Tranny skid

[mrblaine]

Originally posted by Chris L
How bout we mess with Brian

See if you can sell him some shock extenders.

[Jays89YJ]

Originally posted by mrblaine
I disagree strongly that they are designed to withstand only downward force or that is designed as the primary function.

They need to withstand dynamic loads from torque transmission to the drive wheels, rotational both lift and compressive at opposite sides.

They need to withstand centrifugal forces from the weight of the engine assembly at speed around corners.

They need to withstand lifting forces generated when hitting abrupt elevation changes at speed.

They need to withstand forward tension forces when restraining the weight of the drivetrain under heavy braking.

And, there are times when they withstand combinations of those forces in rapid succession in a very short period of time. I have never seen or heard of an instance where the frame mounts have been damaged in any manner.

They are substantial both in design and material selection as well as the formed and welded clamshell structure. I'd venture that any skid will fail long before the mounts do.

Which leads me to say the skid appears to be weak along the obtuse angle members. I know the forces that go through the mounts. The most constant force is downward. Obviously the mounts undergo other loads while the engine is running and the vehicle is driving. Let's not beat around the bush here. All those forces don't even equal the force you're about to put on them with the weight of the Jeep and the speed of the Jeep falling colliding onto a rock if the skid doesn't fail.

[Jays89YJ]

Originally posted by mrblaine
You know, me and Jay was having a perfectly fine engineering/practical experience conversation and ya'll are messin it up, now cut it out. Go mess with yates or something.

Blaine... You a M.E.?

[Jeff Weston]

Jay,

It's good that you are going to school to study engineering. I, myself, am a Registered Professional Engineer and in no way do I want to minimize the importance of proper engineering, especially when it comes to protecting human life.

One of the things you'll see in my state's Professional Engineer's Act is:

A licensed Professional Engineer shall practice and perform engineering work only in those fields in which the engineer is fully competent and proficient as a result of education or experience.

For the reason that automotive engineering is not my area of expertise, I won't attempt to convince anybody of the strength of the frame mounts based on calculations. Hell, I couldn't even come close to quantifying the forces that they would be subjected to.

All that said, intuition tells me that short of falling off the top of Lion's Back or off a cliff (in which case none of this will matter), no amount of force on that skidplate that would even come close to what my Jeep could see in a traffic collision.

I'm not trying to convince you to run this or any other skid. I do think that it is quite a reach to compare the need for calcs on this motor mount to that of sizing members of a tower.

[blkTJ]

Originally posted by mrblaine
See if you can sell him some shock extenders.

[Jays89YJ]

Originally posted by Jeff Weston
Jay,

It's good that you are going to school to study engineering. I, myself, am a Registered Professional Engineer and in no way do I want to minimize the importance of proper engineering, especially when it comes to protecting human life.

One of the things you'll see in my state's Professional Engineer's Act is:

For the reason that automotive engineering is not my area of expertise, I won't attempt to convince anybody of the strength of the frame mounts based on calculations. Hell, I couldn't even come close to quantifying the forces that they would be subjected to.

All that said, intuition tells me that short of falling off the top of Lion's Back or off a cliff (in which case none of this will matter), no amount of force on that skidplate that would even come close to what my Jeep could see in a traffic collision.

I'm not trying to convince you to run this or any other skid. I do think that it is quite a reach to compare the need for calcs on this motor mount to that of sizing members of a tower.

I concur. I'm halfway finished my degree. I'm going back for mechanical design engineering and specializing in materials, finite element analysis and mechanical design. How long did it take you to get your PE License after graduating?

Ok, the tower was a bad example... I did calculations on a .50cal gun mount I did for the US Army. Theirs were falling apart out here in Iraq & Kuwait. The general asked us to make the one that's better. They gave us several mounts that broke on the HMMWV's. I got to meet some soldiers who use the weapons and got some cool info on the weapons... That was an awesome project... At least that one is on a vehicle.

I'm a mechanical designer working in Kuwait right now. What I'm saying as a mechanical designer hired to design something for a vehicle, I would without a doubt go through the calculations. ESPECIALLY if this product is going to be produced and sold. While working in the US I would always do my calcs and have them ready to submit with my design to the mechanical engineer I worked for. He would skim through the calcs, but focus more on the design of the product. We disagreed on some things. Sometimes I was right and sometimes he was right. He would always destroy me with calling out welds. I was still in school and it was a great real-world learning experience that nobody else in my class was fortunate to experience.

