In the process of rebuilding the 12a out of my '85 which, despite running perfectly, leaked profusely from the dowel o-rings. Everything is apart and I'm part way through inspection, and the only issue I've found so far is that one (1) of the apex seal springs is bent. I'm 99% sure it came out like this (as in I didn't do it!), and doesn't seem to have been causing problems... but obviously I'm not putting it back.

Question is: Would it be stupid to buy a single spring for just this one apex, or should I just order a full set and change them all? It's a stock engine, heavily worked on carb and exhaust - nothing crazy. Just want it reliable (and not gushing oil) for regular use.

(Also going to the later flat-style corner seal springs because one old one somehow escaped between pulling the rear iron and setting it on the bench, and I can't for the life of me find it)

 

You can never go wrong replacing internal seals, springs, o-rings, and bearings. I wouldn't reuse that apex seal spring. I also think that moving to the FD corner seal springs is a great move regardless of how many of the old style ones you lose

 

It makes sense. The newer springs are probably, if nothing else, a little stiffer without having been compressed for however long and heat cycled a zillion times. I'll be doing all the o-rings/soft stuff, hard seals so far all seem a-okay (and the rotor housings are in fantastic shape, thankfully).

Oh and I found the last wire style corner spring but I'm still going to replace them, those wire springs are pretty janky and the flat ones are cheap

 

how many miles on the engine? chances are good the they're out of spec if u mic them. i'd put new in it. depending on the ware u probably can reuse the metal oil rings. i was able to reuse mine when i did my build yrs ago. the problem i had when reusing everything was low compression during hot starts. if i remember right, i put new apex seals/springs, side seals/reused springs, corner seals/FD style springs. shaft/rotor bearings, all gasket, seals, O-rings needed. viton O-rings for the oil seals.

 

3mm apex seal springs usually look that way for me after a handful of miles. I try to replace them any time I have an engine apart.

 

No idea on the miles on the engine, it's not original to the car (all signs point to it being an '81-82 engine, and it's in an '85) but wear-wise, everything is in good shape. It started without hesitation hot or cold, only tearing down because it was misplacing most of its oil via first the dowel o-ring. I'll plan on replacing all of them (the non-bent ones are juuuuuuuuuust barely within spec so fresh ones should be an upgrade).

This is the only one that doesn't have a nice smooth arch shape, but they seem a bit tired so I'll change them out. Would much rather spend the little extra now than have to take it apart again in a couple years