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I have a few questions about the rings for my 383 stroker that I’m building. I’m using SRP pistons and rings and it will be a NA engine, I don’t plan on ever using nos or boosting it in anyway. Recommended ring gap for top ring from SRP is bore x .0045 which I got to be .018 gap, second is bore x .0050 which I got to be .020 gap, oil ring rail is recommended minimum of .015. So first question is do those gaps sound reasonable? I’ve heard people say anywhere from .012 to .016 for NA 383s and it seems SRP recommends a little wider. Second question is these rings came with “oil ring support rails” I’ve never built an engine that had these oil ring support rails and it does not say what to gap them to it only tells me where to line up the gap on the piston so do they even need to be gapped or do I gap them the same as my regular oil rings? They all came overlapping on each other by almost a 1/4”. Next question is do I install those underneath the bottom oil ring? It came with 16 top&bottom oil rings and 8 of the “oil ring support rails”. I’ll include a picture of the 4 different bags of rings it came with and the part numbers. Thanks in advance for the help.
Oil ring spacer goes in first then an oil ring goes on each side of it. They may appear long till you get them fitted. Check the compression rings, they should have a side marked up with a dot or something. As for the gap, unless they are file fit rings your gap may be a little larger than recommended but check them all to be sure. Dont go under manuf, specs, a little larger wont produce excessive blowby but if they are too close and butt up youll score the cylinder walls and break the ring lands out of the pistons.
Oil ring spacer goes in first then an oil ring goes on each side of it. They may appear long till you get them fitted. Check the compression rings, they should have a side marked up with a dot or something. As for the gap, unless they are file fit rings your gap may be a little larger than recommended but check them all to be sure. Dont go under manuf, specs, a little larger wont produce excessive blowby but if they are too close and butt up youll score the cylinder walls and break the ring lands out of the pistons.
yea unfortunately still waiting on my piston ring filer go come in the mail, so far it seems all the rings are a little tight but these oil ring support rails are the only ones overlapping on each other by a lot. I still don’t exactly know which order the oil rings need to go in though, it has 16 of the top and bottom oil rings and then 8 of the “waffle” style rings, that’s what I call them there’s probably a better term for them but then there’s also 8 of these “oil ring support rails” which it doesn’t quite say where they are supposed to go. From what I can guess they are supposed to be underneath the bottom oil rings but i want to make sure. Also doesn’t say what to gap them to and since they overlap so much and none of the other rings do I’d have to take almost 1/4” off them just to get them so they don’t overlap. I’ll probably call SRP and ask them about it if I don’t get any other answers.
The support rail goes in the lower part of the oil ring groove. Their should be a small tab or locating device that points down to the wrist pin bore. That keeps it from rotating and getting a ring gap over the wrist pin bore. After it goes in the oil rings go in as usual. If the oil rings didnt go thru the wrist pin bore you wouldnt need the support rails.
Last edited by 78blueta; Mar 18, 2021 at 05:21 PM.
.018 and. 020 are good for a N/A pump gas engine with a 4.030 bore.
The rail support ring should not need to be gapped. It should fit tightly into the oil ring groove when installed on the piston... thats why it overlaps not installed. Also if you look at it there is a dimple that should be installed down and located in the wrist pin cut. This keeps it located in the correct position. It does go under the oil ring and after the pistons are installed on the rods, it's the first thing to be installed on the piston.... then you can install the oil rings, then the second ring then the top ring.
Will
Last edited by rklessdriver; Mar 19, 2021 at 02:20 PM.
.018 and. 020 are good for a N/A pump gas engine with a 4.030 bore.
The rail support ring should not need to be gapped. It should fit tightly into the oil ring groove when installed on the piston... thats why it overlaps not installed. Also if you look at it there is a dimple that should be installed down and located in the wrist pin cut. This keeps it located in the correct position. It does go under the oil ring and after the pistons are installed on the rods, it's the first thing to be installed on the piston.... then you can install the oil rings, then the second ring then the top ring.
Will
thank you, luckily ended up calling SRP yesterday asking about it and they told me they don’t require any sort of specific gap for them guy just said as long as they don’t touch I’ll be fine. Got the last of my parts in so tomorrow will probably be assembling everything and getting ready to measure pushrods and once those are in hopefully engine should be done and good to go.
LT1 383 stroker ring gap
