Questions Re: New Piston Rings & Refreshing Cylinders
11-22-2007, 06:56 PM
#16
Rennlist Member
That stuff i use is all gone in a couple of cranks. ask me how i know.
again, from the deveks and greg browns of the world, there is not the break-in in the tradtional sense. Again, the main objective is to protect the piston skirts and bores on the initial start. as you know, this is a dangerous time, especially if it doesnt start right away. the rings are soaked in oil along with the pistons and a little assembly lube/oil mix is spread over the skirts. (and a coating on the cylinders. we are talking a very light coating. again, a couple of cranks and you cant even feel a film on the cylinders
mk
again, from the deveks and greg browns of the world, there is not the break-in in the tradtional sense. Again, the main objective is to protect the piston skirts and bores on the initial start. as you know, this is a dangerous time, especially if it doesnt start right away. the rings are soaked in oil along with the pistons and a little assembly lube/oil mix is spread over the skirts. (and a coating on the cylinders. we are talking a very light coating. again, a couple of cranks and you cant even feel a film on the cylinders
mk
Ring do break in on 928 engines too. I think they will wear in very fast compared to more normal setup. Using stuff that prevent fast wear in might be very bad idea.
IIRR factory says to use normal motor oil on practically everywhere on engine rebuild. For some reason they didn't see the need to use special assembly fluids.
IIRR factory says to use normal motor oil on practically everywhere on engine rebuild. For some reason they didn't see the need to use special assembly fluids.
11-22-2007, 06:58 PM
#17
I think for your response to have the correct information, you would need to adjust some things for our 928 engines which have quite different characteristics.
1. Redline assembly lube doesnt have moly.
2. our 928 bores couldnt be MORE different than Chevy or iron bore engines, for which that information was in reference to.
3. There is not the charateristic "seating" that the rings go through like on a chevy block for example.
4. Honing (cross hatch honing in the traditional sense) with a 928 bore, for example, will destroy itself before it even starts. Honing is using to catch small volumes of oil for ring lubrication. the rings seat and wear this area down to fit. 928s do not break in this way.
By the way, i used the mix of assembly lube (redline) and oil on the cylinders and on the pistons skirts. I was avoiding the ring area, basically like your 1st reference from the lawn mower guide
mk
2) Porsche engines are not made from Spok's Spunk - they are still engines, and follow physical break in principles.
3) Incorrect.
4) I never mentioned honing. Earlier, I menioned Lapping, which is one of the last few steps in a full rebore of an alusil block. Felt pads and a certain paste is used to wear away the aluminum and let the silicon stand proud microscopically. Because of this process, the rings basically wear more than the bores do in a long term relationship. But it wears very slowly.
Break in on these engines is very important in this area, and Assembly lube anywhere near the rings or skirts (which will smear it on the bore and the rings will pick it up) is an incorrect procedure.
11-22-2007, 07:06 PM
#18
Rennlist Member
Its a wonder the engines i built even work at all.
do a search on the break-in process of a chevy vs the porsche and its a little different process. with the porsche we are talking .002" clearance, while the iron blocks are near .015". in one of your excerps, they speak of having the pistons tied to the crank spinning with very easy force. with a 928, the engine is much tighter and takes more to spin it than is referenced there.
Again, you are reading lawnmower articles, and ive fed information by the guys that build some of the most powerful 928 engines in the world.
I think if you saw what i had done, you wouldnt have a problem with it. However, this mixture did touch the rings as it was on the bores. if you have seen the oil ring in action, not much is left on the surface after one stroke of the piston. a little differnt than the iron bore cousins.
mk
do a search on the break-in process of a chevy vs the porsche and its a little different process. with the porsche we are talking .002" clearance, while the iron blocks are near .015". in one of your excerps, they speak of having the pistons tied to the crank spinning with very easy force. with a 928, the engine is much tighter and takes more to spin it than is referenced there.
Again, you are reading lawnmower articles, and ive fed information by the guys that build some of the most powerful 928 engines in the world.
