Piston ring gap specifications?

[Jon K]

My friend who is building my bottom end is asking what I want to run in terms of ring gap and I told him "I am not sure."

I was wondering what the stock default ring gap setup is like for an M50 non vanos.

[632 Regal]

3?

[Jon K]

Thanks for wasting my time Jeff.


Bill R/Winfred do you guys know? I have a formula given to me on how to open up the gap for Nitrous/Turbo, but I want to see how their derivative compares to the default gap.

[whiskychaser]

Well I'm not taking mine out just to let you know :-) But you might find this article of interest:

http://www.diagnosticengineers.org/Page%20B5-37.htm

[pgrindstaff]

Found this (http://forums.bimmerforums.com/forum/archive/index.php/t-411517.html), not sure if they are the numbers you are looking for.

[Jon K]

Hey guys I am not looking for ring size, I am looking for gap size. Thanks though!

[632 Regal]

Your very welcome Jon

Thanks for wasting my time Jeff

[632 Regal]

really for a smart guy you arent very resourceful now are you?
Piston rings : Gap: Top & bottom compression rings = 0.0080-0.0160" ; oil ring = 0.0080-0.0180

Hey guys I am not looking for ring size, I am looking for gap size. Thanks though!

[Jon K]

really for a smart guy you arent very resourceful now are you?
Piston rings : Gap: Top & bottom compression rings = 0.0080-0.0160" ; oil ring = 0.0080-0.0180

Actually Jeff I am at work, I was on my lunch break. I don't sit around all day online... unfortunately ;)

[632 Regal]

im not sitting around and i dont get a lunch break, i've been working all day too.... I can multi task and manage time :D
Actually Jeff I am at work, I was on my lunch break. I don't sit around all day online... unfortunately ;)

[NovceGuru]

Today, 01:29 PM
Today, 02:23 PM
Today, 02:58 PM
Today, 05:10 PM

In Jeff's defense google DOES load faster then bimmer.info (especially when it's down ;))

[NovceGuru]

google.com

Download Times*
Connection Rate Download Time
14.4K 8.97 seconds
28.8K 4.69 seconds
33.6K 4.07 seconds
56K 2.60 seconds
ISDN 128K 1.08 seconds
T1 1.44Mbps 0.46 seconds

bimmer.info

Download Times*
Connection Rate Download Time
14.4K 15.31 seconds
28.8K 9.26 seconds
33.6K 8.39 seconds
56K 6.31 seconds
ISDN 128K 4.15 seconds
T1 1.44Mbps 3.28 seconds

[632 Regal]

long lunch today jon?
Originally Posted by Jon K
Actually Jeff I am at work, I was on my lunch break. I don't sit around all day online... unfortunately

Today, 01:29 PM
Today, 02:23 PM
Today, 02:58 PM

[attack eagle]

ENOUGH!


Like most businesses, I am sure Google and most other websites are blocked.

Question is answered, now move on.

[Jon K]

long lunch today jon?

I take a broken up hour of lunch. You see, I multitask too, across 48 servers managing ballistic missile data structures... kthxbye.

Jeff I get a distinct feeling you don't like me. Is it a jealousy thing?

[Sam-Son]

really for a smart guy you arent very resourceful now are you?...
Hey who said Jon was a smart guy? Just because he can reengineer his car better than the BMW factory can all by himself doesn't make it so:p

[632 Regal]

Hit the nail on the head jon, your my idol.
is it a jealousy thing?

[Jon K]

Hit the nail on the head jon, your my idol.

Well the theories that be say that must be it, because I have never even exchanged posts with you, so there is no contextual exchange that could have caused your being an ******* toward me.

Needless to say, engines built with google are the easiest ones to pass on the drag strip. Sorry for being anal, but I am not about to google "M50 piston ring gap" and call it done... I have a little too much labor invested in my motor to **** it up.

[attack eagle]

SHUT UP! BOTH OF YOU!

[Blitzkrieg Bob]

SHUT UP! BOTH OF YOU!

Oh oh, he's pissed now...he's using the big font!

