02GF74 Posted October 12, 2006 Share Posted October 12, 2006 Reducing the pulley diameter is not a good idea due to the strong possibility of increasing cavitation damage. Even with the standard pulley setup the EFI water pump is renowned for cavitation damage to the ali timing cover (the pump housing). The area that suffers most is right behind the impellor around the two outlets. Speeding up the pump will only worsen this situation.This effect is more pronounced when no coolant has been used in the engine (just plain H2O)………. But it is still a problem even with added coolant. I have yet to find a EFI time cover without some indication of this type of damage. Ian Can I politely ask how are you qualified to know the timing cover is damaged due to cavitation? Do you work in this field, heard it from someone else or speculation? I am not saying you are wrong or anything, just curious. My knowledge on cavitation is pretty limited - it happens when you try to push water so fast that the pressure created causes instanteantous vaporsisation (ok, that may not be right but is close) and the effect is that instead of pushing against water e.g. a propeller, it is pushing against little bubbles of gas so is less efficient. I can also imagine, and this is guesswork since I have not looked into this, that the vaporisation causes tiny explosions, and it the shockways from these that over time cause fractures in the metal. (specualation since I do not know the type of damage you mention). As I said in the original post - but re-read it and I think I used higher instead of lower - me bad ) - the rpm that cavitation would occur would be lower if you have a smaller water pulley. by the time the EFI engine came out, I would imagine Rover had quite a few years of data/failures/experience to know what size pulley to fit on the water pump for the max. rpm of the engine so am a bit surprised that this problem occurs. Is it just the RR EFI or did it affect the carb P6 and RR? All this means is that the engine shouldn't be revved as high so in the case of the orignal poster, that should not be the issue since the hot engine syndrome is occuring offroad at low speed and probably at lowish rpm, certainly shouldn't be redlining the engine (speculation on my part). Quote Link to comment Share on other sites More sharing options...
white90 Posted October 12, 2006 Share Posted October 12, 2006 why not just send Ian a PM then? if you have a direct question to ask. Quote Link to comment Share on other sites More sharing options...
02GF74 Posted October 12, 2006 Author Share Posted October 12, 2006 why not just send Ian a PM then? if you have a direct question to ask. I am not having a go at him; I did consider PM but thought others would benefit. I can do PM - makes no difference to me; no different to the drawn out discussion on anti-freeze. Quote Link to comment Share on other sites More sharing options...
headhunter Posted October 12, 2006 Share Posted October 12, 2006 why not just send Ian a PM then? if you have a direct question to ask. Ditto Quote Link to comment Share on other sites More sharing options...
white90 Posted October 12, 2006 Share Posted October 12, 2006 looks like the makings of an antagonistic post to my untrained eye. Ian knows his stuff and doesn't make posts of hearsay(not the crappy band) Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted October 12, 2006 Share Posted October 12, 2006 Dear O2, As you like to discuss issues in the public domain........... It would seem that you are not being particularly polite or perhaps your grasp of English diplomacy is a little lacking………. It would also seem that every time I post, you have something negative or a problem with the content. For me there are two options in this matter, 1) Ignore your negative comments as I don’t have to answer to anybody. 2) As in your eyes, I seem to adding little or no value to the forum, then perhaps I should refrain from posting here any more. Option 2 seems to be the most appealing art the moment. BTW: do you live near the sea …….. have you ever worked on outboard motors or small boat propellers …….. have you never seen cavitation damage to these items or the internals of boat engines …………. the impellor of the V8 water pump is much harder then the ali casing …….. once you have seen cavitation damage, it is not difficult to recognise …….. but what the f&*k do I know. I would like to add that it has been nice being here and I have made many friends …….. however, my future here is now uncertain ………….I don’t know that I can be bothered with something that is becoming annoying and a chore. Ian Quote Link to comment Share on other sites More sharing options...
white90 Posted October 12, 2006 Share Posted October 12, 2006 Ian you need to find the Ignore user button initiate it then carry on your valued input would be badly missed. Quote Link to comment Share on other sites More sharing options...
