mounts

[compig]

Or another way to look at it , I don't have enough garages !! LOL !!

[Tom]

Here is what I did. It isn't going very far, but it does move.



The main problem I see with resilient mounting is that if something happens you could have a lot of weight swinging around trying to get away.

[sailawayrb]

The main problem I see with resilient mounting is that if something happens you could have a lot of weight swinging around trying to get away.

Interesting, I concluded exactly the opposite.  For a worse case engine seizure scenario, where all the inertia of both fly wheels was suddenly applied to the mounting structure, I concluded that 1/2 " mounting bolts (or engine cast iron feet) would likely fail and potentially allow the engine to dynamically depart a rigid mounting structure with significant velocity.  Where as with a resilient mounting structure, the mounting bolts would not fail, but the combination engine/generator/structure would move, albeit a relatively small amount compared to the aforementioned.   This is because dynamic motion of an object is proportional to the force (which is the same for both these cases) and inversely proportional to the mass of the moving object...the mass of the moving standalone engine is significantly less than the mass of the moving combination engine/generator/structure...so the acceleration/velocity of the moving standalone engine is significantly more than the moving combination engine/generator/structure.  I would certainly advocate using steel cables to ensure that the engine/generator/structure can NOT travel very far if one chooses to go the resilient mount approach.

I do agree with mobile_bob that whatever approach you elect to do, you should take time to do the research and plan your design very carefully.  These engines can be very dangerous and one can't be too careful and safety conscious.

[compig]

Can't say I agree with the postulation that an engine seizure would cause catastrophic failure of the engine base or bolts. The weakest components most directly associated with the seizure would fail 1st and in my experience that would be the piston & con rod. Seizures are rarely light switch sudden events , the piston would tighten then if that force was greater than the yield strength of the rod, that would that bend or break which would possibly pierce the crankcase , but by then the energy would be greatly dissipated and probably not cause very dramatic damage.
I've known race car motors seize at 7k + rpm and not do much more than break a rod and hole the block. I've also seen a car diesel after a hydraulic lock on water with the same sort of results. CS's only work at 650 rpm and are considerably more substantial in construction than a  typical car engine , I think they would sustain seizure without causing another stellar big bang !! 

[Tom]

My dad had a '66 Yamaha 250 that seized up on the freeway near Tracy, CA. It seems the pistons were prone to melt and stick to the cylinder walls. The did lockup quickly and the bike came to a skidding stop. IIRC there was not much damage to the engine.

I don't think a seizure on a Lister is to likely, especially with a CI piston. A failure mode I was thinking of was that after a few thousand hours of spinning unbalanced flywheels the crank might break. Has it ever happened, I don't know, but Murphy's law always applies.

Any one want to volunteer to do some destructive testing and record the results. 

[Stan]

If you go waay back to almost the beginning of the forum, this discussion went for quite awhile.  Someone posted the url of an online article containing many instances of failed flywheels and the devastating results.  Pics included.  Interesting reading, not sure if the url is still current or not.  Maybe someone with more time than I have could research this.  It bears repeating.
stan

[lendusaquid]

I used a 4ft x 2f x2f block sunk into the ground by about a foot.It was lined with 2" polystyrene sheet before the pour and removed at ground level when set.This is to isolate the block from the floor.Lister Did give details of the block size required.You could not go far wrong by following their example.You also could experiment to your hearts content on top of the block and still have a sound foundation to go back to.

[mobile_bob]

it depends on which lister recommendation you go with, the first called for about 605lbs of concrete
the second (later recommendation)called for about a ton.

as for seizures i have been around the block several times with all types of diesel engines and have never
seen a single example of an instantaneous siezure, not one, nada, zip.

as for resilient mounts there are two basic types, all rubber, and those that have a protective steel surround
that contains the unit should something catastrophic happen that would rip the rubber loose.

most modern mounts use the containment method.

properly thought out and built, a resilient mounting system would be several times stronger than simply bolting the engine down
to concrete, if for no other reason the mounts can be moved substantially outward from the crank centerline which reduces the amount
of torque delivered to the mounts by whatever factor you wanna build to.

i don't want a 6/1, but am tempted to get one and mount it in a floating cradle mount just to demonstate the concept.

i am so convinced of its viability that once demonstrated to the unbelievers they too would likely never mount to concrete again
save for very few applications where it was more expedient to do so.

bob g

[Lister Rob]

Hi guys, i have my lister 6-1 startomatic bolted to a 10 in. concrete pad with a shed over it and haven,t had any hopping or movement at all. I quess i was lucky and came across a good one. Thanks Rob.