I think if you saw what i had done, you wouldnt have a problem with it. However, this mixture did touch the rings as it was on the bores. if you have seen the oil ring in action, not much is left on the surface after one stroke of the piston. a little differnt than the iron bore cousins.
mk
1) It has EP. Thats why its assembly lube in the first place.
2) Porsche engines are not made from Spok's Spunk - they are still engines, and follow physical break in principles.
3) Incorrect.
4) I never mentioned honing. Earlier, I menioned Lapping, which is one of the last few steps in a full rebore of an alusil block. Felt pads and a certain paste is used to wear away the aluminum and let the silicon stand proud microscopically. Because of this process, the rings basically wear more than the bores do in a long term relationship. But it wears very slowly.
Break in on these engines is very important in this area, and Assembly lube anywhere near the rings or skirts (which will smear it on the bore and the rings will pick it up) is an incorrect procedure.
2) Porsche engines are not made from Spok's Spunk - they are still engines, and follow physical break in principles.
3) Incorrect.
4) I never mentioned honing. Earlier, I menioned Lapping, which is one of the last few steps in a full rebore of an alusil block. Felt pads and a certain paste is used to wear away the aluminum and let the silicon stand proud microscopically. Because of this process, the rings basically wear more than the bores do in a long term relationship. But it wears very slowly.
Break in on these engines is very important in this area, and Assembly lube anywhere near the rings or skirts (which will smear it on the bore and the rings will pick it up) is an incorrect procedure.
11-22-2007, 07:40 PM
#19
Looking at the pictures you post of you doing it on the garage floor, it is indeed.
I don't need to search on this. You need to search on the original topic instead of giving out advice that will make other people's lives very expensive needlessly. Admit you were wrong, and move on Mark.
You are getting on my nerves now. I am here on Thanksgiving arguing a common sense point with someone who has reading comprehension issues, as well as a good dollup of ignorance. And short term memory problems maybe - did you not read the other articles I linked just so you wouldn't focus on the lawnmower? Of course not, because you have no idea what you are talking about in this instance, and you will focus on the lowest common denominator like anyone else in over his head.
Again, you seem to have a fundamental misunderstanding of what an assembly lube is and what it would be normally used for. And as I had originally intended to simply state to the OP that he needs to NOT listen to your comment on assembly lube anywhere near the pistons in this engine or ANY OTHER FREAKING 4 stroke engine, whether it powers a John Deer Tractor or a John Force Top Fuel Dragster, and not get into it with you, I have no idea why I am even still typing.
But hear me now: I am FLUPING glad that you won't be touching the internals of the engine that the "handout" drive is slowly acquiring for you. I hope to high hell that that lump will arrive assembled and Sealed so you can't crack a nut on it. Just plug it in, and continue to drive well and have fun.
I think if you saw what i had done, you wouldnt have a problem with it. However, this mixture did touch the rings as it was on the bores. if you have seen the oil ring in action, not much is left on the surface after one stroke of the piston. a little differnt than the iron bore cousins.
mk
mk
But hear me now: I am FLUPING glad that you won't be touching the internals of the engine that the "handout" drive is slowly acquiring for you. I hope to high hell that that lump will arrive assembled and Sealed so you can't crack a nut on it. Just plug it in, and continue to drive well and have fun.
11-22-2007, 07:44 PM
#20
I am coming off a little harsh here, but I need to make sure I am firm and uncompliant, lest you believe there is a snow flake's chance in hell you were correct with the assembly lube near the piston rings or bores.
11-22-2007, 07:55 PM
#21
Rennlist Member
yeah, you are coming across harsh.
again, the guide did say assembly lube, moly based even, on the skirts. i did this too, plus a mixture of lube on the walls, not focusing on the rings. yes, there would be some residual assembly lube picked up by the rings, but with the skirts coated as well, you would see it on the rings too. So, we can say we have a tie in the argument (that you have made out of this)
there is a world of difference on how a 928 engine "breaks In" vs a iron block.
