12-2 Genset Mounting

[skeeter]

About 6 month ago, I decided that building a CHP solution was for me. Since then I've been planning, purchasing (12-2 power solutions JK-son engine and ST head and alot of associated paraphania), and building a home for it all. Its final home is a 12' x 11' room, part of a 48' x 36' pole barn structure. Now I'm ready to start pouring concrete but before I do, I want to make sure I'm on the right track as far as the genset mounting. As of now I have a 2 1/2' x 4' x 1 1/2' deep rectangular hole dug. My plan is to take the anchor rods that came with the engine, and properly position in the dug hole for later mounting of 2 - 42"  4" box channel or 4" x 4" PT post. The plan is to pour the concrete, filling the hole and a 12" slab above the hole. When the genset is mounted it will be sitting on top of its 4' x 4" mouting, secured to  2 1/2' of concrete underneath, with the rest of the room having a 1' thk slab. So far I think I'm on the right track. Please comment. I have some 1" thick, high durometer rubber matting that I've used for horse stalls. Should I use it under the genset mounting? Should I cushing, to lessing shock and vibration? The engine home is 50' - 60' from my house, the ground that everything sits on is sand, below the 1 1/2' - 2 ft' of sandy loom top soil. I live in a rural setting, so neighbors are not a problem. Would be thankful for any comment, especially from those that have been done this path. Any lessons learned, would be appreciated. Thanks.

[Procrustes]

Hi Skeeter Scooter,

Or is that Skeeter's Cooter?  Sorry couldn't resist.  That reminds me of some notorious URL's: the Pen Island penisland.com, Therapist Finder therapistfinder.com, Mole Station Nursery molestationnursery.com, etc.

Anyway, there are a couple of good threads on the subject in this forum.  Flexible mounts are hotly contested.  However the Lister manual recommends a 42" (if memory serves) block of concrete with the motor grouted into the top.  Hotater put up some good photos of his setup for which you can find a link.  Stationary motors with flywheel in general use the fixed mount.  The block will dampen vibration.  A slab on the other hand will broadcast vibration for many yards.  Search on 'mount' and maybe 'flexible' or 'block' to find the threads in question.

Best luck.

[dkwflight]

Hi Put some foam insulation on the studs. Leave the bottom 8 or 10" bare. The mount studs can then be moved around and the steel will have some strech.
I wouldn't put ru8bber between the concrete and the bottom of the engine.
Do a search on "grouting machinery". On the forum and off.
Good luck
Dennis

[hotater]

skeeter---

I just got my crankcase bolted to the mount today.  Pictures here-



and here---



I'd suggest changing the hold-down bolts to either 3/4" like I did, (drilling the base is tough on wrist!) or going to American half inch bolts.   The hold-downs with it is Whitworth thread and if you lose one.....

You have a LOT of reading to do!!
   

[MeanListerGreen]

  Alas....is that a cresent wrench made in Tawain I see in that pic.......

[hotater]

That wrench is a Yakamodo Fits'em-all.  My favorite.     

Actually my favorite of ANY tool is the one I find first.   

[skeeter]

Procrustes - I think I'm going to change my screen name to skeeter scooter. Somehow that space makes a difference.

Dennis -

Hi Put some foam insulation on the studs. Leave the bottom 8 or 10" bare. The mount studs can then be moved around and the steel will have some strech.

I'm not sure what you mean. By foam, are we talking styrofoam, close cell insulation board, or that spray foam. Where do you put it.
Also, not sure what you mean by "Leave the bottom 8" or 10" bare.     Was this in a previous post? Anyhow, with the little bit of additional reading since my post, I think the rubber cushing is out.

Hotater - Wow, nice job.  I'm still studying what you did, questions will follow.  I think I quickly have to rethink what I'm doing. The weather is changing where I'm at.  Anyway the Whitworth threads are out. Thanks for bringing this to my attention.

