Feedback on my motor mounts
07-24-2011, 12:50 PM
#1
On The Tree
Thread Starter
Feedback on my motor mounts Think I've got the motor where I want it (will need to move the alternator and compressor to top mount style) in my 55 Olds.
Can't use the FatMan tubular mount kit as I have the motor too far behind the crossmember for that style. I made some templates for a flat style mount that fits into the frame rails. I'd like some feedback on whether I am on the right track or not.
Thought about 1/4" for the top plate? Maybe 3/8" for the gusset rib or is that over kill?
The mount is angled up from the edge of the frame about 5 degrees from being horizontal.
I will need to cut a hole in the gusset for the steering linkage to pass through.
It looks like everything will work out this way. The steering will need some engineering, but it looks like it will work and clear the header.
Oh, and just to confirm, the engine and trans should be at about 3 degrees down angle relative to the frame? in other words with the frame level the trans and engine should angle down toward the rear by about 3 degrees?
Appreciate any feedback.
Joe
Can't use the FatMan tubular mount kit as I have the motor too far behind the crossmember for that style. I made some templates for a flat style mount that fits into the frame rails. I'd like some feedback on whether I am on the right track or not.
Thought about 1/4" for the top plate? Maybe 3/8" for the gusset rib or is that over kill?
The mount is angled up from the edge of the frame about 5 degrees from being horizontal.
I will need to cut a hole in the gusset for the steering linkage to pass through.
It looks like everything will work out this way. The steering will need some engineering, but it looks like it will work and clear the header.
Oh, and just to confirm, the engine and trans should be at about 3 degrees down angle relative to the frame? in other words with the frame level the trans and engine should angle down toward the rear by about 3 degrees?
Appreciate any feedback.
Joe
07-24-2011, 05:41 PM
#4
Yeah.. I Beam it or double Gusset for the side.. almost boxing it in if possible. just have to work around the steering as you noted.
You should really get the frame at ride angle, before thinking that the engine angle is set. Unless you are sure your frame will be level (0 Degree) at ride height. You have to take into account suspension and rear pinion angle and weight, etc. But you can make the motor mounts now and adjust it later with the trans crossmember. So.. leave some wiggle room in the trans crossmember for now and adjust later..
You should really get the frame at ride angle, before thinking that the engine angle is set. Unless you are sure your frame will be level (0 Degree) at ride height. You have to take into account suspension and rear pinion angle and weight, etc. But you can make the motor mounts now and adjust it later with the trans crossmember. So.. leave some wiggle room in the trans crossmember for now and adjust later..
07-24-2011, 07:37 PM
#5
On The Tree
Thread Starter
Thanks for the help. I think I should be able to "I-beam" the thing. What's the bottom plate add as far as strength?
Boxing it might be a bit messy (I will look at it again though) as the steering shaft will pass just below the upper horizontal plate.
The frame will not be level at ride height. Car will be sitting pretty low and I plan to have a bit of a rake. Haven't messed with the rear yet, but my plans are to have a 9" made for the car at some point.
I guess I was just shooting for the 3 degrees down relative to the frame. Am I really just shooting for 0-3 degrees at ride angle?
Boxing it might be a bit messy (I will look at it again though) as the steering shaft will pass just below the upper horizontal plate.
The frame will not be level at ride height. Car will be sitting pretty low and I plan to have a bit of a rake. Haven't messed with the rear yet, but my plans are to have a 9" made for the car at some point.
I guess I was just shooting for the 3 degrees down relative to the frame. Am I really just shooting for 0-3 degrees at ride angle?
07-25-2011, 11:21 AM
#6
Stress and stiffness for an I beam are a lot better than for the "T" shaped beam you've shown because the peak loading within the beam is at top & bottom where you have the most width (and therefore area) in an I-beam. I would use 1/4" and plate the frame side. Fully boxing isn't really necessary IMO.
Regarding drivetrain angle, the important thing is to get the pinion angle approximately parallel with the tranny output (or at whatever angle you think is appropriate for your rear suspension setup and intended use). That can be done either by positioning the engine or by positioning the rearend or both. You'll have some room to wiggle by raising and lowering at the transmission end, but that depends on tunnel clearance among other things. Having the drivetrain level with the ground isn't critical; it can be a few degrees off and still function fine. It is more critical for a carbureted engine to have the floats level, but even then a few degrees off wont hurt anything.
Regarding drivetrain angle, the important thing is to get the pinion angle approximately parallel with the tranny output (or at whatever angle you think is appropriate for your rear suspension setup and intended use). That can be done either by positioning the engine or by positioning the rearend or both. You'll have some room to wiggle by raising and lowering at the transmission end, but that depends on tunnel clearance among other things. Having the drivetrain level with the ground isn't critical; it can be a few degrees off and still function fine. It is more critical for a carbureted engine to have the floats level, but even then a few degrees off wont hurt anything.
Last edited by -TheBandit-; 07-25-2011 at 11:38 AM.
07-25-2011, 01:39 PM
#7
TECH Senior Member
iTrader: (7)
The engine mounts look pretty good.
As for the angle, here is a good document to reference:
http://www.pro-touring.com/%7Eandrew...11-1-HVTSS.pdf
If the car will be riding low that means the rear end will be up into the body a good bit. I would set the engine level with the frame. But to do it properly, you need to have the rear end installed at ride height. It is critical to have the engine/trans and the rear positioned properly to minimize u-joint working angles, which should be as small as possible, but not zero.
Andrew
As for the angle, here is a good document to reference:
http://www.pro-touring.com/%7Eandrew...11-1-HVTSS.pdf
If the car will be riding low that means the rear end will be up into the body a good bit. I would set the engine level with the frame. But to do it properly, you need to have the rear end installed at ride height. It is critical to have the engine/trans and the rear positioned properly to minimize u-joint working angles, which should be as small as possible, but not zero.
Andrew
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07-25-2011, 08:32 PM
#9
On The Tree
Thread Starter
If I'm planning on having a custom 9" rear made later (slow project), is it not OK to get the motor and trans locked down now?
It may be a while before I have the cash for the rear-end.
I plan to use a leaf spring set-up, just lowered and with limited slip.
I think I understand the equal and opposite angles with the goal of a straight line under load.
Just trying to visualize my set-up. I have a FatMan from stub installed and can easily set the front height where it should be with the wheels and tires I want to use.
How do I figure out the rear? Should I just install lowering blocks in my stock rear end to get the proper axle centerline relative to the frame? Then set the centerline to the floor according the rear tire size?
This is confusing, but I am learning a lot.
It may be a while before I have the cash for the rear-end.
I plan to use a leaf spring set-up, just lowered and with limited slip.
I think I understand the equal and opposite angles with the goal of a straight line under load.
Just trying to visualize my set-up. I have a FatMan from stub installed and can easily set the front height where it should be with the wheels and tires I want to use.
How do I figure out the rear? Should I just install lowering blocks in my stock rear end to get the proper axle centerline relative to the frame? Then set the centerline to the floor according the rear tire size?
This is confusing, but I am learning a lot.
