From my own experience, it should not really be a great cause for concern, if they were installed properly - I will gladly stand corrected.
We had a 1940 J-5A which was our first "Cub" with a 180 HP using X-Winds mount. After all, it was a "Piper Cub Cruiser." It had wooden spar splices from June 1940 when my grandfather put the plane into the trees in Spencer Mass - on a gusty day with 3 people and 75 HP. We replaced the rear spars for condition, but never touched the front left which had an original 1940 wood splice.
We gave this plane a 40th birthday party in 1980. Well, any excuse in the goood old days.
We used metal spar splices from Univair for our wing extensions on our PA-12 and they seem to work really well. Wood and metal are two VERY different animals. Just my 2 cents worth.
While I'm here, I want to say that we've had really good luck with the X-Winds STOL 180 set up, which we've used about 5 times. :-?
Fortysix12,
At one time Piper offered a spar splice "kit". It consisted of spar splice plates, rivets and spar section.
I agree with Stearman 600, if the splice was done properly, it's just as good as the original spar. I use spar splices on my wing extensions also.
Yep"
I've used them. You can splice Piper metal spars outboard of the lift strut attach points. The Piper Kit came with a section of spar material, the plates to attach the two pieces of spar together with and a bag full of rivets.
See Piper Service Memo No. 3A.
If they were done properly, I wouldn't worry a bit about them.