[attack eagle]

no kidding, I am pissed off.
It's getting to be like a freaking e36 forum in here, what with the constant personality conflicts between these 2-4 people.
And coming to check my subscriptions only to find multiple worthless e penis posts is really annoying.

How about you all just pm each other your insults and snide comments and save the forum from reading your e-posturing... or do you feel that you need an audience to play to for approval since your Daddy wasn't there?

http://www.youtube.com/watch?v=vC555fTgqfk

[Jon K]

no kidding, I am pissed off.
It's getting to be like a freaking e36 forum in here, what with the constant personality conflicts between these 2-4 people.
And coming to check my subscriptions only to find multiple worthless e penis posts is really annoying.

How about you all just pm each other your insults and snide comments and save the forum from reading your e-posturing... or do you feel that you need an audience to play to for approval since your Daddy wasn't there?

http://www.youtube.com/watch?v=vC555fTgqfk

Dude wtf though, I posted a question and Jeff has to be an ass? I have no issue with anyone on this forum - I never have! I don't understand his hostility - I find it childish. Last time I checked I am the 20 something and he's the ....? It's lost its amusement factor when he chimes in "3" - great way to bump his post count to 15,000. I'd suffice to say that maybe 10% of those posts had useful information in them. Why **** up someones thread with ********? Why bring this up like I am trying to have this conversation? I want to know piston ring gap earlier in the day. I never asked for this ********!

[Blitzkrieg Bob]

There are far worse BMW forums out there.

I go to a regional one where half the posts are for other cars and crap.

[Jon K]

There are far worse BMW forums out there.

I go to a regional one where half the posts are for other cars and crap.

I'll be honest - I post on .info for two reasons:

1) Bill R
2) Winfred

(in no order)

In doing that, I update my build progress to let people in on what I am up to. Other than that, I don't post on here regarding too much non-technical ****. That's why I expected, at the very least, to come back to the thread and see some TIS clips or postings from Bill/Winfred - not Jeff being an as...

[Blitzkrieg Bob]

Face it, you're just Jeff's Pinata

[Jon K]

Face it, you're just Jeff's Pinata

And he's just a mile marker to me.

[94_e34_525i]

Jon I don't know you but damn calm down buddy he was probably just joking LOL. No need to take things seriously. Can't we all just get along.

BTW: Ive been a member for a while even tho i have like barely any posts, and I follow your work it is very impressive i wish i had your patience with all those electronic gizmo's you put in your car, and of course the huge turbo which i show my friends when they ask me what i can do to my car lol. It would also be nice to have a lot of funds like yourself. :D

[Anton CH.]

Wow, you start **** on every forum? It used to be a daily thing on BF.c and now on here?

I found Jeff pretty helpfull when I was doing my diff. If anything he did you a favor by giving a free bump.

[Jon K]

Jon I don't know you but damn calm down buddy he was probably just joking LOL. No need to take things seriously. Can't we all just get along.

I am really chill trust me - thats the ironic part. If it were just in this thread I'd blow it off. But recently Jeff has been giving me **** every which way! For no founded reason!



BTW: Ive been a member for a while even tho i have like barely any posts, and I follow your work it is very impressive i wish i had your patience with all those electronic gizmo's you put in your car, and of course the huge turbo which i show my friends when they ask me what i can do to my car lol. It would also be nice to have a lot of funds like yourself. :D

Thanks man - you can do it - I built most of the car how it is today on a college student budget of saving and working on the side doing ECU builds. If you know what to buy and know how to build it, anything is possible.

[Macv]

buddy he was probably just joking LOL

Really, I laughed at the 3 comment. And I laughed at yours after his... I didn't realize you were upset. However, I do see why you would be. You didn't expect a quick dumbass response.

Reminds me of this...

http://www.collegehumor.com/video:1771556

Halarious... :)

[Jon K]

Wow, you start **** on every forum? It used to be a daily thing on BF.c and now on here?

I found Jeff pretty helpfull when I was doing my diff. If anything he did you a favor by giving a free bump.

