 | Home > Technical > Puma 2.2 engine break |
 
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| ericvv Member Since: 02 Jun 2011 Location: Near the Jet d'Eau Posts: 5816   
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Descending at normal mountain roads it must be possible to find a gear that keeps rpm down to 3000 or less without using the brakes?
I guess your truck with all the serious mods is quite heavy of course (my own 110 SVX with not much mods was defined as weighing more than 2.4MT by our tech inspection here recently), so you have a lot of weight to slow down. Personally when I drive down from mountain altitudes here, the worst that I may have to do is select 2H to keep the engine at 3000 rpm, normal descents usually even 3H works for that. Sometimes I have to help with a short brake pedal push, but surely not continuously. There is one big difference of course between the Puma 2.4 and your Puma 2.2. Engine compression of the 2.4 is 17.5:1 while that of the 2.2 is only 15.5:1. I have experienced it with a Puma 2.2 of a friend here (also a 110SW like mine), his engine braking is much less than mine. I guess the only solution is to select even lower gears than you have been doing. Eric You never actually own a Defender. You merely look after it for the next generation. http://youtu.be/yVRlSsJwD0o https://youtu.be/vmPr3oTHndg https://www.youtube.com/watch?v=_GtzTT9Pdl0 https://www.youtube.com/watch?v=ABqKPz28e6A https://www.youtube.com/watch?v=rLZ49Jce_n0 https://www.youtube.com/watch?v=XvAsz_ilQYU https://www.youtube.com/watch?v=K8tMHiX9lSw https://m.youtube.com/watch?v=dxwjPuHIV7I https://vimeo.com/201482507 https://www.youtube.com/watch?v=ZSixqL0iyHw |
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23rd Sep 2016 5:38am |
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| Penguin Member Since: 08 Dec 2014 Location: Tienen Posts: 247  
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Even 1H can't hold it on mountain roads.
Only thing that worked was 2L, but then we descended at a very very low speed. Putting it in 3L and it went to the max RPM True our def is no longer at original weight, but still not at maximum weight. I do want/need to find a solution for this, as I'm afraid one day I'll be ending up having no breaks anymore. 28/02 - Loss of a good friend... 
In a time of chimpanzees, I was a penguin. |
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23rd Sep 2016 5:43am |
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| ericvv Member Since: 02 Jun 2011 Location: Near the Jet d'Eau Posts: 5816
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Replace the 2.2 by a 2.4...
Seriously, guess only thing you can do in such extreme descending situations is use 2L or even 1L when required. Too much speed at such steep tracks may quickly make you loose control if something unforeseeable happens. Eric You never actually own a Defender. You merely look after it for the next generation. http://youtu.be/yVRlSsJwD0o https://youtu.be/vmPr3oTHndg https://www.youtube.com/watch?v=_GtzTT9Pdl0 https://www.youtube.com/watch?v=ABqKPz28e6A https://www.youtube.com/watch?v=rLZ49Jce_n0 https://www.youtube.com/watch?v=XvAsz_ilQYU https://www.youtube.com/watch?v=K8tMHiX9lSw https://m.youtube.com/watch?v=dxwjPuHIV7I https://vimeo.com/201482507 https://www.youtube.com/watch?v=ZSixqL0iyHw |
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23rd Sep 2016 9:56am |
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| mk1collector Member Since: 17 Sep 2009 Location: West Yorkshire Posts: 6769  
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You could replace the brakes, bigger callipers and discs should brake better and cool quicker with the bigger surface area. Ray
My build thread http://www.defender2.net/forum/topic17615.html |
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23rd Sep 2016 10:12am |
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| Penguin Member Since: 08 Dec 2014 Location: Tienen Posts: 247
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it's not even extreme descending. Just riding in the mountains.
How does a ford transit van with this engine cope with it? Other brakes might be a solution, but then I'll first have a word with Land Rover. As if that is the only option, it's a design failure, with accidents waiting to happen. 28/02 - Loss of a good friend...
In a time of chimpanzees, I was a penguin. |
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23rd Sep 2016 11:05am |
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| VeeTee Member Since: 06 Mar 2011 Location: Somewhere Posts: 1512 
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Weird... When driving my old 300Tdi in the Alps in most cases I can select 3H or 2H with an occasional short press on the brake to maintain a safe speed on descents. I think it should be the same in the Puma, otherwise I certainly would have Land Rover do some checks on this subject. Cheers, Vincent
1959 Polynorm 1/4 Ton Trailer, Olive Drab Green (sold) 1970 M416 Military Trailer (Camping Trailer Conversion), Epsom Green (sold) 1975 Series III 88 V6, Light Green (sadly sold) 1996 Defender 110 CSW 300 Tdi, Epsom Green (sold) 2000 Freelander 1 TD4 3-drs, Silver (sold) 2006 Freelander 1 TD4 5-drs Facelift Automatic, Tonga Green (sold) MySite |
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23rd Sep 2016 1:52pm |
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| Penguin Member Since: 08 Dec 2014 Location: Tienen Posts: 247
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It did that with our TD5 and D3 also, except this one.