MogLite Posted October 12, 2006 Share Posted October 12, 2006 Ian you need to find the Ignore user buttoninitiate it then carry on your valued input would be badly missed. Absolutely - not everyone here is going to see eye-eye, just work around it Who else would post the list of Intermotor fan switches if you went away and take the p155 out of me. Hold on actually there are a whole bunch of people queuing up for that Quote Link to comment Share on other sites More sharing options...
Tonk Posted October 12, 2006 Share Posted October 12, 2006 Dear O2, why does that make me larf? stick around Ian, its a big forum, theres enough room Quote Link to comment Share on other sites More sharing options...
02GF74 Posted October 12, 2006 Author Share Posted October 12, 2006 BTW: do you live near the sea …….. have you ever worked on outboard motors or small boat propellers …….. have you never seen cavitation damage to these items or the internals of boat engines …………. the impellor of the V8 water pump is much harder then the ali casing …….. once you have seen cavitation damage, it is not difficult to recognise …….. but what the f&*k do I know. No I do live by the sea. No I have not worked on propellors. No I have not seen cavitation damage. No I donlt know what you know. THAT IS EXACTLY WHY I AM ASKING!. WHAT IS WRONG WITH THAT!? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 12, 2006 Share Posted October 12, 2006 O2 - It does seem to be a pattern that no matter who posts what you have some reason to question them over it. Nothing wrong with that per se, but when you do it non-stop and often from an uniformed angle it can appear to be antagonistic, especially when it's someone like BBC who by now you should've worked out does not post bullsh*t. Perhaps your post came over wrong but it does seem a little agressive asking how BBC is qualified to talk on the subject. Perhaps before you post stuff like that it would be an idea to use Google which often turns up a lot of useful information and would show you that Ian does know what he's on about, rather than questioning him straight off without checking the facts Can I ask, then, how are you qualified to understand Ian's answer? Quote Link to comment Share on other sites More sharing options...
PeterW Posted October 12, 2006 Share Posted October 12, 2006 No I do live by the sea.No I have not worked on propellors. No I have not seen cavitation damage. No I donlt know what you know. THAT IS EXACTLY WHY I AM ASKING!. WHAT IS WRONG WITH THAT!? To put a 'neutral' spin on this - I'm not involved with either party here - I've read O2s first comment, and I've read Ians response.... Whats the problem...??? O2 asked a question, which appears to be about 12 questions in one, and Ian took offence, rightly or wrongly, about his experience and knowledge being called into question. To quote O2.... Can I politely ask how are you qualified to know the timing cover is damaged due to cavitation? Do you work in this field, heard it from someone else or speculation? I am not saying you are wrong or anything, just curious.My knowledge on cavitation is pretty limited There was a recent thread started about 'who knows what and whos an expert' which got caned cos it would promote elitism etc, and we all know who to listen to etc. As it is, and until about 2 minutes ago : - I didn't know BBC's real name was Ian... - I didn't know BBC knew about cavitation in depth... So I, and the 1700 odd other users of this board who do not know Ian personally, now know something new... Ian - I'll be coming to you for this subject from now on ! We're all adults here - lets play nicely together ! Cheers Peter Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted October 12, 2006 Share Posted October 12, 2006 Man! I must be too stupid to notice these things! BBC - I see you as one of the most valuable forum members in terms of good quality input/tech B) , I hope your suggestion of an uncertain future here is not serious. 02 - the question may have been innocent, though from others comments, perhaps it is a trend? I'm all for the Spanish Inquisition, but for crying out loud why not do the very basic searching first so you don't sound like an utter muppet when you ask the question? Al. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 12, 2006 Share Posted October 12, 2006 for crying out loud why not do the very basic searching first so you don't sound like an utter muppet when you ask the question? There was me trying to say it politely too Quote Link to comment Share on other sites More sharing options...
simonr Posted October 12, 2006 Share Posted October 12, 2006 'Scuse me chaps - don't want to interrupt a good arguement but...... I was actually quite interested in the answer too. I have a bit of an understanding of cavitation (long ago, did a hydrodynamics module) at least what it is. What is the mechanism by which it causes damage? Not keen on the little explosions theory - but I suppose you might get a shock wave as the bubbles colapse? Could it be just that the velocity of pockets of the fluid gets quite high as it flows round the bubbles - maybe an abrasion effect? I thought the bubbles contained low pressure water vapour / vacuum. Created because, if something moves fast enough through a fluid, the lamina flow over the surface breaks up. Where the flow lifts off the surface, it leaves a low pressure zone behind. If the pressure differential is great enough, the fluid cavitates, i.e a bubble of vacuum opens. If any of you know how this causes damage in a water pump - I'd be very interested! Si Quote Link to comment Share on other sites More sharing options...