Anton please, stay out of what you don't understand. I didn't start anything. If you want to follow me around on forums, search my name on here and see how much "****" I start. This is the third or fourth thread Jeff has started with the ridiculous posts. I don't do anything here but post technical ****.

He didn't bump my thread, look at the time stamps before you try and make a comment like that - a 20 min bump? Eh....right.

[94_e34_525i]

Jon thats exactly how I approach my car as well with a limited budget thats how its been since ive had it because I attend university, and you know how that is. And i find when I approach things that way I get more innovative, but innovation can only help so far as money tends to be my limiting factor on my car.

[Jon K]

Jon thats exactly how I approach my car as well with a limited budget thats how its been since ive had it because I attend university, and you know how that is. And i find when I approach things that way I get more innovative, but innovation can only help so far as money tends to be my limiting factor on my car.

That is true but for instance I couldn't afford to get my pistons ceramic/teflon coated so I researched and found the materials myself for $30 ea. Did the work myself, would have cost me like $250. My turbo setup (without engine work and recent add ons) was only ~$2750

[94_e34_525i]

$2750..? wow thats pretty cheap considering some kits for the m50 are around like $5400. I think it all comes down to finding the right parts at the right price at the right time. Oh since Ive seen that one of your friends has a GTI (on your site), are the Mk2's any good? I found a 88' 16valve for 700 bucks. Would that be a good project car?

[attack eagle]

Heck yes, especially if you are down for an engine transplant.
Good chassis, good moddability, very light weight by today's standards.

[Evan]

I thought romance was dead until I saw Jon and Jeff parading their thinly-veiled homolust for each other in plain view.

Anayone care to make it a trois?

[Jon K]

$2750..? wow thats pretty cheap considering some kits for the m50 are around like $5400. I think it all comes down to finding the right parts at the right price at the right time. Oh since Ive seen that one of your friends has a GTI (on your site), are the Mk2's any good? I found a 88' 16valve for 700 bucks. Would that be a good project car?

16v motors dont stay in for any amount of time around us here. grab a 2.8L VR6 12v from a passat/jetta glx and swap it and its a pretty fun car (as fun as fwd can be). similar power/weight as a M50 swapped E30.

[Blitzkrieg Bob]

Anayone care to make it a trois?

You volunteering?

I'll sponser your Astroglide tab

[94_e34_525i]

16v motors dont stay in for any amount of time around us here. grab a 2.8L VR6 12v from a passat/jetta glx and swap it and its a pretty fun car (as fun as fwd can be). similar power/weight as a M50 swapped E30.

Thanks for the input Jon, ill keep that in mind do I have to make custom motor mounts to pop a VR6 in?

[Jon K]

Nah you don't everything already fits what you normally do is use the subframe from the other car.

[ironie]

I thought romance was dead until I saw Jon and Jeff parading their thinly-veiled homolust for each other in plain view.

Anayone care to make it a trois?

It could be Chuckie was right...You do seem a bit of a twat, And you were giving Bob A hard time...Hummm

The e-penis's seem to rage every now and then don't they

[Jon K]

Guys not to break up the self-reflection but I do need to know stock M50 Non vanos 84mm bore piston ring gap. I am looking around and not finding anything official.

[ironie]

Guys not to break up the self-reflection but I do need to know stock M50 Non vanos 84mm bore piston ring gap. I am looking around and not finding anything official.
I see nothing definitive or authorititive on a short search. The best info seems to come from

http://bmwe34m5.com/book/export/html/1

"The piston clearances:
New engine:
S38 0.03 - 0.06 mm
S14 0.03 - 0.06 mm
M20 0.01 - 0.04 mm
M30 0.02 - 0.05 mm
M50 0.01 - 0.04 mm
Used engine:
S38 0.15 mm
M30 0.15 mm
M50 0.15 mm
- Also the Oil control piston ring has a side clearance of 0.02 - 0.055 for all the engine's"



It isn't like it is a varitiable thing for BMW. Builders may mess with such, But certainally at thier own disgression or experience
By builders I mean guys with full machine shops and heafty math degrees.



