rmbuilder

Hpy500,
Pics
http://www.beckracing.com/page10.htm
Bob

Lmarth

No expert here, but I would guess that if they were stretched that they'd want to pop out. Hard to describe, but if it feels right, it is. If it doesn't, it isn't. As I said, they're quite forgiving before they take a deflection set.

Lmarth

Don't want to show my age, but I just re-read Travis' post#3. I can remember when there were only 2 Spiral-Locks per piston. It was two of those or 2 Tru-Arc retaining rings.Just a little trivia on a 20 degree winter morning.

hpy540

Here is the ball park of what i have going on. I know they are theoretical numbers but i am also looking for jetting specs. or at least some ideas. I have done a search and have read the post about what to run but, jetting specs from a Guru would be proffered. Merc Block 502 +.030, H beams, forged 4.25 scat crank, Ferra valves, roller rockers 1.7, team g intake, 850 carb, .613 .629 236 244 dur 112 lsa set up for wet exhaust buy a custom marine cam grinder(roller hydraulic) Mallory dist and i need a box and a coil yet if any one has one they need to get rid of. Any way it should be fun but i will let you know about the locks a little later today. i have a few hours of work this AM and then back into the garage. There was also a post that came up on cometic/felpro gaskets and someone mentioned a second hole for cooling on the felrpo gasket, can someone give me a clue as to what this is about? Or is it non essential. Here is the PDF .......

hpy540

I know there is a heat treat process to both the spiro's and the truearc but i am a Little concerned about the ability for the true arcs. Without the proper heat treat the true arcs would probably anneal and fail thus creating a big gouge in the cylinder wall. Has any one here ever had a catastrophic failure with just one Spiro? I would imagine that the normal hardness of a True arc is probably around a SAE Gr 5 just like most cap screws but i would also like to know if the manufacturer used a different alloy in the true arcs or just off the shelf. I am concerned about the Annealing that might transpire because of the heating.


20 degree it is -4 here

traviss

I think I explained it wrong. on my first motor The instructions didn't tell me how many per piston and they were my first spiro lock pistons. I only put 2 in for each piston, then wondered why they gave me so many extras LOL!!. For entertainment.. motor ran great WFO all season long. My instructions for my second set the year after explained there needed to be 4 per piston... A learning experiance I guess

ratman

i never had a problem... to remove i use a pic tool with a 90* pick on one end. i use a small screwdriver to catch and lift the and tab of the spiralock enough to get the pic behind it and pull it out of the groove. to install i use the small screwdriver to start the end and use push it around the clip until it winds it into the groove. i use a clip twice once in each direction, have done this on v8's and my 2 stroke drag bikes i've never had any problems...

Lmarth

Ratman has the technique down pat. I would ask that everyone understand that my reference to True Arcs was a l-o-n-g time ago. They worked ok and were easy to install, but had a really sharp edge that had to be oriented out. The other edge was slighty rounded (probably part of the blanking process in the die) and if oriented out had a tendacy to dislodge. By design, there's virtually no end play in the pin. My personal opinion is that this gives you a 'failsafe' condition. If you flexed the spiral lock enough for it to yield, it takes a permanent bend that would probably prevent getting all four locks installed without it being obvious that something was wrong. I've personally never heard of a Spiral Lock popping out. When you consider that there is a fairly large gap between the piston pin boss and the cylinder bore, I wouldn't expect the wall to be scored if a Spiral lock popped out,BUT, I would expect the other lock to be pounded out with high probability that the motor would grenade. Just one persons opinion

hpy540

No problem i have it now. just tried one and i will have a post later.

rmbuilder

Lou,
Got your reference to the True-Arcs. When our engines were in rotation using Spiro Locks was out of the question due to the frequency of rebuilds. All our pistons were set up for double True-Arc locks; sharp side toward the piston, and the rounded edges faced each other. The trick was to be sure the retainer groove and the pin ends were both perpendicular to the bore axis. Pin to lock clearance is critical to keep the pin from hammering out the lock. Never had a retainer failure in thousands of racing miles. We could do all sixteen sides in less than ten minutes.
If you have a shop and do a lot of Spiros this tool works well but is pricey
http://www.powerandperformancenews.c...&Store_Code=PH
Many of the piston manufacturers are now using the round wire locks with chamfered pins.
Bob