There are some similarities, but more differences.
again, the assembly lube i used has no moly, and is not like the stuff referenced in the links (and i read them , where much of the stuff is geared toward the iron block engines, and other stuff is the basics).
How do you defenend the article you refernced as saying moly based on the piston skirts, miracle oil on the wrist pins, and oil everywhere else. you dont think the rings can pick up gobs of moly lube by following those instructions?when the lube is on the skirts, its going to find its way to the rings.
anyway, i get you point. You are trying to help someone from making a mistake on assembly. some of the things ive done, like with scots last engine, was done just incase it didnt start right up.
The engine coming will get a shot of oil before i put the heads on and i will run 30 weight for the first 1000miles, just like the article says, and we all know.
However, if it is made right, its probably ready for the dyno within seconds of assembly like Joe fans, andersons and others that have been built by top engine builders.
Hey, no hard feelings. Have a happy thanksgiving. I know we are all trying to help!
Mk
again, the guide did say assembly lube, moly based even, on the skirts. i did this too, plus a mixture of lube on the walls, not focusing on the rings. yes, there would be some residual assembly lube picked up by the rings, but with the skirts coated as well, you would see it on the rings too. So, we can say we have a tie in the argument (that you have made out of this)
there is a world of difference on how a 928 engine "breaks In" vs a iron block.
There are some similarities, but more differences.
again, the assembly lube i used has no moly, and is not like the stuff referenced in the links (and i read them , where much of the stuff is geared toward the iron block engines, and other stuff is the basics).
How do you defenend the article you refernced as saying moly based on the piston skirts, miracle oil on the wrist pins, and oil everywhere else. you dont think the rings can pick up gobs of moly lube by following those instructions?when the lube is on the skirts, its going to find its way to the rings.
anyway, i get you point. You are trying to help someone from making a mistake on assembly. some of the things ive done, like with scots last engine, was done just incase it didnt start right up.
The engine coming will get a shot of oil before i put the heads on and i will run 30 weight for the first 1000miles, just like the article says, and we all know.
However, if it is made right, its probably ready for the dyno within seconds of assembly like Joe fans, andersons and others that have been built by top engine builders.
Hey, no hard feelings. Have a happy thanksgiving. I know we are all trying to help!
Mk
11-22-2007, 08:06 PM
#22
again, the guide did say assembly lube, moly based even, on the skirts. i did this too, plus a mixture of lube on the walls, not focusing on the rings. yes, there would be some residual assembly lube picked up by the rings, but with the skirts coated as well, you would see it on the rings too. So, we can say we have a tie in the argument (that you have made out of this)
However, if it is made right, its probably ready for the dyno within seconds of assembly like Joe fans, andersons and others that have been built by top engine builders.
You keep mentioning top engine builders. If you don't believe me (you obviously don't) then ask them.
11-23-2007, 12:59 AM
#25
Rennlist Member
Thread Starter
Ok, I think I got the lubricant decided upon. I thank you guys for helping me regarding that.
Have any of you had to grind down a bit at the end gaps for proper fit or is it pretty much common to not have to do that and simply install the rings right out of the box? The reason I ask, is that I'm hoping to not have to buy the device for doing this (I'm guessing they're pricey) and I don't want to risk screwing them up by over grinding or grinding at the wrong angle. Mark K., I see where you replied that they are usually fine out of the box, but it would be nice to confirm from a couple testimonials.
Erkka, I do have all of Jim Morehouse's CDs that I bought a couple months back. However, when I open the Technical Publications CD's a greeting page (same on all three) comes up listing what is on them. However, I can't access the info. for some reason. There's nothing to click on that will take you anywhere. I can on everything else though. So, if any of you know the specs for the piston ring end gaps that would be great.
thanks again guys,
Have any of you had to grind down a bit at the end gaps for proper fit or is it pretty much common to not have to do that and simply install the rings right out of the box? The reason I ask, is that I'm hoping to not have to buy the device for doing this (I'm guessing they're pricey) and I don't want to risk screwing them up by over grinding or grinding at the wrong angle. Mark K., I see where you replied that they are usually fine out of the box, but it would be nice to confirm from a couple testimonials.