Can I ask why it is a question for you. Your pistons are a stock diameter I assume, and you want rings for them. Planning on making them yourself?
(not being a smartass, just curious)

Read back, sorry, Friend asked...ok

[Jon K]

You can't just go gapping your rings to the specs of another engine!

[ironie]

You can't just go gapping your rings to the specs of another engine!

"Also the Oil control piston ring has a side clearance of 0.02 - 0.055 for all the engine's" or so it says

[ryan roopnarine]

you need the file from the repair manual disk for that info. i just ran a serach for *.pdf on my comp and only found the bentley, so it must be on one of the hard drives sitting beside my computer.

[632 Regal]

Hahaha that vids great!
.

http://www.collegehumor.com/video:1771556

Halarious... :)

[ironie]

84 mm
- the stock piston ring size of
83.98
equals
.02

That hurt my brain
I need beer

BTW next up is 84.230 and 84.480 which are the 1st and 2nd oversize for rebored pistons

[Evan]

it could be i'm a twat (you can look up my posts and see everything i've written for the past five years)

or it could be that i have a strong dislike for internet tough guys who have no respect or regard for their community...

i doubt any of you act this way in real life at your neighborhood pub... why do it online in a place that is so useful to so many of us.. and in a place where so many people are so generous with their time and expertise?

so i'm not a ''twat'' but i won't stand by while a handful of people piss in my pool....

[ironie]

Your right, when some guy gets up and starts seriously telling his mates and fellow pub gooers about thier "homo lust" someone usally gets slapped and that is the end of it or not. If a slap doen't work a trip out to the parking lot usally does.

I like most of you guys, based on what I have read, But you really put dents into your credibility when you start acting like poorly behaved 10 year olds. And sadly in encorages the idiot in me as well, You guys should settle your personal diffierences in private and not keep trying to score points on the public forum, looking for morons like me to fan the fires.
Maybe that is what happened to Gayle, maybe she got tired of watching the warring e-penis's
Some of us like a good burn, It makes room for new growth

Just my .02 cents as a dead "noob"

Have a pleasant day
Regards
Ron

[Jon K]

Top Comp Ring:
End clearance: 0.008-0.016" or 0.2-0.4mm
Side clearance: 0.0008-0.0020" or 0.02-0.052mm

Bottom Comp Ring:
End clearance: 0.008-0.016" or 0.2-0.4mm
Side clearance: 0.0008-0.0020" or 0.02-0.052mm

Oil Control Ring:
End clearance: 0.008-0.018" or 0.2-0.45mm
Side clearance: 0.0008-0.0022" or 0.02-0.055mm

Thanks to Dave M via PM. Thats all I wanted. Have a nice day guys.

[ironie]

I gave you the same numbers.
You are welcome

[Jon K]

I gave you the same numbers.
You are welcome


Your stuff said 0.01 - 0.04mm versus Dave 0.1 and 0.4mm big difference

Thank you though

[ironie]

My appologies, I misread you

you had better check up on that big difference, I also listed you all availiable stock ring sets for overbores as well

[Jon K]

My appologies, I misread you

you had better check up on that big difference, I also listed you all availiable stock ring sets for overbores as well

I am very much glad you editted your original post. I won't post your original response (though the name calling was cute), I can read, and you posted 0.01 - 0.04mm which is:

0.0003 - 0.0015", which is very different from 0.008 - 0.015"... and like I said, this is why I don't use google to try and find measurements down to the thousandths of an inch.

Thanks anyway for trying to get the figures

[ironie]

I didn't try. if you look at the availiable piston rings availiable you will see I am right, But you could always prove me wrong by using the wrong number, Not all of what I retracted was unappropriate.
It may have just been mistimed
Have a pleasant day

[Jon K]

I didn't try. if you look at the availiable piston rings availiable you will see I am right, But you could always prove me wrong by using the wrong number, Not all of what I retracted was unappropriate.
It may have just been mistimed
Have a pleasant day

You told me to gap my rings 0.0003 - 0.0015"

Correct as per BMW TIS (what i wanted) is 0.008 - 0.015"

That is a very big error...

