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Ring Gap on a 355

7K views 17 replies 9 participants last post by  redcamaro4spd 
#1 ·
Hey guys, just got all my stuff back from the machine shop and am installing my rings. I was just wondering what kind of ring gap I am looking for. Will be used as street/strip engine, bored .030 over, speed pro coated skirt pistions, and sealed power rings (typical economy ring set). Thanks and any advice for how to fit these will be appreciated and install it all is appreciated.
 
#2 ·
Typically the economy sets are already gapped (on the wide side). If you actually have a file fit set, you need to read the instructions that came with the pistons/rings. Piston material plays a role in how much gap you should run as well as if you plan to use nitrous at all.
 
#4 ·
yeh, I thought I mentioned this but I must have not. In a couple of years, I may use a small shot (50-100 shot). It will prolly never happen, but I've thought about it. How much should I account for this? People put 100 shots on stock rings so I figure I could prolly get away with it...Please let me know if this is a bad idea...Also I noticed no instructions for gapping with my ring set, just installation instructions. and BTW, pistons are forged...
 
#8 ·
well when I measured everything, the ring gap was at its lowest tolerance(i.e. top ring=.016"-.017") according to the instructions in mustangjoe's gallery. I believe those are the same rings that I am using so it should be the same. I should be safe as long as they are within the manufacturer's tolerances, correct?
 
#9 ·
redcamaro,
I figured that would be the case. File fit rings will usually come with instructions on how they want them gapped for a particular type of piston or if nitrous or a blower would be used (gaps are also different for alcohol, tighter).

When you said it was an "economy" type of set I was pretty sure they were pre-gapped.

You will be fine with a 100HP shot of nitrous. You usually don't adjust the ring gaps for nitrous until you get to the higher levels. Did you happen to measure the end gaps?

Edit: Yes, you should be fine as long as you are within the MFG's specs.
 
#11 ·
As posted often on this site. Rings for use with hypereutectic pistons require a larger end gap than standard forged or cast pistons. Not sure what piston you've got but if they're hypereutectic then you'll have to gap them .026 or so.

Sorry just re-read your post, you do state what piston it is.

Must be old age setting in.
 
#12 ·
I would gap the second ring 30% larger then the top. In recent years it has gotten out that the NASCAR boys have found that with a larger 2 ring gap it reduces the pressure between the top and 2nd ring and gets rid of ring flutter with is a big HP robber at mid to upper rpm.

Cstraub
 
#15 ·
Ring flutter shouldn't be an issue until you get to very high RPM/HP/High compression (high cylinder pressure) situations (IMO). Doesn't sound like you are building a 8000RPM engine to me.
 
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