I have purchased a new chassis as the basis for my restoration. I want to make a few mods to improve the durability and longevity. I would welcome any feedback on the the wisdom (or otherwise) of my proposed changes. I have TIG, MIG and oxyacetylene available, and am a reasonable amateur welder.
Mod 1. Relieving the chassis next to the exhaust. I am going with the TTR ‘fast road’ system, and want to ensure I have clearance.
Mod 2. Strengthening rear shock towers. This is one of the recommended mods in the Wiki, but I have a Sprint that has the additional bolt on ‘outrigger’ for the seatbelt mounting. The outrigger won’t fit if the reinforcing plates are fitted. Should I fit the reinforcing plates and weld the outrigger on?
The front shock towers are well known mud traps. Should I close off the mouth of the tower to enclose the bottom section so that mud can’t build up in the tower?
The only thing I would say is be careful of the heat warping the chassis. Proceed with caution on that front.
I have a chassis that the PO strengthened extensively for racing. I had to scrap it because a front tower was warped. I do not know for sure that heat warped it but its a possibility for sure.
At the bottom of the front suspension towers is a diagonal weld, rather like the mitred joint in a picture frame. On my replacement chassis the lower wishbones fouled this weld! Correction wasn’t difficult but the chassis had a lovely black finish by this time and correcting the finish was very annoying.
The comment about distortion is well taken, perhaps I am asking for trouble with a significant amount of welding in the front towers. There is a picture of a TTR prepped chassis out there with extensive welding witness marks around the front tower where a sealing plate has been welded in, but perhaps that was done while the chassis was still in the jig. I may investigate other ways of sealing this area.
The rear shock tower tops are the only area that Rohan recommends strengthening (in a post from sometime back), so I will attend to those. The Wiki suggests welding the outrigger on for cost reasons, but as mentioned it won’t fit in standard form so I will have to weld that on.
The exhaust cutout seems sensible, so I will go ahead with that as well. My current chassis has had the exhaust area ‘adjusted’ with what appears to have been a knife and fork by a PO.