[Macgyver]

Originally posted by Jays89YJ
Mounting to the frame is a different story. From the picture, it looks like the skid is going directly underneath the bottom of the motor mount. I still wouldn't mount a single thing to my engine mount brackets besides my engine mounts. 2 members dropping down over a foot to a skid plate is not going to strengthen the frame per say... Especially with the angles and size of the square tubing used. If and when it fails, it will puncture your exhaust.

Was there a testing phase for this product? What is the material selection? Specs? Welds used? Fasteners used?

I would fear broken motor mounts with the engine revving?

This thread has been very interesting to watch. Robert's skid was designed by myself and my step Dad Steve. Steve is in fact an engineer, has been doing so since before most on this board were born. The skid was hand built. Believe it or not there has been 5 to 6 years of testing and thought/ revision to this skid. I'm not going into frame loads, data, theory, or anything else. This skid was designed to protect the engine and tranny, on the trail. It was not designed to drop off of a 10 foot cliff, it wasn't designed to survive a 55 mile per hour collision with a boulder while racing through the Baja 1000........ the frame, belly pan, etc, will all bend at a point. Everything will bend. The long skid plate will bend way before the support frame or the "frame" portion of the motor mounts. And you know what? When and if that skid bends, Robert will know it protected his Jeep and probably meant he didn't have to walk home from a broken oil pan or a broken tranny pan. I've been running a similar plate on my Jeep for years.

I think if you see Robert's skid in person, you would see the see it is pretty stout and well thought out. You can design all you want, test theory's, go on about data and everything else, but put something on a Jeep, and go wheel through Johnson Valley, that place will chew up and spit out more parts than you can shake a stick at. I think experience and practal application sometimes have to win over and over engineered part.

I would love to see a new version designed and engineered not to ever bend, never shear, or never create problems. BTW since it's attached to the Currie Belly pan, go and redesign that too. And make sure to clear the deep tranny pan, the high pinnion front axle, drive shaft, the exhuast, the engine, the suspension during articulation, and everything else going on under a trail Jeep. Oh make it strong and not too heavy. While you are doing that I'm going to take my Jeep and go wheeling and bash some skid plates.

[mrblaine]

Originally posted by Jays89YJ
Blaine... You a M.E.?

No, not even remotely.

Take this anyway you wish- I used to shoot trap with an engineer that worked on the specialized composites on the first stealth fighter.

As is the case with most of us, he always had the back of his vehicle littered with various chunks of stuff he was working on and they always fascinated me to no end. Thus, in between rounds, I was always pestering him to show me the items and tell me what they were used for.

This went on for about a year and he always seemed surprised that it took little explanation for me to grasp the concepts he was working on. The stuff ranged from 2" diameter nitride ceramic ballbearings to an awesomely cool honeycomb made from titanium and cut into an airfoil cross section while it was compressed. When you expanded it and laminated composites to either side, you had this very lightweight, super rigid, super strong wing.

I expressed strong interest in going to school for an engineering degree. He thought for a moment and then told me that the way I thought about stuff would only be ruined by book learning.

I don't know if I agree or not, but that bit of advice has always stuck with me.

[Jays89YJ]

Originally posted by Macgyver
This thread has been very interesting to watch. Robert's skid was designed by myself and my step Dad Steve. Steve is in fact an engineer, has been doing so since before most on this board were born. The skid was hand built. Believe it or not there has been 5 to 6 years of testing and thought/ revision to this skid. I'm not going into frame loads, data, theory, or anything else. This skid was designed to protect the engine and tranny, on the trail. It was not designed to drop off of a 10 foot cliff, it wasn't designed to survive a 55 mile per hour collision with a boulder while racing through the Baja 1000........ the frame, belly pan, etc, will all bend at a point. Everything will bend. The long skid plate will bend way before the support frame or the "frame" portion of the motor mounts. And you know what? When and if that skid bends, Robert will know it protected his Jeep and probably meant he didn't have to walk home from a broken oil pan or a broken tranny pan. I've been running a similar plate on my Jeep for years.

