Door check strap : MY 89 onwards _ The differences

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MetBlue
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Model: Elite 74 & Excel 92 (SEish))
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Year: 1974
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Door check strap : MY 89 onwards _ The differences

Post by MetBlue »

It’s pretty much general knowledge that Lotus introduced changes to the check strap in MY 89 to allow a wider opening angle of the door. However, I’ve never found information about what actually changed and which, if any parts are interchangeable.

The passenger door beam on my MY91/92 car was shot so a visit to Lotus bits resulted in a repairable beam being acquired. Aware of the potential differences, I made sure I got a beam including hinges and strap. The ‘new’ beam was not without corrosion (find one without if you can :!: ), but it was solid enough to cut out the rust and set in new metal.

Come the day of fitting, once the door shell was removed it was clear my replacement beam was from a pre MY89 car. So what are the differences?
Essentially, all Lotus did was move both attachment points for the check strap approx 12 mm nearer to the main hinge point. (The long bolt in the lower ( old ) beam at 160mm is just a clean M6 bolt I screwed in for the purpose of the photo – maybe should have done the same for the pivot bolt at 45mm, but you can just about make it out).

Image
The easiest way to identify a post 89 beam is from the position of the front boss. It is coincident with the bolt hole for the top window frame fixing of the leading frame member. Photo below demonstrates and also shows a good ‘watch out’ to not use a long M6 bolt on the window frame fixing in this position if you have a post 89 beam :!: :!: The silver plate is simply a straight edge to help see the bend – Not sure it was really needed in hind sight !!

Image
To summarise, the check strap is directly interchangeable (same). The top hinge plate is almost interchangeable (just drill and tap a new M6 hole near the hinge point). If you have an older beam that by some miracle is still solid and you want the wider opening door, you could weld a new boss on 12mm nearer the hinge (and drill / tap the hinge plate hole).

According to the parts list, there have been other changes over the production history. The most obvious is the change from the BL parts bin plate and coil spring used on Elite / Eclat, which I believe carried on into the very early Excels ( these also need a top hinge plate with a boss welded on to get the right height!). The pictures in the parts list also infer that once they moved to this simpler design, the spring shape was initially much more complex. Whether these are interchangeable, I’ve no idea as I’ve never seen one.

Tony
What goes together.... Must come apart.

Pete Boole
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Re: Door check strap : MY 89 onwards _ The differences

Post by Pete Boole »

Great write-up Tony. This needs copying to the "Techwiki" section!! :D

Pete

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