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| Piston Ring Gap Locations? https://slantsix.org/forum/viewtopic.php?t=50858 |
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| Author: | nagosnell [ Fri Jan 18, 2013 5:27 pm ] |
| Post subject: | Piston Ring Gap Locations? |
This is probably getting beyond pedantic but do y’all have any suggestions for the ring gaps on the piston? The instructions say to place the rings for the oil spacer an inch on either side of the spacer gap but which way should that spacer gap be facing? Then there’s the compression rings. An old manual I found just says to make sure the ring gaps aren’t in line with the pin and trust direction. I’ve heard some people say in doesn’t really matter while others say that it’s pretty important. What do you think? |
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| Author: | CNC-Dude [ Fri Jan 18, 2013 6:39 pm ] |
| Post subject: | |
Its really irrelevant because they move on the piston when the engine is running, but to begin with, its good to make sure the gaps are opposite each other as much as possible. I typically place the oil ring gap inline with the wrist pin, and then put the second ring 90° to the pin(either pointing toward the pass. side or drivers side of the block, and then the top ring 180° from that. |
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| Author: | slantsik [ Fri Jan 18, 2013 8:39 pm ] |
| Post subject: | piston rings |
Gday Again. From My service manual. INSTALLING PISTON & CONNECTING ROD ASSEMBLY IN CYLINDER BLOCK. (1) Compression ring gaps should be located on the left side of the engine and staggered about 60* apart. Neither gap should line up with the oil ring gaps. (2) Rotate oil expander so that the ends are at the right side of the engine. Rotate steel rails so that the gaps are aproximately opposite and positioned above the piston pin holes. (3) Immerse the piston head and rings in clean engine oil . Slide the ring compressor over the piston and tighten. POSITION OF RINGS MUST NOT CHANGE DURING THIS OPERATION. (4) The notch on the top of the piston must point toward the front of the engine,so that the squirt hole in the connecting rod is toward the right side of the engine. Also check out this thread. http://slantsix.org/forum/viewtopic.php?t=27439 take your time and enjoy. Brendan. |
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| Author: | DadTruck [ Sat Jan 19, 2013 6:39 am ] |
| Post subject: | |
The company I work for builds maybe .5 million diesel engines a year. On the engine assembly lines where the pistons are manually ringed then manually loaded to the case,, there are explicit operator instructions on how to position the piston rings, very much as described in the messages above. With manual operations, in production environments, on the very best days you get 95% compliance. On the high volume assembly lines,, where the pistons are ringed in automated equipment, by an off site vendor, maybe 500 or more miles away from the engine assembly plant, and then the pistons are robotically loaded to the case, there is no requirement for piston ring gap location,, Have never had an engine from either process fail an in plant test or have a warranty claim for pistion ring gap off location... Is clocking the ring gaps a best practice? yes it is, Can the effect be measured? I doubt it. Making sure the ring gap is the proper size is much more important than gap location. Unless you get way out of bounds, no issue with a gap that is too large. Set the gap too small and there will be problems. |
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| Author: | terrylittlejohn [ Sat Jan 19, 2013 4:24 pm ] |
| Post subject: | |
i agree with the too small gap. that can do the most damage under load. |
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| Author: | nagosnell [ Sat Jan 19, 2013 6:26 pm ] |
| Post subject: | |
Great info! Thanks for the tips. |
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| Author: | nagosnell [ Sat Jan 19, 2013 7:29 pm ] |
| Post subject: | |
While we're talking about rings; what's the best method of checking the size of the gap? Is it as simple as squeezing the ring and measuring it or is there another way? |
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| Author: | DusterIdiot [ Sat Jan 19, 2013 7:37 pm ] |
| Post subject: | You can... |
Quote: While we're talking about rings; what's the best method of checking the size of the gap? Is it as simple as squeezing the ring and measuring it or is there another way?
I put the ring in the finished bore use an unringed piston to make sure it's even and down the bore 1/4-1/2" (depends on who you talk to on the depth). Use a feeler gauge to find the gap...if too small time to use a file and vise unless you build enough engines to warrant the need for the professional rotary tool. So far as I've found if you have a good machinist who checks his tolerances you may not need to file the rings the gap will be within the goal posts of the specs.-D.Idiot |
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| Author: | Fopar [ Sat Jan 19, 2013 8:15 pm ] |
| Post subject: | |
Put only the second ring on the piston you are using to get the ring down the bore. It will give you a nice easy way to know it's square. Richard |
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| Author: | DadTruck [ Sun Jan 20, 2013 7:06 am ] |
| Post subject: | |
if you want to really do it right,, file fit the ring gaps to the bore that they will run in. To get an accurate gap measurement the ring must be square in the bore. When using a piston to square up the ring, the piston skirt needs to be about all the way into the bore. The widest cross section of the piston is usually mid skirt. That will put the ring down in the bore a couple of inches. Unless you are working from the crank side, Then you can get the entire piston in and have the ring about an inch from the top deck for ease of measurement. The machine shop that I work with ground down an old piston pin to a slide in size,, so I was able to hang a rod on a piston using that under sized pin, and using the con rod as a handle on the piston, position a ring in a bore for sizing. |
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