I think if you see Robert's skid in person, you would see the see it is pretty stout and well thought out. You can design all you want, test theory's, go on about data and everything else, but put something on a Jeep, and go wheel through Johnson Valley, that place will chew up and spit out more parts than you can shake a stick at. I think experience and practal application sometimes have to win over and over engineered part.

I would love to see a new version designed and engineered not to ever bend, never shear, or never create problems. BTW since it's attached to the Currie Belly pan, go and redesign that too. And make sure to clear the deep tranny pan, the high pinnion front axle, drive shaft, the exhuast, the engine, the suspension during articulation, and everything else going on under a trail Jeep. Oh make it strong and not too heavy. While you are doing that I'm going to take my Jeep and go wheeling and bash some skid plates.

5 to 6 YEARS?!? LOL. So the profit margin isn't looking so good, or it's just a hobby... I wasn't saying an engineer who has never seen a Jeep or wheeled in your environment should engineer a part.

BWAHAAAA. While you tell me what to design for a TJ and I own a YJ, I'm working on designing more important things than a skid plate for the US DoD 10,000+ miles away in the Middle East. Let me take 5 to 6 years off for testing and I'll see what I come up with.

mrblaine: That's pretty cool. I don't really know your way of thinking, but maybe he was right. I would never discourage anyone seeking higher education. You'd probably really like the stuff I do. Lots of machine design, mechanical design, electro-mechanical design etc. etc.

[Macgyver]

Originally posted by Jays89YJ
5 to 6 YEARS?!? LOL. So the profit margin isn't looking so good, or it's just a hobby... I wasn't saying an engineer who has never seen a Jeep or wheeled in your environment should engineer a part.

BWAHAAAA. While you tell me what to design for a TJ and I own a YJ, I'm working on designing more important things than a skid plate for the US DoD 10,000+ miles away in the Middle East. Let me take 5 to 6 years off for testing and I'll see what I come up with.

mrblaine: That's pretty cool. I don't really know your way of thinking, but maybe he was right. I would never discourage anyone seeking higher education. You'd probably really like the stuff I do. Lots of machine design, mechanical design, electro-mechanical design etc. etc.

Jay,

That skid is not my primary business. Those skids are a side line to my main products. If I wanted to produce TJ skids then I would produce this and move forward with it. I have much more profitable items on the agenda then skids. I build them as I have time for people who are interested. BTW, never took 5 to 6 years off for testing. Just stating how long the skid has been around. Profit margins in Jeep parts overall are very poor.......and I guess I must be doing something wrong, my "hobby" is supporting my family, and I don't really have time to build many skids. Too busy building other items. I was just sticking up for stuff I built, since it seemed that you decided it wasn't right. Have a nice day. Enjoy the desert.

[Robert J. Yates]

Originally posted by Jays89YJ
Someone please answer this question I have regarding these 2 pictures.

Why? Why would ANYONE want a tranny skid tied into their motor mounts?!?

When your tranny skid takes a hit guess where the force is going to be distributed? TO YOUR MOTOR MOUNTS. Guess what's going to break? YOUR MOTOR MOUNTS. Motor mounts are for motors and the forces put into them/onto them by motors. Not the force of your Jeep slamming the tranny skid down on a rock.

Are these guys at Boulderbars engineers? Did they do calculations to show the motor mounts won't break?

I hope you have spare motor mounts in your Jeep at ALL TIMES.

wtf. I stop paying attention and some book smart engineer pops in and not only slams the skid but insults the guy who built it for me.

first off jay - you straight up owe quinn an apology. you weren't involved, you don't know the background and you looked at a couple pf internet pix to form your professional engineering analysis. nice.

what school taught you how to evaluate something without all the facts? tell me so I make sure I don't send my kid there.

secondly, how much rock experience do you have with your jeep?

I strongly advise you to address the two points I laid out for you.

[Jays89YJ]

Originally posted by Robert J. Yates
wtf. I stop paying attention and some book smart engineer pops in and not only slams the skid but insults the guy who built it for me.

first off jay - you straight up owe quinn an apology. you weren't involved, you don't know the background and you looked at a couple pf internet pix to form your professional engineering analysis. nice.

what school taught you how to evaluate something without all the facts? tell me so I make sure I don't send my kid there.

secondly, how much rock experience do you have with your jeep?

