Lister Engine Forum
How to / DIY => Engines => Topic started by: GuyFawkes on July 25, 2006, 04:50:45 PM
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from http://www.surfbaud.co.uk/html/concrete_base.html
You may hear a lot of people talk about using “a yard of concrete” by which they mean a cubic yard, a cube three feet per side.
This is only half the story, the biggest mistake people make is in the proportions of the block they pour, they end up pouring a “slab” and not a “block”, presumably because nobody likes digging holes.
Lister specified a block 2’ 6” deep, with 3” above the surface of the surrounding floor, in metric this is 76 centimetres deep, 8 centimetres above the surface of the surrounding floor.
Lister specified width of the block to leave a 3” ( 8 cm) gap all around the standard Start-o-matic base, so for the 6/1 2.5 kW set this meant a concrete base 54” x 26” (137 cm x 66 cm) You were supposed to leave 4 off pits 15” deep (38 cm) from the top of the block for the 4 anchor bolts for the cast iron Start-o-matic base. These bolts were supposed to be 0.75” (19 mm) shaft diameter.
Once the concrete base was poured and set, you placed the cast iron Start-o-matic base on the concrete, lined it up, set the hold down bolts in place, and filled the hold down bolt cavities and any uneven spaces between the top of the concrete base and the bottom of the cast iron base with a slightly different mixture of cement referred to as “grout”
The base concrete should be at least 6:1 with a good proportion of 3/4 gravel, and don’t forget to put it some reinforcing steel before you pour. When you do pour take great care to “float” it off, filling ALL voids and the entire volume with concrete. Give it a few days to set, before you think about the next stage.
The “grout” mix should be just sand and cement, no aggregate, in a much lower ratio, 2:1 or even 1:1
I’m not going to tell you how to mix or use concrete, presumably you already know or can find out for yourself or have a builder friend.
If you’re feeling lazy you can buy premix, just add water and mix, or for quantities of a cubic yard and up you can often get the ReadyMix truck to deliver, seeing as your base will be about a yard and a half no worries there, keep an eye out for local building projects, they often have some “spare” in the wagon...
Every time I read about someone having a problem with a Lister “walking” it is someone who has a “slab” and not a “block”, someone who has insufficient mass, eg less than a yard and a half of concrete, or someone using too small diameter hold down bolts. When you personally have build and sold and installed more stationary diesel engines than Lister, feel free to argue with their specifications as set out here...
A cubic yard of 6:1 Portland cement when set weighs about 1.6 Tons.
(http://www.surfbaud.co.uk/assets/images/rebar.jpg)
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The base concrete should be at least 6:1 with a good proportion of 3/4 gravel, and don’t forget to put it some reinforcing steel before you pour.
This is one area where things can be improved over what Lister recommends.
Add some fibermesh.
http://www.glaciernw.com/dept.asp?d_id=15731&l1=15245&l2=15731
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....Once the concrete base was poured and set, you placed the cast iron Start-o-matic base on the concrete, lined it up, set the hold down bolts in place, and filled the hold down bolt cavities and any uneven spaces between the top of the concrete base and the bottom of the cast iron base with a slightly different mixture of cement referred to as “grout”...
Nice Post. Maybe a little more detail here, though: When I've done this, I set the engine (base, whatever) on little wood strips - maybe 3/4 inch high. Then you have plenty of space into which you work/pour the grout. The grout is mixed to be pretty watery, relative to normal concrete. You need to build a temporary wood dam around the base so you can keep the grout puddle where you want it.
And don't mention anything about no stinkin' vibration isolators, rubber tires, wood block mounts, discarded mattresses, soggy croutons or any other cushiony crap. The system being described is a rigid mounting system.
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Thank You, Guy---
It's surprizingly similar to what I've planned for my engine. The main difference is in the height above the surrounding floor.
How do they plan for oil changes at that level, not to mention having to crawl around on the floor when working on the bottom end?
Mine is now 21 inches floor to center of shaft and I'll raise that by 3 inches next time. The other addition will be a stout, welded drip pan with a drain in it.
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How do they plan for oil changes at that level, not to mention having to crawl around on the floor when working on the bottom end?
Mine is now 21 inches floor to center of shaft and I'll raise that by 3 inches next time. The other addition will be a stout, welded drip pan with a drain in it.
1/ working on the bottom end sir? not with a lister.
2/ back in the day EVERYONE had those big old brass syringe pumps for this, I haven't even seen one for decades... googles
kinda like the image below but about 2' long
3/ listers do not leak oil sir, they mark their spot.
(http://antiquescientifica.com/pump_Ferguson_brass_c._1860.jpg)
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If this is to commercial just say so and I will delete it.
On this page is a video showing some engine installations.
Near the end is a generator install, note that the engine generator and the base are several thousand lbs and then note the size of the concrete slab/block I am guessing it is not just floating on top of the ground. And these engines are a lot better balanced then your average listeroid.
http://www.arrowengine.com/aboutarrow.htm
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I'm not a concrete expert, but what's the advantage of using form ply as shown in the photo?(or do I need glasses?) I thought the idea was to fill the hole with concrete and steel and have it "key" into the dirt.This is a genuine question cos' i've got to pour the block for another motor (1936 and better than a lister ;D ;D
cheers ,
Brian
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I'm not a concrete expert, but what's the advantage of using form ply as shown in the photo?(or do I need glasses?) I thought the idea was to fill the hole with concrete and steel and have it "key" into the dirt.This is a genuine question cos' i've got to pour the block for another motor (1936 and better than a lister ;D ;D
cheers ,
Brian
Not positive but I do not think there is anything lining that hole just a 2X4 (or the metric equivalent) frame around the top. I think I see some roots coming out of the sides. But I must say whom ever dug that hole did a real nice job of it. They also do not have the rocks that I do.
