Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > Porsche 911 Technical Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
TedSlick's Avatar
 
Join Date: Apr 2002
Location: So.Cal
Posts: 266
Garage
Quote:
Originally posted by 125shifter
I'll second the comealong idea. Just make sure your rafters can handle it, most can. There should be a lifting lug near the rear of the engine and use the mustache bar at the front to run a chain or strap through so you can lift it level.
Can the rafters handle it? Try a quick calculation as a sanity check?...

The worst place to hang the engine (point load) would be at the center point of the span, so do the calc at that (worst case) point. Formula would be:

PxL/4

P=load (say 500lbs. for a 911 engine)
L=span of joist in inches

For a 20 ft. span (240 inches)...assuming the rafter has no other vertical loads on it:

(500 lb x 240 in)/4 = 120,000/4 = 30,000 in-lb

Divide this result by 'S' value for the joist size:

2x6 = 7.56 cu. in.
2X8 = 13.14
2X10 = 21.39
2x12 = 31.64

For a 2x8 for example: 30,000/13.14 = 2,283 psi (max. bending stress on the joist created by the engine load)

Once this value is known, look at the wood quality to see if it can handle this amount of stress. Assume for a garage rafter you have decent No. 2 wood which has an allowable bending stress of ~1,450 psi. Beam WON'T hold, in theory, since 2,283 > 1,450.

However, if it were a 2x10: 30,000/21.39 = 1,402 psi
Beam WILL hold, in theory, provided there are no other loads on the beam. If you hang the engine closer to either support point, the situation improves as you get closer to the support.

This is likely simplifying your actual conditions, but try it as a sanity check. In my case, my wimpy 2x6x20ft rafters are useless. I do the HF hydraulic cart thing.

Old 01-28-2004, 07:57 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #21 (permalink)
Registered User
I could swear my come-along specifically states not to use it to lifting a load but rather for pulling only.
__________________
Warren & Ron, may you rest in Peace.
Old 01-28-2004, 08:33 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #22 (permalink)
Registered User
 
Join Date: Mar 2001
Location: Geosynchronous orbit over Boulder, CO, USA
Posts: 1,087
Garage
Classic! There is an engine-only jack adapter because the engine+trans unit won't adjust to balance properly with just the engine ? Sorry, I'm not blowing ~$400 (shipping "aint" free!) for both, the +trans one makes sense for installing/removing but if it can't balance the engine alone for what we've been discussing then I guess I have to look elsewhere.
__________________
Charlie Baer
'79 Euro 911SC (Guards Red)
'83 Quattro (Mars Red)
Old 01-28-2004, 08:34 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #23 (permalink)
Registered User
 
cary's Avatar
 
Join Date: Oct 2000
Location: Sherwood, Oregon
Posts: 2,119
When mine was in my regular unfinished garage. I hung the chain hoist from a chain choker wrapped around a 4 * 4. This 10 foot 4 * 4 was spanned across 4 rafters, speading the load. So that put maybe, 150 on each rafter.
__________________
Cary
77 Carrera RS w/3.2 #59
73 914S 2.0 AG
73 914 1.7 Driver ( daily driver, under complete rustoration )
74 914 2.0, 71 914 Tub, 74 914 2.0 Tub + 73 914 donor
Old 01-28-2004, 10:15 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #24 (permalink)
Registered User
Good idea, Cary.
__________________
Warren & Ron, may you rest in Peace.
Old 01-28-2004, 10:37 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #25 (permalink)
KTL KTL is offline
Schleprock
 
KTL's Avatar
 
Join Date: Sep 2000
Location: Frankfort IL USA
Posts: 16,244
I use a collapsible engine hoist/cherry picker. I lift the motor by the lifting loop in the rear and hook up a chain arrangement that connects to the front mustache bar just like it bolts into the car. With an equalizer rig, it's cake to balance a motor or motor and trans.

Hoist stores tightly in the corner of my garage without any problems, taking up little room at all. You can usually pick one of these up cheap (around $200) at a local discount tool store. Comes in handy for other things too. Like lifting huge landscape rocks out of a pickup........
__________________
Kevin L
Present: '86 Carrera, '79 911SC widebody conversion rolling racecar shell
Past: '87 Carrera
Old 01-28-2004, 10:56 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #26 (permalink)
 
Registered User
 
Join Date: Nov 2000
Location: dana point, ca USA
Posts: 863
Garage
Send a message via Yahoo to tmctguer
by the way, cowtown, if a prison GUARD is not available, a prison INMATE will do the trick.
__________________
Rick G.
1973 911E (sold)
1989 911 Speedster (sold)
1993 Beck Spyder
2006 Ford GT (why I sold my Porsches)
Old 01-28-2004, 11:19 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #27 (permalink)
Registered User
 
TedSlick's Avatar
 
Join Date: Apr 2002
Location: So.Cal
Posts: 266
Garage
Cary, that's a great way to do it, spreading the load over rafters, if possible.

Let's see, the 4x4 becomes the beam in that case. If the ceiling joists are spaced 24 in.:

500lbs x 24 in = 12,000 in-lb
divided by 7.15 cu.in. ('S' for 4x4): 12,000/7.15 = 1,680 psi bending stress on the 4x4.

LOL...theory says a cheapo 4x4 might be in jeopardy in that case. I take it you never had a problem...so, perhaps it was a good piece of lumber. Then there's always the diff. between theory and reality
Old 01-28-2004, 11:36 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #28 (permalink)
Registered User
 
cary's Avatar
 
Join Date: Oct 2000
Location: Sherwood, Oregon
Posts: 2,119
Never been an issue. Just a left over pressure treated fence post.

