Engine mount design. Expert opinions required.
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Engine mount design. Expert opinions required. Can any of the resident experts have a look at these two images of a design for my engine mounts.
What I would like to know is are there likely to be any loading differences?
Or are they equally sufficient?
Personally I prefer the design of picture 2 for the simple fact that with the mount removed it would free up space around the block for engine removal and installations as the once the load is on the engine hoist the mounts could be unbolted and removed completely out of the way.
Would appreciate any thoughts.
Thanks in advance.
What I would like to know is are there likely to be any loading differences?
Or are they equally sufficient?
Personally I prefer the design of picture 2 for the simple fact that with the mount removed it would free up space around the block for engine removal and installations as the once the load is on the engine hoist the mounts could be unbolted and removed completely out of the way.
Would appreciate any thoughts.
Thanks in advance.
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Joined: Feb 2007
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From: Raleigh, NC
Image two would have less shear loading on the longitudinal bolts and less bearing load on the polyurethane mount inserts. I might put a few more gussets between the long arm and the motor plate in order to increase weld length in image two, but I don't know if they are really necessary, just a cheap insurance type thing.
Otherwise, I see no significant difference between the two.
Otherwise, I see no significant difference between the two.
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Image two would have less shear loading on the longitudinal bolts and less bearing load on the polyurethane mount inserts. I might put a few more gussets between the long arm and the motor plate in order to increase weld length in image two, but I don't know if they are really necessary, just a cheap insurance type thing.
Otherwise, I see no significant difference between the two.
Otherwise, I see no significant difference between the two.
As you rightly say extra triangulation plates on the tubular end I feel would be worth it, apart from the one underneath the tube at the plate I chose not to add them in for the drawings as I was not only trying to save time but wanted to retain some clarity in the drawings.
Appreciate you input. Thanks again.
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From: Raleigh, NC
One thing you may want to do, which I did not do while building my motor mounts, is to decide which headers you want to run and then buy them, and design the motor mounts to not hit the header primaries.
Otherwise you may be building or modifying your headers. Like I am.
Otherwise you may be building or modifying your headers. Like I am.
Yeah the bearing load in 1. will be more extreme than in 2. Also in 1. it will require engine removal to change the bushing, where as 2. you may be able to do it by supporting the engine from the bottom and removing one side at a time.
Couple questions:
1. Are you planning on running poly bushings or Delrin?
2. Why the round tube design? I know its simple to make, but it does place a lot of stress on the urethane.
Just an idea, but I have attached a pic of a setup using a solid puck like a trans mount or one of Energy or prothanes universal offerings. You might also consider in your design using a rect tube instead of square to alleviate the need for extraneous gussets. Your mounts should definitely be designed in conjunction with headers.
Couple questions:
1. Are you planning on running poly bushings or Delrin?
2. Why the round tube design? I know its simple to make, but it does place a lot of stress on the urethane.
Just an idea, but I have attached a pic of a setup using a solid puck like a trans mount or one of Energy or prothanes universal offerings. You might also consider in your design using a rect tube instead of square to alleviate the need for extraneous gussets. Your mounts should definitely be designed in conjunction with headers.
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Thanks guys for the replies.
With regards to headers I may need to end up getting them made from scratch so should be able to get them around the mounts.
I already have Poly bushes which came with the steel tube housing. I also now have the square tube section for the support. I still plan to cut extra strengthening pieces to support the tube section for added security.
I intend to go with my option 2 picture.
Thanks again to all of you who replied.
With regards to headers I may need to end up getting them made from scratch so should be able to get them around the mounts.
I already have Poly bushes which came with the steel tube housing. I also now have the square tube section for the support. I still plan to cut extra strengthening pieces to support the tube section for added security.
I intend to go with my option 2 picture.
Thanks again to all of you who replied.
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From: Raleigh, NC
One thing to think about with headers is how straight the front most primaries can be and how far forward the rear most primaries can push in order to shorten the front primaries while lengthening the rear primaries.
It may help you if you put a bend in the tube for the mount instead of making it straight. In my application, I have set the engine as low and as far back as I possibly can, and effectively this makes the motor mount towers and motor mounts straight.
The straight motor mount towers means I have to route the #1 and #2 (#2 is green in the image, #1 is on the header not shown) primaries straight back for a short distance before turning downward. This makes it hard to equalize lengths. It probably won't make much difference in reality, but my longest primary is 32 inches and my shortest is about 28 inches. Ideally I really wanted my lengths to be the same within about 5%, but at the same time, I'd rather have the 700lbs of drive train back and down as far as possible.
