40 Ply front frame crossmember thoughts

[40plyguy]

Thinking of my on again off again project 40 Ply 2 dr sedan again. Anyway the front crossmember on the frame is rustedbadly on the bottom and rust is creeping up the sides to the top of it. The rest of the frame is fine. a couple years back when I removed the eng and front end I thought just the bottom of the crossmember was bad and was planning on making a new lower piece out of steel stock and bolting it in place. looking at it more recently I've discovered the damage is more severe.  I've found a possible source for a rust free front crossmember. I'm thinking of getting the crossmember with about 2 ft of the frame rail on each side. Any thoughts on how far back on the frame rail to make a splice between the old and new pieces. Any ideas or thoughts would be appreciated. Thanks in advance.

[kencombs]

Without a pic I can't be sure.  But, my kneejerk reaction is don't cut  the rails.  Just separate the crossmembers and insert the replacement.  Much less likely to become misaligned in the process that way.

[sidevalvepete]

Hd the same issue. Sandblasting revealed the extent. Put in whole new crossmember.

[blucarsdn]

Been there, done that...
The front cross-member and spring towers on my '38 P8 conv was in terrible shape having suffered many years of a being driven over Montana unimproved roads. After much research I came to the conclusion that the best fix was to upgrade the chassis to a more modern disk brake, rack-pinion front clip. I chose a FatMan setup because they are the only company that makes components for the DPCD vehicles. Everything fit together perfectly, most people would never know the upgrade had been done.

A word or two of caution.. Make sure your chassis is square/parallel.. I have done four vehicles in the past fifteen years, in all four of the vehicles we found that the chassis were out of square/parallel when checked prior to doing any fabrication, welding. Wm.

[40plyguy]

Thanks for the replies. Wondering if after doing the Fatman conversion you still used the flattie engine? Thanks again.

[Andydodge]

My Oz 1940 Dodge is Plymouth based so I know the frame of which you speak & installing an aftermarket front end in one of these is a much more involved job than the semi elyptic sprung cars due to the complex shape of the front crossmember.............ideally if you could find a non rusted front crossmember then it maybe possible to remove your one and replace it with a non rusty version but its a LOT of work........same goes for the replacement at the frame rails, its a lot of work and your welding skills have to be 100%.............in some respects it maybe easier overall to find a complete chassis anyway as you will be looking for one to chop up and once found why not just swap the whole frame over........still a LOt of work but at least you know that it is straight and square...............anyway, Welcome Aboard if I haven't already said so..............Andy Douglas     

[blucarsdn]

22 hours ago, 40plyguy said:

Thanks for the replies. Wondering if after doing the Fatman conversion you still used the flattie engine? Thanks again.

Regardless of what you do to the chassis has no bearing on what kind of a power train you use. In my case I like vehicles that run well and are safe. To that end, I used a modern V8 engine, AOD transmission, PS, PB and AC. However, there is no change from the stock '39 Plym appearance. Wm.

[kencombs]

3 hours ago, blucarsdn said:

Regardless of what you do to the chassis has no bearing on what kind of a power train you use.

 

That is true, but it does complicate things somewhat.  If the front crossmember is changed, or removed, with the fatman mod, the front engine mounts are gone also.  And the front mounting method for the Mopar flatheads is sort of unique.  Will require custom fab work.    Replacing the front crossmember with a good stock unit is easier, IMO.

[blucarsdn]

You are assuming that a good serviceable front cross member can be harvested from a chassis, then once the cross member is installed you still have the problem (s) of dealing with the rest of the 80 + year old suspension, brakes, etc.

I looked into the whole picture of what was involved, going with the FatMan front clip gave me all new components, I specified the engine I was going to be using, everything bolted right onto the FatMan clip like it was factory. If you try to go cheap, you get what you paid for.
A friend of mine that feel in love with my 39 Conv bought one, he thought the FM was to expensive, bought a brand X, which turned out to be one size fits all for a Ford. The net result was a first class mess.

We are in the process of finishing up a chassis modernization for a '37 GMC. We used a unit from TCI to convert to independent, coil overs, disk brakes and a power rack. The TCI did not require cutting the frame rails, however, the frame had to be boxed, the metal to do this came with the kit. The engine in the truck is going to be a newer version of the Chevy OHV 6 cyln in lieu of the original 230 CID 6 cyln FH Olds. GMC did not come out with their OHV 6 until '39. Wm,

[40plyguy]

I already got a modern daily driver. So i want to keep the 40 closer to what it was in the 40's if you know what I mean. I know I have to redo brakes and suspension. That's not a problem I can't justify moving forward with that stuff til I have the frame issue resolved. unfortunately the crossmember isn't just riveted in place. It looks like the frame rails would need to be spread apart or one frame rail removed befor the new crossmember could be installed then put the other rail in place and weld everything back together again keeping everything aligned.  The pictures below may help a little. At this point hoping to find a whole  frame . Thanks much for the input.

[Young Ed]

Not sure what's left of it now but a couple summers ago french lake had a great looking 40 4 door

[40plyguy]

Tks Young Ed. I’ll contact them. Any possible lead is worth pursuing.

[Lloyd]

On 12/5/2020 at 1:16 PM, kencombs said:

Without a pic I can't be sure.  But, my kneejerk reaction is don't cut  the rails.  Just separate the crossmembers and insert the replacement.  Much less likely to become misaligned in the process that way.

 

Be my concern as well. But looking at your pics it does look like you would have to cut a rail or spread them to get the donor in place, if you went from rail to rail. Perhaps leave just the ends of the crossmember in the rails then cut the donor to fit in between? At least enough to get rid of worse part. If any is left you might be able to cut and patch.

[Knaveofdarts]

I am looking at doing something similar. My '50 front frame is so rotted out the the drivers side lower control arm is bolted to almost nothing.

 

French Lake cut a whole frame from the rear of the fenders forward and shipped it to me on a pallet. I will probably have to upgrade my welder to do the job, but for now I bought a plasma cutter and will start learning how to use it.

 

 

 

Edited December 21, 2020 by Knaveofdarts
added picture

[40plyguy]

Sounds like they may be helping me as well. Planning on picking up a complete frame from them. Never heard of French lakes auto til Young Ed chimed in. Thank you, thank you, thank you....

[Sniper]

lol, my core 230 I mentioned in another thread is coming from French Lake too. 

[Andydodge]

If you end up getting a complete frame then I would definately suggest just doing a complete swap over.........the amount of work by the time you finished will be about the same and by using a complete frame, so long as its straight then everything should just bolt up, yeh, still a big job but you can clean and tidy up the new frame before starting, then as you unbolt everything from the old frame then you can at the very least clean/refresh those pieces before attachment and you'll have a nice "new" car..........and whilst its good to improve or gain new welding skills, learning and/or practicing on a car frame is to me not the best way to learn, especially since its the original project cars frame.............for me.......I'd just do the frame swap.............andyd 

[Young Ed]

You guys are going to suck up all the parts before I get out there again!

[40plyguy]

There’ll be a couple nuts and bolts left for you. Lol!