Erkka, I do have all of Jim Morehouse's CDs that I bought a couple months back. However, when I open the Technical Publications CD's a greeting page (same on all three) comes up listing what is on them. However, I can't access the info. for some reason. There's nothing to click on that will take you anywhere. I can on everything else though. So, if any of you know the specs for the piston ring end gaps that would be great.
thanks again guys,
11-23-2007, 02:13 AM
#26
A little trick related to the ring grinding is that you want to file the outer edge of the gap - so there is no sharp edges to cut into the bore wall on break in or initial startup.
11-23-2007, 02:19 AM
#27
Rennlist Member
This is an area I would have left for the pros. The 4 times Ive done this, the rings had the right gaps so I just put them in from right out of the box. If they would have needed grinding, i certainly wouldnt have done it, I would have sent them out to get cut. (but I didnt need to do it. They always were fine)
mk
mk
Last edited by mark kibort; 11-23-2007 at 02:40 AM.
11-23-2007, 02:19 AM
#28
Rennlist Member
Hey Nicholas, welcome aboard. I'll give some of your questions a shot:
1) Factory spec for end gap on the compression rings is 0.20-0.40mm and 0.40-0.90mm for the scraper ring.
2) When the cylinder is measured for bore spec, that measurment is taken 62mm from the top of the cylinder. This is actually the resting point of the piston skirt at TDC. May not be a bad place to take the ring end gap measurement.
3) Don't mess around with this Nicholas, get the ring installation tool. With the tool installation is a 2 minute job, without it, it takes much longer, is high stress, and if you end up bending a ring or breaking one, you're gonna hate it.
4) You can get these at any automotive supply store, or even Sears or any other department store that carries automotive tools should have it.
5) I believe the ring packet provides the location of the end gaps, and my recollection is that they are 120 degrees offset like Mark mentioned. I don't know how critical the inital positioning of the end gaps are.
6) I'd have good luck with Permatex gasket remover for de-carbonizing the crowns and taking the varnish off the ring lands. I'd leave the pistons on the rods unless you plan on installing new circlips when rehanging the pistons on the rods. The 928 uses floating wrist pins, which means that they sit loose in the piston bosses. There is a wire circlip on either end of the wrist pin which sits in a channel in the pin boss which keeps the wrist pin from sliding out the side of the piston.
7) Sounds like you've made your decision on this one. I dip the pistons upside in a tin of oil up to the wrist pin, and then install. I wouldn't worry about wiping off the excess. Between all the cycling the engine is going to be doing while adjusting cams, timing belt, etc., all the excess will get worked off the cylinder walls.
8) Personally, I wouldn't touch the cylinders short of having a machinest do the final lap sequence with the silcone paste on a proper machine. The clearances are just too tight to be messing with doing anything by hand. JMHO.
You will not have to use a ring end gap tool on these rings. They will be in spec if your bores are in spec. The tolerances on the 928 motor are unreal. It is basically a blue printed motor, and all of the oem parts are built to such high standards that they are blue printed when produced. See for yourself. Load one of the pistons in the cylinder without the rings, take the thinnest depth gauge you have (probably .001"), and try sticking it inbetween the piston and cylinder.
1) Factory spec for end gap on the compression rings is 0.20-0.40mm and 0.40-0.90mm for the scraper ring.
2) When the cylinder is measured for bore spec, that measurment is taken 62mm from the top of the cylinder. This is actually the resting point of the piston skirt at TDC. May not be a bad place to take the ring end gap measurement.
3) Don't mess around with this Nicholas, get the ring installation tool. With the tool installation is a 2 minute job, without it, it takes much longer, is high stress, and if you end up bending a ring or breaking one, you're gonna hate it.
4) You can get these at any automotive supply store, or even Sears or any other department store that carries automotive tools should have it.
5) I believe the ring packet provides the location of the end gaps, and my recollection is that they are 120 degrees offset like Mark mentioned. I don't know how critical the inital positioning of the end gaps are.
