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Leak Down Test Problem on #2 Cylinder #2970959 10/05/21 02:29 PM 10/05/21 02:29 PM
Joined: Jan 2005 Posts: 3,635 Oakland, MI D dizuster OP master
dizuster OP master D Joined: Jan 2005 Posts: 3,635 Oakland, MI	Anybody got some JB weld or a caulk gun I can borrow? Seems like I need to make a minor repair to #2 piston.

Re: Leak Down Test Problem on #2 Cylinder [Re: dizuster] #2970976 10/05/21 02:56 PM 10/05/21 02:56 PM
Joined: Aug 2003 Posts: 4,675 On the parachute mount N n20mstr master
n20mstr master N Joined: Aug 2003 Posts: 4,675 On the parachute mount	Ring Gap looks to be a little too big. Thats why your leakdown was excessive ....BAD A$$ STREET CAR.....

Re: Leak Down Test Problem on #2 Cylinder [Re: n20mstr] #2970977 10/05/21 02:57 PM 10/05/21 02:57 PM
Joined: Dec 2013 Posts: 4,672 Wichita G GY3 master
GY3 master G Joined: Dec 2013 Posts: 4,672 Wichita	Yikes! And here I figured the cast crank would be the first to go! How much boost were you throwing at it? '63 Dodge 330 11.19 @ 121 mph Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs. 10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.

Re: Leak Down Test Problem on #2 Cylinder [Re: n20mstr] #2970986 10/05/21 03:11 PM 10/05/21 03:11 PM
Joined: Jan 2003 Posts: 13,360 Marion, South Carolina [><] an8sec70cuda I Live Here
an8sec70cuda I Live Here Joined: Jan 2003 Posts: 13,360 Marion, South Carolina [><]	Originally Posted by n20mstr Ring Gap looks to be a little too big. Thats why your leakdown was excessive Only to be made worse by the too large gas porting. CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 18 spline 4 speed, Dana 60 '71 Demon, 340, low gear 904, 8.75 '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax

Re: Leak Down Test Problem on #2 Cylinder [Re: dizuster] #2971008 10/05/21 03:51 PM 10/05/21 03:51 PM
Joined: Aug 2003 Posts: 43,157 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,157 Bend,OR USA	Originally Posted by dizuster Anybody got some JB weld or a caulk gun I can borrow? Seems like I need to make a minor repair to #2 piston. Welcome to the I broke parts racing club Time to get to work to make it stronger so it will take more abuse and make more power Sorry for your loss Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Leak Down Test Problem on #2 Cylinder [Re: Cab_Burge] #2971080 10/05/21 06:17 PM 10/05/21 06:17 PM
Joined: Mar 2011 Posts: 3,074 Michigan A A727Tflite master
A727Tflite master A Joined: Mar 2011 Posts: 3,074 Michigan	Not sure where that piston came from originally, doesn’t look at all like this Chinese piston. 😂. Ah So. Last edited by Transman; 10/06/21 10:26 AM.

Re: Leak Down Test Problem on #2 Cylinder [Re: A727Tflite] #2971088 10/05/21 06:55 PM 10/05/21 06:55 PM
Joined: Jan 2003 Posts: 8,164 Plymouth, MI Blusmbl master
Blusmbl master Joined: Jan 2003 Posts: 8,164 Plymouth, MI	There are better ways to reduce the compression ratio! '18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III - 11.37 @ 118

Re: Leak Down Test Problem on #2 Cylinder [Re: Blusmbl] #2971129 10/05/21 08:50 PM 10/05/21 08:50 PM
Joined: Feb 2005 Posts: 20,172 PA. pittsburghracer "Little"John
pittsburghracer "Little"John Joined: Feb 2005 Posts: 20,172 PA.	Wholly meltdown Batman!! Sorry to see that. 1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27 Livin and lovin life one day at a time

Re: Leak Down Test Problem on #2 Cylinder [Re: dizuster] #2971137 10/05/21 09:03 PM 10/05/21 09:03 PM
Joined: Jan 2003 Posts: 1,020 Andrews,In. U.S.of A. 6 67_Satellite super stock
67_Satellite super stock 6 Joined: Jan 2003 Posts: 1,020 Andrews,In. U.S.of A.	I have nightmares that end looking like that.

Re: Leak Down Test Problem on #2 Cylinder [Re: 67_Satellite] #2971158 10/05/21 09:45 PM 10/05/21 09:45 PM
Joined: Mar 2011 Posts: 3,074 Michigan A A727Tflite master
A727Tflite master A Joined: Mar 2011 Posts: 3,074 Michigan	Did it launch a breather off the valve cover when this happened ?

Re: Leak Down Test Problem on #2 Cylinder [Re: A727Tflite] #2971194 10/05/21 11:11 PM 10/05/21 11:11 PM
Joined: Apr 2006 Posts: 4,220 West Plains, MO DrCharles master
DrCharles master Joined: Apr 2006 Posts: 4,220 West Plains, MO	Originally Posted by Transman Not sure where that piston came from originally, doesn’t look at all like this Chinese piston. That one looks more like the head came off a Chinese valve and beat the crap out of the piston and cylinder head?