I did the same thing in my new shop. But I bought a 12 footer. So I could hit 5 of them. But there like 2 *14's, that laminated chipboard stuff.

Then I put another eye bolt in the steel girder that I used as a header for the garage door. Just in case I needed to take something out of the back of a truck.

With 11 foot ceilings in the shop I just leave the chain hoist in place.
__________________
Cary
77 Carrera RS w/3.2 #59
73 914S 2.0 AG
73 914 1.7 Driver ( daily driver, under complete rustoration )
74 914 2.0, 71 914 Tub, 74 914 2.0 Tub + 73 914 donor
Old 01-28-2004, 11:45 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #29 (permalink)
Registered User
 
Join Date: May 2002
Location: St Louis
Posts: 4,213
Hey TedSlick

From the facts and figures you have I just assume you know something about it, but how much weight can I hang from trusses made of 2 X 4s? Two car garage, two triangular sections on the outer portions of the truss.
Old 01-28-2004, 11:52 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #30 (permalink)
Registered User
 
Tim Walsh's Avatar
 
Join Date: Sep 2002
Location: Green-Salem, NC
Posts: 3,914
Garage
Send a message via AIM to Tim Walsh
Interesting calculations. There's definitly a decent amount of stress there by hanging the engine like I did. I can't really quantify it but I did know that it wasn't up there for more than 5 minutes and that those rafters held up both sides of this tractor while we replaced the clutch. (it involved splitting the tractor in two)

http://www.fridayparty.org/users/tpwalsh/corellia/jamies/Davestuff/IM001217.JPG
__________________
Tim
1973 911T
2005 VW GTI
"Dave, hit the brakes, but don't look like your htting the brakes...what? I DON'T KNOW, BRAKE CASUAL!!!" dtw's thoughts after nearly rear ending a SHP officer
Old 01-28-2004, 12:06 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #31 (permalink)
Registered User
 
cary's Avatar
 
Join Date: Oct 2000
Location: Sherwood, Oregon
Posts: 2,119
Some of the engineered numbers include the snow load for your area.

I probably wouldn't use mine with 2 feet of wet snow on my roof.
__________________
Cary
77 Carrera RS w/3.2 #59
73 914S 2.0 AG
73 914 1.7 Driver ( daily driver, under complete rustoration )
74 914 2.0, 71 914 Tub, 74 914 2.0 Tub + 73 914 donor
Old 01-28-2004, 12:19 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #32 (permalink)
Registered User
How about sandwiching the 4x4 with a microlam on each side.
__________________
Warren & Ron, may you rest in Peace.
Old 01-28-2004, 12:23 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #33 (permalink)
Registered User
 
ckissick's Avatar
 
Join Date: Jan 2003
Location: the beach
Posts: 4,122
What about this?

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=44006

Sounds great for the price, or are they junk?

Charlie
Old 01-28-2004, 12:34 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #34 (permalink)
Registered User
The problem is you need a place to attach it safely.
__________________
Warren & Ron, may you rest in Peace.
Old 01-28-2004, 12:37 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #35 (permalink)
Registered User
 
ckissick's Avatar
 
Join Date: Jan 2003
Location: the beach
Posts: 4,122
I have a large steel I-beam spanning my garage.

Charlie
Old 01-28-2004, 01:11 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #36 (permalink)
Registered User
 
Randy Webb's Avatar
 
Join Date: Nov 2002
Location: Planet Eugene
Posts: 4,348
"I'm most interested in how to do things "alone""

For general tips there is a carpentry book called working alone or something similar. Be sure to have a cell phone handy -- if something happens that doesn't knock you out or kill you right way...
Old 01-28-2004, 01:16 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #37 (permalink)
Registered User
 
Join Date: Mar 2001
Location: Geosynchronous orbit over Boulder, CO, USA
Posts: 1,087
Garage
As long as you're hanging a beam across your rafters you could nail together some tall chocks to bear the weight on either side of the hoist. If you don't trust the roof frame with the load and are desperate for a solution, that's only a few $ and they sit in the corner until you need them again or use them to build something else.

( bind them to the rafter at the top so they don't slip and let the beam pull down your roof )
__________________
Charlie Baer
'79 Euro 911SC (Guards Red)
'83 Quattro (Mars Red)
Old 01-28-2004, 02:19 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #38 (permalink)
Registered User
 
TedSlick's Avatar
 
Join Date: Apr 2002
Location: So.Cal
Posts: 266
Garage
Quote:
Originally posted by rick-l
...how much weight can I hang from trusses made of 2 X 4s? Two car garage, two triangular sections on the outer portions of the truss.
That simple calc outlined above is for a simple beam (two supports, one on each end) and a simple point load, in this case an engine. Similar to what l33t9eek shows in his pic.

It gets more complicated for beams supported at multiple points and for trusses. The truss calc would involve knowing all the parameters such as span, all dimensions, lumber quality, load on the roof, and the angles involved. So, I couldn't tell ya. I'd guess your 2x4 trusses are not sized to carry significant loads beyond those required by code (incl. snow as Cary mentioned).

If hoisting a large load from your rafters for a quick lift, such as transferring an engine to a stand, consider securing a couple temporary 4x4 posts (vertically) close to where the load is, on either side. In other words, shore it up. That's a safe bet. Closer to the wall (vs. center span) is better also.
Old 01-28-2004, 02:40 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #39 (permalink)
Registered User
 
blue82coupe's Avatar
 
Join Date: Oct 2003
Location: Louisville KY
Posts: 493
HAVE TO AGREE WITH JOHN WALKER ... 2 OR 3 FRIENDS OR NEIGHBORS. DAN

Old 01-28-2004, 03:38 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #40 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 11:19 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2020 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.