|
|
|
#1
|
|||
|
|||
NAILING
I have seen posts that mention NAILING. What exactly is nailing and how does it sound. My 240D engine sounds like a diesel. How do I know if it is NAILING.
Anthony |
#2
|
||||
|
||||
Nailing is caused by worn injectors. When injectors get worn out they can leak fuel even when not at pop pressure. This causes excess fuel in the cylinder which creates hard combustion which is the noise you hear. It's an extra loud sharp clacking noise.
__________________
Andrew '04 Jetta TDI Wagon '82 300TD ~ Winnie ~ Sold '77 300D ~ Sold
|
#3
|
|||
|
|||
It sounds like someone driving a spike into a piece of oak, hence nailing.
__________________
1977 300d 70k--sold 08 1985 300TD 185k+ 1984 307d 126k--sold 8/03 1985 409d 65k--sold 06 1984 300SD 315k--daughter's car 1979 300SD 122k--sold 2/11 1999 Fuso FG Expedition Camper 1993 GMC Sierra 6.5 TD 4x4 1982 Bluebird Wanderlodge CAT 3208--Sold 2/13 |
#4
|
||||
|
||||
I would say it sounds more metal-on-metal hammering but I guess thats splitting hairs
__________________
TC Current stable: - 2004 Mazda RALLYWANKEL - 2007 Saturn sky redline - 2004 Explorer...under surgery. Past: 135i, GTI, 300E, 300SD, 300SD, Stealth |
#5
|
|||
|
|||
When I had the problem on one of my diesel MB cars of past -- It was almost like a "spark knock" you would get in a gasser...Replaced the injectors and noise went away...
__________________
71Inka02 62 W121 190DB - Original CA/AZ Car - Excellent Example 99 E300 Turbo Diesel - 362,000...Awesome Daily Driver 01 E320 Wagon - 297,xxx (wife's work car) 01 E320 Wagon - 131,000 02 Land Rover Disco SE- 110,000 87 BMW 325is (E30) Full Restore - Son's 06 Mini Cooper 'S' - Son's 87 Toyota FJ60 Land Cruiser - Showroom Condition - 152,000 84 300D - 142,xxx :cool - "Sold" 83 300D-"Sold" - 211,456 85 300SD-"Sold" - 213,789 |
#6
|
|||
|
|||
Not to split hairs, but the hammer would be striking a metal spike.
__________________
1977 300d 70k--sold 08 1985 300TD 185k+ 1984 307d 126k--sold 8/03 1985 409d 65k--sold 06 1984 300SD 315k--daughter's car 1979 300SD 122k--sold 2/11 1999 Fuso FG Expedition Camper 1993 GMC Sierra 6.5 TD 4x4 1982 Bluebird Wanderlodge CAT 3208--Sold 2/13 |
#7
|
|||
|
|||
nailing is a detonation at any undesirable time during the stroke.
like an explosion that is not absorbed by the movement of the piston ()think of catching an egg from an overhand pass() |
#8
|
||||
|
||||
If that's the case, the injectors may not be the only possible culprit, right? Incorrect IP timing could cause undesirable results. Would this sound like nailing?
__________________
1982 240D, sold 9/17/2008 1987 300D TurboW124.133 - 603.960, 722.317 - Smoke Silver Metallic / Medium Red (702/177), acquired 8/15/2009 262,715 and counting |
#9
|
|||
|
|||
there are certainly more culprits.
IP timing could do it as well. |
#10
|
||||
|
||||
Fue Injection Pump Timing can case Nailing, worn Injectors as well as air in your fuel system.
If you get your Engine started on a cold day without using the Glow Plugs you will hear the Nailing sound until the combustion chambers warm up enough for the Fuel to burn properly.
__________________
84 300D, 82 Volvo 244Gl Diesel |
#11
|
|||
|
|||
My Mitsubishi Fuso glowplugs only activate below about 35 degrees. When I start it at 40 degrees it nails like crazy until it warms up.
__________________
1977 300d 70k--sold 08 1985 300TD 185k+ 1984 307d 126k--sold 8/03 1985 409d 65k--sold 06 1984 300SD 315k--daughter's car 1979 300SD 122k--sold 2/11 1999 Fuso FG Expedition Camper 1993 GMC Sierra 6.5 TD 4x4 1982 Bluebird Wanderlodge CAT 3208--Sold 2/13 |
#12
|
||||
|
||||
Is Nailing to be expected in a cold engine? Mine nails a little during warm up and is gone when the engine reaches 80C.
__________________
1993 W124 300D 2.5L Turbo, OM602.962 2000 Chevrolet Cavalier, 2.4L DOHC 2002 Ford Explorer, 4.0L SOHC 2005 Toyota Prius, 1.5L http://www.fuelly.com/sig-us/40601.png Last edited by Oldwolf; 09-28-2009 at 09:21 PM. |
#13
|
||||
|
||||
I wouldn't necessarily say expected, but certainly a common experience among higher-mile cars with questionable injectors so don't be too freaked out.
__________________
TC Current stable: - 2004 Mazda RALLYWANKEL - 2007 Saturn sky redline - 2004 Explorer...under surgery. Past: 135i, GTI, 300E, 300SD, 300SD, Stealth |
#14
|
|||
|
|||
The Genesis of 'Nailing'
All of the following are from my personal experiences so please challenge me as you see fit. Some of this has not been written about or at least I have not come across it.
'Nailing' has many causes. The sound is produced from a secondary combustion event which is temporally and/or spatially separated (usually retarded in time) from the main explosion. Generally it can be caused by an Injector with an uneven spray pattern or with an imperfectly atomized trickle flow. In a normal situation a coherent explosion with a smooth well defined flame profile occurs at the expected time. Nailing represents a perturbation to this process caused by one or more of the following:
I did this from my head so I may have missed some but you get the point. As was pointed out it does acoustically sound somewhat like what is referred to as 'pinking' or 'pinging' or 'pre-ignition' where low octane gasoline is used in a hi-compression gasoline engine. It is a different phenomenon however in a Diesel engine since it is usually a retarded timing event that gives rise to 'Nailing'. Is it bad for an engine?? Let us agree that it is not good but since these engines are extraordinarily robust it does no harm as long as it does not persist all through the operation. After warm up most nailing will disappear. 'Pre-ignition' in a gasoline engine however is very destructive. I have seen a piston with what looked like a bullet hole through its face from the effect. Does it negatively affect MPG?? Of course the answer is yes. Energy is being used in an undesired manner that is not contributing to the desired power flow.
__________________
Dionysius |
#15
|
||||
|
||||
I would add mal-adjusted injectors to Dion's very complete list as well. Differing pop pressure between cylinders will affect timing and/or combustion. The spec on my engine is < 3 bar between cylinders.
__________________
327K on 1986 W201, 602.911, 722.414 2.5 190D ("The Red Baron") 139K on 1993 W124, 104.942, 722.433 2.8 300E ("Queen") http://farm5.static.flickr.com/4081/...0bb92d3c_m.jpg http://i370.photobucket.com/albums/o...g?t=1325284354 Do not worry about your difficulties in Mathematics. I can assure you mine are still greater. - Albert Einstein take a walk down memory lane... |
Bookmarks |
Thread Tools | |
Display Modes | |
|
|