g-mack Posted February 5, 2016 Share Posted February 5, 2016 I've been thinking about that too, but surely a worn cam lobe would mean inlet valves are not opening fully, can't see how it would make them open early. for gases to be escaping into inlet it must be happening on the exhaust stroke. so exhaust stroke : exhaust valve is open, inlet might be open a fraction to early as the next stroke is induction, (only stroke the inlet valve is open) Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted February 5, 2016 Share Posted February 5, 2016 Does it do it with the inlet manifold just open to atmosphere? Quote Link to comment Share on other sites More sharing options...
Kurt Posted February 5, 2016 Author Share Posted February 5, 2016 No cannot detect it at inlet manifold with pipe disconnected. Neither with intake disconnected from turbo? Quote Link to comment Share on other sites More sharing options...
Kurt Posted February 5, 2016 Author Share Posted February 5, 2016 I've been thinking about that too, but surely a worn cam lobe would mean inlet valves are not opening fully, can't see how it would make them open early. for gases to be escaping into inlet it must be happening on the exhaust stroke. so exhaust stroke : exhaust valve is open, inlet might be open a fraction to early as the next stroke is induction, (only stroke the inlet valve is open) I did wonder if a leak/crack between the turbo housings could be behind this? But then again , as I posted above , I cannot detect anything at turbo when inlet is removed? Quote Link to comment Share on other sites More sharing options...
g-mack Posted February 5, 2016 Share Posted February 5, 2016 i find it hard to tell if i can detect it at turbo or inlet, i think as the diameters are much bigger its difficult. i can defy feel it at the oil breather inlet just before turbo! Quote Link to comment Share on other sites More sharing options...
g-mack Posted February 5, 2016 Share Posted February 5, 2016 interesting http://www.crturbos.co.uk/index.php/blog/articles/what-is-surging/ also found this quote on another forum but i would also check the turbo, ive had one before that was leaking exhaust gases out of the compressor side of turbo, this made a loud induction noise that was probably actually from exhaust side, take the inlet to turbo off(2 bolts) and rev it to check for back pressure. winterheating Transit ExtremistPosts: 10676 Joined: Tue Jul 01, 2008 10:21 pm Location: Co.Durham Darlington Quote Link to comment Share on other sites More sharing options...
g-mack Posted February 6, 2016 Share Posted February 6, 2016 well after hours of researching turbos last night, i can say 100% its not my turbo! removed inlet to intercooler top pipe, NO more air coming from air box! if it was turbo related i would still feel air. there is also a constant flow of air out the inlet pipe at the engine. so it is 100% engine related!!!! Quote Link to comment Share on other sites More sharing options...
Kurt Posted February 6, 2016 Author Share Posted February 6, 2016 G-mack, With your hand over the air cleaner does the backpressure disappear when rev'd from idle like mine ( have no rev counter but guessing an increase of around 500 revs ) ? Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted February 6, 2016 Share Posted February 6, 2016 well after hours of researching turbos last night, i can say 100% its not my turbo! removed inlet to intercooler top pipe, NO more air coming from air box! if it was turbo related i would still feel air. there is also a constant flow of air out the inlet pipe at the engine. so it is 100% engine related!!!! Are you saying that with the pipe removed off the inlet manifold there is a flow of air coming out of it when the engine is running? Not sure how that is possible while still allowing the engine to run. Maybe take it for a drive like that, perhaps on a drier day than today, see if it still booms. Quote Link to comment Share on other sites More sharing options...
g-mack Posted February 8, 2016 Share Posted February 8, 2016 kurt, not checked but will! retro, yep exactly what I'm saying! so I'm back to thinking this has got to be a timing issue! now as the engine runs smooth, it seems bizarre the timing could be out, unless the keyways have worn and allowing slightly off cam ! Quote Link to comment Share on other sites More sharing options...
Kurt Posted March 14, 2016 Author Share Posted March 14, 2016 G-Mack, Couple of things I have done over the last few days... 1. disconnected my snorkel from filter housing to see if this made any difference to the booming issue my engine has been suffering from. booming still remained though positive air pressure at filter housing was greatly reduced at blanking point on filter housing. Good strong vacuum at air intake on filter housing where the snorkel pipework previously connected. Booming at load however still remained! 2. Advanced pump timing.This one was done to hopefully cure some ( not to bad in all honesty ) white smoke on cold start that had become apparent recently. Used a 9mm steel pin in pump with pulley hard clockwise upon tightening. previously had used a 9.5mm pin which came with my timing kit when I did the belt. Result? No more ( or very little ) white smoke on cold start and interestingly the booming noise under load now ceases to exist! Also pulling a lot better. Maybe worth a check on yours if only to eliminate as its such an easy thing to check/adjust. Quote Link to comment Share on other sites More sharing options...
