Discussion in 'Builds and Fabricators Forum' started by FinoCJ, Aug 10, 2019.
This is how I did mine.
Think this is as good as the cross-member is going to get....
Added a vertical rib to help stiffen in that direction - tried to extend it a couple inches beyond the cut-out to distribute the stress away from the cut-out corners. Used mostly plug welds through the vertical face to weld it in place...haven't decided if I should add more to the top seam.
Added in the horizontal section - I extended this as well beyond the cut-out - had to leave a small notch for a nut access for the parking brake lever mount:
Fought getting all the holes to line up - but with enough cussing and swearing it seems to all go together:
Put 1/2" spacers under the D18 side mount to keep everything level:
Using a lot of random/mismatched hardware I have laying around...as soon as it all looks good, it'll get nice new, proper strength and length set with correct washers etc...I think I might open the bottom holes in the crossmember up just another bit size to make installation a bit easier. Also thinking about using some button head bolts for the upper isolator mount to create a bit more clearance with the top of the cross-member.
For the motor mounts, I have two options for how the mounts work - they end up in the same place in terms of engine placement etc, just slightly different geometry.
I like this one where the mount is higher (compared to the frame rail) as it raises the bottom horizontal brace a bit to help with clearing stuff like steering shaft, but the trade-off is the brace mounts kind of high in comparison to the frame rail - in other words, I wonder if it will put too much stress or leverage on my questionable welds? Keep in mind that the frame rails are curving downward towards the rear at this point, so the front edge of the bracket sticks up about 1/2" above the frame rail, its quite a bit more in the rear (a full inch at least).
The passenger side here has the lower mount geometry, and I like that the mount will be more directly matched to the frame rail where the plug welds will be on the bracket - seems a bit stronger, but I my general inclination is always to keep things 'tucked up' as much as possible. Its not like the horizontal brace is lower than the oil pan or anything, so maybe it doesn't matter.
Again, both of these positions create the exact same engine placement (there is both a high and low position on the engine side and on the frame rail side) - its just a matter of which arrangement to use with the bracket mounts for clearance and what not.
Not that it matters but I like it the way you have it right now, high on one side to clear steering (always an issue) and low on the other side for strength. Does either mounting cause issue with exhaust?
Looks good to me!
Weld er to the frame and tighten the brackets as is if you find you need driveshaft clearance or a steady block for the steering shaft you can still adjust. Then once you go around the block a few times and feel right you can weld the mounts solid.
Not that I can tell...the higher mount maybe makes accessing the flange/bolts between the pipe and header collector a bit easier, but in terms of routing the exhaust, all of this is in front of the exhaust pipe routing. The bigger issue will be routing the passenger side exhaust around the starter and front driveshaft and then getting it across to 'y' with the driver side somewhere under the bellhousing or right behind the oil pan. Here is the passenger side with the 'low' mount position.
Here is a different view of the driver side mount with the high position...shows better how the bracket will mount to the frame - it will pretty much be in this position whether its the high or low mount. This also shows better how with the high mount, it will have more leverage on the top of the bracket above the frame. Definitely would be better for this side to stay high for the steering shaft to go under more easily and have a bit more flexibility with how that will work. In the pic, the steering shaft isn't in place - its just resting on top of the MC - it will be a bit higher when all is said and done.
Can you take advantage of the bottom hole on the braket? By welding a brace to the bottom of the removable mount and bolting it trough the botton hole you could put the stress lower on the frame rail.
Not sure....but you did give me the idea that maybe I could weld a little angle iron on top of the frame rail and then weld the vertical piece against the backside of the motor mount brackets to help re-enforce the top edge....Also, while the frame rail brackets are rectangular in shape, the pre-drilled holes for plug welding to the inside of the frame rails are NOT evenly/symmetrically distributed, and thus which end is placed up or down affects how many of the holes are set-up over the inside of the frame rails. In other words, its kind of like they were designed with it in mind that one end would either stick and inch or so above or below the frame rail, and has no holes to keep it a bit stronger, and the other end has the holes to make it easier to weld.
FWIW - its looking like I am going to go with the engine mounts in the higher bolt holes on the frame rail bracket side, and this allows me to use the mounts on the engine block side that are 'lower' in terms of engine height. If at some later point I need to raise the engine up a bit for clearance say with the starter and driveshaft, then moving the engine block mounts will raise the engine just over an inch...If I need more than that, then I've really screwed up, will probably have hood clearance issues and I'll probably accidentally forget to set the parking brake, and without big john around, it will roll off a really large cliff and possibly explode into flames before even hitting the ground....Plus I do like the extra clearance under the horizontal portion of the mount, and it will help provide a bit more flexibility with regard to the steering shaft.
Its getting close...don't want to celebrate yet as I still need to check front driveshaft-starter clearance and figure out battery mount, but....after taking jen out for a surprisingly nice cocktail and tapas on Sat night, hot springs and motel, then mtbing this morning, I got her to help me out for the afternoon/evening in the garage. The engine and drivetrain is sitting on the frame mounts and cross-member mount under its own weight. Everything in the engine bay looks good. Hood clearance is not an issue, but its hard to get the engine higher due to the large sm465/D18 combo hitting the floorpans...hopefully this is it:
I really like the clearance in the rear with the firewall, distributor and wiper motor....air cleaner is maybe a bit tight with the wiper motor, but its not as bad as it looks, and can probably change that pretty easily to a slightly smaller diameter or 2 inch thick filter instead of 3" thick.
