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#1 |
Registered User
Join Date: Dec 2009
Location: edmonton ab
Posts: 73
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Blazer 4x4 flexing
I am building a 72 blazer on 37 inch tires. From past experience i find the doors dont close properly after a good day in the mud and trails. How do i stop this from happening? Do i stiffen the frame or body?
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formerly cooter |
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#2 |
Registered User
Join Date: Sep 2007
Location: Rolla Mo.
Posts: 667
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Re: Blazer 4x4 flexing
Top on or off makes a big difference, also are the torsion boxes/rocker boxes good and solid?
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"85" Monte Carlo SS "71" K5 (SOLD) "64" Chevelle 1930 Chevy two door rat |
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#3 |
Registered User
Join Date: Dec 2009
Location: edmonton ab
Posts: 73
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Re: Blazer 4x4 flexing
torsoin boxes and rockers are perfect, want to prevent damage to the body with the top off.
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formerly cooter |
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#4 |
Registered User
Join Date: Mar 2011
Location: Corcoran
Posts: 32
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Re: Blazer 4x4 flexing
I would love to here more opinions on this subject.
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#5 |
Registered User
Join Date: Mar 2007
Location: Oakland, Ca
Posts: 1,382
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Re: Blazer 4x4 flexing
Boxed frame rails and a full cage would be the way to minimize the flex.
But let's be honest here - it's a convertible, and you're likely never going to eliminate it. |
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#6 |
toys'r'us
Join Date: Nov 2010
Location: Penticton, BC, Canada
Posts: 347
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Re: Blazer 4x4 flexing
Are you running a body lift?
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71 jimmy bone stock 350 sm465 33x12.5 rallies 79 caprice landau full load crate350 th350 lowered 20"wires 00 f150 reg cab sb 4x4 5.4L |
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#7 |
Registered User
Join Date: Dec 2009
Location: edmonton ab
Posts: 73
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Re: Blazer 4x4 flexing
3 inch body lift. Does the body flex and bend in the floor when the doors dont close properly? Has anyone else had this happen?
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formerly cooter |
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#8 |
Senior Member
![]() Join Date: Oct 2006
Location: Wichita, Kansas
Posts: 1,050
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Re: Blazer 4x4 flexing
The body is flexing in the door opening area because there is very little stiffness to resist it. You only have the floor and the rocker/torsion boxes to stop the flexing. And they're not really that effective since they are pretty close to the neutral axis of the cross section. That's why in the 2nd gen Blazers 1976+, they incorporated the upper part of the cab because it stiffens up the door opening cross section. Since the upper part of the cab is quite a ways from the NA of the cross section, it is very effective in reacting the bending moment across the door opening.
One way to stiffen the tub is to tie in a full cage from behind the door opening to in front of the door opening into the floor and firewall. I've also seen some take out the torsion boxes and build in truss type stiffening members in their place that are more effective than just the sheetmetal boxes. As mentioned, boxing the frame will also stiffen things up. |
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#9 |
Registered User
Join Date: Feb 2000
Location: Modesto, CA
Posts: 1,842
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Re: Blazer 4x4 flexing
My door open when flexing sometimes. Also If I try to open my door when flexed, my door is usualy jammed shut...my body flexes all over the place but it's still in one piece
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1972 K5 MPFI454/Sm465/Np205/D60/14FFd/Re-Centerd H1s w/Swamper Iroks ![]() |
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#10 | |
Senior Member
![]() Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,912
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Re: Blazer 4x4 flexing
Quote:
Still, you are correct that the added metal increases the stiffness in that part of the cab. But what fun is a Blazer if you can't see the sky above you? (Unless that sky is full of cold, white flakes, of course). |
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#11 |
Registered User
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 2,396
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Re: Blazer 4x4 flexing
I like the box frame idea.
If you could do sections of it so as to minimize difficulty in working on anything inside the frame (aka: fuel lines, clips, brackets) Then I wonder if boxing the frame would still be somewhat beneficial? Hmmm. |
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#12 | |
Senior Member
![]() Join Date: Oct 2006
Location: Wichita, Kansas
Posts: 1,050
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Re: Blazer 4x4 flexing
Quote:
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#13 |
Registered User
Join Date: Mar 2009
Location: Idaho
Posts: 111
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Re: Blazer 4x4 flexing
I haven't been on any tough trails in my k/5 yet but i can tell you from experience that the body will flex considerably with the top off, even on paved roads. It's way harder to get the top on than it is to get off because of this. So i'd imagine with the top off the flex will be even worse on a trail.
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1972 k/5 Blazer 350V8/TH350/NP205 "The Ox" ![]() |
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#14 |
toys'r'us
Join Date: Nov 2010
Location: Penticton, BC, Canada
Posts: 347
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Re: Blazer 4x4 flexing
I know its often nescesary for tire clearance, but I dont like body lifts on suv's. When flexing it multiplys the stress on the body. The side twisted to the right is 3" further from the axis, as is the left. If you are doing this to a 40 year old suv with no roof and want no body damage i think your going to need to remove the doors, or the body.
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71 jimmy bone stock 350 sm465 33x12.5 rallies 79 caprice landau full load crate350 th350 lowered 20"wires 00 f150 reg cab sb 4x4 5.4L |
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#15 | |
Registered User
Join Date: Feb 2000
Location: Modesto, CA
Posts: 1,842
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Re: Blazer 4x4 flexing
Quote:
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1972 K5 MPFI454/Sm465/Np205/D60/14FFd/Re-Centerd H1s w/Swamper Iroks ![]() |
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#16 |
Registered User
Join Date: Dec 2009
Location: edmonton ab
Posts: 73
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Re: Blazer 4x4 flexing
thanx for all the replies, i dont intend to beat this blazer to death but want to keep it looking good. i figure the 8 inch lift will allow the leaf springs to flex more, box the frame and stiffen the torque boxes and we will be good to go.
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formerly cooter |
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#17 |
Registered User
Join Date: Mar 2007
Location: Oakland, Ca
Posts: 1,382
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Re: Blazer 4x4 flexing
Did you say 8" leafs and flex in the same sentence?
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#18 |
Registered User
Join Date: Sep 2005
Location: Bay City, MI
Posts: 128
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Re: Blazer 4x4 flexing
So did you box your frame?
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#19 |
Registered User
Join Date: May 2000
Location: Petrolia,Ontario,Canada but working in Port Huron,Mi.
Posts: 1,771
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Re: Blazer 4x4 flexing
My 71 has stock suspension with solid torsion boxes.
In this shot you don't see too much body flex. Bottom corners of the door is out a little but I opened + then closed the driver's door to get out the truck to take this shot. Solid (rust free) torsion box's are a key in my opinion. ![]() ![]() .
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71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE |
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