Monte Carlo bar

[pcmenten]

I tried a quick search on the forums but didn't find anything about this in my first pass.

Early Mustangs were sometimes fitted with 'Monte Carlo bars' that braced the tops of the shock towers to each other. I have also seen this with the later MGBs. I was looking at posts about suspension, handling, and shocks and it occurred to me that the Sunbeam might benefit from something like this. I realize that the top radiator support is in the vicinity of the shock towers, but I'm wondering if Monte Carlo bars are ever fitted to Sunbeams.

Paul

 

[Barry]

The only reasonable place to put a "Monte Carlo bar" would be between the forward ends of the "cowl braces".

I am pretty sure that the early series Alpines had a connection between the top of the front crossmember and the forward ends of the cowl braces, so a bar between the forward ends of the cowl braces should logically reduce flex in the front suspension.

IIRC, the connection between the top of the front crossmember and the forward ends of the cowl braces was eliminated beginning with the Series IV. Without that connection, I cannot see how a bar between the forward ends of the cowl braces would accomplish much.

As always, there would be the issue of finding room in the Alpine engine bay.

Just my opionion, YMMV.

 

[V6 JOSE]

Since the suspension on the Alpine is directly bolted to the front crossmember, which is very stiff on the Alpine, there isn´t really a need for one. The Mustangs didn´t have this strong front crossmember to which the suspension was bolted. IRRC, the Mustang only had a tube crossmember under the engine, and the suspension was bolted to the body pannels directly, which would flex under hard and constant cornering.

Jose

 

[Gary M]

They are far more commonly used on MacPherson strut style cars as the top of the strut towers flex a lot under cornering. My Ford Taurus SHO had that problem until I installed cross supports. What a difference it made in cornering. I don't see any advantage to doing anything like that on the Alpine. The rear shock mounting points already connect across the body directly, and the fronts are non flexing due to being welded to the stiff front cross member.

 

[MikeH]

Since the suspension on the Alpine is directly bolted to the front crossmember, which is very stiff on the Alpine, there isn´t really a need for one. The Mustangs didn´t have this strong front crossmember to which the suspension was bolted. IRRC, the Mustang only had a tube crossmember under the engine, and the suspension was bolted to the body pannels directly, which would flex under hard and constant cornering.

Jose

That is correct.

 

[pcmenten]

I get the logic being used, but there's a small problem of two braces between the firewall and the front wings. If torsional (relative to the front/back axis of the car) bending forces aren't a problem, why are those braces arranged on an angle instead of straight back? Those braces are arranged exactly like the stock braces in the upper part of Mustang engine compartments.

Me, I'm going to take a close look at the radiator brace to see if it is enough and located in the right place and if I decide not, I'll make a Monte Carlo bar.

On the web forum for Kawasaki Triples, some ambitious person with access to FEA software made a model of the Kawasaki H1/H2 frame, ran simulations on it and then simulated the results of the various frame stiffening techniques developed over the years. The results showed that the mods people were doing were exactly what that bendy frame needed. The software also showed one or two additional locations of potential improvements.

It would be fun to do a FEA on a stock Sunbeam chassis, then look to see what are the areas for improvement and also look to see what is the result of activities like cutting the floor for transmission clearance, or reworking the firewall for V8 (Tiger) engine clearance.

 

[Cactusmasher]

Go for it...should be interesting to find out.

 

[alpine_64]

The front braces were installed to prevent scuttle shake they discovered during pave testing at MIRA . on the early cars they decided to tie them to the suspension but they obviously decided this was not needed as by later cars they no longer did. As for angle I'd say triangulation helped brace the scuttle and if straight they would impact much more on engine bay space if mounting to brace the scuttle

 

[pcmenten]

Scuttle = firewall. I believe what you say when you tell me that the scuttle (firewall) was shaking, but I'm trying to figure out what that means and how that happens. I'll guess it's a matter of the chassis flexing near or at the point of the scuttle/firewall. Something that might show up in an FEA exercise.

There seems to be some free FEA software so maybe, someday I'll load it and see what I can do.

 

[65beam]

bar

the problem of the shake probably came from the alpine being built on the husky platform. the husky was an estate car in the form of a box which gave it strength and when an open body was added something had to be added to strengthen the body. the bulk head braces did the job. rootes had a habit of building a car using a previous design and then solving problems that popped up. the X frame is also an addition that seemed to work well. the only time I have seen bending of the frame rails was in a hard crash. the chassis seems to have held up good. the alpine cross member is also a strong unit. the series alpines are 55 year old technology and if you want something different to drive try the third generation of the alpine. they can be a chore to drive.

 

[V6 JOSE]

The Alpine unibody design is really tough. When I had my turbo Alpine, I used to do 5,000 rpm starts at the drags, and the front left tire lifted off of the ground, but after many years of doing this, it never shook, or rattled while going over railroad tracks or bumps. It still cornered like a stock Alpine after much abuse. I can´t say as much about other British cars though.

Jose

 

[pcmenten]

Jose,

I was remembering a 66 Tiger I owned in 74. When I bought the car there was a rope tied to the passenger car door handle and tied off to the seat or something. I didn't know what that was for so I took it off. I soon found out what it was doing when I made a left turn and accelerated in the turn; the door popped open and swung out. I assume the torque of that V8 caused the chassis to twist and flex enough to unlatch the door.

One of the things I like about the V6 kit is the design of the transmission crossmember. From the looks of the way the original crossmember was designed into the chassis, it helps to stiffen the floorpan and frame, bridging the transmission tunnel. The crossmember in the kit looks like it preserves that structural/mechanical element of design.

Paul

 

[Charles Johns]

I have 2 series V's and a 1965 Mustang. The Sunbeam is STIFF in the front compared to the Ford. I made a custom bar for my 65 as it is a six and I did not want to move it forward as required by the store-bought one. I also installed an export brace and gas shocks to help front end control. All helped handling and were needed when one corners the little but modified six aggressively. As for the Sunbeam, I am building a 2.3 with about 150 HP and an A4LD and see no need to add to what Rootes did. My driving is limited in the Beam but having built dozens of Street Rods over 40 years it looks like a well designed support system. Those with much experience please let me know if I am wrong and I will take a look at modifications to my build.

 

[Charles Johns]

front braces

On the Mustang (I have owned several) the Monte Carlo brace and export brace are to help keep the shock towers from flexing inward and/or back. The unabody must have support as the front frame horns, where the suspension mounts, just hang out there but must support the frontend. For everyday driving it is not a problem but put some real HP under the hood or corner like Andretti and things start to move. The Sunbeam has a much stronger front cross-member and the suspension hangs on it...kinda!? Just leave what the factory did and keep weight as low as possible. Just sayin'!