I strongly advise you to address the two points I laid out for you.

Woah. By no means did I mean to insult anyone. I was just expressing an opinion. A valid opinion actually and the person who built the item backs up other opinions expressed by other members on this board with facts.

I apologize if anyone was insulted by my opinions and posts. I did jump the gun a little bit from seeing 2 photos. Probably if I saw the product in person it would be a different story. It's sort of like looking at a catalog and seeing something thinking, "Why would I bolt/weld that on there?" Then you hear how it's pretty good and call to inquire information about it.

Now hold on a minute. First of all imagine for a second the school I went to wasn't any good. Plus I'm sure you wouldn't send you kid across the country to an engineering school and pay a lot more money to do so... CA has excellent engineering schools if that's what you kid is leaning towards.

Secondly, I did not namecall anyone or insult anyone's education as you have chosen to do.

I have rock experience with my Jeep, but it's probably different than. It's not dry, jagged rock, it's slick, wet, smooth, round rock. When you slip, the Jeep falls and slams on other slick rocks then it slides around, continuing to slam into rocks until it stops. It is very unstable.

Macgyver, by no means are you doing anything wrong. You're supporting your family and family comes first. Plus you gotta stand up for what you build. I don't have any experience with a transmission skid as shown. Where I wheeled, I didn't have a need for one. Most of my wheeling was done in dense forests. My transmission is pretty tucked away for wheeling in the North East.

I don't know either of you from a hole in the wall. I expressed my different opions and people flip. This is a technical forum. I expressed my opion and get jumped on. Sorry I'm not from your neck of the woods and and expressed my Different opinons based on my experience and knowledge from my native environment. Mounting a skid as shown would take some masive hits.

I am sorry if I have offended anyone.

-Jason

[Jeff Weston]

Originally posted by Jays89YJ
I expressed my different opions and people flip. This is a technical forum. I expressed my opion and get jumped on. Sorry I'm not from your neck of the woods and and expressed my Different opinons based on my experience and knowledge from my native environment. Mounting a skid as shown would take some masive hits.

I am sorry if I have offended anyone.

-Jason

I don't think you're trying to offend anybody on purpose. However, if you take a step back, you may see why some would. Without ever seeing the skid in person or seeing it in action, you basically discredited it due to a lack of structural calcs. Without quantifying the strength of the mounts or analyzing the loading conditions that the skid could be subjected to in real world wheeling experiences, you insist that the mounts are not designed to withstand such loads and that the engine is sure to break free while revving and then all hell will break loose, going so far to suggest carrying spare mounts as spares.

I think you bring up a valid point about items being brought to production without proper engineering analysis. Had this discussion been about a suspension component or something else in which that part's performance is critical to human safety, things may be different. The fact of the matter is that it is a skidplate whose sole purpose is to keep the rocks out of the tranny and oil pans and give you the best possible chance of getting off of the trail. You may think it easy to analyze the loading and do the calculations, but I certainly wouldn't even try. The dynamic forces incurred while crawling and slamming into rocks out at JV are certainly much more complicated and difficult to obtain than simply supporting the weight of the Jeep for instance.

I can think of several parts on a Jeep which are "underengineered" for what we use them for. Sticking to skidplates, none of our factory "engineered and cal'd and tested more than you could imagine" gas tank or belly pan skidplates can stand up to the abuse seen on the rocks.

So, to make a long reply a little longer, I would advise being a little less sure (publicly) that a guy's skidplate is going to fail because it does not fit within the factory blueprint and isn't backed up by calculations. One thing to consider is that a lot of engineering calculations used today are empirical and were derived the same way this skidplate was ... guided by practical experience and experiment and not theory.

[Jays89YJ]

Let's not forget, criticism is a form of flattery in the engineering profession. Support your experiences & theory, accpet criticism and take it lightly. People who criticize, question and voice their opinions, often show great interest in the subject.

To tell you the truth, I like the way the skid looks and how basic (K.I.S.S.) it is. It looks very clean and symmetrical and it is obvious this is built by a professional or someone who has skills comparable to one.

