Strengthening Chassis Rails

[Burdekin]

Has anyone got any advice / knowledge on strengthening a P1800 chassis rails? I'm going to be replacing sections of the chassis rails and was wondering as I'm going to be working on the chassis already it may be worth also looking into strengthening the chassis if it is required or if it is a good idea? I'm upgrading the engine to 175 to 200 hp and lowering and stiffening the suspension so the chassis may see some additional stress.
Is it legal in the UK to weld strengthening sections over the existing chassis rails or is this an MOT fail?

[classicswede]

The chassis is quite stongon the 1800 and with the mildpoweout put that you are looking at there is not to much to worry about. The main area to strengthenis the kick up over the front crossmember. It wants bracing back to the bulkhead.

[Burdekin]

Thanks. That is pretty much what I was thinking. I haven't looked at the logistics or the fine details as yet but was thinking of welding a 4mm plate along the edge of the chassis rail from around the bulk head forward to just past where the suspension/crossmember bolts on. Also thinking of doing the same at the rear of the car.

[DJS]

Hi Mitch,

It's possibly worth looking at Escort Mk 1 and Mk 2 chassis mods in that area. A stiffener from the longitudinal to the firewall would be easy enough to weld in as would a bulkhead strengthening plate. These are common Escort mods. You could also look at putting a small strengthening plate on top of the shock absorber mounting as per the Swedish Iron book.

[classicswede]

The escort isa totaly different car for bracing. For one it is quite flimsy with a lot of body flex and secondly it has struts up front.

What is done on rally amazons is to box in the area between the bulkhead and the front cross member kick up with 2mm plate. I would not go any thicker than that or you will just be adding weight.

If you want to do work on the front crossmember then you can weldin a big washer on the top shock mount as they do often crack but that is mainly due to corrosion. It is a good idea to brace from one side of teh bottom wishbone mounts to the other. The tube that goes through the crossmember for the bottom wishbone bolt can part company when heavily loaded in rough rally conditions. I personly like to brace teh crossmember regarless of aplication.

For the rear shock mounts welding in extra washers would not be a bad idea especialy if there is any corrosion problems.

[Burdekin]

Thanks guys for the advice, appreciated... I thought there would be more info on strengthening the chassis on the net as the P1800 has been used for racing in Sweden and the US, but maybe this is an indication that not a lot needs to be done.