If you put a bend in your mount tube, you could make your front primaries more straight and also have more room for the rear most primaries.
If you have a ton of room, you should look at designing around inexpensive off the shelf headers. I'll have more money in my DIY steel headers than it would cost me to buy a set of Texas Speed stainless fbody headers. Granted, most likely no other header is going to fit with my engine relocation, so I don't really have a choice.
Doing it over again I might have cut the motor mount towers off the k member and just welded on new ones to accept off the shelf headers, but there is really no guarantee that would even have enough room for my application.
More pictures are here should you be interested:
https://ls1tech.com/forums/generatio...m-headers.html
https://ls1tech.com/forums/conversio...rag-strip.html
It may help you if you put a bend in the tube for the mount instead of making it straight. In my application, I have set the engine as low and as far back as I possibly can, and effectively this makes the motor mount towers and motor mounts straight.
The straight motor mount towers means I have to route the #1 and #2 (#2 is green in the image, #1 is on the header not shown) primaries straight back for a short distance before turning downward. This makes it hard to equalize lengths. It probably won't make much difference in reality, but my longest primary is 32 inches and my shortest is about 28 inches. Ideally I really wanted my lengths to be the same within about 5%, but at the same time, I'd rather have the 700lbs of drive train back and down as far as possible.
If you put a bend in your mount tube, you could make your front primaries more straight and also have more room for the rear most primaries.
If you have a ton of room, you should look at designing around inexpensive off the shelf headers. I'll have more money in my DIY steel headers than it would cost me to buy a set of Texas Speed stainless fbody headers. Granted, most likely no other header is going to fit with my engine relocation, so I don't really have a choice.
Doing it over again I might have cut the motor mount towers off the k member and just welded on new ones to accept off the shelf headers, but there is really no guarantee that would even have enough room for my application.
More pictures are here should you be interested:
https://ls1tech.com/forums/generatio...m-headers.html
https://ls1tech.com/forums/conversio...rag-strip.html
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Thanks usdmholden,
Great pic's
I have been looking at my mounts again tonight and think that it should fine with the tubular section located in the 2nd quarter from the front with triangulations added to the rearward side and the top.
My install is slightly different in that instead of passing rearwards the pipes will exit at right angles to the block.
Thanks again for your reply i appreciate you taking the time.
Great pic's
I have been looking at my mounts again tonight and think that it should fine with the tubular section located in the 2nd quarter from the front with triangulations added to the rearward side and the top.
My install is slightly different in that instead of passing rearwards the pipes will exit at right angles to the block.
Thanks again for your reply i appreciate you taking the time.
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Guys, some other variations, any comments?
Basically a thought to move the bush end brackets closer to the engine and thus make the angle of the mount more and effectively make them a shorter protrusion from the engine.
Basically a thought to move the bush end brackets closer to the engine and thus make the angle of the mount more and effectively make them a shorter protrusion from the engine.
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From: Raleigh, NC
I like image 3 the most, just because I do I suppose. Cutting the 90 deg notch in the plates and getting everything lined up nicely will be harder than just cutting a flat edge.
Down side to image 3 is that the mount tube will not sit on top of the frame rail during installation. Probably not a big deal though, you could just add a tab to stop the engine assembly from dropping below the frame during installation. Although if you were going to do that, you might as well just build image 2.
Down side to image 3 is that the mount tube will not sit on top of the frame rail during installation. Probably not a big deal though, you could just add a tab to stop the engine assembly from dropping below the frame during installation. Although if you were going to do that, you might as well just build image 2.
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I like image 3 the most, just because I do I suppose. Cutting the 90 deg notch in the plates and getting everything lined up nicely will be harder than just cutting a flat edge.
Down side to image 3 is that the mount tube will not sit on top of the frame rail during installation. Probably not a big deal though, you could just add a tab to stop the engine assembly from dropping below the frame during installation. Although if you were going to do that, you might as well just build image 2.
Down side to image 3 is that the mount tube will not sit on top of the frame rail during installation. Probably not a big deal though, you could just add a tab to stop the engine assembly from dropping below the frame during installation. Although if you were going to do that, you might as well just build image 2.
The plates with the notch I will get laser gut from steel, so I only need to make templates to ensure a good fit.
With regards to the engine dropping below during install I have a hydraulic engine crane hoist so this shouldn't cause any issues.
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From: Raleigh, NC
I have a crane also.
When building my mounts and setting the engine in the chassis, it was nice to be able to set the engine down and have it stop moving on one side, and have limited travel in one direction (down), which made it easier to pry the motor to move the engine around or reposition the hook on the chains to line up bolts through holes. The engine almost never goes in and lines up correctly, at least not for me.
