47-54 ifs measurement

[whitedog76]

Does anyone have the measurement from the bottom of the frame to the top of the crossmember on a M2 setup? I'm looking into a M2 setup and trying go figure out if I'll have any clearance issues. (I have a front sump oil pan).

[dsraven]

there seems to be a few of them on here but not sure if they have a front sump pan or not. have you checked the build threads? what engine are you using?

if going MII, will you be using a put together system where the cross member is integral with the lower control arm pivot but not the upper? after doing one like that in a 57 chevy I would advise to invest in a cross member that has the upper and lower control arm pivots already welded onto the cross member. there is no guess work to be done as far as dimension between the two pivot points and also the angle of the upper control arm pivot for antidive geometry. that would all be engineered in when the cross member was built. you may want to check out the scotts hotrods front end for a view of what I am talking about. I bought a kit for my 57 and the cross member was not the right fit for the frame, angle wise fore to aft. after some trimming to fit, the upper control arm pivot ended up to be not in the right geometry anymore as well as the antidive angle was not correct. I figured it out as far as anti dive angle and the angle of the upper control arm compared to the lower (this affects the tire angle as the vehicle goes over a bump) but it was no picnic and definitely not a weekend job. research heidts site for a write up on proper MII geometry so you don't end up with bump steer or something else dangerous. some cheaper kits use a mish mash of stuff and the steering rack is not shortened to have the inner tie rod pivot correctly. this equals bump steer. better to spend a bit more and get a reputable kit. also I recommend to buy what you want for brake size, springs, ride height etc right away otherwise you spend more in the long run.
see the attached pic from the scott's site. notice the upper control arm pivots are integral to the cross member, the upper control arms are multi adjustable, there is motor mount plates already in place, inner tie rod pivot points are placed correctly to avoid bump steer (inline with upper and lower control arm pivot points), they use coil overs for adjustability of ride height, large sway bar set up and big brand name brakes brakes. if I was going to do it again I would look for a kit similar to this. then it is just a matter of getting the frame square and level, side to side, then getting the rake angle desired. blocking it up well so it can't move unexpectedly, then set the cross member in place and tack it all together. assemble front end and then assemble sheet metal to check wheel fitment in fender wheel openings (with correct tire size for the finished truck). if you like it all then take it apart and finish welding the cross member in place.
just my thoughts.

[dsraven]

the oil pan sump may be modified to fit the end product or a different pan and oil pump pick up may be installed. depending on the engine being used a stock oil pan from another model of vehicle may fit your needs. got a pic of what you have to work with?

[mr48chev]

I would have to think it might vary a bit between the different manufactures. Not a whole lot by any means but some are set to ride higher or lower than others.

I was trying to find the instructions for the "universal" crossmember I have as I believe it does have the measurements. I'll look on my old laptop when I get home.

[whitedog76]

I'm in the thinking stage of my project. I've thrown around a bunch of ideas in my head. Not really settled on anything. I have a Vortec 4200 mounted in my 54. Originally I was going to use the I beam frontend, but same issue. No room for oil pan. I've thought about a chassis swap. But, finding a Long Wheel base Trailblazer/Envoy that isn't wore out isn't easy. Not to mention all the fab work that would be needed to make it work.

As the truck sits right now, the oil pan is on top of the axle. Maybe 1/4" of give.

Most of the kits I've seen look similar in design. I would really like something with more of a stock ride height. I was just trying to see if anyone had some hard numbers.

Regardless of what I do, I know the oil pan will need to be modified. I'm just trying to figure out my best option.

This might give you an idea of what I'm working with. http://s1074.photobucket.com/user/wh...19939271050273 I've had to trim the front crossmember for the oil pan to clear right now.

Chris

[dsraven]

has anybody seen the classic trucks march 2017 edition? it has a write up on installing a motor and trans in a 47-53 chevy truck. the truck has a MII front end. it talks about CPP's products for motor mounts and trans cross member. the trans cross member bolts to the frame flange and the engine mounts are weld on and all adjustable prior to install by cutting to correct length.
anyway, it has some ideas. the engine trans is a small block chevy with a turbo 350 behind it. the concepts are the same for an LS engine if desired. just bear in mind the angles etc so you don't get a drive line vibration.
sorry, nothing about the atlas engine.
I am planning on using the atlas in my 57 but it will incorporate the envoy frame and running gear. hopefully the engine will fit, fore to aft, without too much trouble. shouldda used a 58-59-they are a bit longer out front. there is one done up on here somewhere though, rustymarco's thread. he sold the truck and moved out of country to the homeland.
for your dilemma, do you plan on welding up a new configuration for the pan or moving the engine up or back to miss the cross member or possibly some other option? have you cracked the pan open to see if there is room inside to allow for a pan modification?

[dsraven]

in regards to using an envoy or trailblazer under your truck, I think it would be too wide of a track width unless you want a huge offset wheel or want to run big truck fenders out front.

[dsraven]

just found this, finally, in my docs. does it help you at all?

[whitedog76]

On the axle center line measurements I've been seing. Most everybody states 18 1/8" back from the shackle mount for an IFS setup. If I drop a plumb-bob on my frame to the leaf spring center, I'm actually about 18 3/4. I'm not for sure if that measurement is because the leaf spring will move forward as it compresses or if it has to do with the caster angle.

On Kugels website, they say to move the upper spring hat rearward in order to set up the caster angle. Doing that changes the spindle center line slightly. So the 18 1/8" may be them correcting for caster.

All the manufactures seem to be a little different. Some say to adjust the upper A arm in the slots. I'll just have to see when I get there.

[dsraven]

thanks for the kind words.
the measurement diff may be because the springs are arced and when they compress they lose that and become flat. possibly accounting for the added measure?

[whitedog76]

If they flattened out, they would actually move things forward making the measurement less. There is a 2 degree caster shim between the springs and leaves. That might be issue. Rolling the axle forward, would move the centerline.

[dsraven]

what about using a regular steering box instead of the rack style. maybe clear up some issues with clearing the pan with rack. you would possibly need to find or build a centre link and make a spot for the idler arm. or build something like a 4x4 steering uses with a solid tie rod from wheel to wheel, bent to fit around your pan, then another rod goes from the box pitman arm down to that.
just some thoughts.

[whitedog76]

Hampshire-

What wheel and tire combo are you running? Also, what rearend are you using?

I have 235/70/16s that I'm planning on using in the front and 245/70/16 for the rear.

I traded my cousin for an Explorer 8.8.

[whitedog76]

On a side note, are those solar panels in the background?

[Hampshire]

What wheel and tire combo are you running? Also, what rearend are you using?

My set up is close to yours - I ended up with 235/70 -16 on front and 255/65-16 on back. They are both on 7” wide rims (8” rims were too tight in back) and both are 28.9” tall. The rear is a 3:73 Posi out of a Nova.

The solar rig is an Allsun Tracker by All Earth Renewables. We have 3 buildings and two services - haven't had to pay a bill since it went on-line, 18 months ago.

[whitedog76]

Hampshire

Thanks for all the info. Getting my truck to look s little more like yours is the ultimate goal. One of these days...