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Skyline RB26DETT Engine Mounts -> Datsun 240Z


Boobala

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I think they are nice, but a bit expensive. I also don't like the sharp, 90 degree cuts. In the aviation business we call those "stress risers," and after a few hundred hours of vibration I would not be suprised to see cracks develope in those areas. I think those areas should have been cut with a small radius in all the corners.

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I think they are nice, but a bit expensive. I also don't like the sharp, 90 degree cuts. In the aviation business we call those "stress risers," and after a few hundred hours of vibration I would not be suprised to see cracks develope in those areas. I think those areas should have been cut with a small radius in all the corners.

 

You are right, they should have been cut with rounded corners. The buyer could always do that themselves, but for $295, sheesh they should have been done right in the first place.

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Thanks, Brad, for backing me up, even though you're selling yours for considerably less.

 

Boobala, are you an engineer or machinist? To make these mounts the way you want them for less than $250 would be an incredibly great deal ($250 is my reserve price, by the way), if you don't have to do the research and development work. I could do it the way you would like them done with all the radiuses and corners, but it would cost considerably more. I'm selling these because I made a few only, there's not a massive demand for these parts. I could sell them cheaper if I had hundreds of customers wanting these, so I could offset my costs (supply and demand :-) I'm not trying to rip anyone off with that price, I think it's reasonable for the quality put into it.

 

Oh yeah, these mounts do not bolt right onto the crossmember mounts of the car. They will bolt up to a pair of heavy duty rubber insulators, and from a machinist point of view, I don't think these mounts will crack over a few hundred hours, like you suggested. I've had mine for a few years now, and there is no wear and tear on them, because they are so thick in construction.

 

If you can make these mounts for cheaper than $250, and the way you want them with all the radiuses, I'll buy them off you! :wink:

 

Rick

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aircraft stresses and car stresses are completly different. the thickness of those mounts will make them in detructable in a car. give me a break... there is now way in hell even a hi HP rb will break those :roll:

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Thanks, Stony, for backing me on this one too. Like Brad and Stony, they both have the RB26 motors in their Z's, they both know how much torque the motor puts out. To my experince as a machinist, I'm 100% sure that the frame will bend or break first before the mounts will ever crack.

 

Thanks,

Rick

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Hi All,

 

first off, hats off to Rick and Brad for making mounts available. I started to make them too, but all the fu#king around and bullc#ap that people were emailing me with, it was not worth the effort or time.

 

Rick, your mounts will NOT break with a high HP RB26DETT. People should see the factory aluminium ones. Mine are modified factory aluminium ones and they are working fine even with a bigger ball-bearing Garrett turbo.

 

I personally feel that there are too many dreamers and it is all to easy for people to judge others work/cars. Unless you have a better built RB26DETT zed then there is no room for negative comments!

 

Cuong Nguyen

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i agree, there are too many dreamers, but it seems like everytime someone on this board says they going to do a rb26dett swap they get called off as unserious dreamers... i am planning my next project myself and it will definetly be a RB engine in it, but if its a rb25 or 26 is yet unsure... depends on what kind of money i can put in it. i dont even have an z yet, does that make me a dreamer? :roll:

 

Sigurd Solberg

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Let me quote my self..

 

I think they are nice[/size'], but a bit expensive....

 

I said "a bit expensive," not "overpriced" or a "ripoff," or anything

remotely like it. I think the RB26DETT is a Nice motor, but it is a

bit expensive. I think the LS1 is a Nice motor, but a bit expensive.

I think that my DVD player is a nice DVD player, but it was a bit

expensive. See the trend?

 

I think it's great that you have made extra mounts, and are offering

them to the world. That's why I posted them here! If I didn't

like them I would have posted a "Hey look at these crappy, overpriced, sure

to crack and destroy your Z, kill you and your dog RB mounts" thread.

 

I am certified to Level II in Dye Penetrant, Eddy Current, & Mag Particle

NDT (Non-Destructive Testing), and have well over a hundred hours in the

classroom learning the various NDT methods and Metallurgical processes.

I have well over 2000 total (documented) hours testing a wide varity of

aircraft parts. Finding cracks is what I do.

 

There is little differrence in automobile and aircraft stresses. In different

areas on a aircraft the stress may be greater or less than those found in

automobiles. In fact, most of the cracks I find are in low stress areas.

It's not always the BIG stresses that cause cracks, it's the little, continuous

stresses (vibration) that do the most damage. Rubber isolators will

help a great deal in this area.

 

I'm no machinist but looking at the part it seems it was cut with one type

of cutting tool (bit), and it appears that the bit has flat tip and cuts

with the side (flute?). It seems to me that by changing from the flat tip

to something with a small radius (Ball End Mill?) on the tip would

eliminate the 90 degree corners.

 

album_pic.php?pic_id=1219

 

In the above pic. you can see the very nice radius cuts. Any Stress

will be evenly distrubted along the radius. Now look at the sharp

interior corner. Here all the stress will be focused and is the

most likely place for cracks to form. I'm not saying cracks

will form, but if any do, this is where they will probably start.

 

They are nice mounts and if I were in need of a pair, I certainly

would not rule them out.

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Guest Zachb55

they deffinately look like the best, most reliable mounts ive seen, i would be more afraid for my rear end then the engine mounts breaking, every mount ive seen made would leave me fully satisfied, i dont think of this as a part that will undergo nearly as much stress as say a half-shaft or the differential will.

 

-Zach

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Hi Boobala,

 

If you are talking about mounts for a car versus an airplaine, they are two totally different things. I do make aircraft parts for Boeing and Bombardier, and the procedure to go through making a part is much more intense in papertrails (you know what I'm talking about) and making the part is again another thing. You have to find the right grain structure of the material for the best stress resistance and all radiuses must be put on in all corners and the part must go through a few stages of stress relief and shot penetration to release any levels of stress, and then go through x-rays or ultrasound in order to pass inpsection for an airplane. Now if you want all those levels to be done for a car, it could be done, but the price of the mounts would be over $1000 easily.

 

But like you said, the rubber insulators will reduce most of the vibration of the motor already, so the corners will be okay. You are also right, ideally everything should be radiused, which I could do right now, and the center section will be thinner. Next time, I'll put a small radius in there to satisfy my toughest critics :-D

 

I'll try to post some more pics from other angles of the mounts soon.

 

Rick

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