I have a question about the plates you can use to pull out an engine. The ones where you take off the carb and bolt the plate on over the intake manifold... They claim that they work with aluminum manifolds, but is the aluminum really strong enough to take the weight? It seems more convient to pull an engine this way, but not if it means stripping the threads out of your manifold. So what's the deal with those? Thanks - Chad
Lifting an engine out by the intake manifold?
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Chad, Just make sure the bolts you use are long enough to use almost all the threads in the manifold and snug them up and you will not have any problems. The downside to them is you cant adjust the angle of the engine with them. I usally use 2 pieces of 1/4" chain and use longer bolts to replace the front and rear manifold bolts on each side. I then use a bolt between the 2 chains to hook to the cherry picker. You can then move the bolt forward or backwards to level or tilt the engine to your desire. Maybe not very flashy but it works well for me especialy if your pulling the trans with it.mm
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DON'T DO IT!!!!
NEVER try to lift a complete engine by the carb studs! Especially if you have an aluminum intake you want to use again...
THINK about it! Those studs are 5/16 inch fine thread studs at best. How much strength do you think those threads have when they're screwed into aluminum? Do you really want to trust your life to lifting 550+ pounds by those puny studs? What if it falls on your header panel or core support? Better safe than sorry!!!!
Take out a couple of your intake manifold bolts (again, only if they are screwed into IRON heads!) don't use your intake bolts, but some spare longer grade 5 or above bolts through the lift chain links and then tighten them down tight. Only then should you attempt to lift the engine!
Better yet is to use a couple of the bolt holes on the ends of the heads, and not touching your intake bolts at all. That way you are lifting in shear with the bolt, and not just by the strength of the threads.
What happened to your engine's factory lift plates? You know, the ones that were attached to your exhaust manifolds? Yeah, I threw mine away, too!
Save a pair next time so you can install them to lift your engine when the time comes!
NEVER try to lift a complete engine by the carb studs! Especially if you have an aluminum intake you want to use again...
THINK about it! Those studs are 5/16 inch fine thread studs at best. How much strength do you think those threads have when they're screwed into aluminum? Do you really want to trust your life to lifting 550+ pounds by those puny studs? What if it falls on your header panel or core support? Better safe than sorry!!!!
Take out a couple of your intake manifold bolts (again, only if they are screwed into IRON heads!) don't use your intake bolts, but some spare longer grade 5 or above bolts through the lift chain links and then tighten them down tight. Only then should you attempt to lift the engine!
Better yet is to use a couple of the bolt holes on the ends of the heads, and not touching your intake bolts at all. That way you are lifting in shear with the bolt, and not just by the strength of the threads.
What happened to your engine's factory lift plates? You know, the ones that were attached to your exhaust manifolds? Yeah, I threw mine away, too!
Save a pair next time so you can install them to lift your engine when the time comes!
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Cougarcj, been there and done that many, many times. NO problems EVER lifting from the carb flange on aluminum manifolds. Add up the size of 4 5/16" bolts. Over 1" of steel to lift 500 lbs. If you buy one of those lift plates there are no instructions telling you not to use on a aluminum manifold. Why is that? Because its purfectly safe to do that way. By the way fine threads hold more than course threads thats why you usally find them in high stress situations. Rod bolts for instance. I also said to use full length bolts through the plate to make sure you use all available threads.mm
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Carb studs vs rod bolts
Not really a fair comparison. Rod bolts are Grade 8 or 185,000psi strength, and are steel bolt and steel nut, being used to compress the rod and cap. The carb studs are Grade 2, are just screwed into the aluminum and lifting just by the threads in aluminum. Even if you are using better bolts in place of the carb studs, say Grade 5 or better, you are still just lifting by the threads. With how easy it is to strip threads out just with normal use, I really don't feel safe lifting 550 pounds by them. I could go on about the tensile strength of the bolts and studs, and the shear modulus of the average aluminum casting, and get technical with engineering equations, but that would really serve no purpose.
The four 5/16" bolts, by the time you take into account the depth of the threads into that diameter, are more like 1/4" in cross section. I could go out to the garage and get the exact measurement for you, but I think you get the idea. To say that that is still 'an inch' of material for lifting strength is not accurate at all. the area is Pi x R^2. R is radius of the 1/4" or half the diameter or .125. .125 x .125 x 3.14159 = .049 square inches of cross section area. Multiply that by the four bolts and you have .196 square inches. Yes, that decimal is in the right place. Just under 1/5 square inch. Even that number is assuming that all bolts are carrying an equal load. Now, if you take just one 7/16 bolt, taking its thread root diameter of 1/2" or .500 inch, you have 1/2 diameter is .25. Put that into the formula you have .25 x .25 x 3.14159 = .196 square inches. You can see that lifting with the four 5/16 bolts has the same strength (of the bolts) as one 7/16" bolt. This is, again, just lifting in tension.
Let's just say that there are better, safer ways to lift the engine.
Not really a fair comparison. Rod bolts are Grade 8 or 185,000psi strength, and are steel bolt and steel nut, being used to compress the rod and cap. The carb studs are Grade 2, are just screwed into the aluminum and lifting just by the threads in aluminum. Even if you are using better bolts in place of the carb studs, say Grade 5 or better, you are still just lifting by the threads. With how easy it is to strip threads out just with normal use, I really don't feel safe lifting 550 pounds by them. I could go on about the tensile strength of the bolts and studs, and the shear modulus of the average aluminum casting, and get technical with engineering equations, but that would really serve no purpose.
The four 5/16" bolts, by the time you take into account the depth of the threads into that diameter, are more like 1/4" in cross section. I could go out to the garage and get the exact measurement for you, but I think you get the idea. To say that that is still 'an inch' of material for lifting strength is not accurate at all. the area is Pi x R^2. R is radius of the 1/4" or half the diameter or .125. .125 x .125 x 3.14159 = .049 square inches of cross section area. Multiply that by the four bolts and you have .196 square inches. Yes, that decimal is in the right place. Just under 1/5 square inch. Even that number is assuming that all bolts are carrying an equal load. Now, if you take just one 7/16 bolt, taking its thread root diameter of 1/2" or .500 inch, you have 1/2 diameter is .25. Put that into the formula you have .25 x .25 x 3.14159 = .196 square inches. You can see that lifting with the four 5/16 bolts has the same strength (of the bolts) as one 7/16" bolt. This is, again, just lifting in tension.
Let's just say that there are better, safer ways to lift the engine.
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Whatever. I still stand by my assertion that its safe by my experiances untill some real world experiance shows otherwise. And no matter what, its done every day without fail. mm
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