6) I'd have good luck with Permatex gasket remover for de-carbonizing the crowns and taking the varnish off the ring lands. I'd leave the pistons on the rods unless you plan on installing new circlips when rehanging the pistons on the rods. The 928 uses floating wrist pins, which means that they sit loose in the piston bosses. There is a wire circlip on either end of the wrist pin which sits in a channel in the pin boss which keeps the wrist pin from sliding out the side of the piston.
7) Sounds like you've made your decision on this one. I dip the pistons upside in a tin of oil up to the wrist pin, and then install. I wouldn't worry about wiping off the excess. Between all the cycling the engine is going to be doing while adjusting cams, timing belt, etc., all the excess will get worked off the cylinder walls.
8) Personally, I wouldn't touch the cylinders short of having a machinest do the final lap sequence with the silcone paste on a proper machine. The clearances are just too tight to be messing with doing anything by hand. JMHO.
You will not have to use a ring end gap tool on these rings. They will be in spec if your bores are in spec. The tolerances on the 928 motor are unreal. It is basically a blue printed motor, and all of the oem parts are built to such high standards that they are blue printed when produced. See for yourself. Load one of the pistons in the cylinder without the rings, take the thinnest depth gauge you have (probably .001"), and try sticking it inbetween the piston and cylinder.
Maybe I'm not looking in the right place in my
WSM. I find a page or two regarding the pistons and rings, but can't locate the answers to these specific questions so I'm just going to ask.
Re: '87-'88 short block to be used in my '90 S4
I have located (but not taken delivery yet) a replacement short block for my '90 S4. It is an '87-'88 (not certain just yet) with approximately 90Kmi. It will come with a set of new piston rings and rod nuts by the dealer to insure good compression when I am through. Although I've done some reading elsewhere on the subject of pistons and rings, I've not answered a few fundamental questions. Can you guys help?
1. When installing piston rings and test fitting them in the cylinders before fitting them onto the pistons, what is the factory tolerance of end gap for this early S4 engine?
2. How far down the cylinder is the best location to make this measurement? Should it be made in multiple locals within the cylinder?
3. Is it really necessary to use the special tool for removing/installing the rings since most of the videos I've seen on the subject simply show the mechanic feeding one end into the piston groove by hand and working it around rather efficiently?
4. If a special tool (spanner) is necessary, where might I find one reasonably as this will be a one time event for me (I hope)?
5. If I understand correctly, all the ring end gaps should not line up and be worked around the piston in such a manner that the end gaps oppose each other. However, is it necessary that the gaps be located in a specific place on the pistons or can it be somewhat arbitrary?
6. When I remove the pistons I will try to clean them up as best I can. Any recommendations on the best chemical or process for cleaning them? Will it be necessary to disassemble the piston from the rod to do this? I'm a little concerned about doing that as I don't know how the rod and piston are married.
7. I realize oil is not desired in the upper portion of the cylinders where combustion takes place. Therefore, how should I go about lubricating the pistons for reassembly? Should I oil them up good and just wipe out the excess after assembly from the upper cylinder walls or am I worrying needlessly about this as I'm just not sure how vital this is?
8. Is there a safe and effective process that you can do at home to lightly hone the cylinders, or at least clean them up a bit for a freshened surface to mate the rings to? I understand some have used the Silicon solution (AN-30 or something like that) with a felt pad, a drill, and special attachment. I'm assuming this would be a very brief activity, but unsure if this is recommended and for how long a duration to hone each cylinder. Someone suggested using sand paper instead (just joking)
.....seriously though.
9. Please include any additional tips or information that you feel would be useful with this project.
Thank you for helping; you guys are great.
WSM. I find a page or two regarding the pistons and rings, but can't locate the answers to these specific questions so I'm just going to ask.
