Anyone try the new 2nd ring gap recommended by Speed Pro?
They recommend the 2nd ring be gapped larger than the top ring.
For example, if in a 4.000" bore, top ring 0.020"---2nd ring gap 0.024"

Quote from Speed Pro, "NOTE: Most of the 2nd ring gap recommendations are larger than the top rings. Recent testing has proven that a larger 2nd gap increases the top ring's ability to seal combustion. This larger "escape" path prevents inter-ring pressure from building up and lifting the top ring off the piston."

Anyone do this?
lmk,
Karl 95 Impala SS

 

I did this on my last 383 and it seemed to work great.

 

We have been making our 2nd ring gaps larger for years in 100's of engines. My 383 is done like that as well. Don't forget to smooth the edges of the side you filed off. Take a small grinding stone or file and smooth all edges off.

 

Hey, that's good news!
I'll do exactly as Speed Pro recommends, now that I see that there has been good success.
Thanks for taking the time to reply guys.

Karl

 

Been doing that way for thirty years.

 

I am familiar the reasoning. SRP tech was concerned with this scenario as well, when they recommended speed pro rings to me.

However, IF that was a major/real issue, would the gapless ring in the second groove still be effective? With the gapless ring in the second groove, you would think the potential problem would be worse.

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I'll be back

 

I'm still not quite certain which way to go. I spoke to two very good engine builders yesterday and they both recommend a smaller 2nd ring gap.
Yet checking the Helms manual for the LT1350, it even has the 2nd ring gap larger than the 1st ring gap.
And at Speed Pro's web site, they make reference to competitors gapless design saying it is not proven, bla, bla and that their's is best.
I've already got the rings gapped at 0.022" top and 0.018" 2nd but I think I'll drop another $70 bucks and file a set for .018" top and .022" 2nd.
It's for a project motor anyway and I do lots of experimenting with it.

Any more comments or info?
Thanks in advance

Karl

 

Increasing second ring to a larger gap than top ring is one thing, but I do not recommend having that accomplished by decreasing the top ring gap. Utilizing a top ring gap that is less than in the recommended range by mftr. is risky business.

The goal is to achieve an end gap as close to zero as possible without 'butting' at the temp you intend to run. But allowances must be made for temps not intended.

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I'll be back

 

Yup,
That's why Total Seal has newly released top rings that are gapless. They run standard rings on the 2nd land. Suppose to help stop ring "flutter". (unseating under pressure) Kb's and many others have accumulator grooves between the ring packs to combat this also...........


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D.O.B. 6-9-69
71 Satellite (Hers/stock)
73 Dart Swinger (Sons-7)
84 Turbo Z (rebuilding 2.2L)
71 Ply Satellite (His/Blown)
24k w/Procharger Todd's Mopar Page
My Kit builder: 401-732-4047 SD Concepts Engineering

 

When I spoke to Total Seal last fall about their new top gapless ring, I was not impressed with their suggestion to use a rougher hone, (compared to standard practices) to accommodate gapless at the expense of second conventional ring. They can get someone else to be a guinea pig.

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I'll be back

 

Oh hey Arnie, I wanted to make sure you didn't think I was lowering my 1st ring gap. The above post where I said I was going from the .022" top down to the .018" top was sort of misleading.

My local machinest, (Terry Samakow...East Coast Pro Stock engine builder, Frantic 7 Director), did the gaps for me and he likes to go on the large gap side. So I certainly didn't argue. He did a top ring of .022 and the 2nd ring of 0.018.

But: when I get home to put the rings in the pistons, I look at the Speed Pro instruction for my street/strip motor, and speed pro recommends .018" top and .022" 2nd.
????????????????? hence the beginning of my wonder.
For now I've decided to go with what Speed Pro says. I'm sure .022 top-.018 2nd will work fine because my motor was originally gapped at .018 top-.015 2nd by The Agostino Shop, (and after 110 1/4 mile runs and 1 year of wear), the "as found" gaps were coincidentally .022 top and .018 bottom.

Whenever I want to learn a little something about engine building in general, I find that Camaroz28.com is THE PLACE. Thanks!

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95impalaSS all Natural 4200lb. lead sled
12.1 @ 113 All Natural Solid Roller 383LT1


[This message has been edited by quickSS (edited July 28, 2002).]

 

I think it depends a lot on what your trying to do. High rpm engines need larger 2nd ring gaps to eliminate ring flutter. At low rpms ring flutter is not a problem. Also, if you plan on using a vacuum pump on the engine, larger 2nd ring gaps can be beneficial, as they will let the vacuum pump do its job. If you don't have a vacuum pump, there aren't big gains from larger 2nd ring gaps.

I will tell you this. Pro Stock, Pro Stock Trucks, and Comp guys have been using larger 2nd ring gaps for years. But, you have to look at the intended usage of these engines; high rpms, and dry sumps (read as high crankcase vacuums).

In the real world of street engines, the top ring will see a much higher temp than the 2nd ring, so even if you set them the same at room temp, the 2nd ring gap will be larger at operating temps.

My advice would be to follow the manufacturers recommendations for the intended usage of your engine.

Good luck.

Shane

 

Whelp. I just installed the pistons and torqued up the rod caps.
I decided on the Speed Pro specs and did 18 top and 22 2nd.

Karl
Thanks for all the input guys.

 

If you look at a factory service manual, the oem specs call for a 2nd ring with gap tolerance of .018-.026....Top ring tolerance of .010-.020. This goes back to at least '94.

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