But you do not really want the dirt near the top of the hole to get a grip on the concrete. As the ground freezes it does so from the top down, if the frozen dirt at the surface can grab onto the block it will lift the block a little as the freezing proceeds deeper and heaves. Then a little dirt can get washed in under the block so that it never settles all the way back down.
Frequently blocks like the one in the picture are made with a taper larger at the bottom then at the top.
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Whether or not you need to form it will depend on your soil type. If you have sandy soil that may collapse during the pour you definitely need to form it all the way to the bottom. If you have heavy stable clay soil you can probably get by with using the earth as a form.
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Thanks, guys.
I've never seen soil like that! Maybe I'll get my eyes tested after all! I've lived on three continents and never had to deal with frozen ground, but I understand it's a major issue for some of you.My biggest problem is BONE dry clay (hard as rock) and trying to keep the concrete moist enough to cure.
I suppose we all have our crosse to bear..... :D
Cheers,
Brian
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Concrete will finish harder and stronger if it is kept from drying out for a period of time. The amount of time is dependant on many variables and differs in any given situation. However, one can ensure that one's concrete will be the strongest possible by simply lining the form with polyethylene (Visqueen) sheathing. Without the sheathing the dry earth will quickly draw the moisture from the concrete accelerating the reaction (calcification) which gives the concrete its ultimate strength. The longer this reaction takes the stronger the molecular bond. Simply adding more water is not a viable solution. This will dilute the mix and cause chalking resulting in a very weak slab. Concrete is not considered fully cured for at least 28 days. Cheers.......
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Crankshaft height is stated in my ASHWAMEGH manual. I forget, but it was about 27 inches? Anyway, it's important for hand starting a twin, so my question is:
How do you cast the concrete foundation and still get the higher crankshaft height called out in the manual?
I consider all soils to be 'semi-fluid' so the foundation block would eventually tip if it was not designed correctly?
I keep going back to the Internal Fire Museum online and looking at the way they make engine beds for the antique diesels that I love looking at.
Scott E
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on concrete strength
this is from a customer of mine, who runs a concrete company,,
if you want a super strong slab,, use no more water than is necessary to work it,,,,
it doesnt take much more water to seriously weaken the end product.
28 days is about 95% cured,,, but the theory goes that it continues to harden for years!
very dry mix concrete is hard as hell after about 50 years,,, ask a guy behind a jack hammer ,, he can tell you
if it was a dry or wet mix.
bob g
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Thats why so many guys do a slump test I guess before the truck starts to unload....
Doug
Also fiber, rebar, air, and ash for strength
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Just a few minutes ago I finished welding together a HEAVY (1/2x3x6) angle iron frame that will be set directly into the concrete about half way and the other half in grout.
The 24x60 x 24"deep hole has been cut through the old concrete and soil below and enough scrap iron and re-bar for a SHO NUFF engine mount.
I'm going to form a 24 x 60 x 12" tall box around the hole and just keep pouring until there's three inches left for grout. With the base of the engine 12 inches off the floor it puts the center of the crankshaft at 24 inches from the floor. Mine is now 19 inches and the extra five will be nice.
The frame is drilled for eight 3/4 x 24" tiedown bolts. The engine can be mounted on either end or the middle position, or two engines will fit on the same mount. I drilled and tapped 12 more 1/2" holes for whatever else might need to be bolted on later.
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Now thats one hell of a mount. Pics please. I'm not sure how much (or if its feasible) concrete you would need to really isolate vibration but my 2600lb. block isn't enough to prevent some minor rattling of a kitchen cabinet door that doesn't close tight 40' away. If I press my ear up against the basement wall I can feel/hear it. The block is isolated about 3" from the garage slab and there is a breezeway between the garage and the house which further isolates the house a bit. A heavy, solid mount is certainly good for the engine but there are ramifications.
Thanks, Geno
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Has anyone considered lining the bottom and sides of their concrete form with several inches of recycled tire mulch? The stuff is very spongy when several inches thick. It is commonly used in playgrounds and would probably make a very good isolater. Just a thought.
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http://community.webshots.com/photo/2910061440028237237bfpyQF
Hole is ready....
I ran into a hell of a problem....the big square just behind the hole is the well head. It's a hot artesian well that blew out around the casing when drilled. They put 12 yards of concrete around the casing to fill in the hole and later poured the pumphouse floor on top of it. Swinging a sledgehammer inside a building for a guy 6'4" is hard work!! I broke two pair of saftey glasses, too.
Half my engine base will be on that concrete and half on the yard plus I'm about to pour. More pics as more progress happens. I've got to drill the well plug for five of the eight hold-down bolts today.
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Instead of bolting your framerails down, why cant you just cement them right in? Just leaving enough sticking out to bolt the engine to.Avoid the grouting step.Just wondering..
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i would imagine that is near impossible to get the rails dead level in all planes, and have them stay as the concrete cures.
my references state that the base concrete should be poored, with mounting studs, then the bed plate/frame is leveled over the studs,
shimmed to level and grouted in.
then attach the motor to the bedplate or frame
bob g