ridge ring

[muscletruck]

i was just curious.....the 350 block i have has a relativly large ridge ring i took it to the machine shop he said boring would be the best....i probebly will end up boring it....i was just wondering what the ring gap does to the engines performance or what is the negative side of keeping the gap?.....just curious not gonna do it..just curious...

[Zkast]

That ridge is the original size of the cylinder before the rings began wearing it down. If you dont cut it out before assembly, You'll take the change (pretty good chance) of breaking a ring installing the pistons and or when at higher RPM when the rod stretches a bit.

If you have that much wear, bore it. At minimal cut that ridge before it does damage to your new parts.

[adamls]

Zcast seems to know his engines WELL. I am glad that there is so much knowledge assembled in one place. Anyways, ring gaps are important to high perf. engines. Make sure your machine shop is reputable. the scar may be too much to mess with and may require a new block. Put some specifics out and someone might be able to help a little more.

[basketcase]

The piston ring end gap is a vital measurement when assembling a new engine. The wider the gap the more combustion pressure excapes past the piston and into the pan and the less power is produced. If your cylinders are worn that much you can also bet that they are hourglass shaped as you travel down the length of the stroke where the rings ride due to different side loads during the crankshaft cycle. Obviously the gap won't remain the same as he piston travels up and down. Also new rings are round and old cylinder walls aren't. That's why machine shops bore and hone with deck plates installed. They simulate the stresses of the heads being installed and torqued to produce a round cylinder after assembly.

Custom engine builders will buy rings that are long and custom file them to obtain the best possible gap. Recently builders have been running gaps a little tighter than specs and the decreased blow by shows up on the dyno in hoursepower numbers. This is also the idea behind gapless rings. Instead of a single ring in the # 2 grove they use 2 thinner ones with the gaps oppisite each other. That way there is no straight through path for the combustion pressures to excape. Sealed Power now has a set with a gapless 1st and 2nd ring claiming even more power gains.

With a gapless 2nd ring a typical performance built 350 would see up to 35 horsepower gain on the dyno. If you want the most from your engine building dollar have it bored and new pistons and rings fitted by a competant machine shop. You will be money ahead in the long run and your engine will be as good as and probably better than a new crate motor.

Decking is another operation that the shops sell with almost every block job that usually doesn't need to be done for a street engine. Briefly, with all the head gasket particles and sealer cleaned off take a long sanding block and 220 paper and sand the deck in long strokes covering all of the holes. If the metal gets bright around the head bolt holes then the threads are pulled up and the block could use a cut.

If not, go ahead and finish sanding the entire surface lightly to make sure it is clean. Lay a machinists straight edge, as long as the block, on the deck surface at every angle you can think of. Shine a flashlight under the edge and check for light between the straight edge and the deck. If you can find any gaps then the block needs decked. Do the same to the heads.

If you have a good straight block and heads you can save significant money by leaving these 2 surfaces alone.

Tom

[muscletruck]

i love this BOARD!!!!!!!!!!.......thanks everyone....an answer for everything.....sweet