It's the thought of mounting anything that will not be cushioned by a bushing to the motor mounts that got me. Hmmm...

[mrblaine]

Originally posted by Jays89YJ

It's the thought of mounting anything that will not be cushioned by a bushing to the motor mounts that got me. Hmmm...

I can see where that would be a sticking point. In order to mitigate your analysis a bit, consider that there are other scenarios in the jeep that are hard mounted and subjected to similar forces.

My belly-skid-
Gas tank skids
rocker skids
roll cages

We even remove bushings from the control arm pivots and hack big chunks out of the frame for our rear shocks and remove the bushings from them.

A lot of time we just figure out what works and go from there.

[Paradiddle]

Originally posted by Jays89YJ
5 to 6 YEARS?!? LOL. So the profit margin isn't looking so good, or it's just a hobby... I wasn't saying an engineer who has never seen a Jeep or wheeled in your environment should engineer a part.

BWAHAAAA. While you tell me what to design for a TJ and I own a YJ, I'm working on designing more important things than a skid plate for the US DoD 10,000+ miles away in the Middle East. Let me take 5 to 6 years off for testing and I'll see what I come up with.

mrblaine: That's pretty cool. I don't really know your way of thinking, but maybe he was right. I would never discourage anyone seeking higher education. You'd probably really like the stuff I do. Lots of machine design, mechanical design, electro-mechanical design etc. etc.

Gotta say for a 23 year old kid you are quite rude. Have you ever owned your own business? Do you have a remote clue as to what goes into making any business run every day. Trust me - you don't. Take the highest pressure you've ever expereinced in your life and double or triple it. Then multiply it times 10 - you are getting close to understanding running a small business.

You can say what you want about his skid design, because that is your opinion, but you really need to back off the man and his company - especially because you lack the real world experience you are bashing.

Here is a formula to calculate stress and owning a business (since you are an engineer and all...)

(The Max Job Stress You've had in your 23 years X 3) x 10 = Stress of running/owning your own business (+/- 10%)

Jeff

[Jeff Weston]

Originally posted by Paradiddle
Take the highest pressure you've ever expereinced in your life and double or triple it. Then multiply it times 10 - you are getting close to understanding running a small business.

Cashflow is fun, isn't it? It is especially fun on those two months a year where there are three paychecks instead of two (like this month for us).

That said, I won't lie and say it isn't worth it.

[Robert J. Yates]

I am no more concerned about my motor mounts than I am with other aspects of things on my rig that are being used in capacities beyond those envisioned by the dc engineers.

lemme see - i'm running 35's on stock axles, my front axle is not stock to a wrangler. I've run a motor mount lift for the last 60k miles. I am running non stock axle gearing, a hydroboost brake system out of a chevy 1 ton truck application and rear disk brakes off a zj.

I take my rig on ocassion on trails that meet the bare definition of the word. i've winched my rig up vertical ledges and have winched much larger vehicles while tied off to another vehicle or tree.

so yea, motor mount failure was not a huge single concern. I destroyed everything previous to this skid made out of 3/16ths. this one works, has not failed yet and does not interfere with other systems on my rig. it also was not comped to me and I have no reason to argue in its favor other than for the fact that it works.

[mrblaine]

Originally posted by Robert J. Yates


so yea, motor mount failure was not a huge single concern. I destroyed everything previous to this skid made out of 3/16ths. this one works, has not failed yet and does not interfere with other systems on my rig. it also was not comped to me and I have no reason to argue in its favor other than for the fact that it works.

and as soon as I get out on a trail, I'll have some more feedback as to whether or not the rocks like it.

[Robert J. Yates]

I hate Blaine

It actually has been tested at TDS and then modifed again.

[StealthTJ]

[i]Originally posted by mrblaine <SNIP>
ranged from 2" diameter nitride ceramic ballbearings
<SNIP>
[/B]

Mmmm, how interesting....
Our "ceramic" bearings in the inline skates that we race with are nitride ceramic.......




