would. As the photo shows, the engine dangling from the hoist matched the firewall/engine mount angle almost perfectly. As with the engine I also installed alone on my -6A, I found no need to use drift pins either. If there is any "secret" to it, I would say to make the engine hoist work for you and allow it to take care of mass and balance issues. Align the engine with the mount, install the first bolt then slightly lift or lower or twist the engine as required to insert the next bolt and so on.

I've participated in a few "engine hanging" parties and in every case found it actually took longer and with more difficulty to get the engine mounted. I think too many cooks in the kitchen can make hanging an engine more problematic especially when each cook has their own ideas and the "help" can end up working at cross purposes with one another.

25587pk.jpg
 
I also used the instructions from this site. One of the things I found was that it helped to get each bolt inserted and then snugged (not torqued). If the engine was too free to move, especially away from the mount, then it was almost impossible to get the next bolt in. The holes only really line up when the engine is in place and the bolts torqued but torquing them makes it too difficult to move the engine slightly to line up the holes. Snugging is the best compromise. Trying to get all the bolts in before snugging any of them is a losing proposition.
 
Avery Bullet Nosed Pins

I found a big help to be the Avery tapered and bullet nosed pins. I don't know of they still stock them.

You install one pair of bolts which is easy - can't remember if it was top or bottom - and then use the pins to lead the way for the other two bolts. The pins have a slightly dished back end to cup the nose of the bolts. You start the pins through the assembly and then use the bolts to tap them all the way through. In the process they line every thing up and lead the bolts through nicely.

I used them to hang the engine single handed in less than 30 minutes.

PS - having the tail low on a tail dragger helps push the cg back once the engine is mounted. If you level the fuselage with the engine mounted it wants to tip forward.

Jim Sharkey
 
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Ahh Yes...

Rick,
As I read your message, I kept thinking "it sure was not the way it worked for me"! I had to raise my tail up about 14'' to get the engine to line up with the mount. Then, it came to me...I had the prop installed which was holding the engine more level! Anyway, you were right on when you advised to "let the hoist work for you".

Not to be contrary but installing the engine without any help, I found it advantageous to let the tail sit on the ground as it normally would. As the photo shows, the engine dangling from the hoist matched the firewall/engine mount angle almost perfectly. As with the engine I also installed alone on my -6A, I found no need to use drift pins either. If there is any "secret" to it, I would say to make the engine hoist work for you and allow it to take care of mass and balance issues. Align the engine with the mount, install the first bolt then slightly lift or lower or twist the engine as required to insert the next bolt and so on.

I've participated in a few "engine hanging" parties and in every case found it actually took longer and with more difficulty to get the engine mounted. I think too many cooks in the kitchen can make hanging an engine more problematic especially when each cook has their own ideas and the "help" can end up working at cross purposes with one another.

25587pk.jpg
 
Engine is hung!!

In my excitement to hang the engine, I forgot about the write up in "27 Years of RVaitor". So, I read the above replies and the article, and combining the advice given, my engine is now hung on my RV-9A!!!!

This is how I chose to do it. I decided to continue to try to the engine mount to the engine first, as it sure seems like it would be more convenient that way. I started with the upper right bolt which went right in and, as suggested, I then tightened it nearly all the way. Then I went to the upper left attachment point. Ugh. I forgot to place the shock mount in that point so I had to loosen the right bolt so I could slip in the inner shock mount. It took a lot of wiggling and pulling up on the bottom of the engine mount but I managed to get the bolt into the hole, and by screwing it in, it started to go into the hole. More turning with the wrench and the bolt finally came out the other side.

Now, on to the bottom right. I did remember that the shock mounts are reversed from the uppers, and I remembered to use the proper bolts (longer on the bottom), and to add the washer. But, dang, holding the washer and trying to wiggle the bolt and move the engine mount around was really difficult as the washer would keep falling as I tried to wiggle the bolt. After at least 20 minutes of trying, I finally got the bolt wedged in the hole. I then moved to the last bolt but after the problem with the washer, I decided to use some Permatex 2 (just happened to have it handy) to see if it would hold the washer in place on the shock mount and it seemed to work. The 4th bolt went in relatively easily - only took 10 minutes!

But even with the bolts in, getting the nuts on was not so easy. None of the sockets from my socket set would fit the narrow confines of the engine, and my open ended socket wrenches were too wide. I barely got the box end to fit, but I finally got them all on.

Eventually I got all the nuts on tight, though I noted by the 4th bolt that using two washers would probably be better. I may get some new nuts and redo the other 3 with 2 washers.

I attached some the oil hoses to the engine then hoisted up the engine and in less than half an hour I had it affixed to the firewall. I had just received the Grove nose wheel, so I assembled it, put it on the nose gear leg, attached the leg (temporarily) and the future N296JR is now resting on all three wheels !! What a sight. This is one of those major milestones!

So, it is possible for a rookie to hand his own engine. And I am glad I mounted the engine mount to the engine first.

Thanks to everyone who offered advice.
 
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