[skeeter]

Ok, since my last post, I read, and read, and read. My heavily reinforced block dimensions are going to be 54" L x 30" W x 24" D below grade, with the block narrowing to 24"- 25" inch width and 6" dept above grade to accomadate the flyweels of a 12/2 . I'm sold on mounting to alot of mass under the genset. I will use Guys 2" x 2" idea for setting anchor rods, will use either 8 -1/2, or 6 3/4" anchor rod.

First question, Should I isolate my mounting block from the surrounding 8" slab. Would the slab still be a good transmitter of low frequency vibration, even with my block under the set. The room is located on a corner of a pole barn structure, having 6"x 6" pt post eight feet apart (additional posts at room corners and doorways), sunk 3' 1/2 feet into the ground, sitting on top of 1 1/2' footings. The slab will use the skit board (surrounding the room) as its form, incapsulating the support posts. I guess I'm trying figure out how much vibration will be transmitted to the structure. Since I've never had a slow speed thumper before, its all kind of theory to me at this point. I would appreciate any insight, and I know their are probably two many variables to know for sure.

Hotater - Forgive me for not figuring this one out. Is the pvc tubes being use as forms for your anchors rods, which you later filled, or is it a provision to allow replacement of the rods if need be.

[peterako]

Hi forget the rubber isolation it is a total nightmare.

For the second part use a blok of concrete as big as possible plu isolation from the slab by foam or rubber.
Also try to take the top of the blok higher than the slab, This avoids exscavations in the soil/sand and the starting handel whit a little calculation will be on a better height for starting.

[skeeter]

To further clarify/ correct my earlier description. The total block dept is 30 inches, 6" above the slab top surface, 24 inches below. After enlargement of the "hole" from the dimensions stated in my first post of this thread, the added fill in the room has reduced the slab hight to about 6". I'm now thinking I may just add expansion joints between the slab and the block sides that pass through the slab. Forget cushioning the block or the set with rubber or other resilent material. I don't wont it to move(or as little as possible), period. Reading hotaters accounts have convinced me of that. I'm just considering detaching the block mass from the mass of the slab. Thats all.

[Guy_Incognito]

Best to separate the block from the rest of the slab with something. Even though it doesn't appear to move, it still will be vibrating somewhat. If it's coupled to the concrete slab, you might be unfortunate to find that you'll crack your slab a little - it's unlikely, but murphy's law states that if you choose to ignore it, it'll happen!

A couple of bits of something to make a gap between block and slab might save you some heartache later on.

[hotater]

skeeter---
 I agree.  Separate the block from the floor slab if possible.   I got in a situation where there was no way I *could* de-couple them, the well plug is part of the block and part of the floor so I'm stuck with a floor that *will* vibrate some, no matter what,  BUT, I haven't cranked the new engine that's mounted to the block, yet.

I found a great Listeroid seismograph  (Seismoroid?)  It's a coil spring out of a couch or bed about four inches tall and tapering from three inches in dia at the bottom to an inch at the top.  I just sit it on something and it picks up the beat in about ten seconds.  The motion of the top describes motion of the place it's sitting, but exaggerated.  My set-up has a 'node' about 88 feet in radius around the engine shed where motion is much more than other places.  Fascinating to study but I'm glad nobody is watching me wander around the yard with a bedspring in each hand and crouching down to watch them intently on the ground every few feet.   

[skeeter]

hotater, interesting seismograph. If you had the sensitivity, I would guess you would have a smaller vibration peak at 176 ft. The measurement of the change in peak vibration radius may also be a cumbersome way to determining engine rpm\ frequency regulation. Thank God for our electronic toys.

[DaveW]

  Hotater -

    You could always say you've heard reports of grabiods (from Tremors) and this is your high tech way of tracking them.  Carrying a large rifle and looking serious would add to the effect.

[gpkull]

cracking the slab is a possibility but the slab will transfer your riods thump. i know of a 12/1 on a block 2x2x4ft long. the block is solid and tied into a slab. not a whole lot of hours on it but the ground can be felt many feet away.,  when you are next to the riod on the slab getting a foot massage its hard to say how far away you can go before you dont feel it anymore. armadilos dont care but moles will have no part of this