I'll contact the dealer on Monday for this 28/02 - Loss of a good friend...
In a time of chimpanzees, I was a penguin. |
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23rd Sep 2016 2:14pm |
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| ericvv Member Since: 02 Jun 2011 Location: Near the Jet d'Eau Posts: 5816
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As said, I had the experience in a Puma 2.2. Much less engine braking than in my Puma 2.4 in exactly the same circumstances. My theory is the lower engine compression plus 200 cc less displacement responsible for that. Eric You never actually own a Defender. You merely look after it for the next generation. http://youtu.be/yVRlSsJwD0o https://youtu.be/vmPr3oTHndg https://www.youtube.com/watch?v=_GtzTT9Pdl0 https://www.youtube.com/watch?v=ABqKPz28e6A https://www.youtube.com/watch?v=rLZ49Jce_n0 https://www.youtube.com/watch?v=XvAsz_ilQYU https://www.youtube.com/watch?v=K8tMHiX9lSw https://m.youtube.com/watch?v=dxwjPuHIV7I https://vimeo.com/201482507 https://www.youtube.com/watch?v=ZSixqL0iyHw |
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23rd Sep 2016 4:37pm |
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| VeeTee Member Since: 06 Mar 2011 Location: Somewhere Posts: 1512
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According to Land Rover Specifications the compression ratio of the 300Tdi engine is 19.5:1. That is a reassuring thought next time I am driving in the Alp mountains...   Cheers, Vincent
1959 Polynorm 1/4 Ton Trailer, Olive Drab Green (sold) 1970 M416 Military Trailer (Camping Trailer Conversion), Epsom Green (sold) 1975 Series III 88 V6, Light Green (sadly sold) 1996 Defender 110 CSW 300 Tdi, Epsom Green (sold) 2000 Freelander 1 TD4 3-drs, Silver (sold) 2006 Freelander 1 TD4 5-drs Facelift Automatic, Tonga Green (sold) MySite |
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23rd Sep 2016 5:39pm |
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| Phil VM2.5 Member Since: 28 Mar 2012 Location: Limelette Posts: 196 
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Hi,
Ik would not be in your place with engine at 4000rpm ! I agree I have the feeling engine brake is less good as before, driving 110 and Defender from 1980. Phil current : defender 110 sw 2.2 puma 2012 and 230.000km today and again my Range Rover VM2.5 engine from 1992 and 528.000km today. One ten 1988 to 1992 1987 BMW GS80 One Ten from 1984 to 1987 One Ten from 1983 to 1984 Serie 3 109 from 1980 to 1983 from 1974 Jeep CJ3B and CJ6 |
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26th Sep 2016 2:38am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6300 
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do some trucks have a valve on the air intake to stall the engine?
could something similar be introduced? |
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26th Sep 2016 11:45am |
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| derbywill Member Since: 25 Mar 2010 Location: Derbyshire Posts: 559 
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They have a flap in the exhaust to close it off
Will 2005 90 XS 1954 86'' Series 1 tilt 1968 88” 2A 200tdi 2002 110 Hardtop |
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26th Sep 2016 9:09pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6300
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thank you.
Am I right in thinking this was also used as a form of additional braking? |
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27th Sep 2016 6:39am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17443  
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There are two systems in widespread use on HGVs. There is the exhaust brake (also widely but incorrectly known as an "exhauster"*) which in simple terms is a valve which blocks or restricts the exhaust cuasing the engine's back pressure to increase, and thus providing more engine braking. This is a relatively simple system but requires the exhaust to be suitable and is not terribly good for the engine.
A more sophisticated and reliable (but much more expensive) system, albeit a properly-engineered one is a device known as a Jacobs Brake or "Jake Brake" after the firm which pioneered the device. This uses an additionale camshaft (or clever camshaft trickery) on the engine to modify the valve events on over-run so that the engine's exhaust valves remain shut until fractionally before TDC is reached, thus turnign the engine into a compressor and providing very effective engine braking, far more so than is prossible with an exhaust brake. The downside of the Jake Brake is that there is an almost explosive release of pressure when the exhaust valve opens, which makes them significantly noisy in operation. You can alsways tell when a Jake Brake is in use, usually from a considerable distance away. For this reason many countries have legislation prohibiting their use in residential areas. There are many videos on YouTube which demonstrate clearly the sound of a Jake Brake in operation. It is probably not economically viable to fit either an exhaust brake or a Jake Brake to a Defender, which is a shame since an exhaust brake woudl be ideal for the scenarion the OP is asking about. (* For info, and "exhauster" is actually a vacuum pump used on some vehicles and more commonly railway locomotives with vacuum brakes for creating the vaccum required for the system to function and is nothing to do with engine braking systems). |
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27th Sep 2016 9:21am |
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