DIY Engine Support


This is my DIY engine support.  The span is around 158 cm for each of the 2x4s.  The wide side of the 2x4 is upright which increases the amount of load the member can take.  The front lift point is going to be in the centre of the span while the back lift point is nearer the passenger side of the car.  I don't really know the tensile strenght of the wood, I think the wood is yellow pipe but maybe not.  I know for sure it is not fir.  While at University, I took a class in statics and dynamics where we calculated load distributions in beams and load deformations etc.  Dan, what is your opinion here since you are the mechanical engineer?  The engine is roughly 400lbs/182kg.

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  •  SecretCorners: 

    Here is the updated engine support.  Much like the original but I added yellow pine to the front and rear and added the corner bracing.  I am confident that the support will keep the engine supported while I have to work under the car removing the tranny.


     129 days ago 
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  •  SecretCorners: 

    I am going to get some yellow pine and add to the front and back of the support and put in some corner bracing as well.  Found a table for wood strengths.  Yellow pine has a bending strength of 14,500 psi and a compressive strength of 8,470 psi.  See:

     130 days ago 
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  •  Midianlord: 

    I knew you'd find a way :)

    Another reason I like early-80s and older cars: Sooooooo much easier to work on, for the most part. Although parts can be much harder to source, as so much simply isn't being made anymore;

    As well, it would seem that the days of a parts-counter person actually knowing cars --or Gods forbid, what to do with a prior-year parts-book-- are done forever.


    Um, maybe you should put some weight on top of that --or better yet, bolt it down to the car (shock-towers, maybe?) so pulling off-axis doesn't just flip the whole thing up and drop the weight onto your head?

    A general figure I've been able to find for most woods' ultimate tensile strength is roughly 5800 pounds/in^2.

    Broadly, that's more than enough, but how is the engine to be supported from the bottom?

    Picture the whole structure like a box-girder/space frame which the bottom (K-frame/engine crossmember, or whatever GM cars of that era call it) is also at least a semi-stressed load bearing member (which it is as the car normally drives, corners, transits bumps, etc.).

    I'd X-brace that thing as much as I could. 2 depending from the centre-front at 45 degrees to the back corners (IE from centre on the car's grille-side, "back" being the bulkhead) with one from the apex of this "V" going straight from front to back, and another diagonal brace from front corners going the opposite way.

    I assumed the Modulus of Elasticity to be around 1,000,000psi (Red Cedar, the lowest value I've found) and your figures, the load will be --very roughly-- 80-ish psi at any given point, with minimal deflection. So the wood should support it, but here's why I advocated the bracings (Oh, and because my Statics and Materials-strength classes were forever and a day ago now Frown):

    Wood doesn't have a lot of "give" to it, and a sudden shock load for whatever reason can dangerously over-stress (IE, past the point of elasticity) weaken things --my idea is to spread that potential shock over as much "area" as possible.

    Get out from under fast if you start hearing any ominous wood-creaking sounds, and stay out.

    Are you sure you can't rent an A-frame? They are made for just this sort of thing, and cn't be that expensive (if you keep rental time down to a weekend or so). Definitely rent a trans-jack if at all possible, though.

     131 days ago·1 replies1 replies 
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    •  SecretCorners: 

      Thanks Dan, I appreciate your input.  Yes, I am not so sure about being under the car.  I am getting strapped for money on this project.  I spent $60 yesterday for two complete strut assembly; coil spring and all because I have done 99% of the work to replace them and they are worn out on the car.  I paid less for a complete unit than Rock Auto wanted for just the strut so it was a good buy.  Then tonight I just spent $79.95 for a complete solenoid set because the old ones are 19 years old and you have to pull the trans if any go bad.  I almost talked myself out of buying them but I don't want to be pulling the trans again in a few months because one of these old solenoid failed.

      I might double up on the long 2x4s; that should provide the strength I need; better safe than smashed under an engine.  I will be leaving the dog bone engine mount in place at the front of the engine, so that will be supporting some of the weight as well.  I will add the corner bracing as you suggested.  I do need to have room to access bolts, but that is mainly at the rear of the engine where it is bolted to the tranny.  Looks like I might be removing the power steering unit or at least disconnect and hang it out of the way to get to that "hidden" bolt.

       130 days ago·1 replies1 replies 
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      •  Midianlord: 

        Take it with a grain of salt, my MET training is now long lapsed (graduating into the 2008 Depression plus...that woman...completely destroying my motivation didn't help any.), but there are numerous calculators on line for this sort of thing.

        Thank Dog, so I didn't have to dig up my old coursework. (My trusty TI-84+ graphics calculator still works a treat, though.)

        Ugh, those "hidden" bolts. Seems like every GM car made after around 1975 has at least one.

        I know you're "committed" at this point in time, but once you get that thing going again, maybe look to saving up for something newer/better (I strongly recommend  early-80s to mid-90s Hondas or Toyotas that have been looked after --they just refuse to die, unless it's from rust.)?

        It's been my experience that American cars don't age at all well, and after a certain point you either just have to keep throwing money into them to keep them barely running, or just do a full restoration.

        Garbage Mobiles are the epitome of good old, all-American disposable planned obsolescence

         129 days ago·1 replies1 replies 
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        •  SecretCorners: 

          GM use to be top notch cars although Dad was a Ford man.  I finally saw the hidden bolt by peeking pass the oil filter housing and a bracket on the trans.  So I am going to attempt removal.

           129 days ago·1 replies1 replies 
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          •  Midianlord: 

            Always a Mopar guy, me.

            The first car my parents got when they came to North America was this '72 Plymouth, and it just wouldn't quit. On the --verty few-- occaisions it did, my late, un-lamented old dad got 'er going with hand-tools and occasional "creative re-purposing."

            Example: Block-coolant frozen, and oil turned to tar because it's parked outside when it's -40 C with no block-heater?

            No problem: Just get a cardboard sheet under the engine, and on that, place a hair dryer (on low/medium speed) between two pieces of wood to aim it up and wait a bit. Then take off the HT lead from the coil, spin it over without ignition for a bit, put the HT lead back on ---> She lights off like it's just been parked in summer!

            Now, you'd think this could work on any car --the fluids, metals, and their properties haven't changed all that much-- but I've tried it on more modern iron, and it just wouldn't light, even after spinning it over became much easier from the fluids being warmed for some reason. It only (mid-80s Chevy Cavalier. Worst. Car. Ever. Made.) lit once I blew a half-litre of ether down the intake pipe.

            The Plymouth never once needed ether whilst we had it, yet more modern cars I've had have, a lot...of the stuff.

            Aside from rust (old Chrysler products rust horribly, but what wouldn't in Montreal and/or Calgary winters?), that thing proved reliable till the day my father sold it.

            All that, and classic Mopars just have this cool, brooding, "don't fuck with me" style and personality that's completely their own, that no other American cars (possible exception: Certain Fords) have ever managed.

             129 days ago 
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Posted: 14.07.2017
Comments: 7
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DIY Engine Support