[compig]

The SOM I bought was resting on bare earth outside. When I went to collect it it was running on a light load then the guy banged on a 2kw load to demonstrate that it was fully working. There was no movement visible. Can't comment on vibration though , and his yard was so big it wouldn't have caused a problem anyway.

[matt]

Sailawayrb and Tom,

The pics you both posted of timber mounting frames look well thought out and solid in construction.

I am about to start constructing a timber frame, and am curious how you bolt down the ST generators to your frames.

What methods do you use?

regards,
Matt

[ronmar]

The SOM I bought was resting on bare earth outside. When I went to collect it it was running on a light load then the guy banged on a 2kw load to demonstrate that it was fully working. There was no movement visible. Can't comment on vibration though , and his yard was so big it wouldn't have caused a problem anyway.

The all up weight of a SOM generator set has got to be well over 1000#.  My generator sled(frame, engine and generator head) ran happily just setting on my garage floor under all load conditions.  Because of smooth frame bottom, smooth garage floor and spilled oil, It did want to creep slightly across the floor over time, depending on how much torque it was making to meet the loads being applied.  I ran it like this for several months while I was working out the particulars of my cooling/heat exchanger system.  I clamped the frame to a 2X4 run over to the garage wall to keep it from moving too far:)     

[Tom]

On my frame I used carriage bolts pointed up through the 4" channel iron used for the side rails of the frame. To keep them from turning I drilled the hole just a bit over 1/2" and used a 3 sided file to make square holes to fit the bolt. The bolt heads sit on the 4X6 underneath the channel iron.

My frame is really an iron frame, I just have the 4x6's between the legs of the channel iron for a bit of cushion. There are 5/8" x 20" foundation tie down bolts embedded in the concrete block. These go through the top and bottom channel iron and the 4x6 timber.

[compig]

The SOM I bought was resting on bare earth outside. When I went to collect it it was running on a light load then the guy banged on a 2kw load to demonstrate that it was fully working. There was no movement visible. Can't comment on vibration though , and his yard was so big it wouldn't have caused a problem anyway.

The all up weight of a SOM generator set has got to be well over 1000#.  My generator sled(frame, engine and generator head) ran happily just setting on my garage floor under all load conditions.  Because of smooth frame bottom, smooth garage floor and spilled oil, It did want to creep slightly across the floor over time, depending on how much torque it was making to meet the loads being applied.  I ran it like this for several months while I was working out the particulars of my cooling/heat exchanger system.  I clamped the frame to a 2X4 run over to the garage wall to keep it from moving too far:)     

Mine weighed out at 900KG , 1980 Lbs , which I have to admit surprised me !! Thats a big chunk of metal !!

[matt]

On my frame I used carriage bolts pointed up through the 4" channel iron used for the side rails of the frame. To keep them from turning I drilled the hole just a bit over 1/2" and used a 3 sided file to make square holes to fit the bolt. The bolt heads sit on the 4X6 underneath the channel iron.

My frame is really an iron frame, I just have the 4x6's between the legs of the channel iron for a bit of cushion. There are 5/8" x 20" foundation tie down bolts embedded in the concrete block. These go through the top and bottom channel iron and the 4x6 timber. 
 

Thanks Tom for the info. I like your idea with the triangle file making straight edges for securing the bolt heads from turning.

How exactly do you attach the ST Generator to your frame, also allowing movement for tensioning?
Many off the pics I see (except rocketboy's) do not show this detail.

regards,
Matt