10-30-2023, 12:35 PM | #1 |
Drives: audi s3 2008 bmw 135 2010 Join Date: Mar 2020
Location: argentina
Posts: 14
|
ring clearence tip
what ring clearance to use on mahle 2618 forged pistons
manufacturers data top ring minimum 0,0070 second ring minimum 0,0070 oil ring rall 0,015 4000 example top 0,028 2nd 0,028 oil ralls 0,015 what measure do you recommend? i think the first measures are with little clearance and the second excessive |
10-30-2023, 03:26 PM | #2 |
Drives: SS 6 speed of course Join Date: Jan 2016
Location: Hilo, HI
Posts: 4,320
|
it all depends what you are doing, a street driver with maybe some mild track action can get away with tighter clearance vs something that is going to road race or run the Texas mile. 2nd, FI and / or meth and / or E85 can add heat load and will need more clearance. I forgot what I set mine at but it is FI and E85. .007 is way too tight off the top of my head. I think I set my top ring at .022 but I'll leave it to others who have build more LT1 and /or actually racing their rides.
My car does not seem to burn much oil say 1/2 quart between 5000 mile oil changes, street driven (but pretty hard on it). I thought it would burn more and have more piston slap with the forged pistons, but nope seems to run fine. You really need a ring grinding tool, doing it with a vice and a file is pain and take WAY more time. https://www.wiseco.com/auto/wiseco-a...bout-ring-gap/
__________________
Forged short block, large duration sub .600 lift Cam Motion cam, 7200 RPM fuel cut, Pray Ported Heads, 3.85 pulley D1X, stage II intercooler, DSX secondary low side, DSX E85 sensor, Lingenfelter big bore 2.0 pump, ported front cats, 60608 Borla, LT4 injectors, ZL1 1LE driveshaft and Katech ported TB, ported MSD intake, BTR valvetrain, ARP studs, ProFlow valves, PS4 tires.
|
10-30-2023, 04:32 PM | #3 |
Drives: audi s3 2008 bmw 135 2010 Join Date: Mar 2020
Location: argentina
Posts: 14
|
thanks
i want to use it in mile races... centri ecs supercharger flex fuel 20% approximate 700 hp at wheel kit Mahle/Molnar LT1/L86 Drop In Piston and Rod Kit LSXLT1STD-KIT ..10.2 compression https://www.lsxceleration.com/mahle-...lsxlt1std-kit/ |
11-01-2023, 10:10 AM | #4 | |
Drives: BLUE CAMARO ZL1 1LE M6 Join Date: Jun 2009
Location: ON THE DYNO WATERBURY CT.
Posts: 15,225
|
Quote:
The ring gaps that are recommended with the rings, estimate how much growth you will have in that particular ring material and diameter due to estimated cylinder temp as a result of intended use. That is why they use a gap calculation, X thousands multiplied by Bore inches. It is safer to go on the big side of spec for your application if you do not have a Highly qualified tuner but you will give up oil control and ring seal. A bad tune will overheat the rings and butt the gaps. I can run on the tighter side of recommended gaps because I tune the cars myself and alway makes sure they have adequate fuel system components for the target Horsepower. Everyone says ring gaps are the problem when an LT1 fails which is not the case. It is and always will be a bad tune, lack of fuel or both. We run Factory stock LT1 long block, up to 750 RWHP. or 860 Crank HP with no issues. Ted.
__________________
www.jannettyracing.com
Celebrating 37 years Performance parts, Installation, Fabrication, Dyno tuning, Remote custom tuning, and alignments. 203-753-7223 Waterbury CT. 06705 email tedj@jannettyracing.com |
|
11-19-2023, 05:41 PM | #5 | |
Drives: SS 6 speed of course Join Date: Jan 2016
Location: Hilo, HI
Posts: 4,320
|
I thought this was a good talk on rings, interesting that hypereutectic pistons need more gap vs forged 4032 / 2618. WEISCO and Jimmy Barton say to run more 2nd ring gap, especially on FI. so that would be at least .0057x 4.065= .023 for me, and you would be something like .0063 x 4.065= .0256, which to my mind is HUGE, but I only build daily driven street cars. Maybe a call to the piston manufacture would be good as you are actually building a racing engine running at high HP over long(er) distances. As stated, my engine maybe burns .5 quarts between oil changes, maybe... The stock ring gap and FI: while maybe OK for guys running on a dyno or 1/4 mile at a time, could be a likely failure point in mile and or road racing; but this extrapolating two extremes, assuming the engine is tuned correctly. Here let me put it this way, if somebody said hey I'm running 700 wheel HP FI on a stock engine what would be the quickest way to fail it, I'd say run the Silver State or the Texas mile a few times back to back or a long road race course over several weekends, I would say a likely failure point would be piston ring at the gap due to heat load. OK, take same engine increase ring gap and then ask what the most likely cause of failure would be... dunno burned intake valve or a burned piston as shots in the dark. Point being the LT1 is pretty strong but runs NA ring gaps on a cast high comp NA piston and just by increasing the gap brings a likely failure point to one a non-issue. Please understand that my labor is free and I'm not advocating everybody drop $2000 to tear their stock short bock apart. I'm just pointing out there is a big gap (pun intended) between OEM NA and a 2618 motor running mile races.. Here is a link to the pistons and you will note a 2618 piston is pretty exotic. https://www.motortrend.com/how-to/na...iston-choices/
__________________
Forged short block, large duration sub .600 lift Cam Motion cam, 7200 RPM fuel cut, Pray Ported Heads, 3.85 pulley D1X, stage II intercooler, DSX secondary low side, DSX E85 sensor, Lingenfelter big bore 2.0 pump, ported front cats, 60608 Borla, LT4 injectors, ZL1 1LE driveshaft and Katech ported TB, ported MSD intake, BTR valvetrain, ARP studs, ProFlow valves, PS4 tires.
Last edited by oldman; 11-19-2023 at 06:28 PM. |
|
|
|
Post Reply
|
|
|