Fred

[Jays89YJ]

Originally posted by Paradiddle
Gotta say for a 23 year old kid you are quite rude. Have you ever owned your own business? Do you have a remote clue as to what goes into making any business run every day. Trust me - you don't. Take the highest pressure you've ever expereinced in your life and double or triple it. Then multiply it times 10 - you are getting close to understanding running a small business.

You can say what you want about his skid design, because that is your opinion, but you really need to back off the man and his company - especially because you lack the real world experience you are bashing.

I ran my own business for over two years. I was a consulting mechanical designer working in NH doing electro-mechanical design. It was mainly medical equipment, but also some defense equipment. Medical equipment + Defense equipment = $$$$. Granted I was my own boss and the workforce. I did hire quite a few jobs out when I felt the need. I figured out how to do so during a full load cirriculum in college by working in the field. I continued to do so until I received an offer from the company I'm with now. Tax free money is very, very hard to turn down.

Again, not trying to be rude.

Originally posted by Robert J. Yates
I am no more concerned about my motor mounts than I am with other aspects of things on my rig that are being used in capacities beyond those envisioned by the dc engineers.

lemme see - i'm running 35's on stock axles, my front axle is not stock to a wrangler. I've run a motor mount lift for the last 60k miles. I am running non stock axle gearing, a hydroboost brake system out of a chevy 1 ton truck application and rear disk brakes off a zj.

I take my rig on ocassion on trails that meet the bare definition of the word. i've winched my rig up vertical ledges and have winched much larger vehicles while tied off to another vehicle or tree.

so yea, motor mount failure was not a huge single concern. I destroyed everything previous to this skid made out of 3/16ths. this one works, has not failed yet and does not interfere with other systems on my rig. it also was not comped to me and I have no reason to argue in its favor other than for the fact that it works.

I was freaked about running 32's with my stock axles. Mine were stock on my YJ though.
We don't have trails (per say) in NH. Somehow manage to get into the woods and go. After doing so the first time, I felt that my stock axles should probably be replaced.
I must say I was much more worried about busting my oil pan than my motor mounts.

[mrblaine]

Originally posted by StealthTJ
Mmmm, how interesting....
Our "ceramic" bearings in the inline skates that we race with are nitride ceramic.......




Fred

And many years ago, I ran the Fuji silicon nitride ceramic line guides on the custom saltwater fishing poles I used to build.

Shock resistant, wear proof, stayed cool, perfect application for the hard ceramics.

As a comparison, way in the old days before I started wrapping rods, the high end stuff similar to what I built used rings of synthetic ruby beryl to accomplish nearly the same thing, but at less performance and much higher cost.

[Robert J. Yates]

Originally posted by Jays89YJ
I must say I was much more worried about busting my oil pan than my motor mounts.

They why were you so freaked out about my oil/tranny skid? That is the exact same logic used behind its development

[Allen]

Originally posted by Robert J. Yates
They why were you so freaked out about my oil/tranny skid? That is the exact same logic used behind its development

He wants to show how smart he is.

Allen

PS-I modified my Mopar Oil Pan skid and connected it to my left motor mount.

I took a hard hit and broke the motor mount.

Allen

[mrblaine]

Originally posted by Allen
He wants to show how smart he is.

Allen

PS-I modified my Mopar Oil Pan skid and connected it to my left motor mount.

I took a hard hit and broke the motor mount.

Allen

You lie

[Allen]

Originally posted by mrblaine
You lie

Ok, maybe he's not that smart.





































And I did too break the mount. Well more of a bend, tweak, and major crack than total destruction.

But it certainly didn't do it any good.

Allen

[Jays89YJ]

Originally posted by Robert J. Yates
They why were you so freaked out about my oil/tranny skid? That is the exact same logic used behind its development

Robert, I didn't have rigid structural steel members supporting a skid from my motor mounts.

Originally posted by Allen
And I did too break the mount. Well more of a bend, tweak, and major crack than total destruction.

But it certainly didn't do it any good.

Allen

Interesting.

[mrblaine]

Originally posted by Jays89YJ




Interesting.

Not really as the design was inherently flawed. It was attached to the motor mount and not the frame bracket the mount rests on.

[Jays89YJ]

Originally posted by mrblaine
Not really as the design was inherently flawed. It was attached to the motor mount and not the frame bracket the mount rests on.

I call BS.