My son is building an engine hoist as part of a welding project at school.

I'd like to ask the group, any ideas on how heavy the 324 is? I know it's really heavy. Thought I'd take advantage of the school project and actually be useful.

 

Just the block alone ~250, w/crankshaft ~325, complete motor w/intake and heads ~600 lbs.

 

What structural type of hoist is he building? I would design in a 3k pound operating parameter, so it doesn't matter the weight of any one particular engine.

 

Yes, and when I was in Engineering School (30 + years ago), we designed everything with and SF=6 (safety factor). We did a jack stand design on paper, calculated everything and then tested it with that safety factor in real life.
I bet everyone here has had the 'ole hoist not have enough reach and pulled the arm further out. I always get nervous seeing those carb plates used to lift engines. So you have 4 bolts, probably 1/4x20 bolts holding up at least a ton of engine/transmission on an engine pull.

 

I've pulled probably 50 engines with/without the transmission attached using a load leveler over the years with a carb plate and not once had an issue.

 

Oh yeah, me too, just saying it always makes me nervous. Those screw type engine levelers are a real pain!

 

I used a brand new load leveller from Princess Auto (Canadian version of Harbor Freight quality) to remove the 350 with transmission from a '72 Cutlass. Once the engine was in the stand and I was patting myself on the back I noticed that one of the chain links on the leveller had opened right up and was one bump away from total failure. I've never trusted one since.

How many people use just 2 bolts into the heads or accessory bolt bosses? Compared to the 4 bolts on the intake manifold plate? Or rely on the two smaller bolts of the forward lifting hook? I suspect many aren't aware of the two factory lifting points to begin with!

Always inspect your lifting equipment before, after and during use.

When people suggest using a longer square tube steel to extend the reach of an engine hoist, all I can think of is how much further out can it go without over balancing...

I guess it all beats a piece of rope, old pulley and convenient tree in the back yard :-D

 

Thanks everyone. I appreciate the quick response. It'll be designed to 4k lbs. Should do nicely.

 

I happen to have been, at a few times in my career, a professional engine picker end effector guy. The way my OEM does it is the engine will come with two large hooks like upside down fishing hooks, and we hook what used to be figure 8 chain links, but are now safety latches, onto them. Those hooks bolt into the heads on aluminum heads with two bolts that will be in shear load. Once we've put the engine on its final spot (the sub frame), the hooks get removed and reused and the bolts get chucked.

However, a Toyota, even a v8, block is lighter than a big old Olds, especially with transmission.

My thoughts on picking Olds engines. The accessory bolt holes are bigger than the carb holes, and they're in shear as opposed to tensile. Two things will drop your engine first, one, shock load, and two, crappy bolts. If you haul on the engine with a serious hoist and go from slack to lifting hard on the bolts, you can rip threads right off bolts, or the intake. Especially aluminum. So, my suggestion is to tension it all up, and lift slowly. In fact, there's no issue with hovering for a little while to make sure you're good before going higher. Secondly, use the best bolts you can. Thirdly, for shear loading, make sure the chain doesn't bind if you're using the head holes, a stress concentration can start a failure if it's pinned.

The Olds factory method was not bad. Don't do that unless you have a bar. A chain using the loop without a bar will bend the loop. It's amazing how the few engine plant end effectors that have survived are considered sacred relics; it's a standard design that I think I even put in the same thing in Mississippi about 15 years ago. The issue with that method is that, if it ever bounces, it can come loose. This shouldn't be an issue with home use.

The best way I would recommend is to fab a load plate that had bolt holes for all accessory bolts on a head, with a large hold for chain at the top and use a spreader bar. I think I will fab some of those. The carb plate way is very easy. I wouldn't do it on an aluminum intake. A lot of guys are like, well, I've done it this way and never had a problem personally. I can't take that stance professionally, some of my hoists have had a few million lifts on them by now.

 

It does not matter what bolts are used to lift an engine, even gr2 bolts are strong enough.

 

A single 5/16 Grade 2 bolt has an ultimate tensile load of 2,900 lbs. Two of them will lift the whole car, ASSUMING they are perfectly loaded. This is the part that people don't understand. Pure tension or pure shear load capability is plenty. The problem is any offset loading from bending will drop that capability dramatically. I've seen too many instances where people have used the accessory bolt holes in the heads and the lift lug isn't bolted up tightly against the head.

I'll also add that having stripped my share of threaded holes in the carb flange of aluminum intakes, that is the reason why I don't like plates that bolt to the carb flange.

And finally, to the original post about building an engine hoist, factor of safety on static load is only part of the design requirements. You have to account for dynamic loads - such as when you lower the load too quickly and crank the hydraulic valve shut as a result. That jerk load when the lift stops can overload an under-designed hoist. Also, the driving case is frequently not strength, but stiffness. This is the willow vs. a plate of glass analogy.

 

I give....what is this analogy?

 

The willow is strong but not stiff. The glass is stiff but not so strong. People who are not structural engineers frequently don't understand the difference. Then again, most people don't understand the difference between "quick" and "fast" when it comes to cars either. A dedicated drag car is quick but not geared for top speed. A Bonneville car is fast but not geared for acceleration.

 

Ah. I thought about it for a minute. Think maybe I got it. A willow will bend and sway and maintain it's weight bouncing up/down while glass will shatter/break under the same type loading?

 

Thanks! Makes sense.