The OEM battery location was driver side firewall - not sure if it doesn't fit with the wider v8 as compared to the L6-226, but the PO moved it to the front passenger fender (the v8 starter is on the passenger side), and it had a poorly designed mount that was bolted to both the body and welded to the frame....need to figure out if it can go back to the firewall (although that is where I put the brake reservoirs for the MC)....or if I can figure out a better mount on the passenger front and make a bracket - maybe something like a FF that attaches to the frame and front cross-member? Its part of why I used a high center alternator mount to leave some clearance for the battery (and maybe an A/C compressor for vintage air one day).
Okay...the driveshaft to bellhousing starter mount was making me nervous....it has about 2.5" of clearance.
Let's see if this makes sense....If the distance from the center of the axle/pumpkin to the D18 u-joint (fixed end) is 36 inches, and the potential point of interference between the driveshaft and bellhousing is 1/3 the distance from the D18 to the axle (12" from the D18, 24" to the axle), then that means the axle end of the driveshaft would have to come up 3x as much (or 7.5") for the driveshaft to hit the bellhousing. On top of that, the portion of the axle that would have to come up 7.5" is the center of the pumpkin, which is some 20" or so from the wms. In other words, the tire/wheel will have to stuff up quite a bit more than 7.5" to move the axle pumpkin up that much. Its hard to identify a fixed pivot point on the solid front axle, but if we take a worst case scenario and assume the driver side end of the axle is fixed pivot point, and total axle length is 57 or so inches, then the pumpkin is about 2/3 of the way to the passenger side, which would require over 11 inches of upward movement at the wms to create 7.5 inches of movement at the pumpkin. And most of the time on a solid axle, the opposite will be drooping, which moves the pivot point more to the center of the axle, and helps the situation even more.....Plus, if the wheel moves up 11", my fenders will be destroyed...in other words, I think its good...Of course, because I am in just over 1 year removed from my physics teaching career and in a bit of withdrawal, if the driveshaft were to hit the bellhousing, it would hit it with 3 times the force exerted at the pumpkin end (in other words, a solid bumpstop to limit up travel and protect the starter is still a really good idea!).
Time to pull stuff and get the engine to the machine shop and finish up some detail work in the engine bay...
I think you’re being mighty optimistic with the expectations of your springs. You might get 5” of loaded up-travel out of your leaf springs before they start passing their point of no return, 6 if you’re lucky. Continued use in that range will fatigue them in short order.
Limit your axle’s up-travel to 3-4” with bump stops when the ride hight is established and don’t look back.
that is my point....I am not expecting 11 inches of travel, just that it would take 11" of wheel travel to cause the driveshaft to hit the bellhousing, and since 11" of wheel travel isn't going to happen, the clearance I have with driveshaft to bellhousing is sufficient...and the force comment was just a snarky way to say that bump stops is the way to ensure no problems even if I was concerned about the clearance...
Truly, the experience was about doing the back of the envelope physics problems. It was also fun to look at what adding 3 degree caster shims would do...3 degrees with a pinion arm of about 12 inches would drop the pinion ujoint about 0.6" (love me some trig), thus providing close to another 0.25" of clearance at the bellhousing, which is a 10% increase and not insignificant if it were needed. Of course it may happen for reasons unrelated to clearance, but rather steering improvement. Building **** can be misery, but calculating stuff can be a fun diversion for me to enjoy the build process more, and yes, I did ignore measurement accuracy and propagation of error through the calculations, in other words, no sig figs.
PS - if people think I am getting too obnoxious, fair, just say so...the fun of this project left quite awhile ago, so I am truly trying to find ways to stay interested and engaged and motivated to see it through. Some of that is releasing the frustration through writing and posting about it here.
Your thread your stress relief, have you read the first 12 years of my "build"
I'm still enjoying it, carry on!
Things have a way of escalating...
A little nip tuck on the belly?
no, just doing a bunch of re-wiring...I just wanted to moved the ignition switch from the column to the OEM dash location. My plan was just to cut and transfer 5 wires from one the old GM column harness to the the old style 4 terminal dash switch. Of course, that also meant I should work on replacing the ammeter with voltmeter - well, actually, the entire tri-gauge cluster will get replaced - and of course found some other odd things that needed cleaning up (Fan switch wire was spliced into something to gain power (hazard lights I think), got some stuff that should be on ACC that are on BAT etc, so just keep finding more stuff to pull apart. But this is way easier with the seats and column removed...oh, that's right, the column has been removed because its getting replaced since finding the right ujoint couplers with longer steering shaft etc was more expensive that just buying all new...plus this way I get to replace the rag joint with a ujoint at the box....most of it was inevitable anyway...At some point I want to stop taking stuff apart, and want to start putting stuff back together. Actually, the wiring is pretty straight forward to me, and I find it rewarding to get all the guages and lights working. Access up under the dash is usually the hard part - so its usually just better to pull stuff apart to get easy access, then put it all back together. Just taking advantage of having stuff pulled apart. Also a good time for fixing up the windshield defroster ducts and wiper cable system.
If you get yours figured out you can come do mine!
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