What size rings?

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Map63Vette

Map63Vette

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So I'm trying to get all the parts together so I can put my 5.7 back together and I'm stuck on the rings. What exactly is the correct size for the standard bore? I'm having my machinist just break the glaze with a hone and am not overboring it any. I would really rather not file fit stuff as this is just a stock rebuild and I really don't want to mess with the chance to screw it up. I'm looking at Summit and have found these rings that seem close http://www.summitracing.com/parts/PCR-41850CP-020/ at 3.918 bore and claim they are drop in fit, but I've also found these http://3rdstrikeperformance.com/ind...t_info&cPath=35_3209_829_833&products_id=9432 that claim drop in is 3.922. Are the rings supposed to be bigger or smaller than the engine bore? How much difference is there supposed to be between the ring size and bore size? I'd just order a stock set from the dealer, but they want $25+ per piston for a set and if the Summit stuff is right I can get a whole engine set for $100.
 
just go hit up the dealer for a new set of ring
 
Well, a little digging found that those Summit rings are apparently oversize rings for a LS engine. The stock hemi ring is evidently 3.917, not 3.918, so I'd have to file them to get them to stock specs. I've found a part number for the hemi rings from Mahle (41904CP), but can't seem to find anyone who sells them.

I really hate the dealer here because they way overcharge for anything. They wanted $2.70 per bolt for the connecting rod bolts, $5 for the special truck main stud that mounts the pickup, and $4 for the dang nut that goes on that stud. They want $290 for a full set of rings, there is no way I'm going to pay that much for them, that's ridiculous. I've seen performance rings for less than $200, there has got to be someone that sells stock rings for a reasonable price.
 
Give Total Seal a call, pretty sure they would have/make them for you. Plus you can get them with a gapless option maybe.
 
Yeah, I was just thinking about him. I know he gets a lot of his stock parts from dealers though, so not sure how much of a discount he could get me, I'll probably shoot him an email though. How horrible would it be to run the LS rings in the hemi? The thicknesses are the same and the bore size is dang close, so I could probably do something about that. Are there any other numbers I should be concerned with that would affect fitment? All the hemi stuff I find is $160+, but the LS rings are only about $100.
 
give stu a call. I personally would at least see what that option is. And ask his opinion on the LS rings. You never know he might just tell you to run them. Stu is a stand up guy. He will tell you what is right. I have been working with him for years now. And I only had an issue once, and it was resolved at his expense and in 3 days. (that included shipping both ways) he will not give you bad advice, and if it's a mistake he will fix it right away.
 
Yeah, I've bugged him several times for stuff and he's always ready to help out. It's just starting to get frustrating trying to get this engine back together. I got used to it dealing with old parts for old cars, but I figured the new stuff would be a lot easier to come by. There isn't a listing for a 5.7 hemi ring in any of the usual catalogues, I have to go to the source, and even then it's still a toss up. It's starting to cost more to replace general wear parts than I paid for the engine to start with, just hard to swallow.
 
Well, my rings just showed up today and I'm a little confused. They listed as being for an 03-05, but my motor is an 06. I figured not much could have changed, and I haven't seen any listings for later model rings, so I went ahead and pulled the trigger. I had my machine shop guy break the glaze on the cylinders, but no boring of note was made. I get the rings and they claim they are file fit, so I take an old ring out with me to check the stock end gap so I can set up the new rings similarly. The stock gap measured in at around .012 inches. I put a new ring in and unfiled the gap is already .024 inches... Is this going to cause any significant issue? I really don't know what else to do aside from ordering oversize rings and grinding them way down until they fit, but I would think at that point that they wouldn't fit right. Any words of wisdom?
 
Where in the bore did you measure the ring gap and was the ring you checked the top ring or 2nd ring? Its actually better if you measure at the bottom of the bore espeically if you only deglazed the cylinder walls, just in case your cylinder bores may have a slight taper. You can check for taper by checking the ring gap at both the top and bottom of the bore. If there is a difference, set your ring gaps at the bottom. As for recomended ring gaps? Your stock .012" is way too tight. I've seen some as tight as .010" and is probably the culprit why the top ring lands break on stock pistons. For a good street motor, I like gapping the top ring at .005" X bore size and the 2nd ring at .0055" x bore size.
 
I measured it right around one inch down (what the spec sheet in the rings suggested). I figured the tight stock gap was probably emissions driven, but I know new engines are weird about a lot of stuff, so I wanted a second opinion. I called Total Seal's tech line too and they gave me the standard "SAE tolerance is anywhere from .012 to .022 for my size bore". That makes me feel better about trying to use them though. Don't plan any real high performance on this engine yet, but don't want to break parts either. I'm still a little on the big side, but I'm crossing my fingers at this point that it won't smoke too bad on startup or anything.
 
1970Duster said:
Give Total Seal a call, pretty sure they would have/make them for you. Plus you can get them with a gapless option maybe.
Click to expand...

The gapless Total Seal ring packs are nothing but problems in these new Hemi engines using a factory hone finish and high idle vacuum. Your engine will smoke so bad at an idle, you'd double guess yourself into thinking you intalled the 2nd ring upside down or something.
 
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