You can do it how you like, I'm just giving advice based on my mistakes. I make lots of mistakes so I can give lots of advice. Just ask my wife, she will explain, at least about the mistakes part. She doesn't listen to the advice anymore.
When building my mounts and setting the engine in the chassis, it was nice to be able to set the engine down and have it stop moving on one side, and have limited travel in one direction (down), which made it easier to pry the motor to move the engine around or reposition the hook on the chains to line up bolts through holes. The engine almost never goes in and lines up correctly, at least not for me.
You can do it how you like, I'm just giving advice based on my mistakes. I make lots of mistakes so I can give lots of advice. Just ask my wife, she will explain, at least about the mistakes part. She doesn't listen to the advice anymore.
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The drawings I created were only based on my approximate measurements. Having looked at No.3 in the last set of my drawings I find there just isn't the room and the tubular section would need to be at a very steep angle. With this in mind I am opting for No.2. I have sent the dimensions away for the locating tabs to be cut then I'll position them in place and take the measurements needed for the tube.
Bit by bit I'm getting there.
Thanks all for the advice and comments
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Ok guys but sorry I'm not finished.... 
I picked up my laser cut plates yesterday (a great job) and having attempted a few mock ups something else came to mind.
Looking at the image below you can see that part is coloured Blue the other is Red.
The reason I have done this is as follows.
I had intended to fit the D shaped plates to the chassis rail and have the bush at the chassis end. But I do not have access to a welder and will be getting somebody to do the job for me. Because of this it then occurred to me that if I flipped them and put the D shaped plates onto the engine block plate (as per the Blue colour) and then the arm and plate with additional triangulation plating (coloured in Red) I could remove both Red and Blue sections and take them away to a fabrication shop to be welded as opposed to having somebody come out to me to weld the D shaped plates to the chassis.
Anything I might be missing about doing it this way? It sure would save me a lot of money.
I picked up my laser cut plates yesterday (a great job) and having attempted a few mock ups something else came to mind.
Looking at the image below you can see that part is coloured Blue the other is Red.
The reason I have done this is as follows.
I had intended to fit the D shaped plates to the chassis rail and have the bush at the chassis end. But I do not have access to a welder and will be getting somebody to do the job for me. Because of this it then occurred to me that if I flipped them and put the D shaped plates onto the engine block plate (as per the Blue colour) and then the arm and plate with additional triangulation plating (coloured in Red) I could remove both Red and Blue sections and take them away to a fabrication shop to be welded as opposed to having somebody come out to me to weld the D shaped plates to the chassis.
Anything I might be missing about doing it this way? It sure would save me a lot of money.
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From: Norn Iron
Just make sure whatever way you build it...it is easy to actually align everything when installing.
ie make sure you can lift the engine high enough to drop it back down vertically between the mounts.
As for strength, I'm sure any of them will be fine. You'd be amazed what mine are made from and they havent broke yet !!!
I'm amazed lol
But always try and spread loads over as much area as you can
ie make sure you can lift the engine high enough to drop it back down vertically between the mounts.
As for strength, I'm sure any of them will be fine. You'd be amazed what mine are made from and they havent broke yet !!!
I'm amazed lol
But always try and spread loads over as much area as you can
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Hello again all,
I'm back for some more input.
I still haven't resolved it, but now am actually in the position (it's been a lot longer than I anticipated!) to make the engine mounts.
I have been making mockups of various plates and find myself wondering whether I would be better off placing the polybush centreline midway between the 2x lower chassis rails.
This should resist the torque best I would have thought. My concern is that when looking at the last of 3x images above the 1st one would cause the outer rail to flex up and down, the 2nd is in the middle so should share the load between outer and the inner tube, and the 3rd would try to flex the inner rail one way and the outer rail the other in the opposite direction to the 1st image.
I may be so insignificant as to not be worth worrying about but any input greatfully received.
Thanks in advance for any replies.
I'm back for some more input.
I still haven't resolved it, but now am actually in the position (it's been a lot longer than I anticipated!) to make the engine mounts.
I have been making mockups of various plates and find myself wondering whether I would be better off placing the polybush centreline midway between the 2x lower chassis rails.
This should resist the torque best I would have thought. My concern is that when looking at the last of 3x images above the 1st one would cause the outer rail to flex up and down, the 2nd is in the middle so should share the load between outer and the inner tube, and the 3rd would try to flex the inner rail one way and the outer rail the other in the opposite direction to the 1st image.
I may be so insignificant as to not be worth worrying about but any input greatfully received.
Thanks in advance for any replies.
