turbogrill Posted December 20, 2018 Report Share Posted December 20, 2018 Hi, On one of my pistons the spirolox edge is close to that "hole" that I assume is used to remove the spriolox. Is that a problem? The installation instructions doesn't mention anything but last thing I want is for these to pop loose at 7000 rpm. Thanks / Carl Quote Link to comment Share on other sites More sharing options...
Slugworks Paul Posted December 20, 2018 Report Share Posted December 20, 2018 (edited) from my perspective, no. That area won't reduce the ability for the lock to work, nor would it allow for it to come out. Edited December 20, 2018 by Slugworks Paul 2 Quote Link to comment Share on other sites More sharing options...
Technical Advisory Committee mcoppola Posted December 20, 2018 Technical Advisory Committee Report Share Posted December 20, 2018 what kind of cheaty engine are you putting together @turbogrill ? (parts look familiar... ) 1 1 Quote Link to comment Share on other sites More sharing options...
turbogrill Posted December 21, 2018 Author Report Share Posted December 21, 2018 3 hours ago, mcoppola said: what kind of cheaty engine are you putting together @turbogrill ? (parts look familiar... ) Oh...I am running stock like everyone else. Nothing to see, move on. Building a hot l28, got 350 pts for engine and suspension. Decided to go with forged pistons, unclear what points that is. 1 Quote Link to comment Share on other sites More sharing options...
mhr650 Posted December 21, 2018 Report Share Posted December 21, 2018 What you are showing is not a Spirolox but a round wire ring combined with a chamfered pin, which is WAY better than Spirolox, I have used genuine Spirolox and they are a massive pain in the ass. With the clip installed as it is in your picture you won’t have any reliability problems when running but you would not be able to remove it since the gap is right over the notch that you use to remove them. You can easily use a small screwdriver to spin them around in the groove if it makes you feel better, the big advantage of the round wire locks is that they don’t have much static tension in the grooves. When the chamfered end of the pin pushes against the ring the angle forces them to expand and get tighter in the grooves so it is nearly impossible for them to ever come out. 1 Quote Link to comment Share on other sites More sharing options...
Technical Advisory Committee mcoppola Posted December 21, 2018 Technical Advisory Committee Report Share Posted December 21, 2018 18 hours ago, turbogrill said: Oh...I am running stock like everyone else. Nothing to see, move on. Building a hot l28, got 350 pts for engine and suspension. Decided to go with forged pistons, unclear what points that is. I thought you were building a Focus now? Quote Link to comment Share on other sites More sharing options...
Technical Advisory Committee mcoppola Posted December 21, 2018 Technical Advisory Committee Report Share Posted December 21, 2018 14 minutes ago, mhr650 said: What you are showing is not a Spirolox but a round wire ring combined with a chamfered pin, which is WAY better than Spirolox, I have used genuine Spirolox and they are a massive pain in the ass. With the clip installed as it is in your picture you won’t have any reliability problems when running but you would not be able to remove it since the gap is right over the notch that you use to remove them. You can easily use a small screwdriver to spin them around in the groove if it makes you feel better, the big advantage of the round wire locks is that they don’t have much static tension in the grooves. When the chamfered end of the pin pushes against the ring the angle forces them to expand and get tighter in the grooves so it is nearly impossible for them to ever come out. Huh? I thought you ran rotary engines? Just kidding, I'm sure you've built piston engines in the past. Thanks for the good explanation. I've always been nervous about running full floating rods due to having a snap ring come out of a piston in my sand dragster many years ago and damaging the cylinder wall. Yes, it was a true snap ring, so we them fitted that motor with teflon buttons to retain the pins. As you said, spirolox are a real pain, but I thought they may be better than the wire rings. Your explanation now has me thinking the wire ring and pin chamfer method is not so bad after all. Quote Link to comment Share on other sites More sharing options...
mhr650 Posted December 21, 2018 Report Share Posted December 21, 2018 I had never seen inside a rotary engine until a couple of year ago, I am an old school drag racer up to and including NHRA Pro Stock. Back in the 90’s I was designing and machining parts like cylinder heads for some really fast cars but doing it completely in the background, only a very few people knew where the parts were really coming from. This kind of experience did mean that I had a clue where to point the grinder when I got some rotary housings in my hands….. It is no contest that the wire ring is the most reliable method of retaining the piston pins, bonus it is also the lightest. The story I heard is that it was Cosworth that developed the design with the wire ring and chamfered pin back in the day for their F1 engines. As you discovered pin buttons are 100% foolproof but quite heavy compared to a tiny wire ring. 1 Quote Link to comment Share on other sites More sharing options...
mender Posted December 21, 2018 Report Share Posted December 21, 2018 I haven't had either style come out. Used to be that I only saw the spirolox on the domestic stuff and the wire ring on the euro stuff. Quote Link to comment Share on other sites More sharing options...
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