Chicken Drumstick Posted March 15, 2016 Share Posted March 15, 2016 Neither does mine! Intercooler pipe off and theres a definate strong vacuum at the inlet. Same if i disconnect inlet pipe from turbo but when i reconnect it the pulsing begins again at the filter box. As mentioned already perhaps some kind of turbulance generated inherit to the intake design is the only other reason i can think of. Im quite intrigued by how many other tdi's may be showing this quirk/symptom. I dont think i would of noticed to be honest if the little rubber cap thingy hadnt of been missing off my air cleaner. I've read the thread and just wanted to check. You (and g-Mack) reckon you get positive pressure out of the air box only. But not directly from the intake manifold? Surely the logic here is, if you are only seeing the symptom up stream away from the engine, then it cannot be engine related and is likely just a quirk of the air box design and resonance frequencies. Have you tried looking at any other Tdi's to see if they also exhibit this same feature? At idle or with no load on the engine, you'll not see boost from the turbo, so the intake system will not be pressurised. When driving and the turbo boosting at 12-14psi and the engine spinning at 2000-2500rpm, there is very little chance you'd get air coming back through the intake and out the filter box. That's a heck of a long way for it to travel from the head, though the manifold, the intercooler and all the pipe work, including the turbo to then come out a drain hole on an air box. I'm no physicist however, so this may be possible. But until someone can come up with some science to explain this, I'm of the belief that you aren't getting positive pressure in the airbox. Maybe fitting a vacuum/boost gauge to it would help establish this? Quote Link to comment Share on other sites More sharing options...
Chicken Drumstick Posted March 15, 2016 Share Posted March 15, 2016 OK here is a vid i done a while ago. you need a good set of speakers as the booming is very low frequency I suspect vids can be deceptive. But yes it does sound boomy inside, but that is not proof that it is intake related or positive pressure in the airbox causing it. Just as a side note and meaning no offense, have you owned and driven other Land Rover's in the past? I only ask, as they can be noisy and unrefined. So without hearing it first hand it's hard to really tell if it's any worse than most others. On the Discovery and Range Rover classic, LR went to a lot of effort to improve NVH. On this note, I've not seen you mention it, but has your Defender always made this booming sound? Or was there a time when it didn't? And if it didn't, when did it start? Quote Link to comment Share on other sites More sharing options...
g-mack Posted March 15, 2016 Share Posted March 15, 2016 Kurt- i might give the pump timing a go, thanks chicken- i get pressure at the inlet manifold!!!! never driven another tdi, only td5s, it never used to do it!! i would be surprised if its normal as once i hit 50 i can't hear the engine! Quote Link to comment Share on other sites More sharing options...
Chicken Drumstick Posted March 16, 2016 Share Posted March 16, 2016 I hope this comes across as helpful banter and not insulting. But I do struggle to believe there is air coming out of the front of the manifold. If this was the case then your engine would be massively down on power and logically you'd have low compression on some cylinders. As the only way air could come from a cylinder back into the intake is via an open valve that should be shut. And then only on the upstroke. The only other way would be from the exhaust manifold or exhaust track in the head. But the gas would still mostly follow the path of least resistance and anything re-entering the intake manifold would simply get sucked into the piston on the down stroke, not to mention the 12-14psi of boost and air flow going the other way. I really can not fathom how you can get air out of the inlet of the intake manifold. Are you able to maybe do a vid showing if this is happening? If you remove the pipe work off the intake manifold and securely tape a short length of wool or cotton over the inlet. If the air flow is only going in it'll try to pull it into the manifold. If indeed you have air coming out the inlet, then the wool will be blown away from the inlet. Quote Link to comment Share on other sites More sharing options...
toenden Posted March 18, 2016 Share Posted March 18, 2016 Hi. I think I would remove the head and have a look. My guess is a head gasket or cylinder head. If the head goes walkabout between cyl. Nr. 2 and 3 I reckon it would pulse in the inlet manifold as when cyl 3 is doing its...erm powerstroke? The inlet valve on cyl 2 will be open for its intake and a pulse in the manifold can be possible... If my head gets the firingorder the right way around :-) the engine should be down on power though. I have tried this on a 2,5 n/a once. It started and ran nice but had a funny fishingboatish sound. Mads Quote Link to comment Share on other sites More sharing options...
Snagger Posted March 20, 2016 Share Posted March 20, 2016 To get positive pressure in the air filter fits well with a booming sound. It is combustion gas escaping either through a damaged inlet valve/valve seat or combustion gas escaping via the cyclonic breather into the intake tract having bypassed extremely worn rings or bores, through a cracked piston or through a bad exhaust valve into the rocker gallery. Either way, you must have significant internal damage. Quote Link to comment Share on other sites More sharing options...
Chicken Drumstick Posted August 30, 2016 Share Posted August 30, 2016 so any updates? Quote Link to comment Share on other sites More sharing options...
Dib-Dab Posted January 17, 2018 Share Posted January 17, 2018 Hi, normally I just read the forums for info. Don’t know enough to contribute. I’ve heard of this. But never understood it. Now this clears it up and a friend is having this issue. Kurt’s was the head in the end. Has g-mack resolved his. If it’s the head, I can tell him that 2 others have had it. If not, maybe another option to look at Quote Link to comment Share on other sites More sharing options...
western Posted January 17, 2018 Share Posted January 17, 2018 Video is not working Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted January 17, 2018 Share Posted January 17, 2018 I think g-mack has sold his 110 now. Quote Link to comment Share on other sites More sharing options...
Dib-Dab Posted January 17, 2018 Share Posted January 17, 2018 Shame, it’s like reading a book. Then someone’s tore the last pages out when you get there. Lol 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.