Sometimes folks send me questions and they are really easy answer such as, “What color paint was used on a 1918 Model T Ford? But other times the questions fall outside of cars I’ve had the opportunity to study or outside of areas that I am familiar with. I recently receive one of those and would like some help to provide a better answer.
They are building a 1920’s speedster with an OHV setup, Ruckstell rear axle, Rocky Mountain, auxiliary rear brakes. They are in the process of some welding on the frame (extra brackets etc..). He would like to know if it would be advisable to add some cross members (cross-profiles) to stiffen up the frame or should I leave it as is ?
I looked at the Northwest Vintage Speedster Site, but yesterday their technical pages are down at the moment (under construction and will return). [There are a ton of neat race car pictures – many of them T based at: http://www.nwvs.org/lawrence-o-hughie-hughes-auto-racing-photo-collection/ ] But I could not check to see if they said anything about doing anything to strengthen the frame.
I also checked the Tulsa Web Site Tech area – which has a lot of great information but they did not address or if they did I missed it – recommendation for or against strengthening the frame.
I thumbed through the old reliable “Fast Ford Handbook” and “Model T Ford In Speed and Sport” and their frame modifications were mainly focused on lowering the chassis with several methods suggested. As well as shortening the chassis for use on dirt tracks.
And the forum provided some comments about “if” someone boxed the frame – to be sure to not just stop the box area but to spread out the area to avoid causing the frame to crack near the area where the boxed area stopped and the traditional area started [see: http://www.mtfca.com/discus/messages/179374/208391.html and see: By David Stroud on Thursday, March 12, 2009 - 01:25 pm: http://www.mtfca.com/discus/messages/80257/83938.html?1236909218 ]
My limited thoughts are the Model T Frame was designed to support the weight from roadster body to a town car. And many of the after market companies put truck bodies on them. I think in the standard length or shortened they could easily support the power and forces of a light speedster.
And then there was that “Low Bucks” speedster that was restored again and had the truss rod running for and aft on each side of the frame. I believe it was on the cover of one of the magazines with a good article about it. Did the truss rod help the driving or was it more for looks (sort of like putting the metal disks over the wooden wheels)?
I’ve never built a speedster [yet] but I know some of you have. Would you please let us know your thoughts about the usefulness of reinforcing the frame and if it is useful what are some practical ways to do that. Or if you have some good references you could point us to that would be appreciated also.
The photo above was cropped from the Jul-Aug 1986 "Vintage Ford" with Kevin Metcalf driving. Would frame cross members help a speedster perform better?
Thank you all for any help or suggestions you can provide.
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Don't think it would make a lot of difference either way, speedsters are light weight, so extra frame parts just add pounds.
Did one a while back, and did 'stiffen' the frame rails just a tad. As the running board brackets/braces on the later T's or the truss rods on the running board brackets on early T's do add some needed strength when loading the car frame.
So for me, just cut off the running board bracket flush with the side of the frame, but 'spun around backward' the brace bar at the top of the frame and bolted it back to the remaining center part of the running board bracket. Gave a bit more strength when boarding and prevents excess frame twist.
Don't know if this would help or not but we didn't add cross member to frame. We did add shocks at all 4 corners to give it stability. Since we were not trying to be original to the era but make it drive better, we just stuck to lower frame, front axle and shocks. Also added a Vega steering box to steer easier along with 10" removed from length of steering column. All this makes for a nice handling car. I will try to attach a few pictures so you can see results.
Welding a frame has always been taboo in our part of the world, even drilling a frame needs to be done with caution or you can weaken it enough to cause a failure. If you beef up one part of a frame you can weaken another part that has not been touched by transmitting loads to a different place.
I used a cross arm support from a telephone pole.It bolts to holes in frame where gas tank originally mounted,It makes the frame stiffer from side to side when getting in/out of car. The gas tank mounted on top of body. If you didn't know it was there,you wouldn't,cause it doesn't show.
Thank you all for your inputs.
Dan -- the running board bracket doesn't add much weight and is period correct.
Fred -- nice looking speedster.
Gustaf -- some of the links posted above about "boxing the frame" also shared your concern about weakening the part of the frame next to the weld. And I agree if we change one part it can often impact another area.
Jack -- good idea and I like that the telephone pole cross arm doesn't show.
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I have a frame that has the rear crossmember dropped. An additional channel was welded in about 18" in front of it. After looking at it I took the additional channel off. I'm thinking the frame was meant to twist some and that additional crossmember did not allow that. In short, it changed the whole geometry about how things were probably designed to work. I was thinking about the old photo I'd seen of the Model T in a ditch with the front axle twisted one way and the rear twisted the other.
I'm planning on building a speedster. Is it ok to lower the front and leave the back stock? Does that mess with the engine oil level? Lower them both? Is that a better driver? Leave the whole frame stock? What do you recommend? Thank you!
I don't see a problem. In fact I have done something like that. I "dropped" the front axle (bent up the ends about 2"). You are not going to get enough slope in the pan to bother the oiling system.
my first racer (Buck T Special)I used three crossbraces. I moved the engine back 6 inches and there was one brace. the orginal brace was left alone and was used to mount Z brackets to its underside. thats two. the third cross member was bolted to the upper portion of the Z brackets to house the front spring. The Z brackets extended the front suppension/axle out 4 inches. so there was three. i expended the straight shift of the hand crank so it could still be used.
I used the same method Dan Treace suggested. It looks period correct and it adds some rigidity too.