ring type and octane rating question

In my pulling tractor I use a Crower cam that has 240 duration @ .050 with .520 lift (works really well with carb and rpm rules). I have a 14.7 compression ratio. After having problems with MY learning curve, I would like to ask what type top ring material others think appropriate. i.e. ductile iron or steel or what? The speed pro grooves are 5/64". This engine did real well with 32 degrees advance and Torco racing fuel but won't stand much more timing than that! Learned that the hard way! Do I need a higher octane fuel, or should I let well enough alone at 32? My advance is all in by 3200 rpm from initial 18 degrees. I have an .045 quench and top ring is about .300 down from the piston flat. Pistons are 2443 Speed Pro with 12.1 c.c. dome. Rebuilding and need help with my education.
Thanks for any help.

with the small cam and high Mechanical compression you dynamic id probably pretty darn high. Have you calculated that yet?

What octane Torco where you using?

With the Old big rings I'm not sure you have a whole bunch of modern race ring options, I'd think the typical plasma moly race stuff should suffice.

Also its not going to matter what rings you use if your experiancing detonation, none of them are going to survive. If the piston doesn't live the rings aren't going got make it.

I'm not smart enough to calculate dynamic compression ratio, or haven't yet got the place found to get the formula. All the fuel supplier can tell me is " 110+ octane". We really didn't see trouble looking at the plugs last season. The # 2 piston has a place on the intake valve side that looks like a very small trench(?) coming from the quench toward the dome. It is not a crack. I sliced it to examine it. Not all of the pistons were this bad, but all are distressed. The head gasket was pushed out at the top, and the top ring had been hot enough that it is literally able to be twisted into an "s" shape.

drop the C/R if you have to stay with that small of a cam and fuel

http://www.diamondracing.net/cocalc.htm


try this and just so you know Speed pros and TRW are el cheapo pistons very heavy also...


Randy

dfree383 wrote:

Also its not going to matter what rings you use if your experiancing detonation, none of them are going to survive. If the piston doesn't live the rings aren't going got make it.

I'd say you're correct there, but my current rebuild and new slugs are getting a set of of rings with the top ring being a tool steel ring. My engine builder has seen those rings go through hell and back and the ring was still usable. Since I run a 300-350 shot of Nos we got a set.
At a bit over $420 for the set they better be worth it.

New slugs for the 565" should come in at 13:1



G-

As always , thanks guys. I can always count on finding answers or getting replies that help on this site! I didn't have the detonation trouble till I had other problems causing timing troubles. Hopefully got 'em cured.

What size engine and what do you rev it to?

G-

Running 472 c.i. NEVER over 6000, like to keep it 56-5800 . Using 650 Holley and MSD box w/ 6k chip as per class rules. Runs 13-15 seconds under load. Just got off the phone with Crower, used their cams for years. Told me to make damn sure straight up time as per their specs, no more than 32 total advance and get the air/fuel right. Tell me it will be OK with 110 Torco. Got along good last year, but I needed someone to hold my hand and tell me it'll be alright, I guess.

Have you called Torco? I'm still sticking to my origional question, and my answer is to much cylinder pressure not enough octane.......

http://torcoracefuel.net/pro-fuels.html

Ok, sometimes you must hit me over the head to get my attention. Torco says < 13:1 for their 110. I will call my local distributer and check on higher rating. If not available right off, can an octane booster be used temporarily? Would a S.G. tester be needed to use additive?
I had a Dynamic ratio calculator downloaded at one time, but must have cleared it out at some point. Does anyone have a link to it again?
Thanks again!!!

Octane booster is a waste of time, get the right fuel. Sell the other stuff to other racers if you have a bunch of it left.

http://www.wallaceracing.com/dynamic-cr.php