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Question - Leak Down and rings #859374 11/21/10 02:09 PM 11/21/10 02:09 PM
Joined: Jan 2003 Posts: 16,925 NC 440Jim OP I Live Here
440Jim OP I Live Here Joined: Jan 2003 Posts: 16,925 NC	I plan to disassemble my 511 low deck this winter and check things out. Before disassembly, I did a leak down check on all the cylinders. It is on the engine stand in my shop, and it was 65F. This is what I measured at 100 psi: #1 95 psi, #2 95 psi #3 93 psi, #4 92 psi #5 95 psi, #6 92 psi #7 95 psi, #8 92 psi Do you think this indicates the need for a quick hone and new rings this winter? 1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1

Re: Question - Leak Down and rings [Re: 440Jim] #859375 11/21/10 02:16 PM 11/21/10 02:16 PM
Joined: Mar 2003 Posts: 2,498 PA moparacer top fuel
moparacer top fuel Joined: Mar 2003 Posts: 2,498 PA	5-8 percent cold? Nothing wrong with it imo. Mines worse then that hot lol. 67 Barracuda street/bracket car 11.27-119 68 Dart 502 BB 8.70s-152 414 cid SB Dragster 7.65-174

Re: Question - Leak Down and rings [Re: 440Jim] #859376 11/21/10 02:25 PM 11/21/10 02:25 PM
Joined: Jul 2010 Posts: 3,502 SOUTH JERSEY HEMIFRED master
HEMIFRED master Joined: Jul 2010 Posts: 3,502 SOUTH JERSEY	all under 10%. not unless otherwise you have been seeing power fall off. in some motors leakage tests can be misleading. I had a Hemi with dykes rings that showed over 15% some at 20% .it had no problems but a leakage test was still a new toy to us. we re did the rings and there was no improvement. I have always done my tests with a warmed engine my thoughts being it does change internal shapes when hot plus at times I have seen better numbers when 140 lb is used if I had tested when new at 65 then retested at that temp at a later date I would feel more confident about the numbers being accurate home of the Sox and Martin Hemi Duster

Re: Question - Leak Down and rings [Re: moparacer] #859377 11/21/10 02:26 PM 11/21/10 02:26 PM
Joined: Jan 2003 Posts: 19,363 Las Vegas Al_Alguire I Live Here
Al_Alguire I Live Here Joined: Jan 2003 Posts: 19,363 Las Vegas	I agree..Those numbers cold show no real issues. Then again if it is out and you have the stuff why not. "I am not ashamed to confess I am ignorant of what I do not know." "It's never wrong to do the right thing"

Re: Question - Leak Down and rings [Re: 440Jim] #859378 11/21/10 02:35 PM 11/21/10 02:35 PM
Joined: Jan 2003 Posts: 16,925 NC 440Jim OP I Live Here
440Jim OP I Live Here Joined: Jan 2003 Posts: 16,925 NC	I didn't think they were too bad either. And the car's ET/mph seem to have held up very good also. This is what I measured using the same gauges when the motor was new. This is after the initial break-in only (no track time, and cold engine: #1 97 psi, #2 96 psi #3 96 psi, #4 96 psi #5 97 psi, #6 95 psi #7 95 psi, #8 96 psi Those new numbers really amazed me at the time. They are Dykes rings, 0.031/0.062 stepped. 1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1

Re: Question - Leak Down and rings [Re: 440Jim] #859379 11/21/10 02:42 PM 11/21/10 02:42 PM
Joined: Jul 2010 Posts: 3,502 SOUTH JERSEY HEMIFRED master
HEMIFRED master Joined: Jul 2010 Posts: 3,502 SOUTH JERSEY	Quote: I didn't think they were too bad either. And the car's ET/mph seem to have held up very good also. This is what I measured using the same gauges when the motor was new. This is after the initial break-in only (no track time, and cold engine: #1 97 psi, #2 96 psi #3 96 psi, #4 96 psi #5 97 psi, #6 95 psi #7 95 psi, #8 96 psi Those new numbers really amazed me at the time. They are Dykes rings, 0.031/0.062 stepped. after seeing the above I would bet that under more pressure like when running you would see less leakage. especially with the dykes that seal tighter loaded than conventional . or for yuks try again at 140 lb home of the Sox and Martin Hemi Duster