Re: '87-'88 short block to be used in my '90 S4
I have located (but not taken delivery yet) a replacement short block for my '90 S4. It is an '87-'88 (not certain just yet) with approximately 90Kmi. It will come with a set of new piston rings and rod nuts by the dealer to insure good compression when I am through. Although I've done some reading elsewhere on the subject of pistons and rings, I've not answered a few fundamental questions. Can you guys help?
1. When installing piston rings and test fitting them in the cylinders before fitting them onto the pistons, what is the factory tolerance of end gap for this early S4 engine?
2. How far down the cylinder is the best location to make this measurement? Should it be made in multiple locals within the cylinder?
3. Is it really necessary to use the special tool for removing/installing the rings since most of the videos I've seen on the subject simply show the mechanic feeding one end into the piston groove by hand and working it around rather efficiently?
4. If a special tool (spanner) is necessary, where might I find one reasonably as this will be a one time event for me (I hope)?
5. If I understand correctly, all the ring end gaps should not line up and be worked around the piston in such a manner that the end gaps oppose each other. However, is it necessary that the gaps be located in a specific place on the pistons or can it be somewhat arbitrary?
6. When I remove the pistons I will try to clean them up as best I can. Any recommendations on the best chemical or process for cleaning them? Will it be necessary to disassemble the piston from the rod to do this? I'm a little concerned about doing that as I don't know how the rod and piston are married.
7. I realize oil is not desired in the upper portion of the cylinders where combustion takes place. Therefore, how should I go about lubricating the pistons for reassembly? Should I oil them up good and just wipe out the excess after assembly from the upper cylinder walls or am I worrying needlessly about this as I'm just not sure how vital this is?
8. Is there a safe and effective process that you can do at home to lightly hone the cylinders, or at least clean them up a bit for a freshened surface to mate the rings to? I understand some have used the Silicon solution (AN-30 or something like that) with a felt pad, a drill, and special attachment. I'm assuming this would be a very brief activity, but unsure if this is recommended and for how long a duration to hone each cylinder. Someone suggested using sand paper instead (just joking)
.....seriously though.9. Please include any additional tips or information that you feel would be useful with this project.
Thank you for helping; you guys are great.
11-23-2007, 02:25 AM
#29
Rennlist Member
Brendan, 5hp lawn mower engines from Briggs and Stratton are 2 stroke?
Really????? dont think so Brendan.
from your article as well, specifically using assembly lube on piston skirts. how it doesnt contaminate the rings, is a mystery (not the oil )
mk
I recommend Marvel Mystery oil for ring land lubrication, use automatic transmission oil on the cylinder bore (any type is fine) and on the piston skirts, wrist pin and the rest of the engine use our 2115 engine assembly lube, do not use on piston rings. These are many engine secrets shared by no one, so take advantage of them; of coarse we teach you these and many more things at our Tech School.
Really????? dont think so Brendan.
from your article as well, specifically using assembly lube on piston skirts. how it doesnt contaminate the rings, is a mystery (not the oil
)mk
I recommend Marvel Mystery oil for ring land lubrication, use automatic transmission oil on the cylinder bore (any type is fine) and on the piston skirts, wrist pin and the rest of the engine use our 2115 engine assembly lube, do not use on piston rings. These are many engine secrets shared by no one, so take advantage of them; of coarse we teach you these and many more things at our Tech School.
No - Forget the lawnmower article. And stop with the chevy engines are different thing. That has nothing to do with what the rings can cut through and cannot cut through. There is no tie, and no assembly lube is supposed to be on the bores or pistons(possibly on the pin, but only under the piston with none on the sides that could squeeze to the skirts. Notice I mentioned 4 stroke. That mower article should not have been there, as those are two strokes and wear out very fast, technically speaking.
You keep mentioning top engine builders. If you don't believe me (you obviously don't) then ask them.
You keep mentioning top engine builders. If you don't believe me (you obviously don't) then ask them.
Last edited by mark kibort; 11-23-2007 at 03:47 AM.
11-23-2007, 02:29 AM
#30
Rennlist Member
Mark, are you commenting here that you've actually had to have 928 rings cut because the end gaps were too tight out of the box? I find that hard to believe.