Diff Posted October 12, 2006 Share Posted October 12, 2006 I took the opportunity to have a quick search. Here is a bit on cavitation and resultant damage: http://en.wikipedia.org/wiki/Cavitation Info on pumps towards the bottom of the page. Regards, Diff Quote Link to comment Share on other sites More sharing options...
simonr Posted October 12, 2006 Share Posted October 12, 2006 Thanks Diff. I wasn't far off then! Si Quote Link to comment Share on other sites More sharing options...
02GF74 Posted October 12, 2006 Author Share Posted October 12, 2006 quote name='Bull Bar Cowboy' date='Oct 12 2006, 02:10 PM' post='92055'] Dear O2, As you like to discuss issues in the public domain........... It would seem that you are not being particularly polite or perhaps your grasp of English diplomacy is a little lacking………. It would also seem that every time I post, you have something negative or a problem with the content. For me there are two options in this matter, 1) Ignore your negative comments as I don’t have to answer to anybody. 2) As in your eyes, I seem to adding little or no value to the forum, then perhaps I should refrain from posting here any more. Option 2 seems to be the most appealing art the moment. BTW: do you live near the sea …….. have you ever worked on outboard motors or small boat propellers …….. have you never seen cavitation damage to these items or the internals of boat engines …………. the impellor of the V8 water pump is much harder then the ali casing …….. once you have seen cavitation damage, it is not difficult to recognise …….. but what the f&*k do I know. I would like to add that it has been nice being here and I have made many friends …….. however, my future here is now uncertain ………….I don’t know that I can be bothered with something that is becoming annoying and a chore. Ian Ian, Please tell me why my question was not polite? How does it differ to the post recently asking what is everyone's area of expertise? Same question using different words if you think about it. I haven't looked in that thread but don't recall you having a problem with it. But now you do? As for being polite, look at your response in the "alternators" thread, trying to pre-empt one of my questions that has since been edited. In my opinion that was rude and uncalled for. I can only guess it was in response to my question about using more efficient bulbs. What is wrong with asking that? Bulb technology is moving on, brighter and more efficient bulbs are appearing on the makret, soon we will have LED headlamps and not everyone knows about them so I thought that was a perfectly valid question yet somehow it caused you a problem. I am puzzled. That is the only post I cna think of that you have got into your head that I am being negative to your posts (I didn't want to raise that but I have unfortunately; it is under the bridge and it doesn't bother me). Your name hasn't gone in the little black book for me to get "my own back", I can't be bothered with anything like that plus the book is full!! This cavitation question has nothing to do with that, believe it or not. If you have examples of where I have said something negative about your posts (all of them?!?!!) then I'd be interested to see examples (but not too many as I know you post a lot). I think ther is a bit of over reaction here. I do not keep tabs to figure out who is qualified in which field so I have no idea where your expertise lies and I really want to know about the cavitation damage. (I have SD1 alloy timing cover running a smaller water pump pulley, approx 20% so it is in my interest to know if I am going to get these problems). Remember forums are not the same as having a conversation as you loose a lot of information in the human voice, maybe that was what was missing from my question, and that often lead to misunderstanding. I hope you don;lt decide from posting here, but if you do, at least answer this last question. 02 - the question may have been innocent, though from others comments, perhaps it is a trend? I'm all for the Spanish Inquisition, but for crying out loud why not do the very basic searching first so you don't sound like an utter muppet when you ask the question? Al. Thank you for your support Al. Did you actually take a look at my posts to figure out this trend for yourself or or did you just go along with the others who responded on this thread? And how many of the posts on here and could be answered by doing a search somewhere else? And where is the sense in me to look/search somewhere else if it appears that there is someone on here who is able to answer my very specific question is on this forum. What does surprise and disappoint me is the respones of quite a few other people "ganging up on me". That has happened before (I think you know the trhead I refer to) and that is just wrong. Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted October 12, 2006 Share Posted October 12, 2006 Ok …………… I’ll tell what I know……….. and more importantly what I don’t know………. Cavitation damage in a pump is hard to explain……….. its like highly polished corrosion ……….. on the V8 water pump it occurs directly behind the impellor, in the area of the two outlet pipes and often will eat right through the casing……….. I suppose that if the casing was steel, then the impellor would suffer damage, although I have seen some very minor damage on the WP impellor. I have always understood it as the creation of minute bubbles in the liquid due to the low pressure area………….when the bubbles burst all hell breaks loose………… most of my knowledge came from an old fashioned ships engineer who was renowned for being on the ball………. He would explain stuff by demonstrating and showing the results of damage etc ………. Once you have seen the damage…….. it stays with you as it is quite unique ……. I think FF has the same problem. Also there is the noise of cavitation ……….. again this is almost unique once you know what’s causing it ……………… almost like a dry screeching / vibrating bearing noise…….. and can be very loud……………….. I last heard it at the weekend from my PTO hydraulic pump when I accidentally applied too many revs (way too many revs)………. I suspect the hydraulic oil began to foam in a low pressure area on the pump. I only know cavitation from experience and know roughly what causes it ………… I will not pretend to know the exact hydro terminology or the detailed mechanism behind it. From experience …….. reducing the speed of the pump cures the problem. Has any body got a V8 efi timing cover apart at the moment ………. If so, post up a pic of the water pump casing. Ian Quote Link to comment Share on other sites More sharing options...
JST Posted October 12, 2006 Share Posted October 12, 2006 Ian, leave him to it he will get bored, he told me pretty much i wasn't in shape to push/pull my landrover around a while back, anyway concentrate on sorting that winch rope and fit those nice new brake pipes...... (both of which i expect you have now done) and dont use that extra 5L in the tank it took my ages mopping the woods up sat night..... Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted October 12, 2006 Share Posted October 12, 2006 Ian, leave him to it he will get bored, he told me pretty much i wasn't in shape to push/pull my landrover around a while back,anyway concentrate on sorting that winch rope and fit those nice new brake pipes...... (both of which i expect you have now done) and dont use that extra 5L in the tank it took my ages mopping the woods up sat night..... git ............. makes a change from mopping up diesel though........... at least the rear x member wont go rusty in a hurry.................... oh .......... and just to make you smile, i called into the local jet wash on the way home ............ the owner came out with a shovel The pipes from LLama go on tonight ................ and 12mm dyneema goes on next week (I spliced the old rope for now) Ian Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted October 12, 2006 Share Posted October 12, 2006 Like I said, I missed the trend [if it exists]. Personally, I think it's probably people getting an idea about you based on the way you ask questions which from your side you see as purely inquisitive. I have no idea - like I said - I'm too stupid to notice these things. Personally, I don't have a problem with your posts. But my comment on research was only what I'd say to anyone - most of your Q (and there was a lot of it ) could have been irradicated by 2 mins on google as above. For one thing, searching rather than asking eliminates the need for people to trawl through the very basics each time a question on a topic is asked, its a question of how much time you expect people to spend on replying I guess. No offence meant. Nuff said. Al. Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted October 12, 2006 Share Posted October 12, 2006 This thread should now be allowed to gracefully slip down the page and die. Ian Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted October 12, 2006 Share Posted October 12, 2006 Ian, As the Armed Police say : "Put 02 down and walk away - you've done enough " .....Your reply I would say is a 10/10 "Virtual Kick in the 'WWW' N*ts" O2 I think the replies above are fair, .... if you didn't mean an insult then it surely didn't read well, ..... the prob with forums is it can come over not as you mean - ask me how I know and hence my sig - .....however reading your post re Ian x3 times ..... I'd have got the hump if it were to me ? I have had a really S****y day, so this has has cheered me up sooooo much. Score 1 : 0 to Ian, classic. ROTFLMFAO Nige Quote Link to comment Share on other sites More sharing options...
Happyoldgit Posted October 12, 2006 Share Posted October 12, 2006 Is this the five minute argument or the full half hour? Must be the shortening daylight Quote Link to comment Share on other sites More sharing options...
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