Re: Question - Leak Down and rings [Re: 440Jim] #859380 11/21/10 03:13 PM 11/21/10 03:13 PM
Joined: Aug 2003 Posts: 43,159 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,159 Bend,OR USA	I take it that your using a single gauge tester, try rocking the pistosn 2 to 4 degrees either side of TDC (carefully )with pressure and see if that helps Then add several squirts of oil into the cylinders to see if that helps, if it does I would replace the rings remember that the rings seal against the cylinder walls and the piston ring lands, both do wear Can you hear any leakage out of the valves? Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Question - Leak Down and rings [Re: Cab_Burge] #859381 11/21/10 03:33 PM 11/21/10 03:33 PM
Joined: May 2006 Posts: 1,073 oregon G greendart408 super stock
greendart408 super stock G Joined: May 2006 Posts: 1,073 oregon	Just curious Jim did you break it in with the injection on alky or e85 or gas or with a carb on gas?? Do you have a vac pump??. I agree not bad #s

Re: Question - Leak Down and rings [Re: Cab_Burge] #859382 11/21/10 07:15 PM 11/21/10 07:15 PM
Joined: Jan 2003 Posts: 16,925 NC 440Jim OP I Live Here
440Jim OP I Live Here Joined: Jan 2003 Posts: 16,925 NC	Quote: I take it that your using a single gauge tester, CAB, No. This is a Summit dual gauge leak down tester (is there another type)? I am thinking about the oil squirt method, but the raw numbers don't indicate a problem. I didn't notice any leakage out of the valves, but it would have to be pretty bad to notice that. I didn't notice any excessive blow by of oil in the header evac lines either. An oil squirt would test if the rings or the valves are leaking, but the total number seems good, so neither seems like a problem from the testing ??? The heads were touched up mid season in 2008 (new cam broke in half) I don't have a vacuum pump. I did the initial break-in with a gas carb, and ran race gas for the first two years. Then an E85 carb the 3rd year, and injection for 2009 and 2010. This engine has 616 passes on the rings! I didn't want to say that so people wouldn't judge the condition on time, but rather condition. And the condition is pretty good? Right???

Re: Question - Leak Down and rings [Re: 440Jim] #859383 11/21/10 09:31 PM 11/21/10 09:31 PM
Joined: Jan 2003 Posts: 6,531 Jacksonville, FL Chris2581 master
Chris2581 master Joined: Jan 2003 Posts: 6,531 Jacksonville, FL	I'd run that shortblock as is. Nautilus Racing- We use Superformance gaskets and Turbo Action converters/products.

Re: Question - Leak Down and rings [Re: Chris2581] #859384 11/22/10 10:30 AM 11/22/10 10:30 AM
Joined: Mar 2005 Posts: 2,172 Ohio T theclutcher top fuel
theclutcher top fuel T Joined: Mar 2005 Posts: 2,172 Ohio	How many passes next year? unless you want to chance re-ring mid season..... At my rate, that would last a long time.

Re: Question - Leak Down and rings [Re: theclutcher] #859385 11/22/10 10:37 AM 11/22/10 10:37 AM
Joined: Jan 2003 Posts: 16,925 NC 440Jim OP I Live Here
440Jim OP I Live Here Joined: Jan 2003 Posts: 16,925 NC	Quote: How many passes next year? unless you want to chance re-ring mid season..... At my rate, that would last a long time. That is a good question. History indicates I will probably put 140-150 passes on it in 2011. But I am considering running less often. I was planning on cutting back racing in 2011 (100 passes?), and not taking the motor apart this winter. But when the oil filter gasket blew out at the finish line, that made my decision to do the tear down. I want to inspect everything, especially the bearings; and perhaps change the rod bolts, rings, etc. 1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1

Re: Question - Leak Down and rings [Re: 440Jim] #859386 11/22/10 11:25 AM 11/22/10 11:25 AM
Joined: Mar 2006 Posts: 9,910 Eighty Four, PA B G Racing master
B G Racing master Joined: Mar 2006 Posts: 9,910 Eighty Four, PA	I would leave it alone [IMG]http://i430.photobucket.com/albums/qq21/ajcasini/max_zpsdppwd9km.jpg[/IMG]

