I have a 31 Chevy 2 door sedan that I am building (build thread to come at some point). I have the front suspension bolted in and now need to notch the cross member for beam clearance. How much space should I leave between the beam and cross member for travel? With no engine installed and the frame holding its own weight, I was thinking 4" minimum distance from the frame to the axle would work, however I am not 100% sure about that number. The front end is a solid axle from a 1952 Chevy half ton truck. I am using stock 1952 springs with two leaves removed. I flipped the axle to sit on top of the springs. I have a 283 and three speed for the engine which is not installed yet to give an idea of engine weight as a factor. See the photo for how it currently sits. This is still work in progress. I need to trim the u bolts a bit but that will come later.
Don't guess. Set an engine/trans in there temporarily or stack the equivalent amount of weight on the frame. Other wise you may be doing it over... BTW, it's great to see you keeping the parallel leaf setup! Looking forward to your build thread.
Right now it seems you have a couple inches of clearance, with no engine or body weight on it. I'd guess you will need a six inch notch through those frame rails. The engine will lower it an inch, the body another inch, and all the rest of the car another inch. How much clearance is left after those three inches are gone? (All measurements are estimates because nobody has exact data for somebody else's project)
I agree with the 3" of settlement once fully assembled, so after that, how much should I expect this to travel...maybe 2" more, then add an additional 1" just in case? So in summary, 6" from current location? That makes sense and seems realistic. I know this is hard to give exact info but I want to open up my plan to others to confirm I am on the right track. It's hard to see in the picture so I added another that is zoomed in. Once I trim the u bolts, I will have 3" clear from the frame to the u bolt. The axle has about 1.5" clear to the cross member. I have some HSS tubing that I will cut the bottom out to make a U shaped member. The plan is to notch the frame 4" and carry that out through the cross member which hangs lower than the bottom of the frame.
I have no answer for your ?. But I wana thank u for posting that pic.... That is almost the same front suspension im going to use on my next buils...following
Thanks. That is good advice. I will need about ten 80lbs bags of concrete for a project soon. I may just set those on a pallet on the frame and see what happens! I almost put a ford front end but changed my mind. I like the look of the front end so far and 1952 Chevy truck parts are very cheap! Good suggestion, thanks. The car sits pretty low which will require more fab work to notch the frame. IMO, stance is an important factor so worth the effort.
If can find a stock '31 (or a dimensional chassis schematic), you could see how the factory did it. Then figure in the weight difference between the original engine/tranny and what you intend to use. Don't forget the bumpstops! Just a thought, Carp.
Good idea. Since my front suspension is from a 1952 Chevy half ton, I thought about maybe following what the factory figured for that truck and running with it. I do plan to run bump stops...not sure which ones though.
That looks like it would need a big notch in a not especially deep frame (your frame looks similar/the same as the one on my '28 Chevy) with the axle on top. Have you thought of using one of Nostalgia Sid's dropped axles with the axle placed back under the spring? then you could use the stock truck bump stops which clamp to the top of the spring and probably wouldn't need a frame notch at all. BTW, I would have thought the SBC motor would be lighter than the Six that lived in there before, the only one (slightly later model year) I've worked on was a real heavy weight definitely heavier than an SBC -on the other hand, the stock three speed trans is very light by modern standards, but the rear end would be seeing some of the weight of a modern trans with it being longer as well as heavier.
Put the axle back under the springs and send the axle out and have it dropped 4", as mentioned above. The heavier axle will take a 4" drop okay, but that would be max and maintain a safe scrub-line. Could also do a 3" drop, and reverse the eyes on the springs...basically have'em re-arched in the other direction.
I am building a 28 Chevy roadster with a 49 Chevy 3100 axle and a 331 Hemi (build thread coming soon). I have 3 inch axle drop by nostalgia Sid and left the axle under the spring like stock. With that heavy motor and no fluids, I have 4 inches of clearance to the frame. I might pull 1 leaf to get a little more drop but going less than 3 inches of clearance is pushing it in my opinion. Obvious statement but check the scrub line going axle over spring.
I sat out to fab the notch yesterday and figured I will switch plans and go for the dropped axle. Did some measuring and the 3" drop with de-arched springs will do the trick and put it where I want it with plenty of clearance between the spring and axle. I set the body on last night and with that front end combo and de-arched rear spring (by 2"), I will be setting perfectly.
@mlagusis, did you get this altogether and if so did you achieve what you were doing without scrub issues...that is if the tire was blown would the rim contact the surface and keep the spring from contacting the ground... Perhaps you put the axle back under the spring as OEM... Share some pics if you don't mind...eye level with axle from the front...and a side shot to show what stance you went with if it's Hamb Friendly of course...
1952 Chevrolet 3100 and 3600 trucks have front springs with 315 lb deflection rates. The compress 1" for every 315 lbs of weight. With a leaf or two removed, you have even less spring rate. https://www.gmheritagecenter.com/do...its/Chevrolet-Trucks/1952-Chevrolet-Truck.pdf page 129 of this document. How would you ever adjust caster angle with the axle above the springs?
Ending up using a 50 1/2 ton truck front axle with the springs on top. Going to send the axle out to get dropped 3" and it should be right where I needed it. The project is on hold as I am working my way through my son's 1950 Chevy fast back and my wife's 51 Jeepster. Should be back on my 31 later this summer. Here is the 31 where I left off. Eli's 1950 is in this thread. here is my wife's 51 Willys with Eli behind the wheel.
I think you need another project to make it an even 4. Looking good! Good find on the Chevy Axle. I know it's sacrilegious but if I were building a Chevy I'd do a Ford front end, transverse leaf and dropped axle.
Hahaha...don't say it. I thought about the Ford axle but have heard good things about running the Chevy set up so figured I will go that route.
I would definitely agree on the latter, couldn't be happier with one of the BEST looking front ends ever under a hot rod!
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