Re: Leak Down Test Problem on #2 Cylinder [Re: DrCharles] #2971204 10/06/21 12:15 AM 10/06/21 12:15 AM
Joined: Aug 2003 Posts: 43,157 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,157 Bend,OR USA	Broken valves don't normally melt aluminum, especially like this one did Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Leak Down Test Problem on #2 Cylinder [Re: Cab_Burge] #2971211 10/06/21 01:11 AM 10/06/21 01:11 AM
Joined: Dec 2018 Posts: 53 Northern Bavaria / Germany MichaelF member
MichaelF member Joined: Dec 2018 Posts: 53 Northern Bavaria / Germany	ouch....lean condition under boost?

Re: Leak Down Test Problem on #2 Cylinder [Re: A727Tflite] #2971212 10/06/21 01:24 AM 10/06/21 01:24 AM
Joined: Sep 2010 Posts: 342 Indiana Gabby63 enthusiast
Gabby63 enthusiast Joined: Sep 2010 Posts: 342 Indiana	That piston has Holloween all over it , lol Gary

Re: Leak Down Test Problem on #2 Cylinder [Re: Gabby63] #2971231 10/06/21 07:50 AM 10/06/21 07:50 AM
Joined: Mar 2006 Posts: 9,834 MI, usa dvw master
dvw master Joined: Mar 2006 Posts: 9,834 MI, usa	Funny thing was it was barely smoking out the exhaust after a 139.7 mph pass. No oil out of the breather. Doug

Re: Leak Down Test Problem on #2 Cylinder [Re: dvw] #2971250 10/06/21 09:01 AM 10/06/21 09:01 AM
Joined: Jan 2005 Posts: 3,635 Oakland, MI D dizuster OP master
dizuster OP master D Joined: Jan 2005 Posts: 3,635 Oakland, MI	It actually shocks me how little it was smoking for how big that hole was!!!! What you're looking at is a custom made Diamond Piston specific for my turbo application. 2818 material, Thick crown, ring is down a bunch, etc... Certainly no fault of the piston. It had hurt the converter at Monster Mopar earlier this year, and wouldn't 60ft at all. So I was leaning on the tune pretty hard to get it to run 10.0 for the shootout (about 20-21psi of boost). Went 9.98@139.7mph on the last pass. It's a little bit strange because the A/F wasn't excessively lean on the data logger, nor do any of the other cylinders look like they had anything wrong with them. #1 and #2 cylinders always run the hottest on this car, so as I was adding boost/timing, I was watching #1 carefully. Whoops... should have been watching #2 apparently! We will see if the block is going to clean up. Hopefully I can just slap another set of pistons in it and go... but we'll see. It is absolutely amazing to me that the piston can take that kind of abuse, and the stock block/cast crank still survives!!!!

Re: Leak Down Test Problem on #2 Cylinder [Re: dizuster] #2971260 10/06/21 09:47 AM 10/06/21 09:47 AM
Joined: Jan 2003 Posts: 4,713 Moved to N.E. Tennessee GomangoCuda master
GomangoCuda master Joined: Jan 2003 Posts: 4,713 Moved to N.E. Tennessee	Sharp edge on the valve notch likely caused that. In theory, there is no difference between theory and practice. In practice, there is.

Re: Leak Down Test Problem on #2 Cylinder [Re: GomangoCuda] #2971294 10/06/21 11:46 AM 10/06/21 11:46 AM
Joined: Dec 2018 Posts: 53 Northern Bavaria / Germany MichaelF member
MichaelF member Joined: Dec 2018 Posts: 53 Northern Bavaria / Germany	What Kind of head gasket do you run with this Engine?

Re: Leak Down Test Problem on #2 Cylinder [Re: Cab_Burge] #2971385 10/06/21 03:38 PM 10/06/21 03:38 PM
Joined: Apr 2006 Posts: 4,220 West Plains, MO DrCharles master
DrCharles master Joined: Apr 2006 Posts: 4,220 West Plains, MO	Originally Posted by Cab_Burge Broken valves don't normally melt aluminum, especially like this one did I thought it was pretty obvious I was referring to Transman's piston pic, not the OP's melted one... This one:

Re: Leak Down Test Problem on #2 Cylinder [Re: GomangoCuda] #2971386 10/06/21 03:39 PM 10/06/21 03:39 PM
Joined: Jan 2005 Posts: 3,635 Oakland, MI D dizuster OP master
dizuster OP master D Joined: Jan 2005 Posts: 3,635 Oakland, MI	Originally Posted by GomangoCuda Sharp edge on the valve notch likely caused that. I 100% agree. No doubt the radial edge of the valve pocket makes this the thinnest area. I hand "massaged" these the best I could to minimize any sharp edge, but at the end of the day every part has a weak point somewhere. Running standard off the shelf Cometics.

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