Especially when I am doing math from the stock numbers to open up the gap for nitrous/turbo. I would have been 10 times too small of a gap!

[ironie]

fruggit

[Jon K]

Maybe I have forgotten how to count, but 3.98 +.02 equals the size of the bore. Your gap is .02 But then again, I do it every day professionaly

The fact you don't know or seem to understand, shows you shouldn't even be considering changing it

Sigh.

Have a nice day.

This isn't the first time I've built an engine - it's the first time I've built an M50 and I want the RIGHT numbers.

What are you talking about 3.98 + 0.02? I think you mean 83.98 + 0.02 yes that takes up my bore. However, I don't know why you're finding the difference between it and the bore. Applications have different gap. I am actually going to be slightly larger than the standard bore/gap because of nitrous and turbocharging. The diameter of the bore is sort of proportional to the gap, but that doesn't mean you just gap a ring 0.02mm because your total bore size is 84mm. It's going to expand more with the application I am using. Trust me - go to CP pistons webpage and look up their information. You will see the figures you're supplying are 10x off.

[Macv]

I didn't try. if you look at the availiable piston rings availiable you will see I am right, But you could always prove me wrong by using the wrong number, Not all of what I retracted was unappropriate.
It may have just been mistimed
Have a pleasant day

Why are you fighting? Swallow your pride if you have to and just let the thread die.

[ironie]

BTW Doing machine work in sae is archaic .02 mm is .00762"
Even before I left the states we did all cnc work in mils. It saves a lot of grief
All mesaurement were of course in metric, Thats the way the BMW you are working on was designed and sold as well. It is after all a 2.5 liter engine not a 2.6425 quarts engine

[Jon K]

BTW Doing machine work in sae is archaic .02 mm is .00762"
Even before I left the states we did all cnc work in mils. It saves a lot of grief
All mesaurement were of course in metric, Thats the way the BMW you are working on was designed and sold as well. It is after all a 2.5 liter engine not a 2.6425 quarts engine


Hey bro - cmon. I really hope you're just confused or tired or something, or maybe you're making being a machinist up, I don't really care, but:

0.02mm / 25.4 = 0.000787" not .00762"

Don't you see?

This is the root of how you were wrong earlier. You are 10x too small in your calculations, and even still ...762 does not equal ...787

And this is the reason I do not want people just feeding me random numbers, this is an engine that has had probably 150 hrs put into it so far, I don't need wrong numbers, I can come up with those easily :)

You're must wrong man. No offense, but it's wrong.

[ironie]

http://www.worldwidemetric.com/metcal.htm

did the math, and you are right, and they are wrong

I am sure they would appreciate your corrections
I didn't bother doing the math myself Jon. It isn't like it is my engine
but all the same the ring sets come in

83.98 mm
84.230 mm
84.480 mm

So the gap is the ring set.
minus what your bore really is.
A number you should have by now as
you are having it machined.

As to what your gap should be for nitrus, you are absolutely right
I don't know a ****ing thing about it.
All I answered is what the "stock gap is" you go where ever you wish with it.

[Macv]

hooray! resolution!

[632 Regal]

looks like I was right on here after all, just a tighter gap because it was for a high performance application... :D



Piston rings : Gap: Top & bottom compression rings = 0.0080-0.0160" ; oil ring = 0.0080-0.0180

[Jon K]

looks like I was right on here after all, just a tighter gap because it was for a high performance application... :D

You open the gap the higher performance you go. Reason being, more power = more heat. Its not necessarily based on power though - nitrous/turbo/supercharged street cars run a slightly more open gap than stock. All nitrous race cars run larger, next up is turbo and nitrous, and then after that is alcohol which has some very large gap to help put more compression behind the "compression" ring so the thing seals.

A guy here has a 6.4 second alcohol blown nitrous racecar fully built motor and runs some ridiculous ring gap. He actually has to have two 8 QT catch cans according to the NHRA rules - the blow by is spectacular.