Re: Question - Leak Down and rings [Re: B G Racing] #859387 11/22/10 02:45 PM 11/22/10 02:45 PM
Joined: Nov 2004 Posts: 6,890 North Alabama M Monte_Smith master
Monte_Smith master M Joined: Nov 2004 Posts: 6,890 North Alabama	Just personal opinion here, but a leakdown tester is for setting the barrel valve on a blown car and virtually useless for anything else. You are testing the very top of the cylinder, with the piston stationary. Hardly an indicator of bore or ring wear. I have always used the cranking compression method to keep an eye on ring and bore wear. When the motor is fresh and sealed up, get it warm and then do a cranking compression test. I do three revolutions myself and record the number the first time the gauge moves and what it is after 3 revs. Do this periodically over the year and you will know when the motor is tired. A motor is good shape, will always bump the gauge to 90-110 psi, the first time the gauge moves. The number of revs you spin it after that does not really matter. Just be consistent, as it is a reference number Monte

Re: Question - Leak Down and rings [Re: Monte_Smith] #859388 11/22/10 04:00 PM 11/22/10 04:00 PM
Joined: Jan 2003 Posts: 16,925 NC 440Jim OP I Live Here
440Jim OP I Live Here Joined: Jan 2003 Posts: 16,925 NC	Monte, Thanks for the info. I do use it to check the barrel valve setting on my Ron's Flying Toilet, LOL. But that is a reference, I make final adjustments based on the wideband A/F readings at idle and staging (footbrake) with the 60ft results. I didn't do any leak down tests since the 1st year (5 seasons now). And since the oil loss event (2 qts left in the pan, perhaps it just drained down...), I didn't want to start it for fear of hurting the crank if the bearings did take a hit. After I take it apart, I will make the final decision, but my initial impression is that since it has 616 runs on it, and it is coming apart, I will have to take the time to have a shop hone it so the new rings seat properly. That is more a pain than the cost. 1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1

Re: Question - Leak Down and rings [Re: 440Jim] #859389 11/22/10 08:46 PM 11/22/10 08:46 PM
Joined: Jan 2003 Posts: 6,591 Canton, Ohio S Sport440 master
Sport440 master S Joined: Jan 2003 Posts: 6,591 Canton, Ohio	Quote: After I take it apart, I will make the final decision, but my initial impression is that since it has 616 runs on it, and it is coming apart, I will have to take the time to have a shop hone it so the new rings seat properly. That is more a pain than the cost. IMO, it does have some more runs left in it. But not another 650 without a reduced performance. If its going to be taken down, I would feel Very compelled to change the rings too. Then youd be good for another 750 runs vs another 150, IMO But, I would be curious as to the current ring gap gain compared to the original build specs. mike

Re: Question - Leak Down and rings [Re: Sport440] #859390 11/22/10 10:14 PM 11/22/10 10:14 PM
Joined: Jan 2003 Posts: 16,925 NC 440Jim OP I Live Here
440Jim OP I Live Here Joined: Jan 2003 Posts: 16,925 NC	Mike, I will try to remember to check a couple at 1" down the bore like originally set. I usually just get the shop that hones it to carefully measure the final bore after the minimum amount of hone to make the new rings seat properly. And the new rings are filed to fit. There is no way I would leave this motor together for 650 passes without a tear down and checking. Mainly to look at the bearings. Once a combination of parts is working well (machining etc.) I think the bearings are the weak link for preventative maintenance. The main bearings have 300ish passes. 1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1

Re: Question - Leak Down and rings [Re: 440Jim] #859391 11/22/10 10:22 PM 11/22/10 10:22 PM
Joined: Jan 2003 Posts: 9,875 Weddington, N.C. Streetwize master
Streetwize master Joined: Jan 2003 Posts: 9,875 Weddington, N.C.	Bearings are an expendable maintenence item...just a periodic cost of racing reliably. Leak downs look extrememly good to Excellent to me Jim....you've obviously got the tune in the optimum zone and it's not fighting itself down the track. I find you can pretty much 'feel' just by how a motor tears down as to how well it's working. WIZE World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker! https://www.youtube.com/watch?v=-mWzLma3YGI In Car: https://www.youtube.com/watch?v=PjXcf95e6v0

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